Sixteen Mile Creek Monitoring Project by gjjur4356

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									Sixteen Mile Creek Monitoring Project

          By: Andrea Dunn
      Mapping By: Brian Jamieson

        We would like to extend our thanks to all the individuals who provided technical
assistance, sampling equipment, data and advice in support of this project. A special
thank you to all members of our technical steering committee including representatives
from the Credit River Anglers Association, Field and Stream Rescue Team, Halton North
Peel Naturalists Club, Conservation Halton, Hamilton-Halton Watershed Stewardship
Program, Ministry of Natural Resources, Fisheries and Oceans Canada, Niagara
Escarpment Commission, Town of Milton, City of Mississauga, Town of Oakville, Town
of Halton Hills and Halton Region.

        Special thanks to the following volunteers, co-op students, summer students and
interns who provided valuable assistance in the field collecting information for use in this

Rachel Nagtegaal              Brenda VanRyswyk               Brian Whitehouse
Tina McGarr                   Warren Cathro                  Simon Wong
Brian Jamison                 Jordanna VanGeest              Dianne Watkins
Shannon Holten                Scott DeVito                   Kevin Martens
Dianne Watkins

       Finally, we would like to extend our appreciation to the Ontario Trillium
Foundation and the Canadian Biosphere Reserve Association for providing funding and
support to the project.

                                                TABLE OF CONTENTS

ACKNOWLEDGEMENTS................................................................................................ 2
INTRODUCTION .............................................................................................................. 4
PHYSIOGRAPHIC CONTEXT ......................................................................................... 6
Bedrock Geology ................................................................................................................ 7
Physiography....................................................................................................................... 7
ECOLOGICAL AND CULTURAL HERITAGE ............................................................ 13
NATURAL AREA DESIGNATIONS ............................................................................. 15
  Niagara Escarpment Biosphere Reserve ....................................................................... 15
  Provincially Significant Wetlands ................................................................................ 16
  Regionally Significant Wetlands .................................................................................. 16
  Areas of Natural and Scientific Interest........................................................................ 19
  Environmentally Sensitive Areas (Halton Region)....................................................... 23
  Natural Areas (City of Mississauga)............................................................................. 28
  Greenbelt Plan Area ...................................................................................................... 31
NATURAL HERITAGE FEATURES ............................................................................. 33
  Wetlands ....................................................................................................................... 33
  Forests ........................................................................................................................... 38
  Aquatic Habitats............................................................................................................ 43
  Special habitats ............................................................................................................. 51
  Wildlife ......................................................................................................................... 52
TERRESTRIAL INVENTORY AND ASSESSMENT ................................................... 59
  Marsh Monitoring- Marsh Monitoring Program........................................................... 59
  Forest Bird Monitoring - Forest Bird Monitoring Program.......................................... 61
  Forest Health -Ontario's Niagara Escarpment (ONE) Monitoring Program................. 61
AQUATIC INVENTORY AND ASSESSMENT ............................................................ 62
  Fish Community Monitoring ........................................................................................ 62
  In-stream Temperature Monitoring............................................................................... 74
  Benthic Community Monitoring-Ontario Benthos Biomonitoring Network................ 74
  Water Quality-Provincial Water Quality Monitoring Network .................................... 78
AQUATIC ECOSYSTEM HEALTH............................................................................... 78
WATERSHED GUIDELINES AND MANAGEMENT.................................................. 83
RECOMMENDATIONS .................................................................................................. 88
  Watershed Recommendations....................................................................................... 89
  Site Specific recommendations..................................................................................... 91
NEXT STEPS ................................................................................................................. 106


        The Sixteen Mile Creek watershed is located at the western end of Lake Ontario
within the Regional Municipality of Halton and the City of Mississauga. The main
branches of Sixteen Mile Creek are formed in wetlands and forested swamps associated
with the Niagara Escarpment. From here the main branches and their tributaries flow
southwards through natural, rural, urban and agricultural lands before meeting its
confluence with Lake Ontario within the Town of Oakville. The resulting watershed
drains approximately 372 km² of land within nine distinct sub-watersheds (see Figure 1).
In addition to the natural channels throughout the watershed, approximately 4.5 km of
concrete channel directs flow from the Urban Diverted Tributaries to the Main Branch of
the creek and another 3 km of concrete channel confines the West Branch as it flows
through downtown Milton. In addition to these flood control channels, three flood
control structures, Hilton Falls Reservoir, Kelso Reservoir and Scotch Block, are also
used as flood storage reservoirs within the watershed.

        This monitoring project was completed to document existing conditions within
the watershed in response to large-scale projects both current and future which have the
potential to impact biological communities within the watershed. These projects include
numerous urban developments for both commercial and residential lands, which may
result in the alteration of natural lands to urban centres. This project aims to document
baseline conditions throughout the watershed to determine if potential affects, both
positive and negative, result from the proposed works.
    This report draws heavily upon previous studies completed within the watershed
including the original Sixteen Mile Creek Conservation Report completed in 1958 by the
Department of Planning and Development. Additional reports including the Sixteen Mile
Creek Watershed Plan in Support of the Halton Urban Structure Plan (1995), the Sixteen
Mile Creek Subwatershed Planning Study, Areas 2 and 7 (2000) and numerous biological
reports, atlases and bulletins were used to compile all biological information available. In
addition to historical information, data was collected in the 2005 field season to
document current conditions in areas where data was lacking/outdated or in areas where
existing monitoring stations provided historical information for comparison. This report
documents existing conditions (where available) and provides recommendations to
restore and improve ecological integrity throughout the watershed.

Watercourse Nomenclature

        Differences in watercourse nomenclature across the watershed, has resulted in
considerable confusion over the years. The official name of the watershed, now Sixteen
Mile Creek, has changed over time with the changes in human habitation. The original
name of the watershed “Ne sauga y onk”, derived from the Mississauga language, was
provided on French maps circa 1756 (Matthews, 1950). This name translates to “having
two openings” which refers to the presence of a pebbly or gravelly island at the mouth of
the river (Matthews, 1950). With changes in the watershed and increased European

settlement, the watershed name was changed to Sixteen Mile Creek, to reflect the
distance between Burlington bay and the Mouth of the creek (Matthews, 1950).
Although, this name has been used for the watershed since time of settlement, the local
name of Oakville Creek has been commonly used, likely reflecting the creeks confluence
with Lake Ontario within the Town of Oakville.
         Similarly, numerous small tributaries feeding the creek have local and/or common
names. Changes in stream drainages have also effected stream naming, which is evident
within the Urban Diverted Tributaries sub-watershed. Tributaries identified within this
sub-watershed form the headwaters of Morrison Creek within the Town of Oakville. A
significant water diversion channel was constructed to divert flow from these tributaries
into the Main Branch of Sixteen Mile Creek and as such, has become a drainage feature
within the watershed. As a result, drainages upstream of the Morrison-Wedgewood
diversion channel are considered a part of the Sixteen Mile Creek watershed and
information collected in this area has been included in the report under the Urban
Diverted Tributaries sub-watershed. Other tributaries with common and/or local names
have been grouped under the larger sub-watershed descriptions within this report in order
to avoid confusion. Local tributary names and associated sub-watersheds can be found in
table 1.

Table 1: Local tributary names and associated sub-watershed within the Sixteen Mile
Creek watershed.

               Local Name                          Sub-watershed
               Osenego Creek                  Main Branch
               Munn’s creek                   Main Branch
               Shannon’s Creek                Main Branch
               West Morrison Creek            Urban Diverted Tributaries
               East Morrison Creek            Urban Diverted Tributaries
               Upper Wedgewood Creek          Urban Diverted Tributaries


        The physiography of Southern Ontario and similarly the Sixteen Mile Creek
Watershed, has been shaped by a number of geological processes including plutonism,
sedimentation, faulting, glaciation, uplifiting, erosion and weathering, all of which have
acted to shape our present day landscape. Glaciation, in particular has had the strongest
influence on the physiography of the watershed as a series of continental glaciations
during the last million years has plucked, quarried and grinded the bedrock and re-
surfaced the surrounding landscape. The most recent glaciation, the Wisconsin, which
covered all of Ontario and extended into Southern Ohio, left the Sixteen Mile Creek
watershed approximately ten to fifteen thousand years ago (Chapman and Putman, 1984).
Before its recession, the Wisconsin glacier advanced through the watershed eroding away
the bedrock resulting in scouring, smoothing and in some cases the cutting of large
grooves into the bedrock surface. Soil and rock were carried forward with the glacier as

it advanced and mixed together resulting in a heterogeneous mix of boulders, stones and
pebbles in a sand, silt and clay mix known today as till. With the retreat of the glaciers
large amounts of material of all sizes ranging from clays to boulders were deposited as
glacial drift on the bedrock. The unconsolidated materials overlying the bedrock
consisted mainly of till, laid down by glacial ice as well as sand and gravels deposited by
streams or water draining the melting glaciers and the clay, silts and sands deposited in
glacial lakes (Chapman and Putman, 1984).

Bedrock Geology

        The bedrock underlying the Sixteen Mile Creek watershed consists of four
geological formations, the Georgian Bay formation, Queenston formation, Cataract
formation and the Amabel formation. The Georgian Bay formation and the Queenston
formation represent the oldest units, formed during the Ordovician age approximately
490 to 443 million years ago. The Georgian Bay formation, the oldest of the four units,
occurs in a small portion of the watershed near the mouth of the creek and along exposed
portions of Lake Ontario. It consists of blue and grey shale with thin interbeds of hard
sandstone, limestone and dolomite (Department of Planning and Development, 1958).
The Queenston formation underlies the majority of the watershed and can be found
extensively throughout the Town of Oakville. The sediments of the Queenston formation
are primarily grey, blue and brown shale with thin layers of limestone, calcareous
sandstone and sandy shale. However, it is the dark red shales of the Queenston formation
that are easily identified in outcroppings along stream valleys and at the base of the
Niagara Escarpment (Department of Planning and Development, 1958).
        The remaining bedrocks of the watershed were deposited within the Silurian age,
approximately 444 to 416 million years ago. The Cataract group, comprised of the
Grimsby, Manitoulin, Cabot Head and Whirlpool formations, result in a mixture of shale,
dolostone and sandstones with occasional interspersing of siltstone and limestone. This
group can be found in escarpment outcroppings sandwiched between the Queenston and
Amabel formations. It is the Amabel formation, comprised of hard, dense crystalline and
erosion-resistant dolostone, which overlies the Cataract group and forms the cliffs of the
Niagara Escarpment (Holysh, 1995). The amabel formation extends from the cliffs of the
Niagara Escarpment to the upper boundary of the watershed.


         A number of physiographic features, created and re-created by the advance and
retreat of the glaciers define the landscape of the watershed today. The dominant feature,
the Niagara Escarpment, consists of steep vertical cliffs of dolostone bedrock that divide
the watershed diagonally from north to south. This feature, formed during the Silurian
age, was the result of differential erosion whereby softer shale bedrock to the east
weathered or eroded away as a result of streams and glacial melt. This gradual removal
of the softer bedrock undercut the more resistant and harder caprock resulting in the large
cliffs of the escarpment that divide the watershed today (Tovell, 1992).
         Other physiographic features found within the watershed include the
Flambourough, Peel and Lake Iroquois Plains, the South Slope Region and the Galt,

Moffat and Trafalgar Moraines. Formed as a result of glacial melting, moraines are
hummocky features with thick, coarse textured soils, which typically act as recharge
areas for local and regional groundwater flow. The Galt and Moffat moraines, found
within the north-west region of the watershed, are a part of a northeast-southwest band of
hummocky, conical-shaped hills typical of end moraines and associated kame deposits.
Together with the Paris moraine, the Galt and Moffat moraines represent the best
example of morainal topography in Southern Ontario (Geomatics International, 1993;
Regional Municipality of Halton 1995).
         The Trafalgar moraine, which extends across the watershed from Streetsville
through Oakville to the edge of the Niagara Escarpment in Zimmerman, is believed to be
a late stage moraine produced by the temporary advancement of the Lake Ontario ice
sheet (Chapman and Putman, 1984). One of five moraines located on the western end of
Lake Ontario, the Trafalgar moraine is the only one of the group formed below the
Niagara Escarpment. It consists of reddish, clayey till with a significant amount of red
shale incorporated into the till matrix. This topographically high feature provides a ridge
of rolling green hills, fields, forest and provincially significant wetlands. The landform,
measuring approximately 20 km in length and roughly 4 km in width, also plays an
important role in maintaining tributaries of Sixteen Mile Creek as well as surrounding
smaller watersheds such as Fourteen Mile, McCraney, Morrison, and Joshua’s Creeks.
The moraine also acts to deflect the East Branch of Sixteen Mile Creek from its
southward course on the northside of the moraine to a more westerly course, where it
connects with the main branch of the creek (Halton Region and North-South
Environmental Inc., 2005).
         Creeks formed at the toe of the Trafalgar Moraine drain the southern side of the
South Slope physiographic region. This region, divided by the Peel Plain consists of the
Trafalgar Moraine to the south and weakly drumlinized till material and glacial outwash
deposits to the north along the base of the Niagara Escarpment (Holysh, 1995). The
South Slope region is generally less drummlinized through the watershed then in regions
to the east and shows little topographic relief. It is also dominated by a clayey-silty
Halton till, which results in poor drainage throughout the area. Between the north and
south sections of the South Slope Region, the Peel Plain slopes gradually towards Lake
Ontario. This region occupies the central and eastern portion of the watershed and is
characterized by an area of clay soils with low topographic relief. The formation of this
plain is attributed to temporary ponding of glacial waters and the resulting deposition of
glacio-lacustrine sediments of gravel, sand, silt and clay. The Peel Plain is bisected by
Sixteen Mile Creek, resulting in variable drainage throughout the region.
         The Flamborough plain extends from Flamborough Township to the Town of
Acton and spans the headwater regions of the watershed. This plain consists largely of
exposed dolostone bedrock along the Niagara Escarpment with a thin overburden layer of
Wentworth Till consisting mainly of boulders, glacial till, sand and gravel. Shallow,
permeable soils and extensive bedrock fractures combined with extensive wetland
features provide significant groundwater recharge/discharge areas for headwater
tributaries of Sixteen Mile Creek and neighbouring stream systems. Extensive forest
cover and drumlin fields across the plain also provide topographic relief and scenic

        The remaining physiographic feature, the Lake Iroquois Plain lies to the south of
the QEW and is the lowland that borders Lake Ontario. A prominent erosional shorebluff
formed by Lake Iroquois marks the northern boundary of this plain. The Lake Iroquois
plain is on average 3km wide and is characterized by stratified sands and in some areas
exposed shale bedrock with a thin cover of till. Physiographic features within the
watershed are seen in figure 2.


          Soils are typically a reflection of the environment from which they were
developed. As a result, the development of any particular soil may depend on a number
of factors including type and composition of the parent material, surface, slope, soil
drainage, climate and vegetation (Department of Planning and Development, 1958). As a
result of these factors, the soils are frequently related to the underlying and adjacent
bedrock formations. Further actions of wind and water, rework surface deposits to
produce local concentrations of fine grain materials. Soils can vary locally throughout
the watershed based on drainage features, vegetation and the time available for
          The soils of the Sixteen Mile Creek watershed, seen in figure 3, are dominated
largely by a combination of till material, specifically the Wentworth Till, located above
the Niagara Escarpment and the Halton Till, located beneath the Niagara Escarpment.
The Wentworth Till is the surface till that extends across the watershed to form the Paris,
Galt and Moffat moraines and the field of drumlins associated with these features. Soils
of the Wentworth Till are typically buff-coloured, stony, sandy and silty and are
relatively coarse in texture (Karrow, 1987). Majority of the lands above the Niagara
Escarpment are dominated by loamy soils that are usually well drained and coarse
however, areas of organic soils occupy low-lying areas and are typically poorly drained.
Closer to the edge of the Niagara Escarpment, the soils become increasingly coarse as a
result of outwash sand and gravel. The resulting soils above the Niagara Escarpment are
varied in permeability thereby creating areas of low to high permeability through the
area. In contrast, the Halton till, located below the Niagara Escarpment is predominantly
a silt till that incorporates red shale bedrock of the Queenston formation (Karrow, 1987).
For the most part, these soils consist of clay loam and silty clay loam, which restricts
permeability throughout the area. Similarly, soils associated with the Peel Plain are
somewhat heavier and may result in restricted drainage in the area. Downstream, of the
Peel Plain, soils become imperfectly drained, whereas soils associated with the Trafalgar
Moraine within the south slope are moderately to well drained.


        Prior to European settlement, the Sixteen Mile Creek Watershed was covered in
dense forests and rich wetlands, which provided extensive habitat for a vast diversity of
species. The cold, clean creeks teemed with fish and dense flocks of birds were often
observed overhead. The first inhabitants of the watershed were the Iroquoian people who
periodically used the pristine creeks, forests and wetlands for hunting and fishing. By
1650, these original inhabitants were displaced by the Algonquin-speaking Ojibwa, who
first came to settle permanently in the lands within the Sixteen Mile Creek watershed.
Often referred to as the Mississauga people, these early settlers used the rich valley and
floodplain lands in the warm summer months to establish camps and grow small
quantities of corn in the rich floodplain soils. In the winter months, they retreated to the
protection of the forests where they hunted for small game. By 1701, many Mississauga
people had settled across numerous river mouths along the northshore of Lake Ontario,
including Sixteen Mile Creek.
        The mouths of many of these rivers and creeks became excellent trading posts and
the Mississauga people quickly built relationships with the French to trade beaver pelts
and fish for European goods. Similar relationships with the British followed after the
treaty of Paris in 1763 and new allies were made. The Royal Proclamation of 1763
followed, officially recognizing and identifying specific “Indian lands” which were then
protected and could only be sold to the crown with the adoption of an official treaty with
the aboriginal people (Oakville Heritage Trails website, 2006). Although these lands
were set aside as part of the Royal Proclamation, the influx in European settlers in the
watershed and surrounding areas quickly pushed the British government to further
negotiate the purchase of these lands from the Mississauga people. On August 2, 1805
the Mississauga Purchase was finalized with the Mississauga people surrendering all
lands from Burlington Bay to Etobicoke, with the exception of the mouths of three
creeks, including Sixteen Mile Creek, which provided fishing and hunting reserves for
the aboriginal people (Matthews, 1950). Lands, with the exception of the reserves
identified at the mouth of the creek, were then surveyed with the early townships of
Trafalgar, Esquesing and Nassageweya being created. By 1820, settlement had expanded
yet again, this time into the southern region of Trafalgar township. As a result, on
February 28, 1820 the “five chiefs of the Mississauga” surrendered the remaining
reserves on both Twelve Mile Creek (now Bronte Creek) and Sixteen Mile Creek to the
British government (Matthews, 1950).
        At approximately the same time, William Chisholme, a soldier who fought in the
war of 1812, settled in Nelson Township. Chisholme, who recognized the potential of
Sixteen Mile Creek as a port along Lake Ontario, desperately sought purchase of the
reserves in order to build a harbour to ship oak staves. By 1827, Chisholme purchased
the reserves from the British Government and quickly advanced the creation of the
harbour with the building of a large dock and the dredging and removal of a gravel island
at the mouth of the creek. With the creation of the harbour a major shipping port and an
adjacent village was quickly established.
        With the increase in shipping and clearing of the land by new settlers, saw mills
quickly popped up along the stream banks to accommodate the large loads of lumber. By
the 1850’s fifteen mills had already been established in Trafalgar Township, five of

which were located between Dundas Road and Lake Ontario (Oakville Heritage Trails
website, 2006). The construction of these mills created large barriers to fish migration,
which prevented numerous fish species from reaching their spawning grounds. Species
such as Atlantic Salmon were so abundant prior to the construction of the mills, that in
the spring, runs of salmon were easily collected by settlers who speared the fish with
pitchforks in the shallows of the creek. Large numbers of salmon were collected with the
average person able to collect eight to ten buckets of salmon a night (Matthews, 1950).
With the increase in settlement and sawmills in the watershed, this quickly changed and
by the early 1840’s Atlantic salmon had disappeared from the Sixteen Mile Creek
watershed and from Lake Ontario by the 1900’s (Matthews, 1950). Similarly, wolves,
which were previously observed howling through the night, quickly disappeared and was
promptly followed by the disappearance of the passenger pigeon. Prior to its extinction,
the passenger pigeon was so abundant in the watershed that large flocks observed
overhead were up to one mile in length, consisting of over two million birds that took
almost four hours to pass overhead (Matthews, 1950). The passenger pigeon was actively
hunted and even at such large numbers was driven to extinction. The passenger pigeon
was last recorded breeding in the region in 1886 (Oakville Heritage Trails Website,
        With the quick clearing of the forest for settlement and sawmills, the rich soils of
the watershed quickly turned into agricultural lands. These lands supported vast field of
grains that were later shipped to Britain and the United States. The demand for grains
quickly grew making sawmills and the production of lumber a secondary industry.
Additional businesses grew up along the watercourses including tanneries, shops, small
hotels and eateries. Villages later abounded and Oakville and Milton were quickly
established. The addition of the railway in the late 1800’s brought more settlers to the
region, resulting in large population growths in Oakville and Milton. With the increase in
business and the focus on railways, the port at the mouth of the creek declined and
industrial growth began. The construction of railways coupled with water and electrical
supplies, invariably lead the way for industries to prosper in the watershed. Factories
along with quarries in the upper portion of the watershed boomed until the great
depression in the 1930’s. Growth and prosperity remained static during that period until
the creation of the 401 highway in the 1950’s re-opened the areas to growth.
        With the increase in growth in the area, growing public concern for the state of
the environment brought a halt to the long period of environmental decline. In 1958, the
Sixteen Mile Creek Conservation Authority was formed in order to mitigate the risks of
flooding and protect valuable natural resources including streams, forests, wetlands and
wildlife. The authority completed the first watershed study in 1958, documenting
environmental conditions and outlining priority areas for flood control structures, natural
reserves and recreational areas. Since then the authority, now Conservation Halton, has
promoted the protection of natural resources while encouraging recreational opportunities
and balanced growth. The later of which has increased drastically in recent years
resulting in urban centres within Oakville and Milton. These two areas continue to grow
with proposed developments north of Dundas Road within the Town of Oakville and
additional residential lands in the west branch of the watershed within the Town of
Milton. Other largescale growth has occurred in smaller sections of the watershed. The
East-Lisgar Branch has portions of Mississauga that has increased drastically with

residential development with similar conditions experienced in the East Branch with the
expansion of the Town of Halton Hills.
        With increased development, the lands of the Sixteen Mile Creek watershed today
differ greatly from the vast forested lands that surrounded early settlers. Large tracts of
forests and diverse wetlands are now largely restricted to areas above the Niagara
Escarpment where agricultural, residential and commercial growth has been limited.
Below the Niagara Escarpment, woodlots and wetlands are less common and smaller in
size. Regardless, the significance of these small natural areas is not ignored. These areas
provide a break from the urban landscape and provide ample educational and recreational
activities for watershed residents, thereby promoting and increasing environmental
awareness throughout the watershed.


        A variety of natural areas are found throughout the watershed ranging from
scrubland and meadows to forested swamps. Each habitat provides unique opportunities
for different species of flora and fauna to flourish. Specific areas, those of which
represent unique habitats, contain a high degree of biodiversity or simply occur in areas
of increased development, require additional protection through federal, provincial and
regional policy. These policies are set fourth to protect the lands from development and
preserve our natural heritage. Many of these designations are recognized at a variety of
scales and as such, some designations may overlap. Natural land designations are as

Niagara Escarpment Biosphere Reserve

        In 1990, the Niagara Escarpment Plan Area was designated as a World Biosphere
Reserve by UNESCO (United Nations Educational, Scientific and Cultural
Organization). One of only six other reserves nationally and 482 sites internationally, the
Niagara Escarpment Biosphere Reserve ranks amongst some of the most ecologically
important areas in the world such as the Serengetti, the Everglades and the Galapagos
Islands. World Biosphere Reserves are areas recognized as the worlds most important
ecosystems, to act as demonstration sites for conservation of biological diversity,
promotion of environmentally appropriate development and for research, monitoring and
education (Riley, et. al., 1996). The Niagara Escarpment has been designated as a
reserve based on its unique ecological and cultural heritage and scientific importance.
        The lands falling within the Niagara Escarpment Biosphere are regulated through
the Niagara Escarpment plan administered through the Niagara Escarpment
Commission. The Niagara Escarpment Plan allows for development under certain
conditions where it is compatible with protecting the Escarpment's continuous natural
environment. The adoption and implementation of the plan was instrumental in having
the Niagara Escarpment designated a World Biosphere Reserve.

Provincially Significant Wetlands

        Provincially significant wetlands are wetlands identified by the Ontario Ministry
of Natural Resources that meet specific requirements based on parameters such as size,
location, species present, hydrology and ecological and cultural heritage. Provincially
significant wetlands in Southern Ontario, located south of the Canadian Shield are
protected by provincial policy outlined in The Provincial Policy Statement (2005).
Policy states that

       “Development and site alteration shall not be permitted in significant wetlands
       …… unless it has been demonstrated that there will be no negative impacts on the
       natural features or their ecological functions” (Province of Ontario, 2005).

