Time lag between deforestation and bird extinction in tropical forest fragments

Journal Article (Journal Article)

Tropical forests are becoming increasingly fragmented, threatening the survival of the species that depend on them. Small, isolated forest fragments will lose some of their original species. What is uncertain is how long this process of faunal relaxation will take. We compiled data on birds in five tropical forest fragments in Kakamega Forest, Kenya, of known date of isolation. We then predicted the original and eventual species richness of these fragments and, from this difference, the eventual species losses. Expressing the losses to date as a fraction of eventual losses suggests that faunal relaxation approximates an exponential decay with a half-life of approximately 50 years for fragments of roughly 1000 ha. In other words, in the first 50 years after isolation, tropical forest fragments of this size suffer half of the total number of extinctions that they are likely to experience. This result sets the time scale over which humanity must take conservation action in fragmented tropical forests, may aid efforts to set priorities, and indicates how high the future global extinction rate will be.

Full Text

Duke Authors

Cited Authors

  • Brooks, TM; Pimm, SL; Oyugi, JO

Published Date

  • October 1, 1999

Published In

Volume / Issue

  • 13 / 5

Start / End Page

  • 1140 - 1150

International Standard Serial Number (ISSN)

  • 0888-8892

Digital Object Identifier (DOI)

  • 10.1046/j.1523-1739.1999.98341.x

Citation Source

  • Scopus