Spatiotemporal Shifts in the Richness and Composition of Mountain Frogs in a Global Biodiversity Hotspot in Southwest China

Mountain amphibians are exposed to a multitude of threats from climate change and anthropogenic disturbances. However, a lack of data hinders the understanding of the responses of mountain amphibians to these threats, which is becoming a conservation concern. Using frogs in the Hengduan Mountains, a biodiversity hotspot in Southwest China as indicators, we attempted to assess the extent and magnitude of changes in alpha diversity(species richness) and beta diversity(community turnover) between two periods(1930–2005 and 2006–2022). We compared elevational patterns for total, endemic and non-endemic frogs between the two periods, evaluated community turnover(i.e., S?rensen and Jaccard binary dissimilarity), and further quantified whether significant homogenization or differentiation of the frog communities occurred over time. Our results showed that the present species richness is greater than the historical species richness. The elevational patterns of total, endemic and non-endemic frogs were similar with slight changes across the two periods and clear increases in richness occurring at low and middle elevations. Although there was no significant biotic homogenization or differentiation over time, the community composition shifted dramatically. This study highlights the importance of assessing spatiotemporal changes in biodiversity in response to environmental changes and contributes to mountain species conservation as global change intensifies. We therefore call for greater efforts in community resurveys to assess biodiversity changes and provide useful insights for conservation strategies and action implementation.