        Within the Sixteen Mile Creek watershed, four provincially significant
wetlands/wetland complexes occur. The Halton Escarpment Wetland Complex and
Guelph Junction Woods, both of which occur in the upper regions of the watershed, have
been designated as provincially significant wetlands since their evaluation in 1982. In
2006 two more wetland complexes, the North Oakville-Milton East and the North
Oakville-Milton West wetland complexes, were added to the list of provincially
significant wetlands within the watershed (MNR, 2006b; MNR, 2006c).

Regionally Significant Wetlands

        In addition to the wetlands classified by the Ministry of Natural Resources as
being provincially significant, regionally significant wetlands also occur throughout the
watershed. These wetlands typically do not meet the criteria on the provincial scale; yet
possess unique attributes that make them significant on a regional scale. Identified
wetlands not classified as Provincially Significant within the Region of Halton are
automatically designated as Regionally Significant according to the 1995 Halton Region
Official Plan (Regional Municipality of Halton, 2002). These wetlands are designated as
such due to the rarity of wetlands within the region as documented in the “Ontario
Wetland Evaluation System 1994 Southern manual”. Regionally Significant Wetlands,
although not protected under the Provincial Policy Statement, are still protected under the
Conservation Authorities Act (Regulation 162/06) and may also be regulated under the
federal Fisheries Act and the Provincial Lakes and Rivers Improvement Act.
        Within the Sixteen Mile Creek watershed eleven Regionally Significant Wetlands
have been identified. Further details on the Provincially and Regionally Significant
Wetlands within the Sixteen Mile Creek watershed can be seen in the Wetlands section of
the report and observed in Figure 4.

Areas of Natural and Scientific Interest

Areas of Natural and Scientific Interest (ANSI) are defined as:

       “areas of land and water containing natural landscapes or features that have
       been identified as having life science or earth science values related to protection,
       scientific study, or education” (Province of Ontario, 1997).

         The Ontario Ministry of Natural Resources is responsible for the designation of
ANSIs throughout the province. Areas with significant representative elements of
Ontario’s biodiversity and natural landscapes including specific forest types, valleys,
prairies, and wetlands along with their native plants, animals and supporting habitats are
considered Life Science ANSIs. These areas typically contain relatively undisturbed
tracts of vegetation and landforms along with their associated species and communities
(Province of Ontario, 1997). Earth Science ANSIs consists largely of significant
representative samples of the bedrock, fossil and landform record of Ontario and include
examples of ongoing geological processes (Province of Ontario, 1997). Areas of
significant earth science features as well as unique biodiversity and natural landscapes
can meet the criteria of both life science and earth science ANSIs.
         Further delineation of sites is completed at the provincial and regional scale.
Provincially significant ANSIs are areas that showcase the best examples of natural
heritage in the province. Regionally significant areas are areas that do no meet provincial
criteria but still provide unique attributes on the regional scale. Regionally significant
ANSIs typically do not meet provincially significant criteria due to size, degree of
disturbance and/or duplication or importance of features. These sites often complement
the provincially significant sites.
         Sites designated as an Area of Natural and Scientific Interest are protected under
The Provincial Policy Statement (2005), which states that:

       “Development and site alteration shall not be permitted in significant areas of
       natural and scientific interests …… unless it has been demonstrated that there
       will be no negative impacts on the natural features or their ecological functions”
       (Province of Ontario, 2005).

        Within the Sixteen Mile Creek watershed, numerous areas meet the ANSI
standards. Three provincially significant life science ANSIs (Halton Forest South,
Halton Forest North and Iroquois Shoreline Woods) and three regionally significant
ANSIs (Brookville Swamp, Speyside Forest and Knatchbull Swamp) are found within
the watershed. In addition to these life science ANSIs the Sixteen Mile Creek Valley,
currently designated as regionally significant, is undergoing a peer review process to
upgrade its designation to provincially significant. A candidate life science ANSI, the
Oakville-Milton Wetlands and Uplands ANSI is also under peer review and awaiting
final designation (MNR, 2006d).
        Designated earth science ANSIs within the watershed are typically associated
with the rock formations of the Niagara Escarpment. The Milton Heights ANSI is
considered a provincially significant earth science ANSI whereas the Milton Quarry is

considered a regionally significant earth science ANSI. A third potential ANSI, the
Trafalgar Morraine, is considered a candidate ANSI and is currently undergoing peer
review (MNR, 2006a). ANSIs throughout the watershed are listed in table 2 and are
displayed in figure 5.

Table 2: ANSIs within the Sixteen Mile Creek watershed.

Life Science ANSIs                                 Earth Science ANSIs

Halton Forest South (P)                        Milton Heights (P)
Halton Forest North (P)                        Milton Quarry (R)
Iroquois Shoreline Woods (P)                   Trafalgar Moraine (Candidate)
Brookville Swamp(R)
Speyside Forest (R)
Knatchbull Swamp (R)
Sixteen Mile Creek Valley (R and candidate P)
Oakville-Milton Wetlands and Upland (Candidate)

P: Provincially Significant
R: Regionally Significant

Environmentally Sensitive Areas (Halton Region)

    Environmentally sensitive areas (ESA) throughout Halton are areas that typically
have unique environmental qualities, support a variety of native species, perform certain
environmental functions and add to the biodiversity and natural landscape of the Halton
region. Natural areas were first designated as such within Halton in 1978 by the
Ecological and Environmental Advisory Committee (EEAC), which was formed to
advise the Region of Halton in matters pertaining to Halton’s Natural Environment
(Halton Region and North-South Environmental Inc., 2005). As a result,
environmentally sensitive areas were identified throughout the region in order to
achieve the following objectives:

•     To preserve and enhance natural biotic diversity.
•     To preserve the ecological integrity, including inter-connections, within and between
      natural ecosystems.
•     To preserve native species communities that are rare, threatened or endangered based
      on regional, Provincial or national scales of assessment.
•     To preserve examples of the landscape that display significant earth science features
      and their associated processes.
•     To preserve examples of original, characteristic landscapes that contains
      representative examples of bedrock, surface landforms, soils, flora and fauna, and
      their associated processes.
•     To preserve and enhance the quality and quantity of groundwater and surface water.
•     To preserve and enhance air quality.
•     To provide opportunities for scientific study, education and appropriate recreation.
•     To preserve the aesthetic character of natural features.

   Sites selected for ESA designation fulfilled the objectives outlined above and have
met specific criteria. Criteria used to assess sites for designation of an ESA, is outlined
by Halton Region and North-South Environmental Inc. (2005) as follows:

    Primary Criteria

•     Areas that exhibit relatively high native plant and/or animal species richness in the
      context of Halton Region.
•     Areas that provide functional links among two or more adjacent natural systems.
•     Areas that contain a relatively high number of native plant communities in the context
      of Halton Region.
•     Areas that contain large (in a regional context), relatively undisturbed expanses of
      natural, native plant communities, in particular those that support interior forest
•     Areas that contain remnant native plant communities that are rare within Halton
      Region or that are not represented in other ESAs.
•     Areas that contain plant and/or animal species that are rare or in peril provincially or

•   Areas that contain representative earth science features and/or processes typical of
    those, which were instrumental in creating Halton's landscape.
•   Areas that are determined to contribute significantly to local and/or regional
    groundwater recharge.
•   Areas that are determined to be significant groundwater discharge areas.
•   Areas that contribute significantly to groundwater quality.
•   Areas that contribute to maintaining surface water quality and quantity.

Secondary Criteria

• Areas that contain regionally rare plants.
• Areas that contain high quality assemblages of native plant and/or animal species.
• Areas that are recognized as highly aesthetic themselves or that provide designated
• The location of the area, combined with its natural features, make it particularly
  suitable for scientific research and conservation education purposes.

    Within Halton, 48 natural areas have been considered for ESA designation of which
45 have achieved official designation within Halton Region. The remaining natural areas
are considered candidate ESA’s. Within the Sixteen Mile Creek watershed, eleven
designated ESAs and one candidate ESA, the Trafalgar Moraine, have been identified.
ESAs within the Sixteen Mile Creek watershed can be seen in figure 6. Descriptions of
each ESA are found below.

Iroquois Shoreline Woods (ESA # 13)

        Iroquois Shoreline Woods is a forested area that contains a portion of the Glacial
Lake Iroquois shoreline earth science feature. This ESA falls within a relatively urban
setting and as such provides important habitat for a variety of species, including a variety
of herpetofauna as well as nationally, provincially and locally rare species.
        A single extension to the ESA is proposed in the Halton Natural Areas Inventory
Dwyer (2006). This extension is relatively isolated and surrounded by residential

Sixteen Mile Creek Valley (ESA # 16)

        The Sixteen Mile Creek Valley is a deeply incised valley cut into both the
Queenston Formation and Georgian Bay formation shales (Halton Region and North-
South Environmental Inc., 2005). A wide variety of bottomland, slope and tableland
vegetation communities occur within the area, which extends from the Lake Ontario
Shoreline in the Town of Oakville to Britannia Road in the Town of Milton (Ecoplans,
1995; Dwyer, 2006).
         Due to its large size and variety of vegetative communities, this area supports a
vast array of native plant, butterfly, odonate, herpetofauna and avian species many of
which are nationally, provincially and regionally rare. The length and location of the
valley also provides corridors for fish and wildlife movement including migratory birds

and large mammals such as white-tailed deer and red fox (Dwyer, 2006). The steep and
treed valley walls help to lower stream temperature and the valley serves as a major
groundwater discharge area as well as a spawning and migratory route for a number of
Lake Ontario fish. This area encompasses the regionally significant Oakville Creek
wetland and portions of the ESA are considered a regionally significant life science ANSI
by the Ontario Ministry of Natural Resources. The Sixteen Mile Creek valley and
surrounding natural areas is also identified as a priority stewardship area (natural)
according to the Nature Conservancy Canada’s Great Lakes Conservation Blueprint for
Biodiversity (Nature Conservancy Canada, 2004).
        The ESA connects to other natural areas and as a result provides north-south and
east-west corridors for wildlife movement. Natural areas within the vicinity of the ESA
were studied under the Halton Natural Areas Inventory (2006) and recommendations to
include them as extensions to the ESA were made. Drumquin woods (ESA # 43) falls to
the east and south of the proposed extensions, resulting in further wildlife corridors
through the Town of Milton.

Milton Heights (ESA # 17)

        The Niagara Escarpment is the dominant feature within the Milton Heights ESA.
This area contains the northern edge of the Milton Outlier, which has become detached
from the main scarp due to glacial and post-glacial erosion (Dwyer, 2006). Numerous
springs emerge along the face of the Niagara Escarpment, which serve as groundwater
recharge areas to tributaries of the West Branch of Sixteen Mile Creek. As a result of the
unique geological features on site, the Ontario Ministry of Natural Resources recognizes
this area as a provincially significant earth science ANSI.
        Extensions to this ESA have been recommended as part of the Halton Natural
Areas Inventory (2006). Proposed extensions would connect Milton Heights to Crawford
Lake-Rattlesnake Point (ESA # 18).

Crawford Lake-Rattlesnake Point (ESA # 18)

         The north-eastern tip of the Crawford-Lake Rattlesnake Point ESA falls within
the Sixteen Mile Creek watershed. This unique area boasts the highest number of
herpetofauna within Halton region and has over 470 different species of plants within the
ESA (Dwyer, 2006). In addition to its unique ecological diversity, this ESA also has
unique geologic features including the talus slopes of Rattlesnake Point featuring the
Southern section of the Niagara Escarpments Milton Outlier. Additionally, Crawford
Lake is a miromictic lake, which is a unique feature within Halton Region. Portions of
the site (outside of the Sixteen Mile Creek watershed) are also designated as provincially
significant life science ANSI as well as provincially and regionally significant earth
science ANSI.
         Extensions proposed in Dwyer (2006) would connect this ESA to Hilton Falls
(ESA # 18) as well as additional extensions proposed as part of Milton Heights (ESA #
17) and Guelph Junction Woods (ESA # 20).

Guelph Junction Woods (ESA # 20)

        Guelph Junction Woods is an extensive, relatively undisturbed mixed forest and
wetland located on the Flamborough Plain region, with thin soils over dolomite bedrock
(Halton Region and North-South Environmental Inc., 2005). The area features extensive
rock outcrops, wetland areas and a variety of native plant communities that sustain a
large number of native flora and fauna, many of which are nationally, provincially and
regionally rare (Dwyer, 2006). The large tracts of forest associated with the Guelph
Junction woods provides interior forest habitat for a number of species and links natural
areas within the Region of Halton. Additionally, the Guelph Junction wetland complex is
considered to be of provincial significance.
        The Guelph Junction Woods ESA, is separated by the Hilton Falls ESA (# 25) by
the 401 highway. Extensions to the ESA proposed by Dwyer (2006) would further
connect Guelph Junction Woods to Crawford Lake-Rattlesnake Point (ESA # 18) and
Calcium Pits (ESA # 19) on Bronte Creek within the Region of Halton as well as the
Mountsberg East Wetlands and the Mountsberg Wildlife Area on Bronte Creek within the
City of Hamilton and the County of Wellington.

Brookville Swamp (ESA # 22)

        The Brookville Swamp ESA is approximately 116 hectares in size and is
dominated by a silver maple swamp, which forms a portion of the provincially significant
Halton Escarpment Wetland Complex (Halton Region and North-South Environmental
Inc., 2005). The ESA provides interior forest habitat for a number of species including
some that are provincially and locally rare (Dwyer, 2006). The large wetlands also
maintain surface water quality within Sixteen Mile Creek. The swamp is considered a
regionally significant life science ANSI.
        Brookville Swamp connects on the south west side of the Brookville Drumlin
field (ESA # 44). A single extension proposed by Dwyer (2006) would connect the
swamp to proposed extensions of Hilton Falls (ESA # 25).

Hilton Falls (ESA # 25)

        The Hilton Falls ESA is Halton’s largest ESA at 2,646 hectares in size. Due to its
large size and unique features, the Hilton Falls ESA contains the highest number of
native vegetation types within the Region of Halton (Dwyer, 2006). The forested and
wetland areas contribute to the groundwater and surface water quality and significant
discharges maintain coldwater temperatures for resident brook trout populations. Large
tracts of relatively pristine and contiguous forest provide excellent interior habitat for the
highest number of bird and mammal species found in the area. The vast swamp lands of
the ESA form a portion of the Halton Escarpment Wetland Complex, a provincially
significant wetland. The ESA is also considered a provincially significant life science
ANSI (Halton Forest South/Halton Forest North) and a regionally significant earth
science ANSI for the Milton Quarry (Dwyer, 2006). Recreational usage of the ESA is
high as a large proportion of the ESA is in public ownership both by the Region of

Halton and Conservation Halton. Adjacent extractive operations may also have a
potential effect on the ESA.
        Hilton Falls connects to Speyside Escarpment Woods (ESA # 29) at the northeast
limit of the ESA. Recommendations to include extensions to the ESA, found in Dwyer
(2006), would further connect Hilton Falls to Brookville Swamp (ESA # 22), Brookville
Drumlin Field (ESA # 44) and proposed extensions of Guelph Junction Woods (ESA #
20) and Acton Swamp (ESA # 28).

Acton Swamp (ESA # 28)

        Acton Swamp is a large mixed swamp that forms a portion of the Halton
Escarpment Wetland Complex, a provincially significant wetland. A large portion of the
wetland has been lost within the Acton Swamp ESA as an active quarry has expanded
into a portion of the swamp. A proposal for a landfill within the quarry (Halton Region
and North-South Environmental Inc., 2005) may result in further degradation. The
remaining natural areas still support a number of provincially and locally rare species,
and one nationally rare plant species. Moreover, a number of interior forest bird species
are located within the swamp. The dense vegetation and soils of the wetland also help
contribute to both surface and groundwater quality (Dwyer, 2006).
        Extensions to the Acton Swamp ESA are recommended as part of the Halton
Natural Areas Inventory (2006). These extensions would connect Acton Swamp with
Speyside Escarpment Woods to the south east and to proposed extensions to Hilton Falls
(ESA #25).

Speyside Escarpment Woods (ESA # 29)

        The Niagara Escarpment is the dominant feature within the Speyside Escarpment
Woods, one of the largest ESAs found within Halton Region. This expansive tract of
woodland, provides a rich diversity of habitats, alternating between dry upland
communities dominated by sugar maple and wet lowlands consisting of red and silver
maple swamp (Halton Region and North-South Environmental Inc., 2005). A variety of
vegetation types found within the ESA are considered rare along the Niagara Escarpment
Biosphere Reserve (Riley et. al., 1996). Additionally, the ESA provides habitat for a
wide array of plants and butterflies as well as interior forest habitat for birds. The area
acts as a groundwater recharge and discharge area and feeds tributaries of Sixteen Mile
Creek. The ESA is also considered a regionally significant life science ANSI.
         Speyside Escarpment Woods ESA is adjacent to other natural areas proposed as
extensions to both Hilton Falls (ESA #25) and Acton Swamp (ESA #28)

Drumquin Woods (ESA # 43)

        Drumquin woods, consists of a large silver maple swamp, which supports
nationally, provincially and locally rare species as well as a small number of interior
forest bird species (Dwyer, 2006). It encompasses a glaciolacustrine shoreline and
deposits associated with the ponding of glacial Lake Peel. The area overlies Halton Till
comprised of fine sands and silts. As a result the dense woods act as a recharge and

discharge zone for Sixteen Mile Creek and the slow release of water into the creek helps
to maintain surface water quality (Geomatics International, 1993; Regional Municipality
of Halton, 1995; Sharp and Associates, 2000). The ESA has a moderate to low level of
disturbance, mainly a result of nearby roads and adjacent pasture lands. The dumping of
refuse and the removal of trees within the ESA may have additional impacts (Halton
Region and North-South Environmental Inc., 2005).

Brookville Drumlin Field (ESA # 44)

        The Brookville Drumlin Field is the best representation of a drumlin field within
Halton Region (Geomatics International, 1993; Regional Municipality of Halton,). These
drumlin fields consist of elongated hills separated by flat, poorly drained till plain, which
was deposited as ice advanced over the area. Although not well known for its vegetation,
a number of natural vegetation communities and a few provincially and locally rare
species have been identified (Dwyer, 2006). Portions of the drumlin field have been
developed for agricultural lands.
        Brookville Drumlin field falls adjacent to Brookville Swamp (ESA # 22).
Proposed extensions to Hilton Falls (ESA # 25) would form a contiguous stretch of
natural area between these three ESAs.

Trafalgar Moraine (Candidate ESA # 48)

        The Trafalgar Moraine was recommended for ESA designation in 2005 (Halton
Region and North-South Environmental Inc., 2005). This moraine it the only glacial
landform feature in Ontario which marks the position of the Ontario Lobe at the time of
glacial Lake Peel. This event marked the last major glacial event of the Late Wisconsin
glaciation (Halton Region and North-South Environmental Inc., 2005). The presence of
the moraine is instrumental in the formation of Sixteen Mile Creek as it caused the
deflection of the East Branch westward to form a tributary of the main branch. Without
this moraine the east branch would likely have flowed directly to Lake Ontario and the
Sixteen Mile Creek Valley (ESA # 16) would not have been as deeply incised (Halton
Region and North-South Environmental Inc., 2005). Although there is no published
information about plant and animal species within the area, this candidate ESA is
recognized as a regionally significant earth science ANSI by the Ontario Ministry of
Natural Resources. The Trafalgar Moraine falls to the east of the Sixteen Mile Creek
Valley (ESA # 16).

Natural Areas (City of Mississauga)

        City of Mississauga natural areas are areas that typically provide ecological
functions such as groundwater recharge, surface water storage, soil stabilization and
production as well as numerous other functions such as providing wildlife habitat.
Although natural areas found throughout the City are often quite degraded compared to
remote wilderness areas, they are still legitimate urban natural areas that provide habitat
for a variety of species and recreational opportunities for local residents (Geomatics

International, 1996). Natural areas throughout the city have been incorporated into the
Natural Areas System whereby the goal of the system is

        “ To protect, for the long term, remnant natural areas in the City of Mississauga
        that are representative of the indigenous ecosystems and landscapes that once
        characterized the area. The maintenance and restoration of ecological integrity
        of natural areas shall be paramount in this regard” (Geomatics International,

    In doing so, the objectives of the Natural Areas System is to:

•   Maintain and where possible and feasible, restore natural ecological processes in
    remnant natural areas and the surrounding areas, which affect them.
•   Maximize biological diversity through the protection of native flora and fauna.
•   Protect identified natural areas in the City from further fragmentation by
    development, road construction and utility routing.
•   Maintain, restore, or create functional ecological linkages between remnant natural
•   Minimize impacts on identified natural areas through designation of compatible
    adjacent landuses.
•   Develop and initiate a stewardship program that will accurately involve the public in
    the management and protection of natural areas.
•   Minimize harmful disturbances to identified natural areas.
•   Develop and implement natural area management in natural areas requiring
    mitigation of existing of historic impacts.
•   Periodically update the inventory of natural areas.
•   Develop and implement a public education program to increase general awareness of
    the value of natural areas and the protection and management required to preserve
    them. (Geomatics International, 1996).

    Areas classified through the natural areas system fall under three main descriptions:
significant natural areas, natural sites and natural green space. Within the Sixteen Mile
Creek watershed one significant natural area and two natural sites occur. Significant
natural sites include:

• ANSIs, ESAs and other areas designated for outstanding ecological features
• Areas with a floristic quality index < 40 and a mean floristic coefficient of >4.5.
• Woodlands > 10 ha and/or those with the potential to provide interior forest
• Areas that support provincially significant species of special concern, and/or
  threatened or endangered species.
• Woodlands supporting old growth trees.
• Wetlands > 2 ha (regardless of rank)

Whereas natural sites include:

• Woodlands > 2 ha.
• Forests composed of uncommon canopy species or represent uncommon vegetation
  associations in the city.
• Areas that support regionally rare or significant plant species.
• Area with a floristic quality index of 25-39.99 and/or a mean floristic coefficient of
  3.5 to 4.9
• Ares that include natural landscape features. (Geomatics International, 1996).

Descriptions of Natural Areas found with the Sixteen Mile Creek Watershed are found
below and observed in figure 6.


        LS1, a significant natural site, is located between Ninth and Tenth Line from
Parkgate Drive north to Derry Road west. Through the area, a reconstructed tributary of
Sixteen Mile Creek flows through level floodplain areas surrounded by residential
development and agricultural lands. Three vegetation communities are found in the area
including a silver maple swamp, located in the southwest corner, a bur oak-shagbark
hickory forest in the northeast corner and an open valley land community which connects
the two woodlots (Geomatics International, 1996). A total of 111 floral species and 10
faunal species have been recorded in the area some of which are rare and/or uncommon
within the City of Missisauga. Both the silver maple swamp, an evaluated wetland, and
the bur oak-shagbark hickory forest are uncommon vegetation communities within the
city. The floodplain areas also provide water storage for Sixteen Mile Creek.
        The overall condition of the site is good to fair as there is a high level of
disturbance resulting in trails, dumping, garbage, airplane noise and vandalism. The
tributary of Sixteen Mile Creek has also been channelized with concrete and a man made
marsh has been created within the floodplain.


       LS2 is considered a natural site. It occurs between Forest Park Drive and Tenth
Line West and falls between natural areas LS1 and LS2. The dominant vegetation
community on site consists of an oak-shagbark hickory forest with a sub-canopy
comprised of white ash, hop hornbeam, sugar maple, black cherry and hawthorn. The
community is considered uncommon within the City of Missisauga. Fifty-two floral
species and six faunal species occur on site.
        The area is currently in fair to poor condition and a high level of disturbance is
noted. Garbage and litter are present throughout the site and concrete and grass clippings
have been dumped at the edges. Additional noise disturbance occurs from nearby roads
and overhead airplanes.


        LS3 is a natural site located west of Tenth Line West and surrounded by Trelawny
Circle, within close vicinity of both LS2 and LS3. The site is comprised of three
vegetation communities including a white ash-shagbark hickory forest, an old field and
an open water marsh which together support 95 floral species and 7 faunal species. Both
the white ash-shagbark hickory forest and the open marsh are uncommon vegetation
communities within the city. Additionally, the site is home to four plant species two of
which are considered rare, the other two, uncommon within the city.
        The site is currently in fair condition and disturbances including trails, trampling
of vegetation, soil compaction, past logging evidence and road noise are observed. The
alteration of the open marsh to old field between 1996 and 2001 also indicates that the
hydrology of the area has been altered (City of Mississauga, 2004).

Greenbelt Plan Area

        The Greenbelt Plan Area consists of 1.8 million acres of land stretching across the
Golden Horseshoe from the Niagara Peninsula in the west to Rice Lake in the East. The
area encompasses some of the most threatened environmentally sensitive and agricultural
lands and protects them from major urban development while providing opportunities for
communities throughout the area. Protected within the Greenbelt is approximately
800,000 acres of land protected by the Niagara Escarpment Plan as well as new lands
designated as protected countryside (MAH website, 2006). Areas within the Greenbelt
are protected to encourage sustainable agriculture, provide recreational and natural
resource extraction as well as providing infrastructure for rural communities. In
combination with other initiatives, the Greenbelt Plan Area also provides direction for
urban expansion while still protecting natural areas across the plan area. Within the
Sixteen Mile Creek watershed, the Greenbelt covers lands across the Niagara Escarpment
as well as a river corridor along the Lower Middle and Middle East branches of the


        The Sixteen Mile Creek watershed is comprised of a plethora of unique natural
areas that are the naturalists dream. From forested headwater swamps and rolling green
fields to the cliffs of the Niagara Escarpment, meandering streams and river mouth
marshes, the Sixteen Mile Creek watershed provides a variety of landscapes to enjoy.
Many of these habitats provide unique features, which support a diverse assemblage of
species. These unique natural areas and the functions they provide are discussed below.


