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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
forest)
– Has Highest proportion of
unique species (9%).
– Lowest species richness off all
life zones (121 regularly
occurring species).
This is due to its small
geographic extent and
isolation from the more
diverse higher elevation
faunas.
Zones 5 and 6 (Pre-montane
rain and tropical wet forests)
– On Caribbean slope (315 to
278 species, relatively)
– Most species rich life zone
– These middle-elevation zones
have highest species diversity
of any site in Costa Rica
– They are low enough in
elevation to include the upper
limit of the ranges of many
lowland species as seasonal
migrants.
Zone 6 includes a lake of 2ha 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 nonbreeding 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:
– 91 species or 21% are longdistance migrants.
– Some such as the Swallowtailed Kite or the Yellow-Green
Vireo breed in Montverde and
migrate to South America in
non-breeding season.
– They decrease in number with
increase in elevation,
occurring most commonly in
Zones 1-2 and 5-6.
– Relatively low competition
between resident and migrant
birds.
Elevational Migration:
– Ex: the Resplendent Quetzals.
– The broad pattern is a four
stage annual movement.
1) Courtship and nesting
occur in cloud forest habitats
between January and June.
2) After nesting, adults and
off-spring move to lower
elevations on Pacific slope.
Four months later birds move
back to higher elevations
used for nesting.
They then move across the
continental divide to the
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 RainShadow Forests.
3. Corridor provides critical biological area
for the region.