Does hydrologic regime affect fish diversity? -A case study of the Yangtze Basin (China).

The Yangtze Basin is taken as a case study to investigate statistically whether the hydrologic regime affects fish diversity. Jaccard's similarity index ( I) is used to characterize the fish species similarity of any pair of sample rivers. On the basis of the IHA (Indicators of Hydrologic Alteration) method, a series of hydrologic indicators, some of which are modified according to the practical hydrologic characters of the Yangtze Basin, are used to characterize the hydrologic regime. A new index, named the degree of the hydrologic regime difference ( I) is constructed to measure the difference between hydrologic regimes of any pair of sample rivers. An exponential model is used to estimate the correlation curve of I and I. We observed a negative relationship between I and I, which suggests that hydrologic regime affects fish diversity. [ABSTRACT FROM AUTHOR]