Underlying Spatial Diversity Patterns of Freshwater Crabs in Southern China, With Recommendations for Conservation of Freshwater Biodiversity.

Unveiling the crucial factors influencing species diversity patterns and identifying conservation priorities are recognized as essential in confronting the escalating biodiversity crisis. The south subtropical-tropical zone of China (STZC) is a critical biodiversity area and a major economic zone. However, the conservation of freshwater biodiversity in the STZC faces severe challenges due to a lack of knowledge about the long-term survival of keystone species. Here, we focused on freshwater crabs because they are ideal models to address such knowledge gaps due to their critical role as benthic macroinvertebrates in maintaining the functional integrity of freshwater ecosystems. We tested ecological variables that influence the distribution of identified diversity hotspots, evaluated their extent of protection in the current nature reserves (NRs), and comprehensively identified potential conservation priority areas (CPAs). Our results indicated that freshwater crab diversity was clustered in 11 diversity hotspots, which were significantly influenced by human activities (agriculture, encroachment on freshwater habitats, and urbanization), and were also evaluated in terms of local climates and landscapes. Specifically, only 5.7% of terrestrial habitats and 9.7% of the freshwater crab species were protected by NRs. Increasing the coverage of identified CPAs to either 15/30% could effectively protect nearly six to eight times the number of freshwater crab species (up to 60/82%, respectively). We highlight the potential for increasing the priority NRs and the need to protect the distributional areas of threatened species so as to maximize the future conservation of biodiversity in the increasingly threatened freshwater ecosystems in China.