        Wetlands are an important part of the natural landscape and rank amongst the
most productive ecosystems in the world. These unique areas, defined as “areas of land
that are permanently or seasonally inundated with shallow water, as well as lands where
the water table is close to, or at, the surface”, provide a transition between terrestrial and
aquatic ecosystems. Traditionally viewed as unattractive and nuisance lands, wetlands
are now recognized for the important functions they provide including regulating flow
regimes, acting as areas of groundwater recharge and discharge, providing flood relief
and water storage, as well as improving water quality, cycling of nutrients and gases and
lastly providing recreational and educational opportunities for humans (Daigle and
Havinga, 1996). The presence of wetlands on the landscape increases the complexity and
in turn, the diversity of flora and fauna in the watershed. These diverse ecosystems
typically provide habitat for a number of nationally, provincially and regionally rare
species, which may depend on both the aquatic and terrestrial habitats that wetlands
        Within Southern Ontario four different types of wetlands can be found including
swamp, marsh, bog and fen of which only marsh and swamp occur within the Sixteen
Mile Creek watershed. Marshes are typically characterized by shallow water ranging in
depth from approximately 10cm to 2m, in which an abundance of herbaceous plants
grow. Conversely, swamps consist of deciduous or coniferous trees, shrubs and
herbaceous plants whose roots are periodically submerged by open water during periods
of flooding (Daigle and Havinga, 1996). The majority of wetlands found within the
Sixteen Mile Creek watershed are swamps, largely associated with lands above the
Niagara Escarpment. Small wetlands are also scattered across the landscape interspersed
between residential, agricultural and other natural lands.
        Diverse wetlands historically covered a large portion of land across Southern
Ontario, however following European settlement in the 1800’s numerous wetlands
quickly changed from unique areas of biodiversity to rich agricultural fields through the
draining of wetlands and the extraction of timber. As a result, approximately 20 million
hectares of wetlands were lost due to agriculture alone in Southern Ontario since the
1800’s (Natural Resources Canada website, 2006). Within the Sixteen Mile Creek
watershed, agriculture remained the dominant factor affecting wetlands, followed closely
by development and aggregate extraction (Snell, 1987). These disruptive activities were
largely focused on lands below the Niagara Escarpment where deeper soils allowed for
the farming of fruits and vegetables.

        Natural wetlands throughout the watershed largely occur in rural or natural lands
with a small number occurring in relatively urban areas. Conversely, constructed
wetlands and/or stormwater management ponds have become more widespread across
Southern Ontario and are typically found in urbanized areas. These constructed wetlands
are created as a way to manage stormwater and high flow conditions in order to minimize
flooding hazards on the natural environment, thereby reducing the risks to property and
life. Although constructed wetlands are not preferred habitat for wildlife, numerous
stormwater ponds do provide habitat for a variety of species including fish, turtles, frogs,
small mammals, shorebirds and other waterfowl.

Sixteen Mile Creek wetlands

        Of the remaining natural wetlands within the Sixteen Mile Creek watershed,
fifteen wetlands and/or wetland complexes have been evaluated using the Ontario
Ministry of Natural Resources Wetland Evaluation System. This system aims to evaluate
the value or importance of a wetland based on biological, social, hydrological and special
features. Of the wetlands that have been evaluated in the watershed using this system,
four are considered provincially significant whereas another eleven wetlands are
considered to have local significance. Wetlands within the watershed are described

Guelph Junction Woods and Halton Escarpment Wetland Complex (Upper West

        Located above the Niagara Escarpment, a portion of the provincially significant
Guelph Junction Woods falls within the watershed. This wetland is an extensive and
relatively undisturbed tract of mixed forest containing a variety of organic swamp types.
A large variety of native plant communities sustain an array of floral and faunal species,
some of which are considered nationally, provincially and locally significant (Dwyer,
2006). To the north-east of Guelph Junction Woods, a myriad of small wetlands, all
hydrologically connected, form the Halton Escarpment Wetland Complex. At
approximately 1268 hectares in size, this wetland provides swamp, marsh and riparian
habitat for a number of species including numerous provincially and/or regionally rare
species. It is also associated with the cold headwater streams of the Upper West branch
of Sixteen Mile Creek, which sustains native brook trout populations (Gore and Storrie,

Milton Heights Marsh and Milton Wetland (West Branch)

        Within the West branch of Sixteen Mile Creek the Milton Heights marsh, and the
Milton Wetland Complex constitute approximately 5 hectares and 12 hectares of wetland
habitat respectively. The Milton Heights Marsh is a relatively small marsh comprised
mainly of cattails (Typha latifolia) surrounded by deciduous forests, undulating hills and
agricultural fields. The marsh is completely under private ownership and disturbances in
the area are typically associated with agricultural and rural residential dwellings and
roads. The Milton Wetland Complex, comprised of two individual wetlands, consists of

approximately 76% swamp and 24% marsh habitat (Axon and Newton-Harrison, 1987).
It provides habitat for a number of species and sustains an active heron feeding ground
(Gore and Storrie, 1996). Bordered by roads, an active railway and industrial
development this wetland has a moderate level of human disturbance, which with
increased residential development in the vicinity, may increase in coming years.

Chudleigh Swamp and Scotch Block Wetland (Middle Branch)

        Within the Middle Branch of Sixteen Mile Creek, Chudleigh swamp and the
Scotch Block Wetland Complex can be found. Chudleigh swamp is comprised of 25%
shallow water marsh and 75% swamp, both on a bed of clay loam (Axon and Newton-
Harrison, 1987). Although this wetland has no current records of provincially or
regionally rare species, the undulating terrain and dense cedar woods does provide
wintering habitat for deer and with the exception of nearby roads and rural residences
there is little disturbance to the wetland (Gore and Storrie, 1996). The Scotch Block
wetland complex, is comprised of three small wetlands at 3.4 ha, 4.4 ha and 4.5 hectares
respectively. Comprised of both swamp and marsh habitat this complex falls within the
vicinity of Scotch Block Reservoir, a flood control reservoir operated by Conservation
Halton. Records of regionally uncommon species have been recorded within the wetland

Ashgrove West Wetland, Mansewood Wetland and Hornby Swamp Complex (Middle-
east branch)

        Within the Middle-East branch of Sixteen Mile Creek two wetlands have been
identified and evaluated. Ashgrove West Wetland, a small wetland of marsh and swamp,
is located in the upper reaches of the Middle-East branch. This small wetland has had
moderate levels of disturbance including timber harvesting, dredging and grazing from
surrounding agricultural areas (Axon and Newton-Harrison, 1987). Conversely, the large
North Mansewood Wetland to the south has had little to no disturbance with the
exception of surrounding agricultural fields and rural residences. This wetland provides
habitat and food for a variety of species including regionally uncommon species and
colonial nesting birds (Axon and Newton-Harrison, 1987). The Hornby Swamp
Complex, consists solely of swamp habitat and is dominated by eastern white cedar,
whose dense stands provide winter habitat for deer (Gore and Storrie, 1996). The swamp
discharges directly into tributaries of Sixteen Mile Creek, thereby providing cool to
coldwater temperatures for aquatic life.

East Oakville Swamp (East branch)

       The East Oakville Swamp is the only wetland feature evaluated within the East
Branch of Sixteen Mile Creek. This small swamp is only 2.6 hectares in size and is
bordered by rural residences and agricultural fields. The dominant vegetation consists of
Eastern White Cedar, which provides locally significant deer wintering areas (Axon and
Newton-Harrison, 1987).

Mississauga Wetland and Drumquin Wetland (East branch-Lisgar)

        Within the East-Lisgar Branch of the watershed the Mississauga and Drumquin
wetlands are the only evaluated wetlands. At time of evaluation the Mississauga wetland,
a large silver maple swamp, was surrounded by pasture and agricultural lands with little
to no human disturbance. However, in 2006, this wetland is now surrounded by
extensive residential development, which likely has resulted in large-scale changes to
both the shape and size of the wetland. In contrast, Drumquin wetland, has a moderate to
low level of disturbance, mainly a result of nearby roads and adjacent pasture lands. The
wetland consists of a large silver maple swamp, which supports nationally, provincially
and locally rare species as well as a small number of interior forest bird species (Dwyer,
2006). The dense woods act as a recharge and discharge zone for Sixteen Mile Creek and
the slow release of water into the creek helps to maintain surface water quality
(Geomatics International, 1993; Regional Municipality of Halton, 1995; Sharp and
Associates, 2000).

Oakville Creek wetland (Lower main branch)

        The Oakville Creek Wetland is significantly different from other wetlands within
the Sixteen Mile Creek watershed. This wetland complex is located at the lower reaches
of the creek, within 1km of Lake Ontario and as a result is associated with the deep
channel of the main branch of the creek. The wetland is dominated by marsh habitat with
a small amount of swamp habitat along the banks. Due to its location in the watershed,
this marsh is greatly influenced both by the condition of the watershed upstream and by
Lake Ontario downstream. Nearby marinas and recreational boating may also have an
adverse effect on the marsh. Although the marsh habitat is not known to support a large
number of waterfowl or provide significant staging habitat, it is likely important habitat
for Lake Ontario fish, which may use the emergent vegetation during spring spawning.
The wetland also falls within a migratory corridor for a number of Lake Ontario salmonid

        In addition to these wetlands, two similar wetland complexes located in the
northern portion of Oakville cross over sub-watershed divides. The North Oakville-
Milton East Wetland Complex is a series of 112 wetland pockets that cross the East,
Main and Urban Diverted Tributaries sub-watersheds whereas the North Oakville-Milton
West Wetland Complex is a series of 150 wetlands that crosses the Main and West
Branches of the Creek. Both of these wetland complexes are similar in structure and are
comprised of a number of small wetlands connected through a series of stream corridors,
upland forests, agricultural lands and regenerating fields. The wetlands across both
complexes support a variety of different wetland types and a number of locally
significant plant and animal species. Located on the Trafalgar Moraine, they also provide
spring flows to headwater tributaries and may serve as aquifers along the moraine (MNR,
2006b; MNR, 2006c). Due to their location within a growing urban area, it is important
to maintain the integrity of these wetlands by reducing human impacts and encouraging
the restoration of wooded and stream corridors within the vicinity of the wetlands
(OMNR, 2006).

Table 2: Evaluated Wetlands within the Sixteen Mile Creek watershed (adapted from
Gore and Storrie, 1996).

Wetland         Year        Size      Provincially/   Ownership              Comments
Name            Evaluated   (ha)-     Locally
                            updated   Significant
Guelph          1982                  Provincially    95% Private            Deer wintering
Junction                                              5% Public              area
Halton          1982                  Provincially    85% Private            Deer wintering
Escarpment                                            15% Public             area
North           2006        39.0      Provincially    98% Private            Migratory
Oakville-                                             2% Public              waterfowl
Milton East                                                                  stopover.
Complex                                                                      Kettle wetlands
North           2006        23.04     Provincially    69% Private            Migratory
Oakville-                                             29% Province of        waterfowl
Milton West                                               Ontario Land       stopover.
Wetland                                                   Assembly and
Complex                                                   Parkway Belt       Kettle wetlands
                                                      2% Halton Region
Milton          1984                  Regionally      100% Private
Milton          1982                  Regionally      70% Private            Heron feeding
Wetland                                                                      area
Scotch Block    1981                  Regionally      100% Private
Chudleigh       1981                  Regionally      100% Private           Deer wintering
Swamp                                                                        area
Ashgrove        1981                  Regionally      87% Private
West Wetland                                          13% Public
North           1981                  Regionally      100% Private
East Oakville   1982                  Regionally      100% private           Deer wintering
Swamp                                                                        area
Hornby          1981                  Regionally      100% private           Deer wintering
Swamp                                                                        area
Drumquin        1982                  Regionally      100% private
Mississauga     1982                  Regionally      100% private
Oakville        1983                  Regionally      100% private           Little gull
Creek                                                                        wintering area


        Forests are the dominant terrestrial ecosystems within Ontario. Generally defined
as areas with greater then 60% tree canopy cover, forests provide unique opportunities for
both flora and fauna to flourish. Diverse forests support numerous types of vegetation,
which create the herbaceous layer, understory, sub-canopy and canopy layers typical of
healthy functioning forests. These forest layers in turn support a variety of wildlife
including birds, herpetiles, mammals as well as numerous insect, bacterial and plant
        Within Ontario, forests have evolved over centuries in response to abundant
precipitation and sufficiently deep and fertile soils, which provide the nutrients and
organic compounds required to sustain and nourish forest growth (Daigle and Havinga,
1996). These unique climate and soil conditions result in different forest zones across
Ontario, including the Boreal Region with largely coniferous forest to the north, the
Deciduous Forest region with broadleaf deciduous forests to the south and the Great
Lakes-St. Lawrence Region which forms the transition zone between the other two
regions in Ontario.
         The forests within Ontario have undergone numerous changes since the time of
European settlement. In Southern Ontario it is estimated that forest clearing begun in the
early 1800’s with less then 1% of the land in undisturbed, old growth conditions and 90%
of the original woodlands converted to non-forest landuses by 1920 (Larson et. al., 1999).
After 1920, the availability of fossil fuels and electricity began to relieve the pressure on
forests, which have since allowed for substantial re-growth of forests across Southern
Ontario (Larson et. al., 1999). This resurgence of forest cover is largely attributed to the
removal of marginal farmlands from production and natural succession occurring on
scrublands and abandoned fields.

Sixteen Mile Creek Forests

       Within the Sixteen mile Creek watershed, forest cover was dense at time of
European settlement. Surveyors assessing the land between 1806 and 1819 noted that the
land comprising the watershed was essentially:

        “A primeval forest almost unbroken except for an occasional beaver meadow, a
       few Indian corn fields in the lower valley flats or a patch of windfall”
       (Department of Planning and Development, 1958).

       The upland forests of the watershed were dense and comprised of species such as
sugar maple, beech, elm, ash and basswood interspersed with pine and oak. Large cedar
swamps were also found in the headwater regions of the watershed and southern species
such as chestnut, sugar maple, oak and hickory were found within vicinity of the Lake
Ontario shoreline. With European settlement, forests were cleared for agriculture and the
timber industry, which quickly grew along the banks of the creek. Large species such as
pine and oak were sought for use in ship masts whereas other “less valuable” trees were

burned and shipped to Britain as “potash” for use in soap making and the dyeing industry.
With the increase in settlement these trees were also used for shingles, fence poles and
railway ties (Department of Planning and Development, 1958). Rapid clearing of the
forests in the watershed continued until 1910, which resulted in a drop in total forest
cover in Esquesing, Nassagaweya and Trafalgar Townships from 52.5% in 1851 to
11.6% in 1911. After 1911, forest cover in these townships grew to 17% in 1957. Forest
cover in the entire watershed has grown only slightly since 1957 to just over 20% forest
cover in 2006.

        The forests of the Sixteen Mile Creek watershed form a transition zone between
two different forest regions, the Great Lakes –St. Lawrence Forest Region and the
Deciduous Forest Region, both of which are represented in the unique forest cover found
within the watershed (Federation of Ontario Naturalists, 1999).
        The Great Lakes-St. Lawrence Forest Region extends across Ontario from the St.
Lawrence River to Lake Huron, west of Lake Superior and serves as a larger transition
zone between the southern deciduous forests and the predominantly coniferous forests of
the Boreal Region to the north. Within this area, the lands south and east of the Canadian
Shield have deeper, richer soils, which support coniferous species such as eastern white
pine, red pine and eastern hemlock, as well as deciduous trees such as sugar maple, red
maple, yellow birch and red oak (Federation of Ontario Naturalists, 1999).
        To the south of the Great Lakes-St. Lawrence Forest Region, the Deciduous
Forest Region extends from the eastern United States to southern Ontario between three
of the Great Lakes, Ontario, Huron and Erie. The deciduous forest region, often referred
to as the Carolinian Zone, is characterized by broad-leaf deciduous forests comprised of a
mix of species such as sugar maple, beech, basswood, yellow birch, elm, black cherry,
and red oak. A host of other tree species close to the northern limits of their range are
also found, including tulip tree, black walnut and many species of oak and hickory.
Many provincially rare species including paw-paw, cucumber tree and red mulberry are
also found within this region. Today, these woodlands occur in small numbers scattered
across the most populated area of Ontario. As a result, the Carolinian forests account for
only one percent of the total forest cover in Ontario (MNR, Ontario Forests website).
Regardless, this forest region represents the most diverse region within Ontario and
supports a large number of nationally, provincially and regionally rare species.

        Within the Sixteen Mile Creek watershed, species characteristic of the Carolinian
zone can be found within a few kilometres of the river mouth as a localized climate,
suitable for these species, is created from the moderating effects of Lake Ontario
(Department of Planning and Development, 1958). Bordered between Lake Ontario and
the Queen Elizabeth Way this small patch of Carolinian Forest consists of species such as
sugar maple, white oak, chinquapin oak, white ash, black cherry, bitternut hickory, black
walnut and more isolated records of sycamore and butternut. Shrub cover in this zone is
varied consisting of red-ossier dogwood, grey dogwood, chokecherry, common
buckthorn, alternate-leaved dogwood and raspberry. Understory species such as
bloodroot, white trillium, foamflower, and trout-lilly can also be found. Historically, the
American chestnut tree also occurred in the lower portions of the watershed, however

chestnut blight drastically reduced numbers in the early 1900’s (Department of Planning
and Development, 1958).
        North of the Queen Elizabeth Way, species characteristics of the Great Lakes –St.
Lawrence Forest Region can be observed. Broadleaf forests of sugar maple, white elm,
trembling aspen and beech along with coniferous forests of eastern white cedar, hemlock
and white pine span across the watershed. In dry to well-drained regions of the
watershed, sugar maple, white elm and sugar maple-beech forests dominate whereas
forests of trembling aspen, balsalm poplar and white elm occur as pioneer species in
areas of previous disturbance. Conversely, moist areas associated with river bottoms,
swampy depressions or seasonally flooded areas are typically covered with silver maple-
white elm forests whereas swampy, mucky soils with rich deposits of limestone are
typically covered in eastern white cedar, tamarack and yellow birch (Department of
Planning and Development, 1958).

Interior Forest Habitat

        Interior forest habitat is generally defined as forest habitat that is 100 metres or
more from the edge of the forest. As such, these types of forest habitats are typically
protected against increases in solar radiation, extremes in temperature and humidity,
increased disturbance from wind, water, air and noise pollution, increased development
and vegetation clearing and increased numbers of aggressive, non-native species and
pathogens (Riley and Mohr, 1994). For this reason, many species find seclusion and
protection in the interior forests of the watershed. Species such as interior-specialist bird
species rely on these habitats to successfully forage and reproduce, salamanders including
the Jefferson salamander traverse rich forests floors in search of vernal pools for breeding
and weak flying butterflies such as the West Virginia white are sheltered from extreme
conditions outside of the forest.
        Interior forest habitat within the watershed provides protection for interior bird
species such as ovenbird, veery, wood thrush, black-throated green warbler, brown
creeper and scarlet tanager as well as other species seen in table 3. These species are
limited by the amount of interior habitat within a forest and typically require forests over
10 hectares in size (Riley and Mohr, 1994). These expansive forests thereby provide
protection against predators and nest parasitic birds such as brown-headed cowbird,
which are typically seen along forest edges and openings. Mammals also find protection
and solitude in the interior habitats of large forests. Wide home ranges of large mammals
can be sustained within interior forests allowing for feeding, refuge and breeding.
Species such as black bears and bobcat, recorded within the Hilton falls ESA require
large tracts of forest in order to live out their life cycle. Smaller mammals such as the
woodland vole, a species of special concern nationally and provincially, utilize rich forest
floors, with loose soil and deep humus for burrowing. Old logs, stumps and dead trees
provide additional habitat for species such as squirrels, porcupines and other rodents.
Additional woody debris and leaf litter along the forest floor provide ample habitat for an
array of herpetiles including salamanders and snakes.

       Within the Sixteen Mile Creek watershed, large tracts of interior forest habitat are
found largely in forests above the Niagara Escarpment. Forests associated with the

Hilton Falls ESA (Halton Forest North and Halton Forest South) and the Speyside ESA
form the majority of interior forest habitat within the watershed. Additionally, deep
interior forest habitats (forests 200m from the forest edge) are found in these areas.
Interior forest habitat beneath the Niagara Escarpment is limited to isolated patches
within the Middle, Lower Middle and East Branches of the watershed as well as the
Sixteen Mile Creek valley (ESA#16) within the Main Branch of the creek. Figure 7
illustrates interior forest habitat within the Sixteen Mile Creek watershed.

Table 3: Birds of the Interior and of the Forest Edge habitats (adapted from Freemark,
K., 1999).

Birds of Large Woodlands      Birds of Large Woodlands      Birds of Small Woodlands
With Forest Interior          that may also Nest Near       Edge habitat

Barred owl                   Ruffed grouse                  Northern bobwhite
Pileated woodpecker *        Wild turkey                    Red-tailed hawk
Hairy woodpecker*            Red-shouldered hawk            Great horned owl
Acadian flycatcher*          Yellow-bellied sapsucker       Mourning dove
Veery*                       Red-bellied woodpecker         Red-headed woodpecker
Hermit thrush *              Least flycatcher*              Northern flicker
Swainson’s thrush*           Great crested flycatcher       Eastern kingbird
Black and white warbler*     Eastern wood pewee             Blue jay
Black-throated green warbler Black-capped chickadee         American crow
Black-throated blue warbler* House wren                     American robin
Cerulen warbler*             Blue-gray gnatcatcher *        Cedar waxwing
Blackburnian warbler *       Gray catbird                   Brown-headed cowbird
Mourning warbler*            Northen mockingbird*           Common grackle
Canada warbler*              Wood thrush                    European starling
Ovenbird*                    Red-eyed vireo                 House sparrow
Louisiana waterthrush*       Northern parula*               White-throated sparrow
Northern waterthrush*        Eastern towhee
Scarlet tanager*             Rose-breasted grosbeak

* Indicates birds that are known to decline significantly when forest area is reduced.

Aquatic Habitats

        The Sixteen Mile Creek watershed encompasses an area of approximately 379
km² and is formed at its headwaters above the Niagara Escarpment within the Town of
Milton and the Town of Halton Hills. The stream flows through a variety of different
habitats including headwater swamps, natural forests and wetlands, agricultural fields,
urban developments and finally through a substantial valley and marsh before its
confluence with Lake Ontario in the Town of Oakville. The creek is divided into nine
major branches with numerous smaller tributaries that feed the creek and provide habitat,
food resources and flow to both the species inhabiting the tributaries, as well as the main
branches. Variations in habitat and stream conditions result in localized fish communities
across the watershed ranging from coldwater sportfish communities to warmwater
baitfish communities, as seen in figure 8. Sub-watershed descriptions are provided

Upper West Branch

        The Upper West Branch of Sixteen Mile Creek is formed in the forested swamps
associated with the Halton Escarpment Wetland Complex and the Flamborough Plain
physiographic region. This region, dominated by highly permeable soils of loam and
muck, provide significant recharge and discharge areas, which result in two main cold
water tributaries that form the headwaters of the creek. The east tributary is formed in
swamps within the Halton Forest South, a provincially significant life science ANSI.
From here the creek flows in a south-western direction through cedar swamps until it
turns south and flows through dense cattail marshes alongside 6th Line, before re-entering
the deciduous forests associated with the ANSI and the Hilton Falls Conservation Area.
This tributary then meanders through thick forests before entering the Hilton Falls
reservoir, a flood control structure designed to capture peak flows, reduce flooding and
maintain baseflow conditions in the summer months. From here, the creek continues out
of the Hilton Falls reservoir through a flow control structure and into a small valley
consisting of herbaceous and shrubby vegetation. The creek then continues through a
culvert under Campbellville Road and then the 401 before entering Kelso Reservoir,
another flood storage reservoir.
        The west tributary originates in wetlands north of #15 Sideroad and flows in a
southern direction adjacent to Fourth Line along the northwestern limit of the Halton
Forest South and into the Hilton Falls Conservation Area. Within these dense forests,
numerous small and isolated tributaries are formed from pocket wetland areas and beaver
ponds, which in turn provide coldwater conditions suitable for species such as brook
trout. Abundant woody debris and dams throughout the area result in barriers to fish
migration and isolated populations. Fish migrations is further restricted downstream of
the Hilton Falls Conservation Area as the tributary flows over two large barriers in the
vicinity of Campbellville Road. On the upstream side of Campbellville Road a large
concrete weir approximately 1m in height restricts fish movement upstream. On the
downstream side of Campbellville Road a large pond is dammed with another concrete
dam and cement spillway structure. From here the west tributary flows south under the

401 highway towards #3 Sideroad where it loops back in a northeasterly direction
towards the Kelso Reservoir.

