Publication Date

2009-09-23

Availability

Open access

Degree Type

Dissertation

Degree Name

Doctor of Philosophy (PHD)

Department

Biology (Arts and Sciences)

Date of Defense

2009-09-02

First Committee Member

Michael S. Gaines - Committee Chair

Second Committee Member

William A. Searcy - Committee Member

Third Committee Member

David Janos - Committee Member

Fourth Committee Member

W. Douglas Robinson - Outside Committee Member

Abstract

Habitat loss and fragmentation occur at unprecedented rates, especially in tropical countries where human activities have deforested or degraded around 80% of tropical rainforests. Tropical forest fragmentation is considered the main cause of extinction of tropical forest avifauna, yet the mechanisms by which fragmentation affects bird populations are poorly understood. The present study investigates the pattern of bird species distribution in a fragmented landscape in tropical southeastern Mexico and the relation of bird community and species distribution patterns to landscape and fragment characteristics. Area and isolation of forest fragments were the main determinant of species richness and abundance in fragments, especially for forest-dependent species. The significant effect of isolation on species persistence in forest fragments suggests that limitation of dispersal is one potential mechanism by which fragmentation affects species distribution in the landscape. To understand how fragmentation can affect bird dispersal in a fragmented landscape, the effect of open areas and corridors on movement patterns of forest birds was investigated. The evidence presented in this study supports the idea that bird movement is restricted by open areas, especially for forest-restricted birds. Forested corridors had a positive effect on movement rates of forest birds, potentially acting to preserve movement and dispersal processes, and ultimately species persistence, in heavily fragmented landscapes.

Keywords

Mexico; Gap-crossing; Isolation; Forest Corridors; Species Distribution

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