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 investigated the spatial phylogenetic patterns of forest bird diversity across peninsular India, a region characterized by high topographic and climatic heterogeneity. Using a comprehensive global bird phylogeny, we employed metrics such as Phylogenetic Diversity, Phylogenetic Endemism, Relative Phylogenetic Diversity and Relative Phylogenetic Endemism to quantify the evolutionary history and endemism of forest birds in peninsular India. We examined the roles of contemporary climate, historic climatic stability, and topography in shaping these patterns. Our results revealed a strong gradient in diversity, with the southern Western Ghats acting as a major hotspot for both taxonomic and phylogenetic diversity and endemism. We detected 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 into biogeography in this understudied yet highly biodiverse region for forest birds.