Fish Diversity Patterns and Their Responses to Environmental Factors in a Global Biodiversity Hotspot

Abstract

Biodiversity loss has increased interest in understanding biodiversity patterns and their driving mechanisms in global. A growing of empirical evidence suggests that, in addition to purely species diversity, studies of phylogenetic diversity can provide distinct but complementary information about biodiversity patterns and their driving mechanisms. However, there was still a lack of research on integrating species and phylogenetic diversity to analyse the spatial patterns and driving mechanisms of fish diversity. Here, we evaluated the response of species diversity and phylogenetic diversity of fish assemblages to environmental factors in Jiangxi Province. The results showed that 243 fish species were recorded in Jiangxi province, including 14 invasive species. There were 126 species native to China and 33 species endemic to the Yangtze River Basin. The Red List of China and IUCN assessments showed that 31 (12.8%) and 16 (6.6%) species were Threatened or Near Threatened (1 Extinct; 6 and 1 Critically Endangered; 3 and 3 Endangered, 8 and 5 Vulnerable, 14 and 6 Near Threatened), respectively. The number of species in carnivorous (111), demersal (143) and resident (153) fish were higher than other functional taxa. Fish species diversity was not significantly spatial differences (p = 0.521), and phylogenetic diversity exhibited significantly spatial differences (p = 0.001). The species spatial turnover (0.53) was higher than the nestedness (0.17), a larger number of protected areas would be necessary to conserve the regional biodiversity. Environmental and geographic factors generally had no significant effect on the species and phylogenetic diversity, and only nitrate nitrogen was significantly correlated with the species diversity and phylogenetic diversity. The results highlight the importance of evaluating both species and phylogenetic diversity when identifying biodiversity patterns and their driving mechanisms and provide useful implications and guidance for biodiversity conservation in the Yangtze River and in other regions facing human disturbances.