Boundaries

This ecoregion includes the Pearl River (Xi Yiang, Zhu Jiang) basin and small coastal basins between the Song Hong [ecoregion 761] and Xi Yiang basins. It encompasses the Chinese provinces of Guangdong, Guangxi, and part of Guizhou and Yunnan.

Terrestrial habitats

The Xi Yiang basin includes Yunnan Plateau subtropical evergreen forests, Guizhou Plateau broadleaf and mixed forests, Jian Nan subtropical evergreen forests, South China-Vietnam subtropical evergreen forests, Hainan Island monsoon rain forests (Wikramanayake et al. 2002).

Description of endemic fishes

The ecoregion contains more than 90 endemic species, largely in the Cyprinidae and Balitoridae families. These include species in the genera Acrossocheilus, Beaufortia, Homalosoma, Pseudogastromyzon, Ptychidio, Parasinilabeo, Sinocyclocheilus, Triplophysa, and Yunnanilus. There are also endemic genera such as the monotypic genera Parargyrops (P. edita) and Xiurenbagrus (X. gigas).

Justification for delineation

For Southeast Asia, delineations were determined using a bottom-up approach that employed both published and unpublished field data and expert assessment (Abell et al. 2008). The ecoregion includes numerous and extensive karstic areas in all these provinces (including the famous Guilin area), several hosting endemic species of cave fishes and other aquatic organisms. Detailed information on geographic distribution is too poor to recognize smaller, more specific units, but it seems that once more data are available, this ecoregion will have to be subdivided (M. Kottelat pers. comm. 2006).