Beyond Temperature: Environmental Filtering and Functional Shifts in Desert Bird Communities Under Climate Change

Deserts present unique opportunities for understanding biodiversity under climate change, yet global-scale assessments remain rare. Birds serve as sensitive ecological indicators of ecosystem health and biodiversity dynamics. In this study, leveraging crowdsourced bird occurrence records (GBIF) and multi-decadal hydro-meteorological datasets (ERA5, GLEAM), and vegetation data (AVHRR), we show how environmental filtering and functional shifts in avian assemblages drive divergent spatial and temporal species richness patterns across ten major deserts. Noteworthy, responses to warming are distinct, wherein temperature alone cannot universally predict community dynamics. Climatic determinants such as precipitation, soil moisture, and NDVI shaped by greening and browning trends, play region-specific roles. Analyses reveal pronounced guild turnover, with notable declines in top avian predators and complex shifts in omnivores and aquatic predators, exposing ecosystem-level vulnerabilities and altered resilience. These findings underscore the need for a paradigm shift from one-dimensional models to integrative, trait-based approaches to conserve desert biodiversity and function under climate change.