UBC Theses and Dissertations
Effect of local habitat and landscape attributes on bird species richness and community completeness in shade coffee plantations in Colombia Gonzalez Prieto, Catalina
The loss of tropical forest for agriculture is a principal cause of declines in species diversity in the Neotropics. Shade-grown coffee plantations, where coffee plants grow under a canopy of trees, have been found to support a higher diversity of both Neotropical migrant and tropical resident birds compared to agroecosystems without trees. However, how local and landscape factors interact to affect avian biodiversity remains poorly understood. I studied the influence and interaction of local and landscape attributes on bird richness and community completeness in 160 shade coffee plantations in two regions of Colombia differing in extent of regional forest: Antioquia, where forest covered 20% of the study area and Cauca, where only 1% of forest remained. By using generalized linear models, I determined how species richness and community completeness were influenced by the local scale structure and composition of shade-grown coffee plantations (i.e., tree richness, tree abundance, and coffee density) and landscape variables surrounding the plantation (i.e., plantation distance to forest, cover by intact forest, forest-agriculture mosaic, or the combination of the two). My findings suggest that the extent of regional forest cover affects the landscape-level contribution to bird richness and community completeness within plantations. In Antioquia, richness of bird communities increased with the proportion of all forest elements within the surrounding landscape. Community completeness was influenced by the interaction between the local and landscape scales; tree richness enhanced community completeness only when the forest-agriculture mosaic cover at the landscape scale was greater than 73%. In Cauca, higher richness and abundance of trees at the local scale were associated with greater bird richness and community completeness, while there were no landscape-scale effects. Within highly deforested regions, birds are most likely to benefit in the near-term from increasing the diversity of shade trees within farms. However, reforestation efforts at the landscape scale should be considered as a long-term strategy to provide critical resources that support more complete communities of birds in coffee plantations. In more forested regions, bird communities could benefit by protecting and/or increasing the forest cover in the landscape and increasing the diversity of trees within plantations.
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