Effects of elevation on taxonomic and functional diversity of frog communities in a tropical forest

The assessment of taxonomic diversity (TD) and functional diversity (FD) in natural gradients, including elevation, has grown over the past two decades, but is still relatively little studied. By studying amphibians in the Brazilian forest areas, this research aims to address critical knowledge gaps about biodiversity distribution, while highlighting the need to conserve this fragile and unique hotspot. Herein, we assessed whether and how environmental predictors explain taxonomic and functional alpha and beta diversities of frogs in a Brazilian tropical forest. Elevation significantly and negatively affected TD and FD, with a monotonic linear decrease of both variables with increasing altitude. We did not detect a significant influence of habitat amount (as measured by proportion of forest vegetation cover) on either TD or FD, probably because we observed minimal variation in habitat amount along the elevational gradient. We found a significant influence of elevation on taxonomic and functional dissimilarity values, predominantly explained by the turnover rather than the nestedness component. Our results highlight the importance of functional traits for understanding frog distribution patterns along environmental gradients. Community-level studies on tropical frogs, especially montane species vulnerable to environmental and climatic impacts, remain limited, posing challenges for conservation and management efforts. The high turnover of species composition and functional roles emphasizes the importance of conserving the entire mountain habitat, including the upper elevations.