Skip to main content
WCS
Menu
Library
Library Catalog
eJournals & eBooks
WCS Research
Archives
Research Use
Finding Aids
Digital Collections
WCS History
WCS Research
Research Publications
Science Data
Services for WCS Researchers
Archives Shop
Bronx Zoo
Department of Tropical Research
Browse By Product
About Us
FAQs
Intern or Volunteer
Staff
Donate
Search WCS.org
Search
search
Popular Search Terms
WCS History
Library and Archives
Library and Archives Menu
Library
Archives
WCS Research
Archives Shop
About Us
Donate
en
fr
Title
Ecological meltdown in predator-free forest fragments
Author(s)
Terborgh, J; Lopez, L; Nunez, P; Rao, M; Shahabuddin, G; Orihuela, G; Riveros, M; Ascanio, R; Adler, GH; Lambert, TD; Balbas, L
Published
2001
Publisher
Science
Abstract
The manner in which terrestrial ecosystems are regulated is controversial. The "top-down" school holds that predators Limit herbivores and thereby prevent them from overexploiting vegetation. "Bottom-up" proponents stress the role of plant chemical defenses in limiting plant depredation by herbivores. A set of predator-free islands created by a hydroelectric impoundment in Venezuela allows a test of these competing world views. Limited area restricts the fauna of small (0.25 to 0.9 hectare) islands to predators of invertebrates (birds, lizards, anurans, and spiders), seed predators (rodents), and herbivores (howler monkeys, iguanas, and leaf-cutter ants). Predators of vertebrates are absent, and densities of rodents, howler monkeys, iguanas, and leaf-cutter ants are 10 to 100 times greater than on the nearby mainland, suggesting that predators normally Limit their populations. The densities of seedlings and saplings of canopy trees are severely reduced on herbivore-affected islands, providing evidence of a trophic cascade unleashed in the absence of top-down regulation.
Keywords
TROPHIC CASCADES; COMMUNITY STRUCTURE; HYPOTHESIS; ECOSYSTEMS; VEGETATION; ISLANDS; FOOD
Access Full Text
A full-text copy of this article may be available. Please email the
WCS Library
to request.
Back
PUB11398