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
Increased herbivory in forest isolates: Implications for plant community structure and composition
Author(s)
Rao, M.; Terborgh, J.; Nunez, P.
Published
2001
Publisher
Conservation Biology
Published Version DOI
https://doi.org/10.1046/j.1523-1739.2001.015003624.x
Abstract
Understanding processes driving population declines and, ultimately, species loss in forest isolates has significant implications for the long-term maintenance of species diversity. We investigated a potential mechanism driving loss of plant species in small, medium, and large land-bridge islands in Lago Guri, a 4300-km2 hydroelectric impoundment in the State of Bolivar, Venezuela. Our hypothesis was that elevated Atta (leaf-cutter ants) herbivory on small Guri islands, attributable to release from predation, could result in reduced sapling densities, with potentially negative effects on preferred plant species. We experimentally established Atta preferences among 43 common tree species. Vegetation plots on small, medium, and large land masses were examined for variation in density, size-class distribution, and representation of preferred and less preferred species of small stems. Densities of adult trees of preferred and less preferred species were compared between Atta colony foraging zones and control plots without active Atta colonies, and between foraging zones on the small islands and the large island. Small stem densities were significantly reduced on the small islands, especially in the sapling category (=1 m tall, <1 cm dbh). On medium and large land masses, preferred species were underrepresented in both sapling (=1 m tall, <1 cm dbh) and juvenile (=1 cm dbh, <10 cm dbh) size classes. On small islands, however, both preferred and less preferred species showed reduced representation in the sapling size class. Adults of preferred species were significantly reduced within Atta foraging zones compared with control plots without Atta colonies. Small stem densities were independent of adult tree densities for preferred species on small islands and for both preferred and less preferred species on large land masses. High levels of Atta herbivory could be a potentially important cause of reduced plant recruitment on small Guri islands. Our findings contribute to understanding of the role of altered ecological interactions as deterministic mechanisms driving a process of change in the structure and composition of fragmented communities.
Keywords
community composition; community structure; habitat fragmentation; isolated population; plant community; plant-herbivore interaction; Venezuela; Animalia; Atta; Formicidae; Hymenoptera; LEAF-CUTTER ANT; ATTA-CEPHALOTES HYMENOPTERA; LEAFCUTTING ANT; DIET SELECTION; DIVERSITY; CHEMISTRY; BIOGEOGRAPHY; TOUGHNESS; PREDATION
Access Full Text
A full-text copy of this article may be available. Please email the
WCS Library
to request.
Back
PUB12651