West Branch

        Below the Kelso dam, the West Branch flows through protected parkland with
dense riparian cover, clean cobble/gravel substrate and a natural channel. Extensive
groundwater discharge, emanating from the base of the Niagara Escarpment, provides
coldwater conditions for resident and migratory species such as rainbow trout, brown
trout, brook trout and mottled sculpin. Below the park, the west branch flows between
wooded riparian banks which meander through rural residential and industrial lands
before entering downtown Milton. As it enters Milton, the channel flows through a step-
pool fishway adjacent to the Milton Mill Pond, which supplements its water levels from
the creek. Downstream of the Milton Mill Pond and just upstream of Martin Street,
discharge from the pond enters the adjacent channel resulting in increased stream
temperatures directly downstream of the pond. From Martin Street through downtown
Milton and just above Derry Road, the creek is entrenched into a concrete channel.
Within the concrete channel, storm sewers and the Milton wastewater treatment plant
(WWTP) discharge effluent into the creek. Treated effluent discharged by the Milton
WWTP is suspected to moderate baseflow conditions in the driest months of the summer
and its low temperature likely contributes to coolwater/potential coldwater conditions
downstream of the plant.
        Downstream of the WWTP, the West Branch flows out of the concrete channel
and into a natural channel downstream of Derry Road. Fast flows emanating from the
concrete channel has resulted in a degraded, incised channel that is significantly eroding.
High degree of erosion through this area has resulted in the slumping of banks and an
increased amount of sediment within the creek. A small tributary emanating from the
east provides potential coldwater conditions to the west branch. Species found in this
tributary include redside dace, a species of special concern nationally and threatened
provincially. Downstream of the tributary confluence with the main branch, the west
branch begins to flow through a patchwork of agricultural fields and small woodlots. In
the vicinity of Britannia Road the stream begins to flow through open areas with
herbaceous riparian cover. As a result, stream temperature begins to increase with the
decrease in overhead cover and the fish community shifts towards a warmwater sportfish
community. Downstream the channel flows into the Sixteen Mile Creek valley (ESA #
16) where it joins the Lower Middle Branch.

Middle Branch

        Headwater reaches of the Middle Branch are formed in the Town of Halton Hills
as a result of lacustrine and outwash deposits and highly permeable soils. Within this
area, forested, groundwater fed tributaries originating above the Niagara Escarpment
provide potential coldwater conditions for species within the tributaries of the middle
branch before their confluence with the Scotch Block Reservoir, another flood control
structure. The reservoir itself provides refuge habitat for a variety of species during times
of stress but may also contribute to higher water temperatures and increased algae growth

downstream. This effect is quickly diminished as groundwater discharge areas restore
cool to coldwater conditions to the downstream reaches.
        Downstream of the Scotch Block Reservoir, the middle branch flows through a
patchwork of forested, agricultural, and residential lands before it meets its confluence
with the Middle East Branch of Sixteen Mile Creek. Upstream of the confluence
agricultural and residential land increases resulting in limited amounts of riparian
vegetation, which consists of mainly grasses and herbaceous vegetations thereby limiting
overhead cover.

Middle East Branch

        The Middle East Branch is divided across the sub-watershed into a series of
smaller tributaries, which drain mainly agricultural lands. Upstream reaches in two of the
tributaries maintain coldwater temperatures despite cover removal and agricultural
impacts and are likely groundwater fed. One tributary supports populations of redside
dace, while other isolated records of brook trout have been recorded in the area. Records
of both redside dace and brook trout in the Middle East Branch have been reported as
recently as 2003 and 1999 respectively (Conservation Halton Fish database, 2006). Both
species rely heavily on groundwater discharge and cold, clean water.
        The remaining tributaries are small and relatively open with little riparian
vegetation and overhead cover. One such tributary flows through a large golf course and
may experience adverse affects resulting from potential nutrient loading and water taking.
Like the majority of the watershed, a warming trend occurs as one moves further
downstream from the headwater areas to its confluence with both the Middle Branch and
the Lower Middle Branch.

Lower Middle Branch

         Downstream of its confluence with the Middle and Middle East Branches of the
watershed, the Lower Middle Branch flows in a southeasterly direction over deltaic
glacial deposits and low porosity soils. Here numerous small tributaries, with restricted
drainage span across the Lower Middle Branch, draining agricultural and abandoned
fields, residential developments and construction lands before converging along the east
tributary bounded by 6th Line and Trafalgar Road. In the upper reaches of the sub-
watershed, this large and defined tributary slowly meanders across the landscape passing
through three separate golf courses as it makes it way downstream to its confluence with
the East Branch. As it continues downstream, the channel become more defined and the
substrate moves from fine silts and clay towards rock and cobbles. As the stream
continues on it passes more agricultural fields interspersed with remnant forest pieces
before it meets its confluence with the East Lisgar Branch.
         After the confluence with the East Lisgar Branch, the creek flows into a defined
valley (Sixteen Mile Creek ESA # 16) with steeps forested walls and herbaceous covered
floodplain. The creek meanders through the valley until its confluence with the west

East Branch

        The headwaters of the East Branch are formed in the upper reaches of the
watershed in the Town of Halton Hills. The main tributary within this sub-watershed
flows through numerous agricultural fields with pockets of riparian vegetation and forest
cover. In the vicinity of #5 Sideroad, the stream moves from a warmwater tributary to
potential coldwater, indicating the possibility of groundwater discharge in the area.
Warmwater conditions reoccur downstream of the 401 as the creek meanders through a
variety of natural areas before its confluence with the Lower Middle Branch and the East-
Lisgar Branch.

East-Lisgar Branch

        The East-Lisgar Branch forms as a series of small tributaries and swales
emanating east of the 407 highway in the City of Mississauga. The main tributary flows
through a collection of abandoned fields and then through a constructed channel adjacent
to dense residential housing and a small recreational field. The creek then enters a large
stormwater management pond and continues downstream in a man-made, deep, highly
meandering channel that runs parallel to the 407 before it enters yet another stormwater
management pond. In-stream habitat through this reach is extremely limited as the
stream is entirely clay and silt lined with no riparian vegetation. Adjacent floodplain
vegetation consists of sparse grass cover with the limited shrub and herbaceous
vegetation. The floodplain and accompanying stormwater ponds provide breeding and
staging habitat for numerous waterfowl and shorebirds. The active use of this area by
waterfowl combined with stormwater and runoff, likely results in high nutrient loading
throughout the reach.
        Downstream of the stormwater pond, the creek flows under the 407 and into a
small, relatively naturalized area. From here the creek continues on through a series of
agricultural fields and small wooded areas before it meets its confluence with the Lower
Middle Branch.

Urban Diverted Tributaries

        The Urban Diverted Tributaries are considered the headwaters of Morrison and
Wedgewood Creek, which have been previously diverted to the Sixteen Mile Creek
watershed via the Morrison-Wedgewood diversion channel. These headwaters tributaries
are formed just north of Dundas Road as a series of swales and small agricultural
tributaries. The East Morrison tributary enters a small, yet defined valley south of
Dundas Road and flows between commercial and residential developments. As one
moves downstream the valley becomes deeply entrenched and provides protection to the
creek with dense herbaceous riparian vegetation interspersed between wooded riparian
lands. Potential coldwater conditions provide habitat for numerous forage fish
throughout the reach. The redside dace, a species of special concern nationally and
threatened provincially, has been recorded in the area as recently as 2000. The creek
continues on through the Morrison Creek valley where it meanders through dense
wooded areas adjacent to recreational trails. Poor in-stream conditions resulting from

excessive erosion, likely a result of high fast high flows, have resulted in slumping of
stream banks and numerous trees falling inwards. Attempts to control erosion have
resulted in portions of the stream channel inlaid with gabion baskets and banks hardened
with stone. Downstream of the wooded valley, the tributary enters the Morrison-
Wedgewood diversion channel.
        The West Morrison tributary also formed above Dundas Road flows southward
towards the Sheridan College campus. The tributary goes through a series of culverts
that direct the channel under roads and away from parking areas. Downstream of the
immediate parking area, the tributary flows through a small wooded area and associated
valley lands before it nears McCraney Street. Downstream of McCraney Street, the
tributary is piped underground until its confluence with the Morrison-Wedgewood
diversion channel.
        The Wedgewood creek tributary originates just north of Upper Middle Road
where flows through a naturalized channel within a recreational park. Downstream of
Upper Middle Road the creek flows into naturalized and forested lands before it enters
the Morrison-Wedgewood diversion channel. Just upstream of the diversion channel, the
Wedgewood Creek tributary flows through the southwest corner or Iroquois Shoreline
Woods (ESA#13).
        The diversion channel is a concrete channel, which directs stream flow from
Morrison Creek, north of the QEW to the main branch of Sixteen Mile Creek. The
channel is quite shallow during the summer months with extensive algae growth and
warmwaters. Numerous barriers to fish migration have been observed in the channel,
which were constructed to help reduce stream velocities in the concrete channel.
Although fish habitat is limited throughout the reach, fish have been observed using the
channel as recently as 2005. Additional observations noted creek chub spawning at the
confluence between Morrison Creek and the Morrison-Wedgewood Dviersion Channel in
2005 (A. Dunn, pers. obs.).

Main branch

        The Main Branch of Sixteen Mile Creek below the confluence with the West
Branch is confined to the Sixteen Mile Creek Valley (ESA #16). Here the creek flows
through small areas of riparian cover consisting of deciduous trees with the banks lined
with cattails and other herbaceous vegetation. The majority of the creek remains open as
the channel becomes large and wide resulting in warmer stream temperatures. Fish
community from this reach downstream to the mouth of the creek is classified as a
warmwater sportfish community. On either side of the valley walls, extensive urban
development surrounds the lower main branch of Sixteen Mile Creek. Too the east the
urban diverted tributaries join the main branch through a concrete diversion channel.
        Downstream of the confluence with the concrete channel, the main branch
continues on towards its confluence with the lake. Along the way it passes through a
locally significant marsh, just north of Oakville Harbour. Warmwater fish species such
as pumpkinseed and largemouth bass are found within the marshlands and it is likely that
fish species from Lake Ontario visit the marsh in the spring and summer to spawn. The
lower main portion of Sixteen Mile Creek is a significant corridor for migratory fish in

the spring and the fall allowing species such as rainbow trout, chinook salmon and coho
salmon to utilize the coldwater reaches of the west branch to spawn. Downstream of the
marsh the creek flows through Oakville Harbour, which provides numerous recreational
and boating opportunities within downtown Oakville. The harbour is found just north of
the creeks confluence with Lake Ontario.

Special habitats

The Niagara Escarpment

         The Niagara Escarpment is a ribbon of natural lands running through one of the
most populated parts of the country. More than just a long ridge of rock, the escarpment
is a vital natural link, which ties together plant assemblages, bird life, animals, towns, and
history. In Ontario, it stretches over 700 km in length and runs from Tobermory on the
Bruce Peninsula through to Queenston along the Niagara River (ECO, 2006). This
feature provides unique habitats throughout its range and acts as both a regional and
provincial corridor.
         The Niagara Escarpment supports an extensive array of forest and wetlands that
support numerous rare plant and animal species. Within the Sixteen Mile Creek
watershed above the escarpment, numerous wetland patches, all hydrologically
connected, create the Halton Escarpment Wetland Complex, considered a provincially
significant wetland. Coldwater streams emanating from these wetlands form the
headwaters of the West and Middle Branches of Sixteen Mile Creek while extensive
forest tracts support an array of birds and other wildlife. A high degree of diversity is
recognized in the forests of the Niagara Escarpment, which support numerous nationally,
provincially and locally rare species.
         Other unique habitats are found along the exposed escarpment cliffs and rims.
Areas exposed to the harshest conditions and temperature extremes within southern
Ontario can be found along the escarpment and are comparable to tundra conditions
thousands of kilometres away. These areas provide unique habitat conditions for
uncommon species such as climbing fumitory (Adlumia fungosa), sandwort (Arenia
stricta) and buffaloberry (Shepherdia Canadensis). Additionally, old growth forests of
eastern white cedar can be observed along the escarpment cliffs along Rattlesnake Point
and Kelso Conservation Area. These cedars have evaded harvest due to their location and
as a result, some trees have exceeded 1,600 years in age (Kelly, 1996). These forests are
also considered the oldest and least-disturbed old-growth forests in eastern North
America (Larson, 1989).
         Rock crevices and caves may also provide significant habitat for a variety of
species of bats. Species such as little brown bat (Myotis lucifugus), silver-haired bat
(Lasionycteris noctivagans) and Eastern pipistrelle (Pipistrellus subflavus) have been
recorded within the watershed and may find habitat in areas such as Milton Heights.


        Prairie and savanna habitats formerly occurred in sporadic distribution across
much of Southern Ontario. This unique habitat, characterized by the presence of native
grasses, perennial wildflowers and low growing shrubs, has historically been cleared
across the landscape for increased agricultural and urban development. Today, existing
prairie habitat within Southern Ontario, forms less then one percent of the prairie habitat
present prior to European settlement and as such is considered one of the rarest vegetative
communities within Southern Ontario.

        Within the Sixteen Mile Creek watershed limited information is available about
the presence of prairie habitat in the watershed. The (1978) Environmentally Sensitive
Areas study indicates the presence of “patches of prairie species on the south-facing
slopes” of the Sixteen Mile Creek valley ESA (#16). Similarly, species such as wild
bergamot, wild mint, fringed loosestrife, boneset and calico aster, which are characteristic
of prairie habitats, have been recorded in the ESA in recent years. Further studies to
identify prairie habitat throughout the valley is recommended.

Carolinian Zone

        The Carolinian Zone extends across Southern Ontario and is bounded by an
imaginary line, which runs from Grand Bend eastwards towards Toronto. This area is
characterized by broad-leaf deciduous forests comprised of a mix of species including
ones at their northern limit of their range. The area also boasts the warmest temperatures,
longest frost-free season and warmest winters in Ontario. Forest cover within the
Carolinian Life Zone forms the smallest forest region within Ontario and is the most
densely populated. Species diversity is high throughout the region, which supports
numerous nationally, provincially and regionally rare species.
        Within the Sixteen Mile Creek watershed, the moderating effects of Lake Ontario
provide suitable conditions for Carolinian species to thrive. Small patches of Carolinian
forest can be observed in the Sixteen Mile Creek valley between the QEW and Lake
Ontario. Isolated species, characteristic of the Carolinian Zone can also be found
throughout the watershed, albeit in small numbers.


        The watersheds unique ecosystems provide habitat for a wide array of wildlife.
Common species as well as species that are recognized as nationally, provincially or
regionally rare occur within the Sixteen Mile Creek watershed. Descriptions of the
wildlife within in the area are detailed below. For a complete list of wildlife within the
watershed see appendix A.


        There are 30 herpetiles that have been recorded within the Sixteen Mile Creek
watershed including 16 amphibians and 14 reptiles. One extant species and one
introduced species are also included in the list (Riley et. al, 1996).
        Herpetiles found within the watershed are typically restricted to natural areas,
particularly at sites where abundant wetlands and relatively undisturbed vegetation exists.
Some species such as American toad, leopard frog, green frog, snapping turtle, painted
turtle and garter snake are able to exist adjacent to or within urban areas with moderate
levels of disturbance (Riley et. al., 1996). However, the majority of herpetiles within the
watershed require specific habitats in order to live out portions of their life cycle.
        Species such as the Jefferson salamander, a threatened species nationally and
provincially, requires rich upland deciduous forests and ephemeral pools to complete

their life cycle. The spotted salamander and the blue-spotted salamander share similar
woodland habitats in areas associated with the Niagara Escarpment such as Guelph
Junction Woods, Speyside and Hilton Falls. The blue-spotted salamander and the
Jefferson salamander together form a complex that was first noted in the early 1900’s
(Lamond, 1994). Once thought to be a distinct species, this complex, is now recognized
as the Jefferson salamander complex or more specifically, Ambystoma laterale-
jeffersonianum. The presence of this individual at sites within the watershed strongly
indicates that Jefferson salamander is also present (Lamond, 1994). “Pure” (non-hybrid)
forms of Jefferson salamander are still found in the watershed at sites such as Hilton falls
and Guelph Junction Woods however “pure” blue-spotted salamanders are less common
and according to Lamond (1994) were last seen northeast of Guelph Junction Woods in
1988. A single four-toed salamander has also been recorded within the dense forests of
Hilton Falls in 1980. This species requires boggy pools with a high abundance of moss
in order to breed. Conversely, the redback salamander, a strictly terrestrial salamander,
occurs in both deciduous and coniferous woodlands, well-drained slopes of the Niagara
Escarpment and wooded ravines. This species has also been recorded in urban woodlots
within the Town of Oakville.
         The common mudpuppy and the red-spotted newt, differ greatly from other
salamanders in the watershed. The mudpuppy is a completely aquatic salamander that is
found in the clear waters of streams, rivers and lakes (Lamond, 1994). This species is
rare in Halton and has not been recorded in the area since 1988 (Dwyer, 2006). The red-
spotted newt requires both aquatic and terrestrial habitats in order to live out its three-
stage life cycle. As a result, this species is typically found in adult and larvae form in
stagnant aquatic habitats such as swamps, ponds and stream backwaters whereas a strictly
terrestrial phase occurs with juvenile “red efts” occupying wooded habitats.
         Frogs and toads throughout the watershed are typically abundant with the
exception of the wood frog, chorus frog, pickerel frog and bullfrog, which are considered
uncommon to common within Halton. These species typically are under-recorded largely
due to specific habitat requirements, mis-identification and unique life cycles.
Conversely, species such as American toad, gray treefrog, spring peeper, northern
leopard frog and green frog are abundant across the watershed and can be found in a
variety of wetland habitats. These habitats also support common turtle species such as the
snapping turtle, the introduced red-eared slider and the midland painted turtle. The later
two species can often be observed basking in the sun in marshes, slow sections of rivers
and ponds such as the Mill Pond in Milton. Rare turtles such as the map turtle and the
Blanding’s turtle have also been recorded in the watershed. The map turtle, considered a
species of special concern nationally and provincially, was last recorded in the lower
reaches of the watershed in 1990 (Macadam, 1999). Further upstream a single record of
Blanding’s turtle, a threatened species both nationally and provincially has also been
recorded within the Town of Oakville (ref). It is possible that additional individuals of
both species occur in the lower reaches of Sixteen Mile Creek, however boats and human
disturbance may have a large impact on populations.
         Wooded ravines throughout the watershed also provide habitat for other reptiles
such as northern water snakes, which are found in clusters both above and below the
Niagara Escarpment. Open woodlands, forest edges, clearing and grassy swales provide
habitat for species such as brown snake, northern redbelly snake, milk snake and Eastern

garter snake. Other snakes recorded within the watershed include; the northern ringneck
snake, the smooth green snake and the northern ribbon snake a species of special concern.
Extant records of black rat snake also occur in the watershed. Matthews (1950) cites
records that black water snakes “6 feet long” inhabited “Snake Island” at the mouth of the
Sixteen in 1856. Only three species of snake in Ontario, the black rat snake, blue racer
and eastern fox snake attain that length with the later two ruled out due to colouration,
habitat preference and distribution (Macadam, 1999). No recent evidence to confirm the
presence of black rat snakes in the watershed has been documented.


         Numerous habitats such as urban and residential lands, active and abandoned
agricultural fields, pastures, forests, wetlands, escarpment cliffs and wooded ravines
support a diverse assemblage of bird species recorded within the Sixteen Mile Creek
watershed. These habitats provide refuge, food and breeding opportunities for resident
species as well as stopover opportunities for birds that migrate through the watershed as
part of their bi-annual migration. Within the watershed, 171 birds species have been
documented. This includes species at the northern limit of their range such as the
Louisiana waterthrush and hooded warbler, as well as species at the southern end of their
range including dark-eyed junco, yellow-bellied sapsucker and black-throated blue
         In the lower reaches of the watershed, Oakville Harbour and the estuary reaches
of the creek provide habitat for species such as Canada goose, mallard, American black
duck, mute swan, red-necked grebe, double-crested cormorant, Caspian tern, and ring-
billed gull. Many of these species are common within the harbour and are only mildly
disturbed by the increased activities associate with boats and increased human presence.
Further upstream, small amounts of marsh habitat and deep wooded ravines provide
habitat for great blue heron, red-winged black bird, belted kingfisher and osprey.
         Urban and residential areas within the watershed provide a variety of habitats
such as small woodlots, open grassy areas, and streamside riparian habitat. These
habitats provide resources for generalist and opportunistic species such as blue jay,
American robin, American crow, northern cardinal, song sparrow, chipping sparrow,
mourning dove and common grackle. Naturalized species such as house finch and
European starling are also abundant in these areas. Numerous stormwater ponds
associated with residential developments are interspersed across the landscape thereby
providing habitat for a variety of shorebirds and waterfowl such as mallard, ring-billed
gull, killdear and spotted sandpiper.
          In the middle reaches of the watershed, large rolling hills and agricultural fields
support a variety of grassland specialized species. Often regarded as abandoned fields,
these areas provide habitat for area-sensitive species including bobolink, Eastern phoebe,
Eastern kingbird, savannah sparrow, grasshopper sparrow, ring-necked pheasant and
Eastern meadowlark. Birds of prey such as Northern harrier, red-tailed hawk and
American kestrel are also commonly associated with grassland and open habitats.
         In the upper reaches of the watershed a variety of habitats including marshes, pine
plantations and interior forest habitat can be found. Large marshes, created by beaver
activity provide habitat for species such as common moorhen, American coot, sora, red-

winged blackbird, swamp sparrow, marsh wren, Virginia rail and the nationally and
provincially threatened least bittern. Red-shouldered hawk, a species of special concern
nationally and Cooper’s hawk also nest in woodlands adjacent to these marshes.
Large tracts of upland and lowland forests associated with the Niagara Escarpment
provide breeding, overwintering and resident habitat for a wide array of birds. The
Speyside ESA and Hilton Falls ESA, provide interior forest habitat that supports 65 and
133 different bird species respectively (Halton Region and North-South Environmental,
2005). These expansive forests provide suitable breeding habitat for warblers such as
chestnut-sided warbler, blackburnian warbler, black and white warbler, scarlet tanager,
ovenbird and blue-winged warbler as well as other species such as hermit thrush, veery,
rose-breasted grosbeak, indigo bunting, red-eyed vireo and great-crested flycatcher.
Nationally and provincially rare species such as the acadian flycatcher, hooded warbler,
Louisiana waterthrush and prothonotary warbler have all been recorded in the watershed
within forests with adjacent stream and/or marsh habitats.


         The variety of habitats found within the watershed support numerous wildlife
including 44 species of mammals. Many of the mammals recorded in the watershed are
able to thrive in a variety of habitats where as, some species require specialized habitats
or extensive tracts of habitat to support a large range.
         Species such as raccoon, grey squirrel, opossum and striped skunk, are generalist
species, which are often able to thrive in urban and agricultural settings. Raccoons in
particular are more commonly referred to as “urban” wildlife and are observed frequently
in commercial and residential areas. Introduced species such as Norway rat and house
mouse also thrive in urban settings whereas other species such as coyote and white-tailed
deer may make occasional visits to urban lands.
         The larger tracts of mature forests within the watershed provide sheltered habitat
for more of the secretive mammals. Species such as porcupine, woodland jumping
mouse, white-footed mouse, red squirrel and flying squirrels inhabit the extensive tracts
of forests found above the Niagara Escarpment. Nationally and provincially rare species
such as the woodland vole and the southern flying squirrel, both considered species of
special concern, share these habitats. Large ranges for species such as bobcat and black
bear can also be supported within these forests. Bobcats have been documented in forests
within the Hilton Falls ESA whereas sighting of black bears have been recorded in the
upper reaches of the watershed as recently as 2006.
         Streams and wetlands throughout the watershed provide suitable habitat for
species such as mink, muskrat, long-tailed weasel, water shrew and beaver. The later of
which can also be found in beaver ponds in swamp forests across the watershed.
Conversely, escarpment rims, caves and crevices provide habitat for bats including the
little-brown bat, silver-haired bat, eastern pipstrelle and northern long-eared bat.


         The Sixteen Mile Creek watershed provides amble habitat for a wide array of fish
species to flourish. Fifty-four different species of fish have been recorded in the
watershed including sport and forage fish species as well as resident, migratory and
occasionally incidental species which may enter the creek from Lake Ontario.
         In the upper reaches of the watershed above the Niagara Escarpment, groundwater
discharge areas and old glacial spillways, provide suitable habitat conditions for species
such as brook trout and mottled sculpin. These cold, clear and gravelly streams provide
suitable spawning conditions for these species as well numerous minnow species
including northern redbelly dace and finescale dace. Downstream of the Niagara
Escarpment, coldwater conditions persists thereby providing suitable conditions for both
resident and migratory salmonids including brown trout, rainbow trout and chinook
salmon. Species such as rainbow darter, fantail darter and northern hog sucker also thrive
in this area.
         Smaller cold to coolwater tributaries in the upper to middle reaches of the
watershed provide suitable conditions for numerous species of minnow including reside
dace. This species, a species of special concern nationally and threatened provincially,
relies on cool, clean water, with dense, overhanging herbaceous vegetation in order to
live out its life cycle. It is commonly associated with other species such as creek chub
and common shiner, both of which may inadvertently build redds that are used by redside
dace during spawning. Other small warmwater tributaries throughout the watershed
provide habitat for numerous forage fish including brook stickleback, blacknose dace and
creek chub. The later two species are tolerant to a wide array of conditions and can be
found throughout the watershed, including in urbanized and disturbed reaches.
         In the mid to lower reaches of the watershed, cool to warmwater conditions
dominate and provide habitat for species such as white sucker, longnose dace, largemouth
bass and rock bass. Large, slow-moving pools provide amble habitat for species such as
pumpkinseed, black crappie and the exotic common carp whereas, rocky substrates and
riffles provide conditions suitable for smallmouth bass, stonecat and river chub. The
rocky shores within a few kilometers of the mouth of the creek also provide habitat for
the exotic and invasive round goby, which was first recorded in the watershed in 2005.
The Oakville marsh, located near the mouth of the creek provides suitable conditions for
species such as largemouth bass and northern pike to spawn and also acts as a migratory
corridor for other Lake Ontario species. Numerous species of shiner and minnow also
inhabit this area including the silver shiner, a species of special concern both nationally
and provincially.

