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.

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

Iwokrama Forest in Guyana

Bat Biology Bats are mammals – they have hair, give birth to live young, and feed them milk from mammary glands. Bats, like humans, are mammals, having hair and giving birth to living young and feeding them on milk from mammary glands. However, bats are the only true flying mammals. Bats belong to the mammalian order Chiroptera, which means "hand-wing." The bones in a bat's wing are the same as those of the human arm and hand, but bat finger bones are greatly elongated and connected by a double membrane of skin to form the wing. Bats primarily are nocturnal, although many fly early in the evening, sometime before sunset.

Bat Biology Bats are the only mammals that fly – fingers in the hand have been elongated into a wing. Bats, like humans, are mammals, having hair and giving birth to living young and feeding them on milk from mammary glands. However, bats are the only true flying mammals. Bats belong to the mammalian order Chiroptera, which means "hand-wing." The bones in a bat's wing are the same as those of the human arm and hand, but bat finger bones are greatly elongated and connected by a double membrane of skin to form the wing. Bats primarily are nocturnal, although many fly early in the evening, sometime before sunset.

Echolocation Although bats have relatively good eyesight, most depend on their superbly developed echolocation (or sonar) system to navigate and capture insects in the dark. Bats emit pulses of very high-frequency sound (inaudible to human ears) at a rate of a few to 200 per second. By listening to the echoes reflected back to them, they can discern objects in their path. Their echolocation ability is so acute they can avoid obstacles no wider than a piece of thread and capture tiny flying insects even in complete darkness.

Importance of bats Ecosystem services Seed dispersal Pollination Maintain forest dynamics Regeneration Although bats have relatively good eyesight, most depend on their superbly developed echolocation (or sonar) system to navigate and capture insects in the dark. Bats emit pulses of very high-frequency sound (inaudible to human ears) at a rate of a few to 200 per second. By listening to the echoes reflected back to them, they can discern objects in their path. Their echolocation ability is so acute they can avoid obstacles no wider than a piece of thread and capture tiny flying insects even in complete darkness.

One of the highest species diversity in the world >85 species Bats in Iwokrama One of the highest species diversity in the world >85 species Species accumulation curve for bats collected in Iwokrama Forest, Guyana

Feeding guilds Insectivores (invertebrates) Insect-eating bats may either capture flying insects in their mouths or scoop them into their tail or wing membranes. They then reach down and take the insect into their mouth. This results in the erratic flight most people are familiar with when they observe bats flying around in the late evening or around lights at night.

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 Bats can be caught in mist nets like those used for birds

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? Bats can be caught in mist nets like those used for birds

Tasks for this dataset Research Question 1: Research Question 2: 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? Bats can be caught in mist nets like those used for birds

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. Bats can be caught in mist nets like those used for birds

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. Bats can be caught in mist nets like those used for birds