Abstract:

Aims: Freshwater crabs are one of the representative groups of benthic macroinvertebrates and serve as critical bioindicator of healthy ecosystems, however, their species diversity and genetic diversity have not been effectively conserved. The present study uses the freshwater crabs of the endemic Chinese genus Sinopotamonas a model. Based on extensive field surveys and literature review, we aim to establish a comprehensive species distribution database, assess the key environmental factors influencing both species and genetic diversity, and identify diversity hotspots as well as conservation gaps across its distribution range.

Methods: The distribution data of Sinopotamon species were compiled through field investigations and literature sources. Spatial patterns of diversity were analyzed, and key environmental drivers were evaluated using spatial statistical models. Species and genetic diversity patterns were then overlaid with existing protected area to identify conservation gap regions.

Results: The center of Sinopotamon species diversity lies between the northeastern Yunnan-Guizhou Plateau to the Zhemin Hills. Species richness generally declines from the Yangtze River Basin toward the northern and southern margins. Genetic diversity shows strong spatial heterogeneity, with higher levels concentrated in mountainous regions. Species diversity and genetic diversity are significantly positively correlated. Environmental factors such as altitude and mean annual precipitation have significant positive effects on both. Diversity hotspots are spatially clustered, primarily in the mountainous and hill areas of south-central China. Four conservation gaps were identified in these regions, with the eastern section of the Nanling Mountains recognized as a distinctive hotpot for genetic diversity.

Conclusion: Our results indicate that mountainous ecosystems and warm, humid climates have played a critical role in shaping both species and genetic diversity of Sinopotamon. This study highlights the necessity of integrating species diversity and genetic diversity in conservation planning and provides essential data and scientific support for biodiversity conservation and management in China’s freshwater ecosystems.

Key words: Sinopotamon, freshwater crabs, genetic diversity, spatial distribution pattern, conservation gaps