云南元江水系三条支流鱼类β多样性比较

A COMPARISON OF FISH β DIVERSITY AMONG THREE BRANCHES OF YUANJIANG RIVER SYSTEM,YUNNAN

元江水系具有代表性的３条支流南溪河、绿汁江、李仙江共有土著鱼类８２种，分隶于１５科，６０属。研究中将每条支流视为一个样本，对这３条支流鱼类从种和属两个层次进行β多样性指数分析。结果表明：绿汁江与李仙江相比，鱼类多样性差异不大；它们分别与南溪河相比，鱼类多样性差异性均十分明显。绿汁江与李仙江鱼类的共有种、属最少，它们的种（属）分化隔离程度最大；南溪河与绿汁江的共有种、属最多，它们的种（属）分化隔离程度最小。相似性系数最大的为绿汁江与李仙江，最小的为南溪河与李仙江。造成这３条支流鱼类多样性差异的原因可能有：调查工作深度、鱼类分布与环境因子、人类活动等。

This paper deals with the biodiversity study of freshwater fishes.There are 82 endemic species belonging to 15 families,60 genera in three representative branches (Nanxi River,Luzhi River and Lixiang River) of Yuanjiang River system.Each branch can be treated as a sample.Index number of β diversity are studied among three branches of Yuanjiang River.The results of β diversity analysis indicate that the difference of fish diversity between Luzhi River and Lixian River are not significant,and that is very obvious when these two rivers are compared with Nanxi River.It is less common shared number of species and genera between Luzhi River and Lixian River and this means that there is a bigger isolation in species and genera between these two rivers.It is more common shared number of species and genera between Nanxi River and Luzhi River and this means that there is a more closed relationship in species and genera between these two branches.The reasons that cause the difference of fish diversity among three branches may be probably included that degree of investigation for every branch of Yuanjiang River system,elements of environment and habitat of fish,human activities etc.However,fish diversity among three branches is not related to the length and area of river.Finally,a suggestion for fish conservation is presented.