Abstract
Forests worldwide are experiencing rapid environmental change due to human activity. We aimed to increase understanding of anthropogenic impacts on community composition and species interactions. In a natural experiment, we asked whether subsistence human land use has altered the community composition of a Neotropical rain forest on the island of Tobago, in the West Indies. We surveyed fruiting plants and birds in three adjacent habitat types that varied in level of disturbance, and used multivariate analyses to determine whether changes in the plant community were associated with differences in avifauna composition. The three forest habitats had similar plant and bird diversities, yet markedly different species compositions and abundances. Primary forest had the most diverse plant community, while disturbed habitats had a more homogeneous plant composition. Primary and disturbed forest had distinct community compositions, with canopy cover and the relative abundance of plant types explaining 83 percent of the variation in bird species assemblages. Seemingly moderate human disturbance has led to substantial changes in the plant and bird assemblages of Tobago's rain forest, outside of a protected reserve. Our study highlights the direct links between human disturbance and the structure of rain forests, underscoring the impact of even moderate activity on community composition.