Species at Risk

        Within Canada 487 different species are designated by the Committee on the
Status of Endangered Wildlife in Canada (COSEWIC) as Species at Risk. Species
considered to be at risk are those that are affected by particular stressors, largely human
influenced that may affect the long term survivability of the species. These species
typically have unique life cycles or characteristics and are easily affected by other
stressors including habitat destruction, genetic or reproductive isolation, climate change,
over harvesting, disease, increased human disturbance and invasive species.
        Within Ontario 173 of the designated species can be found. In addition, many
species that may not be at risk at a federal level may still be at risk on a provincial scale.
In these instances species are then assessed by the Committee on the Status of Species At
Risk in Ontario (COSSARO). Species considered to be at risk both within Ontario as well
as federally are protected under federal legislation, specifically the Species At Risk Act,
which protects both the species and its critical habitat once identified through an
approved recovery plan. Additional legislation that may affect species at risk in Ontario

               • Canada Wildlife Act
               • Migratory Bird Convention Act
               • Fish and Wildlife Conservation Act
               • Wild Animal and Plant Propagation and Regulation of International
                 and Inter-provincial Trade Act
               • Canadian Environmental Assessment Act
               • Fisheries Act
               • National Parks Act

        Within the Sixteen Mile Creek watershed 23 species at risk have been
documented. These species live in a variety of habitats ranging from urban lands to
escarpment cliffs and forests. Protection of these species within the watershed is a
priority and recovery teams for both Jefferson Salamander and Redside Dace are in the
recovery planning stages. For a list of species at risk found within the Sixteen Mile Creek
watershed see table 4.

  Table 4: Species at Risk within the Sixteen Mile Creek Watershed.

  Common Name            Scientific Name        S Rank      COSEWIC     COSSARO
                                                              status      status
American hart’s-      Asplenium              S3            SC          SC
tongue fern           scolopendrium
Cerulean warbler      Dendroica cerulea      S3B,SZN       SC          SC
Red-shouldered        Buteo lineatus         S4B,SZN       SC          SC
Hooded warbler        Wilsonia citrinia      S3B,SZN       THR         THR
Least bittern         Ixobrychus exilis      S3B,SZN       THR         THR
Acadian flycatcher    Empidonax virescens    S2B,SZN       END         END
Black tern            Chlidonias niger       S3B,SZN       NAR         SC
Louisiana             Seiurus motacilla      S3B,SZN       SC          SC
Northern bobwhite     Colinus virginianus    S1S2      END             END
Peregrine falcon      Falco peregrinus       S2S3B,SZN THR             END-R
Red-headed            Melanerpes             S3B,SZN   SC              SC
woodpecker            erythrocephalus
Prothonotary          Protonotaria citrea    S1S2B,SZN END             END-R
Jefferson             Ambystoma              S2            THR         THR
salamander            jeffersonianum
Redside dace          Clinostomus            S3            SC          THR
Silver shiner         Notropis photogenis    S2S3          SC          SC
Southern flying       Glaucomys volans       S3            SC          SC
Woodland vole         Microtus pinetorum     S3?           SC          SC
West Virginia white   Pieris virginiensis    S3                        SC
Monarch               Danaus plexippus       S4            SC          SC
Blanding’s turtle     Emydoidea blandingii   S3            THR         THR
Common map turtle     Graptemys              S3            SC          SC
Milk snake            Lampropeltris          S3            SC          SC
Eastern ribbonsnake   Thamnophis sauritus    S3            SC          SC


Marsh Monitoring- Marsh Monitoring Program

        Monitoring of marsh habitats involves the monitoring of marsh birds and frogs at
different times during the spring and summer months. Both marsh birds and frogs can be
used as biological indicators of marsh health as both entities rely on healthy marsh
ecosystems to live out a portion of their life cycle. The presence or absence of particular
marsh species can aid in determining potential impacts to these sensitive wetland
         Marsh monitoring was completed using Environment Canada/Bird Studies
Canada’s Marsh Monitoring Program (MMP) in the spring of 2005 and 2006. Frog
surveys were completed three times, with 15-day intervals, between March 15th and July
31st at identified sites. At each site, samplers listened to frog calls for a period of 3
minutes and recorded the species approximate locations, within a semi-circular station,
and the intensity of their calls. Additional information including air temperature, habitat
conditions and vegetation communities was also recorded. Bird surveys were completed
at the same stations twice between May 20th and July 5th with a 10-day interval between
surveys. Sites were surveyed for ten minutes using a broadcast tape to elicit calling from
a variety of species of birds. Birds identified within a semi-circular station, had their
approximate location mapped and classified as observed, aerial forager or outside/fly
         Monitoring for marsh frogs and marsh birds was completed as part of the Sixteen
Mile Creek Monitoring Project at two sites within the Hilton Falls Conservation Area.
Station A is located within the Hilton Falls off the Red Oak Trail at the northeastern end
of the Hilton Falls Reservoir and is surveyed at the southwestern portion of the marsh.
The marsh is small in size with limited amounts of open water. The vegetative
community is dominated by herbaceous emergent vegetation, largely cattails (Typha sp.)
as well as grasses, sedges (Carex sp.), arrowhead (Sagittaria sp.) and jewelweed
(Impatiens sp.). A thick buffer of deciduous trees and shrubs surrounds majority of the
marsh. Station B is located on the Beaver Dam trail located north of the Hilton Falls
reservoir. This small marsh is dominated largely by open water with herbaceous
emergent vegetation with shrubs bordering the edges of the marsh. Dense stands of
cattails are abundant throughout this marsh although a small number of sedges, and other
wetland species such as Iris sp. and Eupatorium sp. are also found. Landuses potentially
affecting both marshes include the presence of an active quarry, extensive trail systems,
and on-going beaver activity, the later of which is known to affect marsh habitat and
water levels throughout the area.


        Marsh surveys were completed at both station A and station B within Hilton Falls
Conservation Area from 2001-2002 and 2004-2006. Surveys ranged in the identification
of 3-5 amphibian species from year to year with a total of 7 species identified at both
stations over the sampling period. Species captured at both sites show a range of

tolerances and associations both to marsh and woodland habitats. Of the seven species
observed over the 5 years of surveys, three of those species particularly the chorus frog,
spring peeper and Northern leopard frog are considered species indicative of high quality
marsh habitat. Spring peeper, along with green frog was also considered the most
abundant species, being recorded at both stations for each of the years surveyed. In
general, species abundance ranged from moderate to high levels with calling codes
ranging from 1 (individual species identified) to 3 (full chorus).
        Only two species recorded in Halton were not recorded during any of the marsh
monitoring surveys. Wood frog, a species heard calling in very early spring has been
recorded within the Hilton Falls Conservation Area although it was not recorded during
these surveys. The bullfrog, a less commonly found species, has not been recorded in the
area since before 1990 (Macadam, 1999).

        A number of marsh birds were also observed at both stations within the Hilton
Falls Conservation Area. Over the five-year sampling period approximately 28 species
have been recorded at station A with 31 species being recorded at station B. On average
approximately 9-10 species are recorded at each station per year. Of the species
recorded, the vast majority of birds recorded at both stations are classified as non-aerial
foragers such as swamp sparrow, common yellowthroat and veery while water foragers
such as mallard, pied-billed grebe and wood duck were also observed. Aerial foragers
such as tree swallow, eastern kingbird and Eastern wood pewee were less commonly
observed as their presence varied from one year to the next. Numerous marsh nesting
birds were observed with common yellowthroat, red-winged blackbird and yellow
warbler being the most commonly encountered marsh nesters as they were present in
almost each survey year.
         Of the birds surveyed over the five-year sampling period, four species considered
indicative of high quality marsh habitat were observed. American bittern, least bittern
and pied-billed grebe were each recorded in 2004 at station B, whereas Virginia Rail was
recorded at both stations in 2004 and again at Station B in 2002 and 2006. The presence
of least bittern is especially important as this species is considered a threatened species
both federal and provincially as it relies on high quality marsh habitat (NHIC website,

        Overall, marsh health at stations A and B within the Hilton Falls Conservation
Area indicates that there is no strong evidence of impairment. The presence of three
amphibian and four bird indicator species also indicates the marshes has high quality
habitat capable of sustaining sensitive species. Various changes to the marsh amphibian
and bird community vary from one year to the next, which may be a result of either
natural fluctuations in the communities or potential fluctuations in water levels within the
marsh habitats. The Hilton Falls Conservation Area has had on-going beaver problems
for many years, which has resulted in the creation and alteration of numerous marsh
habitats throughout the park. Future monitoring of the sites should include the
monitoring of water levels to determine if community composition changes according to
water levels within the marsh.

Forest Bird Monitoring - Forest Bird Monitoring Program

        Forest bird monitoring is used to monitor Ontario breeding bird species in large
woodlots across Ontario. Stations designated in woodlots are a minimum of 100m from
the forest edge, in order to sample species dependent on interior forest habitat. Interior
bird species can be used as indicators of forest health as they rely on large tracts of forest
habitat that are significant distances from edge-effects such as noise, air and water
pollution, parasitism, exotic/invasive species and increased development and vegetation
clearing. Bird community composition can be compared over time to determine potential
habitat-specific effects on breeding bird populations.
        Forest bird monitoring was completed using the Forest Bird Monitoring Program
(FBMP), first initiated in 1987 by the Canadian Wildlife Service. Surveys were
completed in large woodlots (min 4ha) with each station a minimum of 100m from the
forest edge. Stations were visited twice during the breeding season between the dates of
May 24-June 17 and June 13-July 3 with at least six days between each survey.
Sampling was completed during the early morning hours with relatively calm, clear
weather conditions. At each station, the sampler used a point-count method whereby all
birds seen or heard during a ten-minute period was documented and mapped on a field
card. Additional information including the highest level of breeding evidence as well as
wind speed and direction were also recorded.
        Forest bird populations were monitored in the summer of 2006 as part of the
Sixteen Mile Creek Monitoring Project. Sites selected, which met the criteria for the
Forest Bird Monitoring Protocol, were sampled in the large woodlots associated with the
Hilton Falls Conservation Area.


        Five stations were sampled within the Hilton Falls Conservation Area in the
summer of 2006. A total of 17 different bird species were observed with various degrees
of breeding behaviour noted. Of the species observed, 5 species (Black-throated green
warbler, hermit thrush, ovenbird, scarlet tanager and veery) are considered to be
indicative of healthy interior forest habitat as they are particularly sensitive to outside
stressors including invasive species, nest parasitism, increased development and clearing
of vegetation. Of the other species observed, black-capped chickadee, red-eyed vireo,
wood thrush, and yellow-bellied sapsucker were also considered to be indicative of large
woodlands, however these species may also be found nesting in edge habitats and in
smaller woodlots. Species indicative of small woodlots and edge habitats, such as
American robin, blue jay and ruby-throated hummingbird were also observed. All
species observed in the 2006 study, had been previously noted by Paton and Sharp as part
of a biological inventory of Halton Region Conservation Authority Properties in 1979.

Forest Health -Ontario's Niagara Escarpment (ONE) Monitoring Program

       In 1996, a 1 hectare forest biodiversity monitoring plot was established within the
Hilton Falls Conservation Area through a partnership between Conservation Halton, the

Niagara Escarpment Commission's ONE Monitoring Program and the University of
Waterloo. This year (2006) marked the 3rd inventory of this plot.
        Within the plot, 3rd year University of Waterloo Environmental Studies students
and ONE Monitoring Program staff recorded tree species type, diameter-at-breast height
(dbh), status (alive/dead) and height class (dominant, co-dominant, intermediate,
suppressed) of all trees >4cm dbh. Tree health (e.g. crown vigour, stem defects) were
assessed for randomly selected trees. Ground cover and shrub/saplings were also
sampled. The plot is part of a national and international network of Ecological
Monitoring and Assessment Network (EMAN) plots. Standardized protocols for data
collection, endorsed by EMAN, were applied so that data can be shared amongst
organizations and is comparable to other forests plots across Ontario.
        Now that three inventories have been completed, data analysis will be undertaken
to assess change over time within the plot over the past 10 years. The Hilton Falls plot is
1 of 5 "control", or relatively undisturbed plots, that the Niagara Escarpment Commission
monitors on a 5-year rotational basis. It is intended that the program be expanded to set
up 'pressure' plots for examining the impacts of development on forest health and
biodiversity. The Hilton Falls plot will provide baseline information for these types of
data comparisons.
        In addition to forest plot monitoring, a new ONE Monitoring Program initiative to
examine landscape-level forest cover change was launched in the fall of 2006. A
methodology is being developed and refined to examine forest cover change within the
Niagara Escarpment Plan Area, and to compare these results to forest preservation and
fragmentation outside the Plan Area. This landscape level analysis is scheduled for
completion for the Halton Region in 2007.


Fish Community Monitoring

        Fish communities can be used as indicators of local, temporal environmental
conditions such as in-stream habitat, water quality and water temperature. Comparisons
based on fish community composition may provide an assessment of local aquatic
environment conditions, thereby indicating alterations to instream habitat and water
quality. The presence or absence of specialized and/or rare species may also aid in
assessing potential perturbations to the aquatic environment.

Historical Sampling

       Only two watershed wide fisheries studies have been completed on the Sixteen
Mile Creek watershed to date. In contrast, numerous site and reach specific studies have
been completed in recent years, typically associated with urban developments and
regional projects/planning. Information regarding the two watershed studies is provided

Sixteen Mile Creek Conservation Report
(Department of Planning and Development, 1958)

        The Sixteen Mile Creek Conservation Report was the first and most
comprehensive watershed study encompassing the area and was completed by the
Department of Planning and Development in 1958. Fisheries studies completed as part of
the study were completed in 1957, resulting in sampling at approximately 105 stations
spread across the watershed. Thirty different species of fish were recorded during the
survey including brook trout, smallmouth bass, and yellow perch. Exotic species such as
sea lamprey and alewife were caught at single stations. Of special interest is the wide
distribution of redside dace, captured at 25 of the 100 stations within the watershed. The
only species documented in the study with a larger distribution include (in decreasing
order): creek chub, blacknose dace, fathead minnow, brook stickleback, white sucker,
common shiner and bluntnose minnow, all of which are widespread across the watershed

Oakville Creek Inventory Report
(R. L. Isbester, 1975)

        The Ontario Ministry of Natural Resources completed this study in 1975, which
saw the sampling of 19 stations across the watershed. Additional information collected at
each station included chemical parameters and physical parameters of the water, stream
bed and surrounding terrain. Benthic invertebrates were also collected however, no
information regarding species or community composition is included within the report.

Sixteen Mile Creek Watershed Plan: Halton Urban Structure Plan
(EcoPlans Ltd. 1995)

       EcoPlans limited completed this study in 1995 in support of the Halton Urban
Structure Plan. A total of 17 stations spread across the watershed were sampled for fish
with another nine stations sampled for benthic macroinvertebrates. Thorough habitat and
spawning information for each reach sampled is also included within the study.

        Additional studies and annual monitoring sites have been compiled into the
Conservation Halton Fisheries Database. As a result, information for 412 stations has
been compiled across the watershed for use in this report. It should be noted that
information collected has been collected utilizing a variety of methodologies and capture
efficiencies and as a result, comparisons and detailed analysis between sites may not be

Fish Community Sampling Protocol

        Widespread fish community monitoring was completed as part of the Sixteen
Mile Creek Monitoring Project in the summer and fall of 2005. Fish were collected
according to the Ontario Stream Assessment Protocol (OSAP) using a backpack
electrofishing unit and certified operators. Station designation followed the OSAP

protocol with the majority of stations starting and ending at a stream crossover with a
minimum station length of 40m. Some stations did not meet the specific criteria and
slight modifications to the station length and/or number of crossovers had to be made.
Additional modifications to the sampling methodology included the addition of seine
blocker nets on the upstream and downstream limits of the station. This was added due
to stream width and associated capture efficiencies thereby ensuring that fish that initailly
escaped the electrical field could not emigrate out of the defined station area.
         Fisheries sampling progressed in an upstream manner, systematically sampling all
available habitats. Electrofishing seconds were standardized at the OSAP screening
level, thereby ensuring that each square metre of stream was electrofished for
approximately 2-5 seconds. Information collected was analyzed using an Index of Biotic
integrity (IBI), adapted from Steedman (1988).
         A total of 33 stations were sampled as part of fish community monitoring in 2005.
In addition to fisheries monitoring, benthic community monitoring (OBBN protocol) and
channel morphology assessments (OSAP -point transect methodology) were completed at
the same stations where suitable. Four stations within the watershed were also sampled
monthly as part of the provincial water quality monitoring network, administered by the
Ministry of the Environment (MOE).

Fish Community

    Approximately 54 species have been recorded within the Sixteen mile Creek
watershed (Conservation Halton Fisheries Database, 2006) however, over the 2005
sampling period only a total of 33 species were encountered. Fish community
composition was dominated by tolerant species such as blacknose dace, creek chub and
white sucker found at 73, 67 and 55 percent of stations respectively. Benthic species
such as rainbow darter, Johnny darter, stonecat and fantail darter were the next most
common species encountered at 52,42, and 36 percent respectively. Sensitive species
known to inhabitat the Sixteen Mile Creek watershed, such as redside dace and brook
trout, were not captured during the 2005 study however other sensitive species such as
mottled sculpin, smallmouth bass and central stoneroller were observed albeit in small
numbers. These species were observed only at stations considered to be reflective of
their individual preferred habitats as outlined in Scott and Crossman (1973). The
remaining 26 species were found at less then 35% of stations with eleven of those species
found at less then 10% of the stations sampled.
      Fish community structure throughout the watershed has shown a slight shift since
the original watershed study in 1957 as fifteen of the species (including mottled sculpin,
river chub, central stoneroller, emerald shiner, fantail darter, rainbow darter, northern
pike, largemouth bass, black crappie, brook stickleback, as well as the introduced
rainbow trout and brown trout and the exotic goldfish, common carp and round goby)
encountered in the 2005 study were not captured in the original 1957 watershed study
(Department of Planning and Development, 1957). In contrast nine species (including
sea lamprey, alewife, brook trout, golden shiner, redside dace, lake chub, hornyhead
chub, rosyface shiner and yellow perch) captured in the 1957 study were not captured in
the 2005 study. Figure 9 and figure 10 illustrates species distribution within the Sixteen
Mile Creek watershed in 1957 and 2005 respectively. In comparison, the 2005 sampling

indicates that species diversity has slightly increased with a larger variety of species
being captured at an increased number of sites. Based on the biological communities and
representative habitats described in Trimble et. al. (1999) the overall changes in species
distribution indicates an overall shift towards diverse and/or tolerant warmwater
communities although tolerant and intolerant coldwater communities do still exist.
    Of special interest is the presence of Round gobies within the Sixteen Mile Creek
watershed. Specimens were captured in the lower reaches of the creek in the vicinity of
Cross Avenue and Speers Road in early August 2005, marking the first records of this
species in the watershed. Subsequent presence/absence sampling downstream from
Speers Road to the mouth of the creek found numerous individuals indicating that round
gobies in the lower reaches of the creek are abundant and likely thriving. This is
particularly daunting for the watershed as round gobies are extremely invasive and are
able to out compete native benthic species such as darters and sculpins. These species
and their preferred habitats are widespread across the watershed, and since they share the
same ecological niche as round gobies, opportunities now exist for gobies to spread and
thrive across the Sixteen Mile Creek watershed. In order to reduce disruption to the fish
community and prevent spread of this species further upstream it is essential that further
monitoring and removal programs be explored.

Figure 9: Frequency distribution of individual fish species captured in 1957, adapted
from the Sixteen Mile Creek Conservation Report (Department of Planning and

                                                     Frequency Distribution of Individual Fish Species (1957)

                                  Yellow perch

                                 White sucker


                              Smallmouth bass

                                 Sea Lamprey

                               Rosyface shiner

                                    Rock bass

                                 Redside dace


    Northern redbelly dace

                      Northern hog sucker

                               Longnose dace
     Species Common Names

                                    Lake chub

                                 Johnny darter

                               Hornyhead chub

                                 Golden shiner

                              Fathead minnow

                                   Creek chub

                               Common shiner

                            Central mudminnow

                                   Brook trout

                                Brassy minnow

                             Bluntnose minnow

                               Blacknose dace


                                                 0   10       20      30       40       50       60       70    80   90
                                                                           Percent of Stations

Figure 10: Frequency distribution of individual fish species captured in the Sixteen Mile
Creek Monitoring Project (2005).

                            Frequency Distribution of Individual Fish Species (2005)

                              White sucker
                           Smallmouth bass
                               Round goby
                                Rock bass
                                River chub
                             Rainbow trout
                            Rainbow darter
                                Notropis sp.
                     Northern redbelly dace
 Fish Common Names

                              Northern pike
                       Northern hog sucker
                             Mottled sculpin
                            Longnose dace
                          Largemouth bass
                             Johnny darter
                      Fourspine stickleback
                          Fathead minnow
                              Fantail darter
                             Emerald shiner
                               Creek chub
                            Common shiner
                             Common carp
                         Central stoneroller
                       Central mudminnow
                       Carps and minnow s
                               Brow n trout
                            Brow n bullhead
                          Brook stickleback
                           Brassy minnow
                         Bluntnose minnow
                            Blacknose dace
                              Black crappie
                                               0   10   20       30      40       50   60   70   80
                                                             Percentage of Stations

Index of Biotic Integrity

        Fish community monitoring was assessed using a modified Index of Biotic
Integrity first adapted to Southern Ontario Streams by Steedman in 1988. This
methodology measures fish community associations to identify the general health of a
stream ecosystem based on its upstream drainage area. Steedman’s original IBI utilizes
ten different indices including indicators species, trophic composition and fish abundance
and health. Although these metrics are useful indicators of stream health all indices may
not be suited to all streams. In order to use the IBI analysis for both warmwater and
coldwater tributaries within the Sixteen Mile Creek watershed, two sub-indices were
modified to better suit current stream conditions. The first sub-indice removed was the
presence of blackspot, a common parasite of fish. Although this may affect stream fish it
does not necessarily reflect unhealthy stream conditions and as such was removed from
the analysis. The second sub-indice modified, the presence or absence of brook trout,
was removed to better reflect stream conditions where brook trout would not naturally
occur (i.e. warmwater tributaries). It is noted that historically brook trout would have
likely covered the vast majority of the watershed, as was Steedman’s assumption with the
IBI, but again the absence of brook trout from a station does not necessarily indicate
unhealthy conditions. In order to account for the removal of these sub-indicess, IBI
scores for coldwater stations were based on nine sub-indices whereas warmwater stations
were based on 8 sub-indices and were transformed for direct comparison with coldwater
stations, as was done in the Humber River Fisheries Management Plan (2005). Indices
used to form the Index of Biotic Integrity are found below:

   • Number of native species
   • Number of darter and/or sculpin species
   • Number of sunfish and/or trout species
   • Number of sucker and/or catfish species
   • Presence of absence of brook trout (coldwater stations only)
   • Presence or absence of Rhinichthys species
   • Percent of sample as omnivores
   • Percent of samples as piscivores
   • Catch per minute of sampling

    Index of Biotic integrity analysis was used to determine stream health at 32 stations
across the watershed. Using the modified IBI, stations were scored and categorized as
either poor (score of 9-20), fair (21-27) good (28-37) and very good (38-45) based on
predicted species richness metrics, indicator species, trophic composition and fish
abundance. Scores fell in various ranges indicating varied stream health across the
watershed as expected. Figure 11 illustrates the distribution of IBI scores for all stations
sampled within the watershed.

Figure 11: Frequency distribution of Index of Biotic Integrity scores at stations sampled in 2005.

                                                 Frequency Distribution of IBI Scores for Stations Sampled in 2005



 Number of Stations





                          9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45
                                                                              IBI Scores

         Scores for 2005 ranged from 13 to 32 resulting in a range in stream health from
“poor” to “good”. Majority of stations (13) fell within the “fair” range with twelve
stations classified as “poor”, and seven stations classified as “good”. No stations fell
within the “very good” category. Stations considered to be in “poor” condition were
largely associated with areas of increased urbanization or other large-scale disturbances
(i.e. wastewater treatment plants and reservoirs). In contrast, stations that were
considered to be in “good” condition were largely found above the Niagara Escarpment
in relatively naturalized or rural areas. Stations considered to be in “fair” condition were
spread throughout the watershed. Table 5 and figure 12 illustrates the distribution of IBI
scores for each sub-watershed. Although the majority of stations fell within the “fair”
range, each sub-watershed with the exception of the East Branch and Middle East
Branch, had at least one station considered to be in “poor” condition. In contrast, only
the Upper West Branch, Middle Branch and Middle East Branch had stations that were
considered to be in “good” condition.
         Overall, fish biotic integrity throughout the watershed is limited, however
numerous opportunities exist for improvements to be made. Observations made during
sampling indicate that highly productive fish habitat is restricted throughout a vast
majority of the watershed. Substantial riffle/pool sequences do exist, however additional
refuge habitat, woody debris, undercut banks and large boulders are limited in some
areas. As a result, the existing fish habitat favours benthic fish species but limits species
within different habitat guilds. Providing diverse fish habitat will aid in increasing both
productivity and diversity within the watershed.

