The Influence of Climate Stability and Environmental Factors on the Complexity of Amazonian Bird Distributions

ABSTRACT Aim Evaluate the relative influence of historical and ecological factors: specifically climate, climate stability, soil, vegetation, riverine barriers and topography on the spatial distribution of Amazonian bird species and lineages. Location Amazon Basin. Time Period Contemporary distributions with historical context. Major Taxa Studied Amazonian birds. Methods Generalised dissimilarity models (GDM) and phylogenetic GDM (Phylo‐GDM) were applied to a dataset of 51,358 occurrence records to quantify the contribution of environmental and historical variables to spatial variation in taxonomic and phylogenetic community structure. Results The GDM explained 16.16% of species compositional turnover, with model performance varying across habitat types highest in Campinarana species (80.43%) and lowest in river margin species (20.72%). Phylogenetic patterns were slightly better explained (14.09%), with climate being the most influential predictor (12.60%), followed by climate stability, soil and topography. Riverine barriers had relatively low explanatory power, suggesting a more context‐dependent role in shaping bird distributions. Main Conclusions Amazonian bird diversity is shaped by a complex interplay of historical and ecological drivers. Climate stability and contemporary climate are key predictors, especially in open habitats, whereas riverine barriers, though traditionally emphasised, show limited explanatory power in this context. A multifactorial approach is essential to fully understand the region's biodiversity patterns, and future research integrating genomic, ecological and paleogeographic data will be critical to disentangle the mechanisms underlying Amazonian biogeography.