Bioregionalisation of the freshwater zoogeographical areas of mainland China.

Biogeographic regionalisations extract patterns of co-occurrence from different taxa to form a hierarchical system of geographical units of different scales. This system is useful for revealing biogeographic patterns and can be used as the basis for scientific communication between different fields. The history of Chinese freshwater biogeography is not well known to most modern biogeographers and is reviewed herein. We produce the first quantitative bioregionalisation of the freshwater zoogeographic areas of mainland China based on multiple animal groups. The combined occurrence data of amphibians, freshwater fish and freshwater crabs were subjected to cluster and network analyses. The two different methods yielded largely similar results. We propose four freshwater zoogeographical subregions (Beifang, Tarim, China, and the Tibetan subregion), three dominions for the China subregion (Jianghuai, Dongyang, and the new Dian dominion), three provinces for the Dian dominion (West Hengduan, Diannan Highlands and the new Yungui Plateau province) and two provinces for the Dongyang dominion (Zhemin and the new Huanan province) according to the naming rules of ICAN. The endemic areas of each animal group were then individually studied and were found to reflect the bioregionalisation at the subregion level, but differed from each other at the dominion and province level. Our analyses show that: (1) previous intuitive biogeographical studies have found similar areas; (2) there are recurring large scale biogeographic patterns in Chinese freshwater fishes, amphibians and freshwater crabs; and (3) bioregionalisations derived from quantitative methods can be effective for partitioning areas into biogeographically meaningful units.