Contrasting patterns of land use by resident and migratory bird assemblages in a tropical working landscape

The spatial configuration and management of agricultural and other land-use practices can affect ecological assemblages. However, the differences in how resident and migratory birds respond to land use are not well understood, hindering our understanding of bird biodiversity responses to land use. In a tropical moist broadleaf forest landscape of southeastern Mexico, we assessed alpha, beta, and functional diversity as indicators of ecosystem functioning in resident and migratory birds across landscape- and habitat-level gradients, incorporating distance to a protected area, understory vegetation cover, and three land uses: 1) primary forest, 2) secondary forest, and 3) cattle pasture. Compositionally, resident and migratory bird assemblages exhibited similar gradual shifts across land uses. However, while resident bird richness steadily declined with increasing distance from a protected area and simplification of understory vegetation structure, migratory bird richness did not change. Relative to primary forest bird assemblages, we found that migratory bird abundances were greater in secondary forest and cattle pasture, and migratory insectivores compensated for 68% of the abundance losses of resident insectivores in secondary forest and cattle pasture. Among these insectivores in secondary forest and cattle pasture, increases in migratory birds compensated for the abundance declines of resident birds that utilize foliage gleaning and sallying foraging methods. Our findings emphasize the importance of evaluating and managing landscapes around protected areas, highlight the distinct responses of resident and migratory birds to land use, and reveal the mechanisms that sustain ecosystem functions in modified landscapes.