Urbanization and Wildlife

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					Urbanization
and Wildlife
Why do we care about urbanization?
• Globally
   – Roughly 39-50% of land has been converted to
     human uses
   – The world’s urban population was 50% in 2000 and
     is expected to reach 70% by 2050
   – About 17% of land is protected
• In the U.S.
   – Urban land increased by 1.1 million acres per year
     between 1960-1980
   – By 1989, 74% of the population lived in urban areas
• In Central Puget Sound
   – The population has increased by 2 million people
     since 1960
More and more people are living in urban areas




                                          DeStefano et al (2005)
Location of cities exaggerate impacts:
coasts, river mouths, lakes, fertile inland areas.

Natural resource production is displaced and therefore a larger area of
more intensively used area is needed for wood and agricultural products
      Puget Trough Ecoregion (2)
Occupies 8% of the land area of the state, but
contains over 70% of Washington's human
population.
Urban areas have large                                                     23% too high




                                         Ecological footprint (# earths)
 ecological footprints
• Amount of land and water area a
  human population requires to
  produce the resources it consumes
  and to absorb its wastes
• A larger, more intensively used area
  is needed to support urban areas
• Urban footprints can be highly
  dispersed: Chicago’s famous pizza
   – cheese from Wisconsin
   – flour from Kansas
   – oven from Japan
          Urban Sprawl
A form of urbanization distinguished by
   – Large areas of single-use
     development (residential)
• Heavy reliance on automobiles
  – Minimal public open space
  – Leapfrog patterns
  – Commercial strips
  – Low density
4% population increase drove
 49% increase in developed
            land
Urban sprawl in eastern King County
          (1974  1998)
A Tidal Wave of Sprawl is Likely to
  Come from Developing Areas
                           (WRI 1996)




           Becoming More
           Urban



      Sprawling From
      Urban Centers
              Contrasting Various Land Covers


          High
                              Urbanization

Persistence                                     Effect of
    of                           Agriculture Fragmentation
 Change
                    Timber
                    Harvest
          Low
                 High                   Low
          Similarity of Matrix to Natural Habitat
                                         (Marzluff and Ewing 2001)
Where is Urban?
URBAN IN INDIA
URBAN IN JAPAN
URBAN IN CHINA
URBAN IN PANAMA
URBAN IN CANADA
URBAN IN THE US
URBAN IN BOTSWANA
The World’s Urban Centers
 CITY                                                           POPULATION
                                                                              (millions)
Tokyo, Japan ..........................................................          34.450
Mexico City, Mexico ...............................................              18.066
New York-Newark, USA .........................................                   17.846
São Paulo, Brazil ....................................................           17.099
Mumbai (Bombay), India .........................................                 16.086
Calcutta, India .........................................................        13.058
Shanghai, China .....................................................            12.887
Buenos Aires, Argentina .........................................                12.583
Delhi, India ..............................................................      12.441
Los Angeles-Long Beach-Santa Ana, USA ............                               11.814
Regional Comparison
        URBAN AREA
      Land area within city limits
                    Area: 6200 km² (2418 sq mi)
 SHANGHAI           Population: 14 million


MEXICO CITY         Area: 1,487 km² (574 sq mi)
                    Population: 9.8 million


                    Area: 217.4 km² (83.9 sq mi)
   SEATTLE          Population: 570,800
URBAN GRADIENT




           Land Cover Classes
    The Urban Gradient
urban   suburban exurban           wildland




        • Shift in
          Imperviousness (paved)
          Forest cover
          Exotic species
          Biodiversity
                             r
                                                                                          r   telemetry study sites
                                                                                         2002 classified landcover
                                                                                              heavy-medium urban
                                                                                              light urban
                                         r
                                     r                                                        cleared land
                                                                                              grass
                                                                                              mixed forest
                                                                                              clearcut forest
                     r                                                                        regenerating forest
                                                                                              agriculture
                                                                                              nonforested wetlands
    r                                                                                         open water
                         r
                                                                                              bare rock/snow/ice
        urban        suburban                                                                 shoreline
                                                                                              999
                                                         r                                    No Data
                                                             r
                                                                 r



                                                                 exurban-rural
        Seattle                                                      r
                                                                                 r
                                                                                     r
                                                                             r

                             r
                                                                         r
                                 r
                                             r

                                                 r   r
                                                                             wildland
0               10               20                                      30                     40 Kilometers
Settlement Affects Native Habitat

• Habitat Loss
• Reduced connection
  among remaining patches
• Perforation of large
  patches
• Increased edge &
  degradation of remaining
  habitat
• Introduction of non-
  natives
      Settlement has varying effects on
              wildlife species

 Some benefits:           Some costs:
• Reduced predation       • Increased predation
• Reduced climatic        • Reduction in nest sites
   extremes               • Reduced food
• Available water         • New disturbances
• Supplemental food       • Increased edge and
• New nest sites            vegetative diversity
• Increased edge and
   vegetative diversity
Diversity patterns associated w/ urbanization
                                          Species richness peaks
                                          w/ moderate
                                          development then
                                          decreases.