Table 5: Distribution of IBI scores for each sub-watershed within the Sixteen Mile Creek
watershed (2005).

Sub-watersheds                                            IBI Scores
                                     9 to 20      21 to 27       28 to 37       38 to 45
Upper West Branch                       1 (25%)                       3 (75%)
West Branch                             3 (38%)        5 (63%)
Middle Branch                           1 (50%)                       1 (50%)
Middle East Branch                                     1 (25%)        3 (75%)
Lower Middle Branch                     2 (50%)        2 (50%)
East Branch                                           1 (100%)
East branch Lisgar                      1 (50%)        1 (50%)
Lower Branch                            1 (33%)        2 (67%)
Urban Diverted Tributaries              3 (75%)       1 (25%)

In-stream Temperature Monitoring

        In-stream temperature monitoring was completed in the summer of 2005 and
2006 using a rapid assessment methodology detailed in Stoneman and Jones (2001). This
methodology was developed to determine the presence and locations of coldwater,
coolwater and warmwater habitats throughout Southern Ontario.
        The sampling methodology requires two to three days of relatively stable, warm
weather and no precipitation with a daily maximum temperature above 24.5°C. Water
temperatures are then taken at accessible stations between 4:00 and 4:30pm. The
resulting measurements represent the maximum daily water temperature at that location.
Results are then compared to the maximum daily air temperatures (obtained from nearby
weather stations) and compared to thermal graphing, which classifies stream
temperatures as warmwater, coolwater or coldwater. Coldwater stations are classified as
stations with average maximum temperatures around approximately 14°C, with coolwater
averaging about 18°C, and warmwater at temperatures at or above 23°C. It is important to
note that this methodology is limited in that it only identifies water temperature in site
specific locations and may not identify potential thermal refugia, groundwater upwellings
or areas of thermal stress.
        Major stream crossing throughout the watershed were sampled in the summer of
2005. Temperatures obtained were compared against the daily maximum temperature in
Milton, the central monitoring location for air temperature in the area, and were then
classified as warm, cool or cold based on thermal graphing. Stations sampled and their
resulting temperature classifications can be seen in figure 13.

Benthic Community Monitoring-Ontario Benthos Biomonitoring Network

        Benthic macroinvertebrates are stream dwelling organisms that utilize the
substrate of a watercourse or waterbody for a portion of their life cycle. These organisms
are often used as indicators of water quality and in-stream habitat as they are
continuously subjected to local environmental stressors and show a wide range of
tolerances to pollution and habitat. These indicators are specifically useful as they have
the potential to identify impairments to water quality that may be missed with periodic
chemical analysis. Although some benthic invertebrate monitoring has been completed
for specific projects within the watershed, no widespread sampling of the Sixteen Mile
Creek watershed has been completed prior to this study.
        Benthic community monitoring used the Ontario Benthos Biomonitoring Network
Protocol (OBBN). This protocol uses the “reference condition” approach, whereby sites
are compared to previously selected reference sites, sites typically defining normal
biological conditions for a given habitat. These reference sites are selected based on their
minimal influence from human activity including factors such as point-source
contamination, loss of riparian habitat and aquatic habitat disruption (Jones, 2004).
        Samples collected in 2005 were used to identify stream health across a reach. In
doing so, three transects were sampled at each station; two in stream crossovers (riffle
habitat) on the upstream and downstream limits of the station and a third transect across
pool habitat, between the two crossovers. Samples were collected via the kick and sweep
method across a stream transect thereby sampling all available habitats. The sampler,

standing upstream of a D-net, excavated the top 10 centimetres of sediment with their
feet, allowing any attached and free moving benthic invertebrates to flow into the 500µm
D-net. Once collected, live samples were then taken back to the lab and randomly sub-
sampled. A minimum of 100 organisms were collected per sub-sample (transect) with all
samples being identified to family level for analysis (Jones, 2004).
         Data analysis and interpretation followed a number of indices including the %
EPT (ephemeroptera, trichoptera and plecoptera), taxa richness, % oligochaeta, %
chironomidae, % isopoda, % gastropoda, % diptera, % insect, Hilsenhoff index and the
Shannon-Weiner diversity index. Each indice was assessed separately against the target
values seen in table 6. Final assessments of unimpaired, potentially impaired or impaired
were based on the cumulative results of each individual metric.

Table 6: Target values for selected benthic indices.

       Water Quality          Unimpaired           Potentially           Impaired
           Index                                    Impaired
     EPT                          >10                 5-10                  <5
     Taxa Richness                >13                                      <13
     % Oligochaeta                <10                10-30                 >30
     % Chironomidae               <10                10-40                 >40
     % Isopoda                    <1                   1-5                  >5
     % Gastropoda                1-10               0 or >10               >10
     % Diptera                   20-45            15-20 or>50           <15 or >50
     % Insect                    50-80           40-50 or 80-90         <40 or >90
     HFI                          <6                   6-7                  >7
     SDI                          >4                   3-4                  <3

        Sampling of the 28 sites in 2005 resulted in the collection of 70 different taxa
spread across the watershed. Individual families including chironomidae,
hydropsychidae and elmidae were the most abundant families encountered and were
collected at almost every station sampled. Sensitive families such as chloroperlidae and
leuctridae were less common and were only encountered at one station each. In total, 13
sites were considered unimpaired, 9 as potentially impaired and 6 as impaired. Stations
considered impaired typically had low EPT, a high percentage of isopods, a low
percentage of diptera and low SDI values. These stations were typically associated with
environmental stressors including reservoirs, urban development and habitat alterations.

         Figure 14 and table 7 illustrates the distribution of stations and their associated
classifications across each subwatershed. Trends in impairment were seen across the
watershed with urban sub-watersheds showing higher levels of impairment then in more
naturalized sub-watersheds. This is evident within the urban diverted tributaries, where
all stations sampled were considered impaired. In contrast, majority of stations sampled
in the upper west branches of the watershed, where urbanization is limited, were
considered unimpaired with only one station, located directly downstream of the 401,

considered potentially impaired. Similarly, stations sampled in areas with naturalized
floodplains and undisturbed valleys showed minimal signs of impairment. Potential
cumulative effects from impaired areas upstream were also reduced in the lower reaches
of the watershed where healthy riparian buffers and amble amounts of cobbles and
gravels produced conditions suitable for an unimpaired benthic community.
                The overall benthic community for the watershed is generally healthy but
does indicate levels of impairment associated with particular stressors. In areas where
environmental stressors are minimal, the wide array of rocks, gobbles and organic matter
in the creek provide suitable conditions for benthic invertebrates to flourish.

Table 7: Distribution of impairment across sub-watersheds within the Sixteen Mile
Creek watershed.

Subwatersheds            Unimpaired        Potentially Impaired           Impaired

Upper West Branch              2 (66.7%)                  1 (33.3%)
West Branch                    3 (37.5%)                  5 (62.5%)
Middle Branch                    1 (50%)                                          1 (50%)
Middle East Branch               1 (25%)                   1 (25%)                2 (50%)
Lower Middle                    3 (75%)                    1 (25%)
East Branch                     1 (100%)
East branch Lisgar
Lower Branch                   2 (66.7%)                  1 (33.3%)
Urban Diverted                                                                   3 (100%)

Water Quality-Provincial Water Quality Monitoring Network

        Surface water quality was sampled in 2005 as part of the Provincial Water Quality
Monitoring Network (PWQMN) at five stations within the Sixteen Mile Creek
Watershed. The stations sampled were sampled in periods of wet and dry events and
spread throughout the watershed in order to determine surface water quality in the major
branches of the watershed. Results of the sampling were compared with specific water
quality objectives for aquatic health. Information, where available, was also compared
with historical sampling events to determine if any outliers in information could
determine potential impairments to surface water quality.
        Results are based on 18 parameters measured between 2002 and 2005 between the
months of March and October. Of all samples tested, most of the samples meet the PWQ
objectives for the selected parameters with 95% of the samples below the objectives and
only about 5% of the samples exceeding the samples. Sample exceedences were
generally seen in the middle reach sections of the watershed within both the east and west
branches of the creek. At these locations, elevated levels of total kjedahl nitrogen
occurred 50% of the time, total phosphorous occurred 45% of the time and high levels of
turbidity were observed 10% of the time. Elevated levels observed at these stations likely
reflect agricultural and urban influences in the reaches upstream. In addition, strong
correlations were observed between rain events and increased turbidity indicating much
needed improvements to landuse practices upstream. In contrast, undisturbed reaches of
the creek, upstream of Kelso Reservoir, showed the best water quality even though all
stations sampled indicated elevated nutrient concentrations. Generally, water quality was
similar to the findings with the benthic and fisheries results indicating slight levels of
impairments in areas with increased urbanization or agricultural activities.


        An assessment of aquatic ecosystem health requires the cumulative assessment of
the parameters that make up a healthy aquatic ecosystem. When combined a holistic idea
of ecosystem healthy can be determined while variations in individual parameters may
provide further insight into potential stressors within the ecosystem. Table 8 indicates the
aquatic ecosystem health parameters examined to determine an overall sub-watershed
based assessment of ecosystem health. Reaches were then defined as having high,
moderate or low quality health based on the cumulative parameters. It should be noted
that these are generalized assessments based on a limited data set. Further sampling will
be required for detailed assessments.

Table 8: Parameters of Aquatic Ecosystem Health

    Parameters            High Quality         Moderate Quality          Low Quality
Fish community         Very Good/Good         Fair                    Poor
Water quality          Parameters regularly   Parameters              Parameters do no
                       meet PWQ               occasionally do no      regularly meet PWQ
                       objectives             meet PWQ                objectives
Benthic community      Unimpaired             Potentially impaired    Impaired
Thermal regime         Appropriate based      Marginal based on       Inappropriate based
                       on stream order and    stream order and        on stream order and
                       physiography           physiography            physiography
Natural channel        Natural channel        Some alterations to     Altered channel
                                              aquatic habitat
Riparian buffers       Well buffered          Buffers patchy or       Buffers absent or
                                              sporadic                sparse

Upper West Branch

        Benthic sampling indicates that water quality within this sub-watershed is
unimpaired with the exception of isolated areas in the vicinity of the 401 highway. In
contrast, fish community was considered to be good downstream of the 401, despite the
absence of brook trout and redside dace, which had been recorded in previous years. All
other fisheries stations were considered good with the exception of one station sampled
upstream in the vicinity of 6th Line, which was considered poor. This is likely attributed
to the capture of relatively tolerant species such as creek, chub, blacknose dace and
central mudminnows, rather then sensitive species such as brook trout, which was
predicted through the IBI. Thermal regime in the upper reaches of the sub-watershed
indicate that water temperatures are considered cool to cold, which is appropriate for
first-order streams associated with high permeability soils and limestone plains, whose
cracks and fissures result in cold-water springs dispersed throughout the area. These
features combined with the natural channels and the established buffers support a high
quality and healthy aquatic ecosystem.

West Branch

        The west branch originates directly downstream of Kelso Reservoir whose
warming influences are quickly reduced as a result of groundwater springs and coldwater
draining from the base of the Niagara Escarpment. Amble gravel and cobble originating
from old glacial spillways provide excellent spawning and rearing habitat for coldwater
species to thrive. Benthic conditions in the west branch are considered unimpaired
through this reach, however as one moves downstream, urban influences combined with
treated wastewater result in higher levels of impairment. The channel structure also
changes from a natural channel to a prismatic concrete channel with limited fish habitat
and a shift towards an impaired and tolerant fish community. Water quality samples
downstream of the plant occasionally meet PWQ objectives however nutrient levels are

consistently high resulting in increased algae growth downstream of the plant. As one
moves further downstream, the channel returns to a natural channel, with unstable banks
and erosion resulting from high fast flows coming out of the concrete channel. Riparian
buffers increase downstream however, limited overhead cover results in warming
temperatures. Overall, the west branch is considered to have a moderate level of aquatic
health, although high quality aquatic health is recognized in the reaches immediately
downstream of Kelso Reservoir and at the southern limited of the subwatershed within
the Sixteen Mile valley.

Middle Branch

        Limited amounts of sampling was completed within the Middle Branch sub-
watershed, however definite trends were observed on either side of the Scotch Block
reservoir were sampling was focused. On the upstream side of the reservoir coolwater
conditions, an unimpaired benthic community, a healthy fish community and naturally
forested stream channels indicate aquatic health is high. Downstream of the reservoir,
warming temperatures are evident however, groundwater emanating from the Niagara
Escarpment returns the creek to cool or coldwater conditions. Although coldwater
species are observed downstream of the reservoir, an impaired benthic community and
poor quality fish community are evident in the reaches immediately downstream of the
reservoir. Numerous habitat alterations and barriers were also observed downstream of
the dam, preventing fish migration upstream. However, it should be noted that these
barriers along with the dam associated with the Scotch Block reservoir do act to restrict
migratory species upstream where small tributaries are know to support populations of
native brook trout, thereby preventing competition between these two species. Further
downstream, barriers are limited and natural channel structure and buffers dominate the
reaches. Overall the middle branch is considered to have moderate to potentially good
health, as there are both pockets of high quality and poor quality conditions throughout
the sub-watershed. More detailed sampling is also recommended to determine if effects
of the Scotch Block reservoir is evident significant distances downstream.

Middle-East Branch

        Comprised of mainly first to third order streams, the Middle-East sub-watershed
is comprised of headwater areas that support a varied thermal regime. Warmwater and
cold to coolwater tributaries originate within the sub-watershed and support a diverse fish
community with a good level of biotic integrity. In contrast, benthic sampling indicates
impairments to both the water quality and stream habitat. This is likely a result of the
increased agricultural activities, which have caused increased sedimentation, unstable
banks and degraded stream channels from livestock accessing and crossing the creek in
numerous locations. The patchwork of agricultural and abandoned fields across the sub-
watershed results in patchy and sporadic naturally vegetated stream buffers, many of
which provide little overhead cover and shading. Overall, aquatic ecosystem health is
considered moderate to poor, however substantial opportunities exist to improve
conditions through implementing agricultural best management practices and improving
stream buffers throughout the sub-watershed.

Lower Middle Branch

         The lower middle sub-watershed is similar to the Middle-East branch in that it
also flows through a patchwork of agricultural fields, however additional influences from
at least three separate golf courses may have detrimental effects on the creek. Patchy
areas of riparian buffer provide little thermal relief for stream inhabitants and numerous
stream alterations and degraded habitats provide conditions suitable for opportunistic and
tolerant fish species. Benthic community results indicate that water quality is unimpaired
through this sub-watershed and water quality sampling regularly meets PWQ objectives
although some impairment is indicated with the higher levels of total kjedahl nitrogen,
total phosphorous and turbidity. This sub-watershed is considered to have moderate
quality of health however improvements to fish habitat and riparian buffers along with
the implementation of best management practices will help improve aquatic conditions
within this sub-watershed.

East Branch

        Limited sampling was completed within the east branch of the watershed. One
station in the upper reaches of the sub-watershed was sampled and was found to have a
diverse and highly productive, yet somewhat tolerant fish community, resulting in a fair
IBI grade. Benthic community sampling at the same station indicated that water quality
was unimpaired, however water temperature was classified as warm, which is not
expected for a first to second order stream. Increased urbanization upstream including
the addition of a stormwater pond, which outlets to the creek, may have an adverse affect
on upstream conditions. Riparian buffers throughout the reach are patchy and sporadic
and increased plantings would improve conditions. The aquatic ecosystem health is
considered to be in moderately good health however, further monitoring to determine
conditions downstream are recommended. In addition, it is suggested that this sub-
watershed be monitored as future urbanization directly within the headwater reaches may
result in further degradation.

East-Lisgar Branch

        Limited sampling was completed within the East-Lisgar branch as in-stream
conditions were not conducive to the sampling protocol used. Available fish sampling
within the reach indicates that the fish community is impaired, which is likely a reflection
of the altered stream channel and degraded and/or absent fish habitat along the 407
highway corridor. Instream is essentially absent as the new channel has been formed
within a bed of clay, thereby providing no suitable riffle, pool habitats, cobbles or woody
debris suitable for target benthic or fish species to thrive. The combination of the stream
conditions with stormwater management ponds and the routine use of the area by a large
number of waterfowl likely contribute to poor water quality conditions throughout the
subwatershed. This sub-watershed is considered to be in poor aquatic health.

Urban Diverted Tributaries

        The urban diverted tributaries are comprised of small first to third order streams,
which make up the historical Morrison Creek and Wedgewood Creek headwaters. The
natural channels within these reaches have been heavily altered due to urbanization and
agriculture in the upper reaches and diversion through a concrete channel in the lower
reaches. The middle reaches of these tributaries are relatively natural and confined to
large forested valleys. Unfortunately, encroachment on the valleys slopes, trampling of
the banks and fast flows from storm sewer outlets within the creek have resulted in an
extremely high degree of erosion and degraded instream habitat. Numerous attempts to
remedy erosion problems have resulted in the channels being inlaid with gabion baskets,
many of which have failed. Due to the poor habitat conditions both the fish community
and the benthic community is considered to be poor and impaired through the valley.
Regardless, the natural buffers within the valley provide ample shading and help to
maintain potentially coolwater conditions as expected within first to third order streams.
A cumulative review of the aquatic stressors indicates that this sub-watershed is in poor
aquatic health, however numerous opportunities exist to improve stream conditions
throughout the subwatershed.

Main branch

        The main branch of Sixteen Mile Creek encompasses the lowest reaches of the
creek to its confluence with Lake Ontario. The majority of this reach is protected within
a large valley, created from an old glacial spillway, that provides protection from direct
stressors, however cumulative effects from conditions upstream may be observed. In this
reach, the benthic community was considered unimpaired as the large amount of cobbles
and rocks provide suitable habitats for target benthic species. In contrast, the fish
community was considered to be of only fair to poor quality through this reach. This is
likely a reflection of the limited refuge habitat, woody material and large boulders that
provide habitat for a larger diversity of species. The naturally protected and largely
buffered channel provide suitable riparian habitats for the stream yet provide little
thermal relief to the already warmwaters of the creek. Provincial water quality sampling
within this reach indicates parameters occasionally meet PWQ objectives however
cumulative effects have been noticed within this reach with elevated nutrients,
phosphorous and turbidity. Elevated chlorides have also been observed at the mouth with
one sample exceeding 250 mg/L. This reach is still considered to be in moderately good
aquatic health. Since there is very little stressors directly within this sub-watershed, it is
important to note that the health of this sub-watershed is directly related to the health of
the watersheds above it and as health in these sub-watershed either improve or degrade,
similar conditions will likely be observed in the lower reaches.


A number of guidelines and habitat targets have been produced for watersheds within
Great Lakes Areas of Concern (AOC). Although the Sixteen Mile Creek watershed does
not currently fall within an AOC, guidelines outlined under Environment Canada’s
(2004) “How Much Habitat is Enough A Framework for Guiding Habitat Rehabilitation
in Great Lakes Areas of Concern” provide suitable, measurable and scientifically based
targets to ensure watershed health. The framework was designed to assist government
and non-government restoration practioners, planners and others involved in natural
heritage conservation and preservation in ensuring that there is adequate coverage of
natural wetlands, forests and riparian areas in order to sustain minimum viable fish and
wildlife populations and maintain ecosystem function (Environment Canada, 2004). The
most recent edition (2nd) provides 18 guidelines for wetland, riparian and forest habitats.
Of those 18, seven provide measurable targets, which have been included for assessment

Table 9: Watershed Restoration Guidelines. Adapted from Environment Canada (2004).

Parameter                      Target                         Rationale
Percent wetlands in            > 10% per major watershed      Increased wetland cover
watershed and sub-             > 6% per sub-watershed         regulates stream hydrology
watershed                                                     and water quality.
Percent Forest Cover in        >30% per major watershed       Increased ability to support
watershed and sub-             >10% per sub-watershed**       wildlife species
Size of Largest Forest Patch   >1, 200ha forest patch per     Increased ability to support
                               watershed                      a high diversity of wildlife
Percent of watershed that is   >10%                           Increased ability to support
100m from the forest edge                                     forest-interior species
Percent of watershed that is   >5%                            Increased ability to support
200m from the forest edge                                     forest-interior species
Percent of stream naturally    75%                            Maintain stream integrity,
vegetated                                                     may protect coldwater
Percent of urbanized         <10% imperviousness              Maintain stream integrity
watershed that is                                             and healthy aquatic
impervious                                                    community.
** Indicates Conservation Halton target.

Watershed based habitats targets were determined through the use of available ortho-
photography (dated 2002) and geographic information system (GIS) analysis and
compared against Environment Canada Guidelines. It is recognized that current
conditions may not be the same as those assessed using the 2002 orthophotography but

that this may provide baseline information which can then be used in the assessment of
future conditions. Assessment of the measurable guidelines is provided below.

Percent Wetlands in Watershed and Sub-watershed

         Increased wetland coverage within a watershed aids in regulating the hydrologic
cycle, provides habitat for a variety of flora and fauna and helps reduce air and water
pollution. The target of 10% wetland cover in a watershed reflects the need for wetlands
to stabilize the hydrologic cycle thereby reducing flooding, maintaining higher baseflows
and reducing the number of high and flashy flows. The target of 6% wetland coverage in
sub-watersheds reflects the need for wetlands dispersed across the landscape rather then
just within headwater areas.
         Large wetlands within the Sixteen Mile Creek watershed are limited to areas
above the Niagara Escarpment and as a result, wetland coverage is reduced in areas
below the escarpment. Although the percent wetland coverage for the watershed is
slightly above the target of 10 % at 10.59% (difference of +0.59%), wetland protection is
essential in maintaining current target levels. Additionally, three sub-watersheds have
wetland coverage below target levels. These sub-watersheds include the west branch, the
urban diverted tributaries and the main branch. Wetland management should focus on
maintaining and protecting wetlands above the Niagara Escarpment and significant
efforts to expand natural wetland cover in the west branch, urban diverted tributaries and
the main branch should be investigated.

Table 10: Percent Wetland Cover in the Sixteen Mile Creek Watershed and Sub-

Sub-watershed              Target (%)            Measured (%)          Difference (%)
Upper West Branch              6                    18.37                   12.37
West Branch                    6                     1.08                   -4.92
Middle Branch                  6                    14.63                    8.63
Middle East Branch             6                     7.48                    1.48
Lower Middle                   6                     3.93                   -2.07
East Branch                     6                     6.43                    0.43
East Branch-Lisgar              6                     4.64                   -1.36
Urban Diverted                  6                     1.03                    -4.7
Main Branch                     6                     0.67                   -5.33

Sixteen Mile Creek              10                    8.22                   -1.78

Percent Forest Cover

The amount of forest cover within a watershed directly relates to its ability to support a
variety of wildlife species. The target of 30% forest cover within the watershed ensures
that there is adequate forest cover to sustain species that rely on forest habitats,
specifically mammals and birds. The target of 10% forest cover per sub-watershed
ensures that forest cover is spread across the watershed rather then in localized areas.
Like the percent wetland coverage, forest coverage in the watershed falls largely above
the Niagara Escarpment although smaller, woodlots are spread across the landscape.
Percent forest cover for the watershed is approximately 20.18%, which does not meet the
Environment Canada target of 30% (difference –9.82%). Additionally, only three sub-
watersheds meet and exceed the Conservation Halton target for forest cover in the sub-
watersheds (10%). The remaining sub-watersheds have significantly less forest cover
then the targets indicating the need for additional rehabilitation and tree planting in those
areas. Forest management should look to expand forest cover in reaches below the
Niagara Escarpment.

Table 11: Percent Forest Cover in the Sixteen Mile Creek Watershed and Sub-

Sub-watershed                Target (%)            Measured (%)            Difference (%)
Upper West Branch                10                   49.12                    39.12
West Branch                      10                    9.97                     -0.03
Middle Branch                    10                   30.60                    20.60
Middle East Branch               10                   11.32                      1.32
Lower Middle                     10
Branch                                                  7.96                     2.04
East Branch                      10                     5.33                    -4.67
East Branch-Lisgar               10                     4.20                    -5.80
Urban Diverted                   10
Tributaries                                            8.43                     -1.57
Main Branch                      10                    19.28                     9.28

Sixteen Mile Creek               30
Watershed                                              20.28                    -9.72

Largest Patch Size

Larger patches of forest have a greater diversity of habitat niches and as a result are able
to support a larger diversity of species. The target of 200ha for patch size reflects the
need for large tracts of forests by specific interior forest species.
        Within the Sixteen Mile Creek watershed, the target for minimum patch size in
the watershed is exceeded by approximately, 3300 ha. This is a reflection of the larger
tracts of contiguous forest located above the Niagara Escarpment in the Upper West
Branch and the Middle Branch of the watershed. In contrast, below the Niagara
Escarpment, smaller tracts of forests result in discontinuous forests and smaller forest

Table 12: Largest Patch Size in the Sixteen Mile Creek watershed and sub-watersheds.

