Elevational patterns of amphibian functional and phylogenetic structures in eastern Nepal Himalaya

Aim Exploring the mechanism underlying community assembly processes is considered as one of the central topics for biogeography. As one of the biodiversity hotspots, Nepal Himalaya has attracted increasing attention during the past decade. However, the main processes shaping amphibian assemblages in this area are still unclear. Here, we examined the elevational patterns of amphibian functional and phylogenetic structures to understand the main mechanism driving amphibian assemblages along an elevational gradient in eastern Nepal Himalaya. Location Eastern Nepal Himalaya. Methods Amphibian taxonomic, functional and phylogenetic diversity were calculated, and their responses to the increasing elevations were investigated based on the linear regressions. The environmental determinants of amphibian diversity were revealed based on the incorporation of generalized linear models and hierarchical partitioning analyses. In addition, the mechanism driving amphibian assemblages from low to high elevations was tested by calculating the mean pairwise functional distance and the mean pairwise phylogenetic distance indices. Results Amphibian taxonomic, functional and phylogenetic diversity had contrast responses to the increasing elevations, which were strongly determined by variables such as air temperature, the number of trees, leaf litter cover and water pH. Interestingly, the trends of amphibian functional and phylogenetic diversity along an elevational gradient can be changed after controlling the effects of species richness. Moreover, determining process played a dominant role in shaping amphibian assemblages with the increasing elevations. Conclusions Our results revealed the elevational patterns of amphibian functional and phylogenetic structures in eastern Nepal Himalaya, associated with the change in environmental variables. We also highlighted the dominant role of determining process in shaping amphibian assemblages. Overall, our results can help ecologists and managers better understand and formulate amphibian diversity conservation. In addition, our results also enriched the fundamental knowledge to understand the general patterns of community assembly rules in montane ecosystems.