                 Blair & Johnson (2008)   Why?




                                                 Marzluff (2005)
       Effects of Urbanization
• Convenient to think of wildlife in
  three categories
  – urban avoiders
  – urban adapters
  – urban exploiters
       Effects of Urbanization
• Declining and threatened/endangered
  species are usually native urban avoiders
  suffering from
  – habitat loss, fragmentation
  – interaction with non-native species (predation
    and competition)
      Effects of Urbanization
• Urban avoiders in Puget Sound
       Settlement Benefits Some
               Wildlife
•   Reduced predation
•   Available water
•   Supplemental food
•   New nest sites
•   Increased edge and vegetative diversity
           Effects of Urbanization
• Urban adapters can benefit from urbanization if
  sufficient native habitat remains
  – able to live in small patches and/or
  – adapt to altered environment
          Effects of Urbanization
• Urban exploiters increase with urbanization and
  exploit new & altered environment
  – Both native and non-native
  – Serve to homogenize species in cities
Loss of native specialists (avoiders) and gains in generalist and
synanthropic species (adapters and exploiters) explain diversity
patterns




                                                         Marzluff (2005)
Marzluff & Rodewald (2008)
Other general trends associated w/ urbanization




Blair & Johnson (2008)




                                     Marzluff & Rodewald (2008)
Other general trends associated w/ urbanization




          Blair & Johnson (2008)
    Some birds found consistently in cities
             around the world


Global
homogenization
of some wildlife
communities a
concern.
Wildlife communities change along
  the urban to wildland gradient
   Loss and fragmentation of original habitat

 Shift in vegetative structure and composition of
       habitat fragments and the urban matrix

  Alteration of population dynamics processes
       (reproduction, survivorship, dispersal)

           Species losses and gains
          Effects of Urbanization
• Other organisms in cities:
  – More non-native plants, insects with increased
    urbanization
  – Greater plant diversity in larger habitat patches
  – Small mammal diversity and density decrease with
    urbanization
Primary Problems for Urban Wildlife
• Loss of habitat (amount and
    connectivity)
•   Simplification of habitat (quality,
    exotics)
•   Invasion by exotic species
    (competition, disease)
Primary Problems for Urban Wildlife
• Predation by domestic animals (cats,
    dogs)
•   Predation by wild animals (corvids,
    squirrels, rats)
•   Increase in accidents (cars, windows,
    power lines, fences)
     Raptors as City Dwellers
Some raptor species can thrive in urban areas
• able to use artificial nest platforms
• find abundant prey
• relatively free from persecution
Suburban v Rural Eastern Screech Owls in Texas:
       Nested earlier (urban heat island)
       Larger clutches (more food)
       More and larger fledglings (food and low predation)
       More recruits into population
       Higher fitness
            Controlling Sprawl
• Sprawl is a strong driver of the urban footprint
   – results in loss, fragmentation, and degradation of
     habitat
   – increases energy use
   – increases pollution from commuting
• Growth Management is needed to control it
   – Limits most future growth inside Urban Growth
     Boundary
   – May just displace the problem if regional planning is
     not incorporated (leapfrogging)
Growth Management Act - King County Comprehensive
                      Plan
           Subdivision Planning


                            Clustered subdivision has
                            • smaller lots
                            • higher density of homes
                            • majority of the site left
                            as open space
                                          Gillham 2002


standard        clustered
Wildlife Conservation in Urban
            Areas

1. Preserve large areas of habitat
 the area, numbers, and connectivity of reserves
  should be maximized
 buffers should be maintained around reserves
 the amount of edge and degree of fragmentation
  within reserves should be minimized
 the scale of reserve planning should be expanded
  beyond the local area to include entire watersheds
  and bioregions
(Marzluff and Ewing 2001)
Wildlife Conservation in Urban
            Areas

 2. Enhance habitat locally
 • Retain as much natural habitat
   as possible (especially new
   housing)
 • Plant native plants, fruit-
   producing exotics
 • Retain understory and snags
 • Minimize lawn cover
Wildlife Conservation in Urban
            Areas
 3. Provide essential resources:
     Places to breed (nest boxes, platforms,
     trees)
     Feeding stations (squirrels, birds)
     Water
     Cover (vegetation)
 4. Provide protection from domestic
  predators
    • control dog and cat behavior
Wildlife Conservation in Urban
            Areas
 5. Reduce accidental mortality:
     • Birds crashing into windows
        • 3.5 million birds/yr
     • Birds hitting buildings, towers, etc.
        • 1.5 million birds/yr
     • Avoid planting fruit-bearing plants/trees
       next to highways
     • Clean bird feeders frequently
       (Salmonella)
 Wildlife Conservation in Urban
             Areas



6. Support urban planning
 initiatives and education
    • Clustered development
    • Growth management
    • Open space preservation

				
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