Efeitos da redução da superfície de água sobre a diversidade taxonômica, filogenética e funcional de anuros em três localidades de Cerrado

Abstract

The reduction of surface water availability, intensified by irrigated agricultural expansion and climate change, represents an increasing threat to aquatic and semi-aquatic communities in the Cerrado, a highly diverse and vulnerable biome. In this study, we evaluated the long-term effects of the loss of aquatic habitats on the taxonomic, functional, and phylogenetic diversity of anuran communities across three breeding ponds located in the Formoso River basin, western Bahia, Brazil, integrating historical (1999–2019) and contemporary (2024–2025) data. Species composition was assessed through standardized visual encounter surveys and automated acoustic recordings, while environmental variables were quantified using climate time series, satellite imagery, and drone-based aerial surveys, allowing the estimation of changes in precipitation, temperature, surface water area, and land-use anthropization over time. Functional diversity was calculated using Rao’s Q and functional dispersion (FDis), phylogenetic diversity was assessed through PD, SES.PD, and UniFrac-based distances, and multivariate community structure was analyzed using NMDS, PERMANOVA, and distancebased redundancy analysis (dbRDA), combined with linear mixed-effects models to evaluate temporal trends. Over the study period, 26 anuran species were recorded, of which only 3 persisted in recent years, revealing a significant temporal decline in species richness. Temporal taxonomic beta diversity was consistently high and dominated by species turnover, indicating marked compositional reorganization through time, whereas phylogenetic beta diversity was primarily driven by nestedness, suggesting a progressive loss of evolutionary lineages rather than their replacement. Functional diversity (RaoQ and FDis) and phylogenetic diversity exhibited strong and significant temporal declines, with recent years showing SES.PD values lower than expected under null models, indicating non-random phylogenetic loss. In contrast, multivariate functional composition showed limited temporal reorganization, suggesting environmental filtering without pronounced functional replacement. dbRDA results demonstrated that both taxonomic and phylogenetic community composition were strongly associated with increasing land-use anthropization and reductions in surface water availability, while precipitation lost independent explanatory power when considered jointly with other predictors. Collectively, our findings indicate that long-term water loss and agricultural intensification act as persistent environmental filters, driving taxonomic, functional, and phylogenetic impoverishment of anuran communities, with direct implications for ecological stability and biodiversity conservation in agricultural landscapes of the Cerrado.