Introduction to Central American forests

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Introduction to Central American forests
WALLACE RESOURCE LIBRARY
Module 04 - Ecosystems: Tropical Forests
D04 – Abundance of bat feeding guilds in
the Iwokrama Forest, Guyana
What is a Rainforest?
• Tropical rainforest ecosystems
are characterized by high rainfall
and located in the equatorial
zone between the tropics of
Cancer and Capricorn.
• Mean temperatures are mostly
above 18°C for most of the
year although cloud forests are
generally much cooler.
2
Where do you find the trees?
Trees and plants grow in layers called ‘strata’ - there are 4
layers, each with different plants and animals.
Emergent
Canopy
Understory
Floor herb layer
3
Iwokrama Forest in Guyana
4
Bat Biology
• Bats are mammals – they have hair, give birth to live young,
and feed them milk from mammary glands.
Bat Biology
• Bats are the only mammals that fly – fingers in the hand
have been elongated into a wing.
Echolocation
Importance of bats
• Ecosystem services
– Seed dispersal
– Pollination
• Maintain forest dynamics
• Regeneration
Bats in Iwokrama
• One of the highest species diversity in
the world >85 species
Feeding guilds
• Insectivores (invertebrates)
Feeding guilds
• Frugivore (Fruits)
Feeding guilds
• Nectarivore (nectar)
Feeding guilds
• Omnivores (plant products and animals)
Feeding guilds
• Carnivores (frogs, fish, lizards, even birds)
Feeding guilds
• Sanguinivore (Blood) – Vampire bats
Population Monitoring
• Bats marked to monitor
recaptures
• Mist nets used to sample
the forest understorey
Research questions
• Which feeding guilds are represented by the greatest numbers
of bats in the Iwokrama Forest?
• How does the abundance of bat feeding guilds vary between
sites across the Iwokrama Forest?
Tasks for this dataset
• Research Question 1:
– Which feeding guilds are represented by the greatest numbers of bats in
the Iwokrama Forest?
• Research Question 2:
– How does the abundance of bat feeding guilds vary between sites across
the Iwokrama Forest?
Q1 - Which feeding guilds are represented by the greatest
numbers of bats in the Iwokrama Forest?
• Frugivorous bats comprise the majority of the bat community in
the Iwokrama Forest, with insectivores the next most common
feeding guild, followed by nectarivores, omnivores, and finally
sanguinivores and carnivores.
• This suggests that fruits are a more abundant food source in the
Iwokrama forest, and therefore supports higher numbers of
animals that feed on that resource.
Q2 - How does the abundance of bat feeding guilds vary
between sites across the Iwokrama Forest?
• There is large variation in the abundance of bats from each feeding guild
between sites. At every site however, frugivores are the most common guild,
with insectivores the next most abundant.
• The remaining guilds are consistently much less abundant across all sites.
– Rock Landing, the never flooded savannah edge forest type, contained the highest number of
bats from all feeding guilds.
– Canopy Walkway, the never flooded Dakama forest type (dominated by the plant species
Dimorphandra conjugata), is home to the lowest numbers of bats in general, however
frugivores are still the most abundant.
– The remaining three sites which are seasonally flooded and classed as greenheart forest
(dominated by Chlorocardium rodiei) revealed broadly similar patterns to one-another.
• Forest type may therefore be an important determinant of bat communities in
the Iwokrama Forest, and this may be due to some forest types naturally
containing greater numbers of fruits for frugivorous bat species.

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