长江上游主要河流鱼类多样性与流域特征关系

对长江上游12 条主要河流鱼类种类数与流域特征进行了回归分析和主成分分析. 相关回归分析结果显示: 特有种类数目与全部种类数目呈极显著正相关; 全部种类数目的绝对数与流域面积、干流长度、流量呈显著或极显著正相关, 与比降呈显著负相关; 单位流域面积( 或单位干流长度) 全部种类数与干流长度( 或流域面积) 、流量呈显著或极显著的负相关, 与比降、径流深呈极显著正相关; 特有种类数目的绝对数与流域面积、干流长度、流量呈显著或极显著正相关; 单位流域面积特有种类数与干流长度、流量呈显著或极显著负相关, 与比降、径流深呈极显著正相关; 单位干流长度特有种类数与流域面积呈显著负相关, 与比降、径流深呈极显著正相关. 主成分分析得到的第一和第二主成分分别综合反映了河流鱼类的相对种类数和绝对种类数与流域特征因子之间的关系.

The Relationship Between Species Diversity of Fish and Basin Characteristics of Main Rivers in the Upper Reaches of the Yangtze River

The effects of the characteristics of the river basin on species numbers of fish had been studied by using regression analysis and principal components analysis (PCA).The number of endemic fishes related positively with the number of all species (p<0.01).The diversity of all species related positively with basin area (p<0.01),length of mainstream (p<0.05),and the average river discharge (p<0.01) respectively; related negatively with the falling gradient (p<0.05).The diversity of all species per unit area or per unit length related negatively with length of mainstream or basin area (p<0.01),average river discharge (p<0.05) respectively; related positively with the falling gradient (p<0.01),the runfall of the rivers (p<0.01) respectively.There were positive significant correlationships among the diversity of endemic fishes and the basin area (p<0.05),length of mainstream (p<0.05),and average river discharge (p<0.01) respectively.The diversity of endemic species per unit area related negatively with length of mainstream (p<0.01),average river discharge (p<0.05) respectively; related positively with the falling gradient (p<0.01),the runfall of the rivers (p<0.01) respectively.The diversity of endemic species per unit length related negatively with basin area (p<0.05); related positively with the falling gradient (p<0.01),the runfall of the rivers (p<0.01) respectively.The result of PCA showed that the 1st and 2nd principal components revealed correlations among relative and absolute numbers of fish species and the characteristics of the river basin respectively.