Spatial patterns of diversity in forest birds of peninsular India

Biodiversity is structured via complex interactions among ecological, geological, and climatic processes. Regions with high heterogeneity in climate and topography are known to harbor fine scale patterns in diversity which are often overlooked in global scale analyses. Here, we investigate spatial phylogenetic patterns of forest bird diversity across peninsular India, a region with high topographic and climatic heterogeneity. Using a comprehensive global bird phylogeny, we employ metrics such as Phylogenetic Diversity (PD), Phylogenetic Endemism (PE), and their relative forms (RPD, RPE) to quantify evolutionary history and endemism of forest birds in peninsular India. We examine the roles of contemporary climate, historic climatic stability, and topography in shaping these patterns. Our results reveal a strong gradient in diversity, with the southern Western Ghats acting as a major hotspot for both taxonomic and phylogenetic diversity and endemism. We detect distinct ecological and phylogenetic community structures across the peninsula, likely shaped by regional species pools and biogeographic barriers. Areas with greater topographic complexity, higher precipitation, and greater historic climatic stability were found to support high diversity. Our study provides critical insights for biogeography in this understudied yet highly biodiverse region for forest birds.