Mapping China's freshwater fishes: diversity and biogeography

Abstract

Freshwater fishes worldwide face an array of threats from dam construction, river fragmentation, pollution, over‐exploitation and interactions with introduced species. Such impacts are especially prevalent in densely populated countries undergoing rapid development, and their effects are felt most strongly where regional fish diversity is high. We reviewed studies of the distribution of freshwater fish species throughout China to map a biogeographical pattern and ascertain the environmental factors contributing to this distribution. We then linked this information to identify geographic areas to be recommended as the focus of conservation efforts. A total of 920 species in 302 genera, 54 families and 21 orders were recorded. Among the recorded species, 73% were Cypriniformes and 12% were Siluriformes. Cyprinidae was the most dominant family with 473 species, followed by Balitoridae with 157 species. The administrative division of the biogeography of China's freshwater fishes consisted of nine regions, including the Qinghai‐Tibetan Plateau Region, Oriental Region, Northwest Region, South Region, Loess Plateau Region, Heilongjiang Region, Upper Yangtze Region, 3H Plain Region and Middle‐Lower Yangtze Plain Region. The river system was the primary factor in determining China's freshwater fish biogeography. Under stepwise regression analysis, river discharge was found to be the most influential factor in determining richness, followed by population size and net primary productivity. The higher level of fish endemicity and sensitivity to environmental change led to the identification of Southwest China and the higher areas of Qinghai‐Tibetan Plateau as the primary areas to be considered for fish conservation and potential natural reserves.

Predicting fish species richness and assemblages with climatic, geographic and morphometric factors: A broad-scale study in Chinese lakes

“…Our findings were in accordance with the previous macroecology studies of fish in European lakes (Brucet et al, 2013) and Chinese water bodies (Kang et al, 2013). Some other studies, with a regional scale focus, argued that fish species richness was highly related with water depth (Cheng et al, 2012), habitat (Petry et al, 2003) and other organisms (Xie et al, 2001) in lakes.…”

“…This may partly due to the fact that the lakes investigated span a broad altitudinal extent range from 2 to 4947 m (Table 1), which represents the largest altitudinal extent worldwide (Wang and Dou, 1998). Geographically, these lakes come from both plateaus (Qinghai-Tibet plateau, Yun-Gui plateau, Meng-Xin plateau) and plains (Song-Nen plain, 3H plain region (Huanghe, Huaihe and Haihe) (Kang et al, 2013). Generally, altitude could generate direct barrier effects on distribution and life history traits of organisms, e.g.…”

“…PDM is also considered as having a large impact on niche shifts of freshwater species (Lauzeral et al, 2011), and thereby affecting fish distribution. Indeed, PDM can modify the hydrological conditions of lakes directly, such as water content, water depth, transparency and nutrient supplements (Wetzel, 2001), which in turn will affect fish populations and distributions (Brazner and Beals, 1997;Petry et al, 2003;Mello et al, 2009;Cheng et al, 2012;Kang et al, 2013).…”

“…While lakes distributed in the area with relative lower precipitation and temperature were predicted to have lower fish species richness. For example, in Tibet, Sinkiang and Northeast China, relative lower fish richness was frequently observed due to the lower precipitation and lower temperature (Kang et al, 2013). In addition, the Northwestern lakes are isolated in an inland area where precipitation is scarce (also named as arid and semi-arid zones of China), thus most of the lakes in this region are brackish or saline, and are very poor in fish species although with large surface area, e.g.…”

“…However, we have to acknowledge that it is only a showcase limited by the data available nowadays, which predict fish patterns with climatic (temperature and precipitation), geographic (altitude) and morphometric (lake area) factors in a broad scale. A number of other factors have been identified as potentially affecting fish distribution and diversity, such as land-cover, geographic variables, topological variables, biological invasion, artificial impacts and net primary production (Park et al, 2006;Buisson et al, 2008a,b;Gevery et al, 2009;Maloney et al, 2013;Kang et al, 2013). Further research therefore requires the inclusion of such factors in order to obtain more powerful explanations.…”