PARENT SESSION
Oral Session # 99: Late-Breaking Newsworthy Presentations.
Presiding: E Preisser and G Larocque
Friday, August 8. 8:30 AM to 12:00 PM, SITCC Meeting Room 205.
The impact of fine-scale land cover variation on tropical avian species persistence.
Ranganathan, Jai *,1, Daily, Gretchen1, Ehrlich, Paul1, 1 Center for Conservation Biology, CA, 94305, USA
ABSTRACT- Understanding the role of fine-scale (< 1 km) land cover variation in human-dominated areas is a critical concern in conservation planning. From June-September 2002, we studied this question for avian communities in the vicinity of the Las Cruces Biological Station, Costa Rica, a region with 22% of native rainforest remaining and a fine-grained mixture of coffee, pasture, and other land covers in the cleared areas. We assessed bird communities and patterns of land cover within 12 sites, each centered on a small (1-6 ha) forest fragment and extending outward 300 m from the edge of the fragment. These sites captured the range of land cover variation present in the region (e.g. the proportion of pasture across sites ranged from 0.08 to 0.44, the proportion of coffee ranged from 0.01 to 0.57). Within each site, bird communities were investigated with 50 m-radius point counts in 6 different open and closed habitat types. We found that there were three distinct bird communities across sites: a forest and riparian habitat species suite, a pasture habitat suite, and a cultivated and fallow suite. Variation in land cover across sites did not significantly explain variation within each species suite. However, adjacent land cover (< 50 m distant) did significantly affect bird communities within the central forest fragments, with 42% of the species overlap across sites in forest fragments explained by cover variation. Forest remnants contain the most-threatened species in the region and efforts focused on improving the habitatability of the areas immediately adjacent to them could potentially yield large conservation benefits.
Key words: biodiversity conservation, countryside biogeography, neotropical birds