A large-scale deforestation experiment: effects of patch area and isolation on Amazon birds

As compared with extensive contiguous areas, small isolated habitat patches lack many species. Some species disappear after isolation; others are rarely found in any small patch, regardless of isolation. We used a 13-year data set of bird captures from a large landscape-manipulation experiment in a Brazilian Amazon forest to model the extinction-colonization dynamics of 55 species and tested basic predictions of island biogeography and metapopulation theory. From our models, we derived two metrics of species vulnerability to changes in isolation and patch area. We found a strong effect of area and a variable effect of isolation on the predicted patch occupancy by birds. Tropical forests are among the world’smost threatened ecosystems, which areunder severe pressure by human activ-ities, primarily deforestation (1). Deforestation reduces forest area and frequently isolates re-maining forest patches. Island biogeography (2) and metapopulation (3) theories predict the ef-fects of reduced area and increased isolation on rates of species extinction and colonization an