Land use type, forest cover and forest edges modulate avian cross-habitat spillover.
Natural habitats adjacent to agricultural areas are often considered sources of species that provide beneficial regulating ecosystem services through cross-habitat spillover. Both inter-habitat matrix and landscape configuration can influence spillover by controlling organismal ability to disperse through landscapes, and affecting the provision of additional or supplementary resources that impact organism survival. To understand how landscape structure in terms of matrix land use type, forest cover and edge density might facilitate avian cross-habitat spillover, we sampled avian communities in forest patches and adjacent land use types (coffee plantations or cattle pastures) using a well-replicated study design across 92 sampling sites across a landscape-context forest cover gradient (6%-60%). Land use type was a key factor influencing avian cross-habitat spillover, facilitating species movement into coffee plantations and acting as a barrier to spillover into cattle pastures. We found that 24% of the forest-dependent species pool was capable of spillover into coffee plantations, while spillover was nearly non-existent in cattle pastures. Forest cover was also the main driver of spillover into coffee plantations. There was a positive relationship between forest cover and spillover, potentially due to processes related with (1) a higher density of organism in-patches, (2) decreased isolation among patches facilitating species movement and (3) higher landscape supplementation processes. Finally, we found edge density had an additive effect with forest cover on spillover. Spillover was higher in high-forested landscapes with many forest-matrix edges, possibly due to increased structural connectivity for species able to move through edges, and to improved access for forest-dwelling species to different resource types (complementation processes). Synthesis and applications. We demonstrate that land use type is a key factor facilitating species spillover into agricultural matrices and that the influence of land use type on spillover is further modulated by a combination of native habitat amount and edge density. These results should be considered in efforts to design or manage sustainable agricultural landscapes in order to enhance both bird persistence and the provision of bird-mediated ecosystem services.