Birds in agroscapes: effects of forest cover and landscape heterogeneity on dryland bird diversity and composition

A research challenge for this century is the integration of highly productive and sustainable landscapes. This issue is crucial for semi-arid regions, where historical land management practices have led to habitat loss and desertification processes. In this study, we evaluated the relative effects of habitat amount (forest cover), landscape heterogeneity (landscape diversity) and spatial arrangement (forest fragmentation and edge density) on bird α and β-diversity in the Caatinga tropical dry forest of northeastern Brazil. We separately assessed the complete bird assemblage and three different ecological groups (forest specialist, habitat generalist and open-area specialist species). Our results indicate that habitat amount is the main positive driver of α and β-diversity of birds in the Caatinga landscapes. However, landscape heterogeneity emerged as an important positive driver for habitat generalist and open-area specialist species. Our results highlight the importance of landscape-scale forest cover and increasing landscape heterogeneity on productive lands as a strategy to balance food production and biodiversity conservation in dry forest regions such as the Caatinga.