Tropical forest fragmentation and nest predation - an experimental study in an Eastern Arc montane forest, Tanzania

Abstract

When a habitat becomes fragmented and surrounded by another habitat this generally causes an increase in predation pressure at habitat transitions, often referred to as an edge effect. Edge effect in the form of enhanced nest predation intensities is one of the most cited explanations for bird population declines in fragmented landscapes. Here, we report results from a nest predation experiment conducted in a tropical montane forest landscape in the Uzungwa Mts., Tanzania. Using artificial nests with chicken eggs, we determined predation rates across a fragmentation gradient. The proportion of indigenous forest in four landscapes used in the study were 0.29, 0.58, 0.75 to 1.0. Nest predation intensities on artificial nests were about 19% higher inside intact forest than at edges in fragmented forest landscapes. Furthermore, predation intensities were relatively constant across a forest fragmentation gradient. Our results thus challenge the applicability and generality of the edge effect, derived from studies almost exclusively conducted in temperate regions rather than tropical forest ecosystems. Nest predation levels differences between tropical montane forest and that reported in other forest ecosystems are discussed.

Keywords

Afro-tropical montane-forest; edge effect; fragmentation; nest predation

Published in

Biodiversity and Conservation
2001, volume: 10, number: 7, pages: 1077-1085

SLU Authors

• Carlson, Allan

  • Department of Conservation Biology, Swedish University of Agricultural Sciences
    

• Hartman, Göran

  • Department of Conservation Biology, Swedish University of Agricultural Sciences
    

UKÄ Subject classification

Ecology

Publication identifier

• DOI: https://doi.org/10.1023/A:1016649731062

Permanent link to this page (URI)

https://res.slu.se/id/publ/51809