brian by wanghonghx

VIEWS: 6 PAGES: 19

									      Monteverde

The Study of birds and their
relationships in Monteverde.
What started the interests in bird
       life in Monteverde
The first biologists to enter this region where
ornithologists William Buskirk and George
Powell.
– They where attracted by the low stature of the cloud
  forest, which made research on mixed-species flocks
  more tractable than in tall lowland forests.
– Most research focuses in on autecological studies
  and bird-plant interaction studies (now a days most
  studies focus on plant bird interactions due to
  changes in in scientific fashion).
Reasons Why Monteverde is so
        Attractable
1) Unusual Behavior – many species of birds exhibit bizarre
behavior patterns.
2) Abundance and Ease of Study – most species have large
populations and occur close to or around ground level, making them
easier to study.
3) Changes in Avifauna Small Spatial Scales – one striking
feature is the turn over of fauna from one life zone to the next. In a
short walk one can pass through six life zones and see the different
avian.
4) Dramatic Coloration – many scientists and bird enthusiasts are
attracted to the aesthetic appeal of the avian community (i.e. the
Resplendent Quetzal).
5) Alluring Setting – agreeable climate, spectacular views, bilingual
populace, and international expatriates that welcomes biologists
draws many from ornithologists community.
Distribution, Species Richness, and
               Diversity
 What makes Monteverde so unique is that most
 other areas of Costa Rica have either dry or wet
 forest fauna plus some North American
 migrants, but Monteverde has all three types.
 Three Principle Regions of Monteverde.
 – 1) The Guanacaste fauna on the Pacific slope, which
   represents the Mesoamerican dry forest fauna.
 – 2) The highland fauna, a distinct group of species that
   occur in Costa Rica and Chiriqui, Panama highlands.
 – 3) The wet forest fauna of the Caribbean slope.
      It is derived primarily from South American groups where as
      the highland and Guanacaste fauna are a mixture of North
      and South American groups.
      Life Zone Distribution
With a steep dry season gradient of
increasing moisture from Pacific to
Caribbean slope, create remarkably
distinct vegetation in the different life
zones.
– This also causes Avian species diversity to
  vary across the different life zones.
        Life Zones Continued
Zone 4 (Lower Montane rain          Zones 5 and 6 (Pre-montane
forest)                             rain and tropical wet forests)
– Has Highest proportion of          – On Caribbean slope (315 to
  unique species (9%).                 278 species, relatively)
– Lowest species richness off all    – Most species rich life zone
  life zones (121 regularly          – These middle-elevation zones
  occurring species).                  have highest species diversity
      This is due to its small         of any site in Costa Rica
      geographic extent and
      isolation from the more
                                     – They are low enough in
      diverse higher elevation         elevation to include the upper
      faunas.                          limit of the ranges of many
                                       lowland species as seasonal
                                       migrants.
                                           Zone 6 includes a lake of 2-
                                           ha that attracts water birds
                                           not seen elsewhere in
                                           Montverde.
The Importance of the Corridor
The Corridor is the space between the Cloud
Forest and Rain-Shadow Forest.
The Monteverde Corridor is an ecological
connection between the highlands and the
lowlands. Corridors are critical for area-sensitive
species which require large, interconnected
areas to maintain viable populations.
Corridors will interconnect various plant, and
animal habitats.
Species Accumulation Curve
Zone 6 on the Caribbean slope site is much
more diverse than that of the Pacific slope and
after several hundred captures, there is no
indication of the level of species richness at
which the curve will flatten out.
– Most research takes place on the Pacific slope where
  species richness is intermediate.
The rate of accumulation of species is plotted as
a function of the number of mist-net captures.
– Canopy species are under represented
Differences between Pacific and
        Caribbean slopes
Elevational migration is much less pronounced
on the Pacific slope, breeding species tend to
remain resident year round on their territories.
– Ecological differences are between dry forests and
  the moist highland forests of the Caribbean side: may
  hinder migration.
– Problem: Deforestation is more pronounced on
  Pacific slope where there tends to be more seasonal
  migration between adjacent dry and gallery forests.
Restriction of Species to one life
               zone
The pattern of species occurring only in specific
life zones is remarkable because habitat
specialization occurs on a very small spatial
scale.
Most species of birds can only be found in one
of the six principle life zones.
– As one walks from the Pacific slope to the Caribbean
  slope a series of distinct bird communities is found.
– This causes a high alpha species diversity (many
  species in one habitat) and a high beta species
  diversity (a high turnover of species across adjacent
  habitats.
               Migration
Bird populace consists of permanent
residents, seasonal migrants, and
elevational migrants.
– Long distance migrants either breed in North
  or Central America during the summer and
  migrate down to Costa Rica during the non-
  breeding season.
– Elevational Migrants breed at one elevation
  during the non-breeding season and migrate
  to other slopes during non-breeding season.
               Migration Types
Long Distance Migration:            Elevational Migration:
– 91 species or 21% are long-        – Ex: the Resplendent Quetzals.
  distance migrants.                 – The broad pattern is a four
– Some such as the Swallow-            stage annual movement.
  tailed Kite or the Yellow-Green          1) Courtship and nesting
  Vireo breed in Montverde and             occur in cloud forest habitats
  migrate to South America in              between January and June.
  non-breeding season.                     2) After nesting, adults and
– They decrease in number with             off-spring move to lower
                                           elevations on Pacific slope.
  increase in elevation,
  occurring most commonly in               Four months later birds move
                                           back to higher elevations
  Zones 1-2 and 5-6.                       used for nesting.
– Relatively low competition               They then move across the
  between resident and migrant             continental divide to the
  birds.                                   Caribbean slope until nesting
                                           season approaches.
           Why Migrate?
The pattern is to believed too be the result
of the availability of food sources such as
the family of Lauraceae.
Monteverde Corridor for
 Endangered Species
Distinct Species in Each Reserve
Due to amount of moisture and altitude, the
species are distinctly different in each type of
forest.
Cloud Forest has 160 tree species.
Rain-Shadow Forest has 132 tree species.
Only ten of these tree species can be found in
both areas.
21 bird species in Rain-Shadow Forest never
live in the Cloud Forest.
 Lauraceae Tropical Trees




Part of Avocado Family.
Primary source of food for birds and
mammals.
Rain-Shadow has 17 species.
Cloud Forest has 13 species.
– Not one species can be found in both
  areas.
                    Problems

   Not much rain-shadow forest is left.
    – Due to cattle raising & coffee growing, large Costa
      Rican industries.
• Also because when birds migrate lower, they
crowd into the remaining forest and eat
anything that has not been eaten.
• So little of what is left is protected.
• An estimated 2,000 acres is needed to be
protected to be sure of the rain-shadow forests
survival.
• Currently only 650 acres are protected.
  Three
Important
Ecological
Functions

  1. Corridor is critical habitat for fruit-eating
     birds.
  2. Corridor will Protect Endangered Rain-
     Shadow Forests.
  3. Corridor provides critical biological area
     for the region.

								
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