Sub-watershed               Target (ha)           Measured (ha)          Difference (ha)
Upper West Branch                                   2323.94
West Branch                                          155.62
Middle Branch                                       1191.05
Middle East Branch                                   102.79
Lower Middle                                         124.59
East Branch                                            13.15
East Branch-Lisgar                                     55.33
Urban Diverted                                         22.74
Main Branch                                           104.43

Sixteen Mile Creek              200                  3571.97                +3371.97

Percent of Watershed that is 100m and 200m from the forest edge

Interior forest habitat provides seclusion for specialized species that may be sensitive to
edge-affects such as air, noise and water pollution, aggressive invasive species,
parasitism and effects from vegetation clearing and development. Forests with large
tracts of interior forest habitat are able to provide suitable conditions for interior-
specialized species to life out portions of their life cycle. The target of 10% forest cover
100m from the forest edge and 5% forest cover 200m from the forest edge reflects
specific habitat needs for forest interior birds and mammals.
        Interior forest habitat within the watershed that is 100m and 200m from the forest
edge does not meet the targets of 10% and 5% respectively. However, it is important to
note that substantial amounts of interior forest habitat are represented in the Upper West
Branch and Middle Branch of the watershed. Interior forest habitat that is 200m from the
forest edge is also found in these two sub-watersheds. The large tracts of interior forest
habitat within these two watersheds, is largely associated with the Halton Forest North
and Halton Forest South. These forests form one of the largest tracts of contiguous forest
in the GTA. Little to no interior forest habitat is present in the remainder of the

Table 13: Percent of Interior Forest Habitat 100m from the Forest Edge in the Sixteen
Mile Creek Watershed and Sub-watersheds.

Sub-watershed              Target (%)            Measured (%)           Difference (%)
Upper West Branch                                   18.55
West Branch                                          0.99
Middle Branch                                        9.37
Middle East Branch                                   1.02
Lower Middle                                         0.39
East Branch                                           0.07
East Branch-Lisgar                                     0.5
Urban Diverted                                        0.13
Main Branch                                           1.59

Sixteen Mile Creek              10                    5.46                   -4.54

Table 14: Percent of Interior Forest Habitat that is 200m from the Forest Edge in the
Sixteen Mile Creek Watershed and Sub-watersheds.

Sub-watershed               Target (%)           Measured (%)           Difference (%)
Upper West Branch                                    9.58
West Branch                                          0.09
Middle Branch                                        4.19
Middle East Branch                                   0.13
Lower Middle                                         0.00
East Branch                                           0.00
East Branch-Lisgar                                    0.06
Urban Diverted                                        0.00
Main Branch                                           0.00

Sixteen Mile Creek               5                    2.52                   -2.48

Percent of Stream that is Naturally Vegetated

        Naturally vegetated riparian buffers provide protection to nearby streams by
reducing overland flows, reducing sediments and nutrients from entering the stream and
protecting the banks from erosion. The target of 75% reflects the need for streamside
protection from adjacent landuses in order to maintain stream integrity.

Table 15: Percent of naturally vegetated streams within the Sixteen Mile Creek

Sub-watershed               Target (%)           Measured (%)            Difference (%)
Sixteen Mile Creek             75%                 45.14%                    -29.86

Percent of Impervious Land

         The replacement of naturally vegetated lands with impervious lands across the
watershed results in a decrease in wildlife habitat, increase in flooding and high, “flashy”
flows, increased erosion and decreased water quality. Effects of imperviousness are often
permanent resulting in healthy streams shifting towards degraded conditions. The target
of less then 10% impervious land reflects the threshold for healthy streams and fish and
wildlife communities. An upper limit of 30% imperviousness represents a threshold for
degraded systems. For this analysis, detailed information on imperviousness was lacking
so a broad based example was used based on the % developed land. We recognize that
all developed lands have varying levels of imperviousness as a result of greenspace,
lawns, urban forests, other natural covers and varying degrees of imperviousness with
hard materials (i.e. concrete vs. gravel). This parameter is used strictly as an example
and combines low-density, medium-density and high-density development.

Table 16: Percent developed land in the Sixteen Mile Creek Watershed and Sub-

Sub-watershed               Target (%)            Measured (%)           Difference (%)
Upper West Branch                                     0.00
West Branch                                          20.94
Middle Branch                                         0.95
Middle East Branch                                    0.00
Lower Middle                                         13.17
East Branch                                            3.70
East Branch-Lisgar                                    22.23
Urban Diverted                                        63.81
Main Branch                                           36.80

Sixteen Mile Creek              10                    12.34                   +2.34


Through the monitoring of both the aquatic and terrestrial ecosystems and a large degree
of ground truthing across the watershed a number of recommendations have been made

to improve the overall health of the ecosystem with the Sixteen Mile Creek watershed.
Some recommendations are general and pertain to the entire watershed whereas other
recommendations are site-specific. Recommendations are as follows:

Watershed Recommendations

Barrier Removal

    Air photo interpretation and ground truthing of the Sixteen mile Creek watershed was
completed in 2005 and 2006 to identify barriers throughout the watershed and to
determine rehabilitation potential and priority for removal. Through the study, over 1200
potential barriers to fish migration was identified with approximately 100 of those
ground-truthed and documented. Barriers within the stream channel result in numerous
detrimental effects to the immediate and downstream areas. Barriers may result in:

   • damage to immediate and upstream areas from flooding and erosion
   • disruption in the sediment balance within a creek causing excess siltation
     upstream and increased scouring and erosion downstream
   • isolated populations of aquatic organisms including fish and benthic invertebrates
   • creation of lentic (lake-like) habitats which favour non-indigenous species and
     may result in shifts in the native communities
   • potential increases in stream temperatures

   It is recognized that numerous dams throughout the region have historical value, may
be used as a safety measure (i.e. flood control structures), or act to separate native and
exotic species. As a result, it is important to continue to investigate these barriers and
determine which barriers are the most beneficial to remove.

Riparian Planting and Enhancement

       Riparian buffers are essential for the health of a watershed. The naturally
vegetated areas adjacent to streams and wetlands contribute to the ecosystem in a number
of ways including:

       •   maintaining cooler stream temperatures by shading the creek through the hot
           summer months
       •   reducing erosion through extensive rooting systems which also help to reduce
           and slow runoff and absorb nutrients
       •   overhanging vegetation, fallen logs and tree roots provides overhead cover for
           aquatic species
       •   decaying leaves and woody material provide important food sources for
           benthic invertebrates which provide the basis of the food chain in stream
       •   riparian buffers provide natural wildlife corridors across the landscape

        The amount of naturally vegetated streams throughout the watershed is limited.
By simply planting native trees, shrubs and herbaceous material alongside the
watercourse improvements to the immediate and downstream stream environments can
be easily achieved. It is important to note, that in order for riparian buffers to function
properly they should coincide with natural adjacent habitats in order to maintain
continuity within a specific ecosite. This is especially important for the maintenance of
specific habitats (i.e. wetlands) and for specific species, for example redside dace, which
prefer grassed and herbaceous riparian buffers over forested riparian buffers.

Corridors and Linkages

        Corridors are generally considered to be elongate, naturally vegetated areas that
link or border natural areas within and between watersheds (Riley and Mohr, 1994).
They can exist at different scales across the watershed including fine scale linkages,
along fence and hedgerows or at larger scales, which may provide substantial
passageways for a variety of flora and fauna.
        Corridors provide numerous functions across the landscape. They connect natural
areas, thereby allowing for the movement of species between tracts of natural areas. In
turn, they result in increased genetic diversity within species as well as increased
biodiversity within the area. Corridors also provide suitable habitat, breeding and feeding
opportunities for a vast assemblage of plant and animal species. In addition, to these
functions corridors also act as buffers to natural areas, thereby protecting them from
adjacent landuse activities.
        Within the Sixteen Mile Creek watershed majority of corridors in the lower
reaches of the watershed are associated with the Sixteen Mile Creek valley. These lands
provide extensive corridors for the migration and dispersal of plants and wildlife through
the main branch upwards to its confluence with both the West Branch and Lower Middle
Branch of the watershed. Beyond these valleylands, extensive corridors are limited in the
lands beneath the Niagara Escarpment with the exception of small riparian corridors,
hedgerows and fencerows. Conversely, in the lands north of the Niagara Escarpment
corridors provide linkages between extensive natural areas.
        The creation of natural corridors should be further examined to link smaller and
more isolated tracks of land to the large expanses of natural areas above the Niagara
Escarpment. Potential corridors should follow existing protected lands to improve upon
existing conditions and link these lands to other areas across the landscape in order to
build a tapestry of natural lands across the watershed. Potential corridors and linkages
have been identified and can be seen in figure 15. It should be noted that in addition to
the positive benefits of corridors, potential adverse effects might be associated with some
corridors. Some view corridors as natural pathways for the spread of exotic and invasive
species, which can potentially affect native species communities. This is evident in
small, narrow corridors, which provide habitat for edge-tolerant species such as brown-
headed cowbird and European starling.


         In order to follow changes in the watershed and the potential effects they may
have on the local environment it is important that long term monitoring of the watershed
be incorporated into future projects. Thorough monitoring of both the aquatic and
terrestrial ecosystems is recommended for completion throughout the watershed on a
regular basis. Through Conservation Haltons Long Term Environmental Monitoring
Program, long term monitoring will be completed throughout the watershed on a 5-year
rotation, thereby ensuring that any potential changes to the local environment are
monitored and appropriate rehabilitation plans will be explored where needed.
Incorporation of information from site-specific projects is also recommended to reduce
the duplication of efforts and ensure that all information is available to obtain the most
comprehensive examination of the watershed. In addition, numerous opportunities exist
to expanding community-based monitoring throughout the watershed. Existing programs
such as the Ecological Monitoring and Assessment Network (EMAN) uses a number of
different indicators that are easily used by community members, to document existing
conditions and monitor changes throughout the watershed. Expanding this type of
monitoring across the watershed will help engage the community while obtaining
additional environmental information.

Site Specific recommendations

        Numerous site-specific recommendations have been developed as part of the
Sixteen Mile Creek Monitoring Project in order to rehabilitate potential problem areas
and to restore ecosystem health. Projects vary across the watershed and range from in-
stream habitat creation and bank stabilization to tree planting, cattle fencing and water
conservation. Through the partnership of numerous conservation groups including
stewardship organizations, naturalists groups, fishing clubs, and most importantly private
landowners, many of the projects can be completed thereby helping to improve site-
specific conditions and the entire watershed as a whole. Table 17 provides descriptions
of potential projects, which can be located on the proposed revitalization maps (figure 16
to figure 24). Projects are listed based on subwatershed and in no particular order or

Table 17: Proposed Revitalization Projects

     Site ID              Sub-watershed          Road Crossing                         Recommendations
1                Upper West Branch           #3 Sideroad to 401       Reforest fields (where unused) to re-establish
                                             HWY                      interior forest habitat adjacent to Kelso Reservoir.
2                Upper West branch           Directly downstream of   Riparian buffer plantings to shade the creek and
                                             Kelso Reservoir          stabilize streambanks.
2                Upper West Branch           Kelso Reservoir to       Revisit and reconstruct instream habitat
                                             Kelso Road               improvements and barrier removal.
3                Upper West Branch           #15 Sideroad west of     Reforest fields (where unused) to re-establish
                                             HWY 25                   interior forest habitat.
4                Upper West Branch           #17 Sideraod west of     Reforest fields (where unused) to re-establish
                                             HWY 25                   interior forest habitat.
5                Upper West Branch           5th Line and #20         Reforest fields (where unused) to re-establish
                                             Sideroad                 interior forest habitat.
6                West Branch                 HWY 25 and Lower         Golf course naturalization and wildlife corridor
                                             Baseline                 plantings.
7                West Branch                 Derry Road and HWY       Stream bank stabilization and erosion control.
                                             25                       Riparian buffer tree plantings.
8                West Branch                 Commercial Street and    Streambank naturalization (removal of gabion
                                             Laurier Avenue           baskets), instream habitat creation and riparian
                                                                      buffer plantings.
9                West Branch                 Milton Channel           Investigate potential for instream habitat
10               West Branch                 Tremaine Road south of   Removal of gabion walls along stream bank and
                                             Kelso Road               banks stabilization/naturalization.
11               West Branch                 Dublin Line north of     Golf course naturalization and wildlife corridor
                                             Campbellville Road       creation.

     Site ID           Sub-watershed       Road Crossing                            Recommendations
12             Middle Branch           5th Line north of Steeles   Streambank stabilization and riparian buffer
                                       Avenue                      creation.
13             Middle Branch           Campbellville Road          Livestock fencing and riparian buffer creation.
                                       west of 4th Line
14             Middle Branch           Downstream of Scotch        Gabion basket barrier removal and instream habitat
                                       Block Reservoir             creation.
15             Middle Branch           Adjacent to Kelso           Reforestation and riparian buffer creation (where
                                       Reservoir                   possible).
16             Middle Branch           East of HWY 25 and          Reforestation and riparian buffer creation (where
                                       south of #22 Sideroad       possible).
17             Middle Branch           East of HWY 25 and          Reforest fields (where unused) to re-establish
                                       south of #22 Sideroad       interior forest habitat.
18             Middle East Branch      North of Steeles Avenue     Golf course naturalization; riparian buffer creation.
                                       and Hornby Road
19             Middle East Branch      Campbellville Road and      Riparian buffer creation and streambank
                                       4th Line                    stabilization.
20             Middle East Branch      Campbellville Road and      Livestock fencing and riparian buffer creation.
                                       4th Line
21             Lower Middle Branch     Lower Baseline and 4th      Golf course naturalization.
22             Lower Middle Branch     5th Line and Lower          Riparian buffer plantings.
23             Lower Middle Branch     Sixth Line                  Riparian buffer improvements.
24             Lower Middle Branch     Sixth Line and Britannia    Riparian buffer improvements along tributaries
                                       road                        through golf course.
25             Lower Middle Branch     Derry Road and Sixth        Riparian buffer creation.

     Site ID           Sub-watershed            Road Crossing                         Recommendations
26             Lower Middle Branch          Derry Road and Sixth     Buffer creation along agricultural fields.
27             Lower Middle Branch          Derry Road and Sixth     Buffer creation along agricultural fields.
28             East-Lisgar Branch           Adjacent to 407          Floodplain planting and riparian buffer creation.;
                                                                     instream habitat creation.
29             Urban Diverted Tributaries   Upper Middle Road and    Gabion basket removal; streambank stabilization and
                                            Trafalgar Road           trail maintenance.
30             Urban Diverted Tributaries   Upper Middle Road        Improvements to perched and blocked culvert to
                                                                     reduce regular maintenance.
31             Urban Diverted Tributaries   Dundas Road and Sixth    Riparian buffer creation and tree planting.
32             Urban Diverted Tributaries   Postridge Drive          Tree planting throughout parklands.
33             Main Branch                  Cross Avenue and         Tree planting and wildlife corridor creation.
                                            Speers Road (Hogs Back
34             Main Branch                  Upper Middle Road and    Golf course naturalization and riparian buffer
                                            Dorval Drive             creation/improvements.
35             Main Branch                  Dundas Road at Lions     Tree planting and riparian buffer creation; stream
                                            Valley Park              bank stabilization; restrict motorized vehicles
                                                                     (trucks, ATVs) from accessing the creek.


        Through the Sixteen Mile Creek monitoring study, baseline environmental
conditions have been obtained and potential rehabilitation projects within the watershed
have been identified through a variety of stakeholder groups, ground truthing, field work
and air photo interpretation. As a result, a comprehensive inventory of the watershed is
now complete with specific areas identified for rehabilitation. In conjunction with the
release of the document, a series of presentations outlining the outcomes of the project
have been initiated. The technical steering committee who guided the project, was
presented with the information in the summer of 2006 with further presentations
scheduled for interested parties in 2007.

        The Sixteen Mile Creek Monitoring Project report will be forwarded to interested
community groups across the watershed in order to inform and further engage groups in
environmental protection and rehabilitation. In addition, projects identified after the
release of the report can be forwarded to Conservation Halton and its partnering agencies
to be added to an on-going list and database of project sites within the watershed. This
continued evaluation of sites will ensure that the goals of the Sixteen Mile Creek
Monitoring Study will continue on into the future, thereby documenting potential
problems sites and engaging the community in improving the environment that surrounds
them. Sites identified for rehabilitation can then be completed through partnerships with
private landowners, stewardship groups and community and environmental groups.


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           Appendix A : Mammals of the Sixteen Mile Creek Watershed

Virginia Opossum           Didelphis virginiana     S4                           Common
Shrews and Moles
Masked shrew               Sorex cinereus           S5                           Common
Smoky shrew                Sorex fumeus             S5                           Common
Water shrew                Sorex palustris          S5                           Rare
Northern short-tailed
shrew                      Blarina brevicauda       S5                           Common
Hairy-tailed mole          Parascalops breweri      S4                           Uncommon
Star-nosed mole            Condylura cristata       S5                           Common
Bats (Chiroptera)
Little brown bat           Myotis lucifugus         S5                           Common
Northern long-eared bat    Myotis septentrionalis   S3?                          Common
Silver-haired bat          noctivagans              S4                           Migrant
Eastern pipistrelle        Pipistrellus subflavus   S3?                          ?
Big brown bat              Eptesicus fuscus         S5                           Common
Red bat                    Lasiurus borealis        S4                           Common
Hoary bat                  Lasiurus cinereus        S4                           Common
Rabbits and Hares
Eastern cottontail         Sylvilagus floridanus    S5                           Common
European hare              Lepus europaeus          SE                           Common
Rodents (Rodentia)
Eastern chipmunk           Tamias striatus          S5                           Common
Woodchuck                  Marmota monax            S5                           Common
Gray squirrel              Sciurus carolinensis     S5                           Common
Red squirrel               hudsonicus               S5                           Common
Northern flying squirrel   Glaucomys sabrinus       S5                           Rare
Southern flying squirrel   Glaucomys volans         S3       SC        SC        Common
Beaver                     Castor canadensis        S5                           Common
White-footed mouse         Peromyscus leucopus      S5                           Common
Deer mouse                 maniculatus              S5                           Common
Meadow vole                pennsylvanicus           S5                           Common
Woodland vole              Microtus pinetorum       S3?      SC        SC        Rare
Muskrat                    Ondatra zibethicus       S5                           Common
Southern bog lemming       Synaptomys cooperi       S4                           ?
Norway rat                 Rattus norvegicus        SE                           Common
House mouse                Mus musculus             SE                           Common
Meadow jumping mouse       Zapus hudsonius          S5                           Common

Woodland jumping mouse   Napaeozapus insignis     S5                           Uncommon
Porcupine                Erethizon dorsatum       S5                           Common
Carnivores (Carnivora)
Coyote                   Canis latrans            S5                           Common
Red fox                  Vulpes vulpes            S5                           Common
Black bear               Ursus americanus         S5                           Extirpated?
Raccoon                  Procyon lotor            S5                           Common
Ermine                   Mustela erminea          S5                           Rare to uncommon
Long-tailed weasel       Mustela frenata          S4                           Common
Mink                     Mustela vison            S5                           Common
Striped skunk            Mephitis mephitis        S5                           Common
Bobcat                   Lynx rufus               S5       NAR       NAR       Extirpated?
Deer and Bison

White-tailed deer        Odocoileus virginianus   S5                           Common

Appendix B: Birds of the Sixteen Mile Creek watershed.

Common Loon          Gavia immer             S4B,SZN                         Uncommon migrant; casual summer resident

Pied-billed Grebe    Podilymbus podiceps     S4B,SZN                         Common migrant; uncommon summer resident
Red-necked Grebe     Podiceps grisegna       S3B,SZN                         Uncommon resident; common migrant

Pelican and Allies
Double-crested       Phalacrocorax auritus   S4B,SZN                         Abundant local summer resident, Casual winter
Cormorant                                                                    resident

Herons and
Great Blue Heron     Ardea herodias          S5B,SZN                         Common summer resident, Casual winter resident
Green Heron          Butorides striatus      S4B,SZN                         Uncommon summer resident
Least Bittern        Ixobrychus exilis       S3B,SZN     THR       THR       Rare summer resident

Turkey Vulture       Cathartes aura          S4B,SZN                         Common summer resident

Ducks, geese and
Canada Goose         Branta canadensis       S5B,SZN                         Abundant resident
Trumpeter Swan       Cygnus buccinator       S2S3                            Uncommon local winter resident

Mute Swan            Cygnus olor             SE                              Introduced; Uncommon local resident
Wood Duck            Aix sponsa              S5B,SZN                         Fairly common summer resident
Mallard              Anas platyrhynchos      S5B,SZN                         Abundant resident
American Black       Anas rubripes           S5B,SZN                         Uncommon resident
Blue-winged Teal     Anas discors            S5B,SZN                         Uncommon migrant; Uncommon resident
Hooded Merganser     Lophodytes cucullatus   S5B,SZN                         Uncommon migrant and summer resident

Hawks and
Osprey               Pandionhaliaetus        S4B,SZN                         Uncommon migrant
Northern Harrier     Circus cyaneus          S4B,SZN                         Uncommon summer resident; Rare in winter
Sharp-shinned        Accipiter striatus      S5B,SZN                         Uncommon summer resident; Common migrant
Cooper's Hawk        Accipiter cooperii      S4B,SZN                         Uncommon migrant; Local resident
Northern Goshawk     Accipiter gentilis      S4                              Uncommon migrant; Local resident
Red-shouldered       Buteo lineatus          S4B,SZN     SC        SC        Rare resident; Uncommon migrant
Red-tailed Hawk      Buteo jamaicensis       S5B,SZN                         Common resident
Broad-winged Hawk    Buteo platypterus       S5B,SZN                         Common migrant; Rare summer resident
American Kestrel     Falco sparverius        S5B,SZN                         Common resident
Merlin               Falco columbarius       S4B,SZN                         Uncommon migrant
Peregrine Falcon     Falco peregrinus        S2S3B,SZN   THR       END-R     Casual; Release program

Fowl (Galliformes)
Ring-necked          Phasianus colchicus     SE                              Uncommon: Introduction
Ruffed Grouse        Bonasa umbellus         S5                              Common resident
Wild Turkey          Meleagris gallopavo     S4                              Uncommon resident; Release program
Northern Bobwhite    Colinus virginianus     S1S2        END       END       Rare visitor; Possible release


Rails, Cranes and
allies (Gruiformes)
Virginia Rail         Rallus limicola        S4B,SZN                       Common summer resident
Sora                  Porzana carolina       S4B,SZN                       Uncommon summer resident
Common Moorhen        Gallinula chloropus    S4B,SZN                       Rare visitor
American Coot         Fulica americana       S4B,SZN                       Uncommon local winter resident
Sandhill Crane        Grus canadensis        S4B,SZN                       Casual migrant

Shorebirds, Gulls,
and allies
Killdeer              Charadrius vociferus   S5B,SZN                       Common summer resident
Greater Yellowlegs    Tringa melanoleuca     S4B,SZN                       Uncommon migrant
Solitary Sandpiper    Tringa solitaria       S4B,SZN                       Uncommon migrant
Spotted Sandpiper     Actitis macularia      S5B,SZN                       Common summer resident
Upland Sandpiper      Bartramia longicauda   S4B,SZN                       Uncommon migrant; Rare summer resident
Common Snipe          Gallinago gallinago    S5B,SZN                       ?
American Woodcock     Scolopax minor         S5B,SZN                       Common summer resident
Ring-billed Gull      Larus delawarensis     S5B,SZN                       Abundant resident
Herring Gull          Larus argentatus       S5B,SZN                       Common local resident
Caspian Tern          Sterna caspia          S3B,SZN                       Common local summer resident

Pigeons and Doves
Rock Dove             Columba livia          SE                            Abundant resident
Mourning Dove         Zenaida macroura       S5B,SZN                       Abundant resident

Cuckoos (???)
Black-billed Cuckoo   Coccyzus               S4B,SZN                       Uncommon summer resident

 COMMON NAME            SCIENTIFIC NAME         S RANK   COSEWIC   COSSARO                     HALTON RANK
Yellow-billed         Coccyzus eamericanus     S4B,SZN                       Rare summer resident

Owls (Strigiformes)
Eastern Screech-      Otus asio                S5                            Common resident
Great Horned Owl      Bubo virginianus         S5                            Common resident
Barred Owl            Strix varia              S4S5                          Rare resident
Long-eared Owl        Asios otus               S4                            Uncommon winter resident; Rare summer resident

Common Nighthawk      Chordeiles minor         S4B,SZN                       Uncommon local summer resident
Whip-poor-will        Caprimulgus vociferous   S4B,SZN                       Rare local summer resident

Swifts and
Chimney Swift         Chaetura pelagica        S5B,SZN                       Common local summer resident
Ruby-throated         Archilochus colubris     S5B,SZN                       Common summer resident

Kingfishers and
Belted Kingfisher     Ceryle alcyon            S5B,SZN                       Common summer resident

Red-headed            Melanerpes               S3B,SZN   SC        SC        Uncommon summer resident
Woodpecker            erythrocephalus
Red-bellied           Melanerpes carolinus     S4                            Uncommon resident

