Aim: Mountain systems offer excellent opportunities to understand β‐diversity patterns and the processes driving them. However, β‐diversity patterns and the underlying mechanisms that lead to dissimilarity in mountain amphibian communities across elevational gradients remain elusive. We aimed to evaluate how amphibian communities respond to environmental gradients with elevation and to explore how different ecological mechanisms drive elevational β‐diversity.Location: A 2600‐m elevational gradient along Mount Emei in southwestern China.Methods: We investigated elevational patterns and assembly processes of pairwise β‐diversity across three dimensions (taxonomic, phylogenetic, and functional) in turnover (i.e., species replacement) and nestedness‐resultant (i.e., species lose/gain) for amphibians. We compared multifaceted β‐diversity components and assessed the extent to which β‐diversity responded to environmental and elevational distances. We also quantified the standardized effect size of β‐diversity and its components using null models to examine the dynamics of niche‐based and neutral processes.Results: The turnover component dominated taxonomic β‐diversity, whereas nestedness was relatively more important for phylogenetic and functional dissimilarity. Moreover, taxonomic total dissimilarity and turnover were higher than their phylogenetic and functional analogues. Our results indicated a significant distance‐decay effect for multifaceted β‐diversity of amphibians on Mount Emei and found that effects and directions of predictors on multifaceted β‐diversity were different, with temperature seasonality, annual precipitation, and elevational distance acting as the most important factors. Comparing observed patterns with null‐model expectations, environmental filtering, and competitive exclusion may jointly drive elevational patterns of β‐diversity.Main conclusions: Our study emphasizes the importance of partitioning taxonomic, phylogenetic, and functional components of β‐diversity and community assembly when determining β‐diversity drivers. Although it is difficult to distinguish random communities from outcomes of niche‐based processes, this work highlights the potential roles of environmental filtering and competitive exclusion in controlling elevational communities and provides insights into amphibian community assembly in a biodiversity hotspot.

Several anurans have broad elevational and latitudinal distribution ranges; distinct species and populations may face various environmental and selection stresses. Due to their environmental sensitivity, adaptation is critical for the long-term persistence of anurans. Previous studies have tried to identify the ecogeographical pattern and its mechanism in anurans, suggesting different patterns, but the related explanatory mechanisms are yet to be generally supported and are suggested to be complicated. To explore the elusive mechanisms, we studied the morphological variation of the plateau brown frog (Rana kukunoris) along an elevational gradient on the eastern margin of the Qinghai–Tibetan Plateau. Using body size, extremity length, and the ratio between them (extremities/body size) as testing indicators, we examined potential ecogeographical adaptations and investigated how environmental and biological factors could shape the morphological development in R. kukunoris. We found that males and females showed different variations in body size and extremities along the elevational gradient, whereas both of them showed a decreasing extremities/body size ratio along elevation. Together with the strong correlations between environmental and biological factors and the morphometrics, we identified ecogeographical adaptation and a sexual difference in the selective pressures on the extremities and body size of the plateau brown frog. Our results imply that geographic variations in anuran morphological traits should be understood as an outcome of environmental and biological factors. Furthermore, ecogeographical adaptation in anurans can manifest as an interactive change between body size and extremities.

Considering the increased anthropogenic impacts, species with a limited range and low detectability often lack fundamental information and conservation actions, placing them at a high risk of endangerment. The Chinting alpine toad Scutiger chintingensis is a rare mountain amphibian endemic to the eastern margin of the Qinghai–Xizang Plateau in China. Within its whole distribution range, only three known populations (Wolong, Emei, and Wawu) exist and no recent population status reports have documented for this species over the past two decades. From 2020 to 2023, we investigated the species distribution, and assessed the risk factors for the main populations. We recorded this species in all distribution areas, updated a new distribution site with a lower elevation limit. The relative population density was 0.024 ± 0.012 ind./m² on Mount Emei, whereas only 0.008 ± 0.017 ind./m² on Mount Wawu. No significant difference was observed in the number of individuals between the two populations; however, the relative population density was significantly different. Sewage and waste discharge resulting from the construction of scenic areas, as well as disturbances from tourism, were the primary anthropogenic factors that influenced the survival of this species. Our results provide the updated information on the distribution and population status of the Chinting alpine toad, and suggest that unrecorded populations, as well as a wider elevation range, may exist for this species. Our findings emphasise the importance of timely updates of species distribution and population information and offer a basis for the future conservation of endangered amphibians.

The Taihangshan swelled-vented frog (Feirana taihangnica), an endemic species to the Qinling Mountains, central China, has experienced a dramatic population decline over the last few decades. The aim of this work was to quantify morphological variation in F. taihangnica across the Qinling Mountains and examine environmental correlates of this variation of morphological traits. We implemented a hierarchical partitioning to estimate the independent contribution of each environmental variable on morphological variations. Temperature seasonality was the greatest contributor in variations of snout-vent length (SVL) and head width, and ultraviolet-B (UV-B) radiation of the lowest month was the most influential on both thigh length and tibia width. Then, we used generalized additive models to analyze the relationship between each environmental factor and morphological trait variations. Along the increasing of annual mean temperature, SVL decreased firstly and then increased, indicating no support for Bergmann’s rule. Furthermore, SVL was negatively correlated with annual precipitation, while positively with temperature seasonality. The mean UV-B of the highest and lowest months was positively and negatively correlated with head width, thigh length and tibia width, respectively. The results of this study help us to understand adaptive potential of this mountain frog species via morphological variations in the light of environmental changes.