Yellow-bellied       Sphyrapicus varius       S5B,SZN                       Uncommon summer resident
Downy Woodpecker     Picoides pubescens       S5                            Common resident
Hairy Woodpecker     Picoides villosus        S5                            Common resident
Northern Flicker     Colaptes auratus         S5B,SZN                       Common summer resident
Pileated             Dryocopus pileatus       S4S5                          Common resident

Perching birds
Eastern Wood-        Contopus virens          S5B,SZN                       Common summer resident
Yellow-bellied       Empidonax flaviventris   S5B,SZN                       Uncommon migrant
Acadian Flycatcher   Empidonax virescens      S2B,SZN   END       END       Casual visitor
Alder Flycatcher     Empidonax alnorum        S5B,SZN                       Common summer resident
Willow Flycatcher    Empidona traillii        S5B,SZN                       Uncommon summer resident
Least Flycatcher     Empidonax minimus        S5B,SZN                       Common summer resident
Eastern Phoebe       Sayornis phoebe          S5B,SZN                       Common summer resident
Great Crested        Myiarchus crinitus       S5B,SZN                       Common summer resident
Eastern Kingbird     Tyrannus tyrannus        S5B,SZN                       Common summer resident
Yellow-throated      Vireo flavifrons         S4B,SZN                       Rarelocal summer resident
Blue-headed Vireo    Vireo solitarius         S5B,SZN                       Uncommon migrant
Warbling Vireo       Vireo gilvus             S5B,SZN                       Common summer resident
Red-eyed Vireo       Vireo olivaceus          S5B,SZN                       Abundant summer resident
Blue Jay             Cyanocitta cristata      S5                            Aundant resident
American Crow        Corvus brachyrhynchos    S5B,SZN                       Abundant resident
Common Raven         Corvus corax             S5                            Rare resident
Horned Lark          Eremophilia alpestris    S5B,SZN                       Uncommon summer resident; Common migrant

Purple Martin       Progne subis              S4B,SZN                         Uncommon summer resident
Tree Swallow        Tachycineta bicolor       S5B,SZN                         Abundant summer resident
Northern Rough-     Stelgidopteryx            S5B,SZN                         Uncommon summer resident
winged Swallow      serripennis
Bank Swallow        Riparia riparia           S5B,SZN                         Locally common summer resident
                    Petrochelidon                                             Common summer resident
Cliff Swallow       pyrrhonota
Barn Swallow        Hirundo rustica           S5B,SZN                         Common summer resident
Black-capped        Poecile atricapillus      S5                              Abundant resident
Tufted Titmouse     Baeolophus bicolor        S2S3                            Uncommon visitor
Red-breasted        Sitta canadensis          S5B,SZN                         Common resident
White-breasted      Sitta carolinensis        S5                              Common resident
Brown Creeper       Certhia americana         S5B,SZN                         Common resident
                    Thryothorous              S3S4                            Rare resident
Carolina Wren       ludovicians
House Wren          Troglodytes aedon         S5B,SZN                         Common summer resident
Winter Wren         Troglodytes troglodytes   S5B,SZN                         Uncommon summer resident; rare winter resident
Sedge Wren          Cistothorus platensis     S4B,SZN                         Rare migrant
Marsh Wren          Cistothorus palustris     S5B,SZN                         Uncommon local summer resident
Golden-crowned      Regulas satrapa           S5B,SZN                         Common migrant; Rare summer resident
Blue-gray           Polioptila caerulea       S4B,SZN                         Uncommon summer resident
Eastern Bluebird    Sialia sialis             S4S5B,SZN                       Uncommon summer resident
Veery               Catharus fuscescens       S4B,SZN                         Common summer resident
Swainson's Thrush   Catharus ustulatus        S5B,SZN                         Common migrant
Hermit Thrush       Catharus guttatus         S5B,SZN                         Common migrant
Wood Thrush         Hylocichla mustelina      S5B,SZN                         Common summer resident
                    Turdus migratorius        S5B,SZN                         Abundant summer resident: Uncommon winter
American Robin                                                                resident

Gray Catbird          Dumetella carolinensis   S5B,SZN                         Common summer resident
Northern              Mimus polyglottos        S4B,SZN                         Uncommon resident
Brown Thrasher        Toxostoma rufum          S5B,SZN                         Common summer resident
European Starling     Sturnus vulgaris         SE                              Abundant resident
Cedar Waxwing         Bombycilla cedororum     S5B,SZN                         Common resident
Blue-winged           Verivora pinus           S4B,SZN                         Uncommon local summer resident
Golden-winged         Vermivora chrysoptera    S4B,SZN                         Rare local summer resident
                      Vermivora chrysoptera
Brewster's Warbler    X V. pinus                                               Rare local summer resident
Nashville Warbler     Vermivora ruficapilla    S5B,SZN                         Common migrant; Rare summer resident
Yellow Warbler        Dendroica petechia       S5B,SZN                         Common summer resident
Chestnut-sided        Dendroica pensylvamia    S5B,SZN                         Common migrant; Uncommon summer resident
Magnolia Warbler      Dendroica magnolia       S5B,SZN                         Common migrant; Rare summer resident
Black-throated Blue   Dendroica                S5B,SZN                         Uncommon migrant; Rare summer resident
Warbler               caerulescens
Yellow-rumped         Dendroica coronata       S5B,SZN                         Common migrant; Rare summer resident
Black-throated        Dendroica virens         S5B,SZN                         Common summer resident
Green Warbler
Blackburnian          Dendroica fusca          S5B,SZN                         Uncommon migrant; Rare summer resident
Pine Warbler          Dendroica pinus          S5B,SZN                         Casual summer resident
Black-and-white       Mniotilla varia          S5B,SZN                         Common migrant; Uncommon summer resident
American Redstart     Setophaga ruticilla      S5B,SZN                         Common summer resident
Prothonotary          Protonotaria citrea      S1S2B,SZN   END       END-R     Casual visitor
Ovenbird              Seiurus aurocapillus     S5B,SZN                         Abundant summer resident

 COMMON NAME          SCIENTIFIC NAME           S RANK   COSEWIC    COSSARO                      HALTON RANK
Louisiana            Seiurus motacilla         S3B,SZN   SC        SC         Infrequent local summer resident
Mourning Warbler     Oporonis philadelphia     S5B,SZN                        Uncommon summer resident
Common               Geothlypis trichas        S5B,SZN                        Common summer resident
Hooded Warbler       Wilsonia citrinia         S3B,SZN   THR       THR        Rare summer resident
Canada Warbler       Wilsonia canadensis       S5B,SZN                        Uncommon migrant; Rare summer resident
Scarlet Tanager      Piramga olivacea          S5B,SZN                        Common summer resident
Eastern Towhee       Pipilo erythrophthalmus   S4B,SZN                        Uncommon summer resident
Chipping Sparrow     Spizella passerina        S5B,SZN                        Common summer resident
Field Sparrow        Spizella pusilla          S5B,SZN                        Common summer resident
Vesper Sparrow       Pooecetes gramineus       S4B,SZN                        Uncommon summer resident
Grasshopper          Ammodramus                S4B,SZN                        Uncommon summer resident
Sparrow              savannarum
Song Sparrow         Melospiza melodia         S5B,SZN                        Abundant summer resident
Swamp Sparrow        Melospiza georgiana       S5B,SZN                        Common summer resident
                     Passerculus               S5B,SZN                        Abundant summer resident
Savannah Sparrow     sandwichensis
House Sparrow        Passer domesticus         SE                             Abundant resident
White-throated       Zonotrichia albicollis    S5B,SZN                        Common summer resident; Uncommon winter
Sparrow                                                                       resident
White-crowned        Zonotrichia leucophrys    S4B,SZN                        Common migrant
Dark-eyed Junco      Junco hyemalis            S5B,SZN                        Abundant winter resident
Northern Cardinal    Cardinalis cardinalis     S5                             Common resident
Rose-breasted        Pheucticus                S5B,SZN                        Common summer resident
Grosbeak             ludovicianus
Indigo Bunting       Passerina cyanea          S5B,SZN                        Common summer resident
Bobolink             Dolichonyx oryzivorous    S4B,SZN                        Common summer resident
Red-winged           Agelaius phoeniceus       S5B,SZN                        Abundant summer resident
Eastern Meadowlark   Sturnella magna           S5B,SZN                        Common summer resident

Common Grackle       Quiscalus quiscula      S5B,SZN                       Abundant summer resident
Brown-headed         Molothrus ater          S5B,SZN                       Abundant summer resident
Orchard Oriole       Icterus spurius         SZB,SZN                       Rare local summer resident
Baltimore Oriole     Icterus galbula         S5B,SZN                       Common summer resident
Purple Finch         Carpodacus purpureus    S5B,SZN                       Uncommon resident
House Finch          Carpodacus mexicanus    SE                            Abundant resident
Pine Siskin          Carduelis pinus         S5B,SZN                       Common winter resident; Sporadic
American Goldfinch   Carduelis tristis       S5B,SZN                       Abundant resident
                     Coccothraustes          S5B,SZN                       Casual migrant
Evening Grosbeak     vespertinus

Additional species
listed in Gore &
Storrie, 1996
Black-crowned        Nycticorax nycticorax   S3B,SZN                       Uncommon local summer resident
Northern Shoveler    Anas clypeata           S4B,SZN                       Uncommon migrant
Black Tern           Chlidonias niger        S3B,SZN   NAR       SC        Rare migrant
Clay-colored         Spizella pallida        S4B,SZN                       Casual local summer resident
Green-winged Teal    Anas crecca             S4B,SZN                       Common migrant
Ruby-crowned         Regulus calendula       S5B,SZN                       Common migrant; Uncommon winter resident
Palm Warbler         Dendroica palmarum      S?                            Uncommon migrant
Bay-breasted         Dendroica castanea      S5B,SZN                       Uncommon migrant
Red Crossbill        Loxia curvirostra       S5B,SZN                       Casual winter visitor
Dickcissel           Spiza americana         SZB,SZN                       ?

            Appendix C: Herpetiles of the Sixteen Mile Creek watershed.

        COMMON NAME                    SCIENTIFIC NAME            S RANK   COSEWIC   COSSARO     HALTON
Newts and Salamanders
Common Mudpuppy                    Necturus maculosus             S4                           Rare
Red-spotted Newt                   Notophthalmus viridescens      S5                           Common
Jefferson Salmander                Ambystoma jeffersonianum       S2       THR       THR       Uncommon
Jefferson Salamander Complex       Ambystoma laterale-            S2                           Uncommon
Spotted salamander                 Ambystoma maculatum            S4                           Uncommon
Four-toed Salamander               Hemidactylium scutatum         S4                           Rare
Redback Salamander                 Plethodon cinereus             S5                           Common

Frogs and Toads (Anura)
American Toad                      Bufo americanus                S5                           Abundant
Gray Treefrog                      Hyla versicolor                S5                           Abundant
Spring Peeper                      Pseudacris crucifer            S5                           Abundant
Chorus Frog                        Pseudacris triseriata          S4                           Common?
Wood Frog                          Rana sylvatica                 S5                           Common
Northern Leopard Frog              Rana pipiens                   S5                           Abundant
Pickerel Frog                      Rana palustris                 S4                           Uncommon
Green Frog                         Rana clamitrans                S5                           Abundant
Bullfrog                           Rana catesbeiana               S4                           Uncommon

Turtles (Testudines)
Common snapping turtle             Chelydra serpentina            S5                           Common
Midland Painted Turtle             Chrysemys picta marginata      S5                           Common
Common Map Turtle                  Graptemys geographica          S3       SC        SC        Rare
Blandings's Turtle                 Emydoidea blandingii           S3       THR       THR       Rare
Red-earred slider                  Trachemys scripta elegans      SE                           Common -

Snakes (Squamata)
Eastern Garter Snake               Thamnophis sirtalis sirtalis   S5                           Abundant
Eastern Ribbonsnake                Thamnophis sauritus            S3       SC        SC        Rare
Northern Water Snake               Nerodia sipedon sipedon        S5                           Uncommon
Northern Redbelly Snake            Storeria occipitomaculata      S5                           Common
Brown Snake                        Storeria dekayi                S5                           Common
Smooth Green Snake                 Opheodrys vernalis             S4                           Rare
Northern Ringneck Snake            Diadophis punctatus            S4                           Rare
Milksnake                          Lampropeltris triangulum       S3       SC        SC        Common

Extant/Possible species
Black Rat snake                    Elaphe obsoleta obsoleta       S3       THR       THR       Extirpated

     Appendix D: Fish of the Sixteen Mile Creek Watershed

Sea lamprey              Petromyzon marinus         SE                           restricted
Freshwater Eels
American eel             Anguilla rostrata          S5                           restricted
Herrings (Clupeidae)
Alewife                  Alosa pseudoharengus       SE                           restricted
Salmon and trout
                                                                                 Rare to
Rainbow trout            Oncorhynchus mykiss        SE                           uncommon
Chinook salmon           Oncorhynchus tshawytscha   SE                           Rare
Brown trout              Salmo trutta               SE                           Rare
Brook trout              Salvelinus fontinalis      S5                           Rare
Pikes (Esocidae)
Northern pike            Esox lucius                S5                           Rare
Central mudminnow        Umbra limi                 S5                           Uncommon
Carps and Minnows
Central stoneroller      Campostoma anomalum        S4                           Rare
Goldfish                 Carassius auratus          SE                           Rare
Redside dace             Clinostomus elongatus      S3       SC        THR       Rare
Spotfin shiner           Cyprinella spilotera       S4                           Rare
Common carp              Cyprinus carpio            SE                           Uncommon
Brassy minnow            Hybognathus hankinsoni     S5                           Rare
Common shiner            Luxilus cornutus           S5                           Common
Pearl dace               Margariscus margarita      S5                           Uncommon
Hornyhead chub           Nocomis biguttstus         S4                           Rare
                                                                                 Rare to
River chub               Nocomis micropogon         S4                           uncommon
Golden shiner            Notemigonus crysoleucas    S5                           Rare
Emerald shiner           Notropis athernoides       S5                           restricted
Spottail shiner          Notropis hudsonius         S5                           restricted
Silver shiner            Notropis photogenis        S2S3     SC        SC        Rare
Rosyface shiner          Notropis rubellus          S4                           Rare
Mimic shiner             Notropis volucellus        S5                           Rare
Northern redbelly dace   Phoxinos eos               S5                           Uncommon
Finescale dace           Phoxinos neogaeus          S5                           Uncommon
Bluntnose minnow         Pimephales notatus         S5                           Common

Fathead minnow        Pimephales promelas       S5                           Common
Blacknose dace        Rhinichthys atratulus     S5                           Common
Longnose dace         Rhinichthys cataractae    S5                           Uncommon
Creek chub            Semotilus atromaculatus   S5                           Common
White sucker          Catostomus commersoni     S5                           Common
Northern hog sucker   Hypentelium nigricans     S4                           Uncommon
Shorthead redhorse    macrolepidotum            S5                           Rare
Bullhead catfishes
Yellow bullhead       Ameiurus natalis          S4                           Rare
Brown bullhead        Ameiurus nebulosus        S5                           Rare
Stonecat              Noturus flavus            S4                           Rare
Brook stickleback     Culaea inconstans         S5                           Common
Sculpins (Cottidae)
Mottled sculpin       Cottus bairdi             S5                           Rare
Rock bass             Ambloplites rupestris     S5                           Uncommon
Green sunfish         Lepomis cyanellus         S4                           Rare
Pumpkinseed           Lepomis gibbosus          S5                           Common
Bluegill              Lepomis macrochirus       S5                           Rare
Smallmouth bass       Micropterus dolomieu      S5                           Uncommon
Largemouth bass       Micropterus salmoides     S5                           Uncommon
Black crappie         Poxomis nigromaculatus    S4                           Rare
Perches (Percidae)
Rainbow darter        Etheostoma caeruleum      S4                           Uncommon
Fantail darter        Etheostoma flabellare     S4                           Uncommon
Johnny darter         Etheostoma nigrum         S5                           Uncommon
Yellow perch          Perca flavescens          S5                           Rare
Walleye               Sander vitreum            S5                           restricted
Gobies (Gobiidae)
Round goby            Neogobius melanostomus    SE                           Rare

           Appendix E: Odonates of the Sixteen Mile Creek Watershed.



Broad-winged Damsels
River Jewelwing           Calopteryx aequabilis     S5                           Uncommon
Ebony Jewelwing           Calopteryx maculata       S5                           Common
American Rubyspot         Hetaerina americana       S4                           Rare

Spreadwings (Lestidae)
Spotted Spreadwing        Lestes congener           S5                           Uncommon
Common Spreadwing         Lestes disjunctus         S5                           Rare?
Emerald Spreadwing        Lestes dryas              S5                           Common
Amber-winged              Lestes eurinus            S3                           Rare
Slender Spreadwing        Lestes rectangularis      S5                           Common
Lyre-tipped Spreadwing    Lestes unguiculatus       S5                           Uncommon

Eastern Red Damsel        Amphiagrion saucium       S3                           Rare
Violet Dancer             Argia        fumipennis   S5                           Uncommon
Powdered Dancer           Argia moesta              S5                           Rare
Aurora Damsel             Chromagrion conditum      S5                           Rare
Azure Bluet               Enallagma aspersum        S3                           Rare
Boreal Bluet              Enallagma boreale         S5                           Rare
Tule Bluet                Enallagma                 S5                           Rare
Familiar Bluet            Enallagma civile          S5                           Common
Marsh Bluet               Enallagma ebrium          S5                           Common
Stream Bluet              Enallagma exsulans        S5                           Rare
Skimming Bluet            Enallagma geminatum       S4                           Rare
Hagen's Bluet             Enallagma hageni          S5                           Rare
Vernal Bluet              Enallagma vernale         S3                           Rare
Fragile Forktail          Ischnura posita           S4                           Rare
Eastern Forktail          Ischnura verticalis       S5                           Common
Sedge Sprite              Nehalennia irene          S5                           Uncommon


Darners (Aeshnidae)
Canada Darner             Aeshna canadensis         S5                           Uncommon
Lance-Tipped Darner       Aeshna constricta         S5                           Common
Variable Darner           Aeshna interrupta         S5                           Rare

Shadow Darner             Aeshna umbrosa             S5                           Uncommon
Common Green Darner       Anax Junius                S5                           Common
Springtime Darner         Basiaeschna janata         S5                           Rare
Fawn Darner               Boyeria vinosa             S5                           Rare

Clubtails (Gomphidae)
Lilypad Clubtail          Arigomphus furcifer        S3                           Rare
Lancet Clubtail           Gomphus exilis             S5                           Uncommon
Dusky Clubtail            Gomphus spicatus           S5                           Uncommon

Twin-spotted Spiketail    Cordulegaster maculata     S4                           Rare
Arrowhead Spiketail       Cordulegaster obliqua      S1                           Uncommon

Emeralds (Corduliidae)
Beaverpond Baskettail     Epitheca canis             S5                           Uncommon
Common Baskettail         Epitheca cynosura          S5                           Uncommon
Spiny Baskettail          Epitheca spinigera         S5                           Rare

Skimmers (Libellulidae)
Calico Pennant            Celithemis elisa           S5                           Common
Eastern Pondhawk          Erythemis simplicicollis   S5                           Common
Chalk-fronted Corporal    Ladona julia               S5                           Common
Dot-tailed Whiteface      Leucorrhinia intacta       S5                           Common
Belted Whiteface          Leucorrhinia proxima       S5                           Rare
Widow Skimmer             Libellula luctuosa         S5                           Common
Twelve-Spotted Skimmer    Libellula pulchella        S5                           Common
Four-spotted Skimmer      Libellula                  S5                           Common
Painted Skimmer           Libellula semifasciata     S2                           Rare, vagrant?
Blue Dasher               Pachydiplax                S5                           Common
Spot Winged Glider        Pantala hymenaea           S4                           Rare, vagrant
Eastern Amberwing         Perithemis tenera          S3                           Uncommon
Common Whitetail          Plathemis lydia            S5                           Common
Wandering Glider          Pantala flavescens         S4                           Rare
Saffron-winged            Sympetrum costiferum       S4                           Rare
Cherry-faced              Sympetrum internum         S5                           Common?
White-faced               Sympetrum obtrusum         S5                           Common
Ruby Meadowhawk           Sympetrum                  S5                           Common?
Band-winged               Sympetrum                  S4                           Uncommon
Meadowhawk                semicinctum
Autumn Meadowhawk         Sympetrum vicinum          S5                           Uncommon

Black Saddlebags             Tramea Lacerata       S4                                Common,breeding

             Appendix F: Butterflies of the Sixteen Mile Creek Watershed

Harvester                    Feniseca tarquinius   S4                                Rare
Common buckeye               Junonia coenia        SZB                               Rare
Purplish copper              Lycaena helloides     S3                                Extirpated
Bronze copper                Lycaena hyllus        S5                                Uncommon
American copper              Lycaena phlaeas       S4                                Uncommon
Acadian hairstreak           Satyrium acadicum     S4                                Uncommon

Skippers (Hesperiidae)
Common roadside skipper      Amblyscirtes vialis   S4                                Rare
Arctic skipper               palaemon              S5                                Common
Wild-indigo duskywing        Erynnis baptisiae     S4                                Rare
Columbine dusky-wing         Erynnis lucilius      S4                                Rare
Two-spotted skipper          Euphyes bimacula      S4                                Rare
Black dash                   Euphyes conspicua     S3S4                              Rare
Dion skipper                 Euphyes dion          S3S4                              Uncommon
Indian skipper               Hesperia asaaacus     S4                                Rare
Leonardus skipper            Hesperia leonardus    S4                                Rare
Common sooty-wing            Pholisora catullus    S3S4                              Rare
Mulberry wing                Poanes massasoil      S3                                Rare
Broad-winged skipper         Poanes viator         S4                                Uncommon
Common checkered white       Pontia protodice      SZB                               Extirpated

Meadow fritillary            Boloria bellona       S5                                Uncommon
Silver-bordered fritillary   Boloria selene        S5                                Uncommon
Eastern pine-elfin           Callophrys niphon     S5                                Uncommon
Silvery checker-spot         Chlosyne nyctcis      S4S5                              Uncommon
Monarch                      Danaus plexiippus     S4        SC            SC        Common
Baltimore checkerspot        Euphydryas phaeton    S4                                Uncommon
Coral hairstreak             Harkenclenus titus    S4                                Uncommon
Aprodite fritillary          Lycaena aphrodite     S5                                Uncommon
Milbert's tortoise-shell     Nymphalis milberti    S5                                Rare
Compton tortoise-shell       Nymphalis valiabum    S5                                Uncommon
Giant swallowtail            Papilio cresphontes   S2                                Rare
Tawny crescent               Phycoides batesii     S4                                Rare

Gray comma                   Polygonia progne      S2                           Rare
Edward's hairstreak          Satyrium edwardsii    S4                           Rare

Whites and Sulphurs
Little sulphur               Eurema lisa           SZB                          Rare
West Virginia White          Pieris virginiensis   S3                 SC        Common
Harvester                    Feniseca tarquinius   S4                           Rare
Common buckeye               Junonia coenia        SZB                          Rare
Purplish copper              Lycaena helloides     S3                           Extirpated
Bronze copper                Lycaena hyllus        S5                           Uncommon
American copper              Lycaena phlaeas       S4                           Uncommon
Acadian hairstreak           Satyrium acadicum     S4                           Uncommon

Skippers (Hesperiidae)
Common roadside skipper      Amblyscirtes vialis   S4                           Rare
Arctic skipper               palaemon              S5                           Common
Wild-indigo duskywing        Erynnis baptisiae     S4                           Rare
Columbine dusky-wing         Erynnis lucilius      S4                           Rare
Two-spotted skipper          Euphyes bimacula      S4                           Rare
Black dash                   Euphyes conspicua     S3S4                         Rare
Dion skipper                 Euphyes dion          S3S4                         Uncommon
Indian skipper               Hesperia asaaacus     S4                           Rare
Leonardus skipper            Hesperia leonardus    S4                           Rare
Common sooty-wing            Pholisora catullus    S3S4                         Rare
Mulberry wing                Poanes massasoil      S3                           Rare
Broad-winged skipper         Poanes viator         S4                           Uncommon
Common checkered white       Pontia protodice      SZB                          Extirpated

Meadow fritillary            Boloria bellona       S5                           Uncommon
Silver-bordered fritillary   Boloria selene        S5                           Uncommon
Eastern pine-elfin           Callophrys niphon     S5                           Uncommon
Silvery checker-spot         Chlosyne nyctcis      S4S5                         Uncommon
Monarch                      Danaus plexiippus     S4       SC        SC        Common
Baltimore checkerspot        Euphydryas phaeton    S4                           Uncommon
Coral hairstreak             Harkenclenus titus    S4                           Uncommon
Aprodite fritillary          Lycaena aphrodite     S5                           Uncommon
Milbert's tortoise-shell     Nymphalis milberti    S5                           Rare
Compton tortoise-shell       Nymphalis valiabum    S5                           Uncommon
Giant swallowtail            Papilio cresphontes   S2                           Rare
Tawny crescent               Phycoides batesii     S4                           Rare

Gray comma            Polygonia progne     S2                           Rare
Edward's hairstreak   Satyrium edwardsii   S4                           Rare


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