香溪河河流连续统特征研究

以香溪河附石藻类密度、藻类叶绿素a浓度、Shannon-Wiener多样性指数及生态系统初级生产力随河流级别的变化为例探索该河流的连续统特征。结果表明，附石藻类密度、藻类叶绿素a浓度和Shannon-Wiener多样性指数总体上都有随着河流级别增加而增加的趋势，但在1～3级河段之间这种趋势并不明显，甚至出现了逆转。河流初级生产力也有随河流级别增加而增加的趋势，并在第4级河流达到最大，随后有所下降。在全水系范围内河流初级生产力(P)与群落呼吸(R)比值P／R均大于1，说明香溪河是一条以自养生产为主的河流。所研究的特征并不完全与连续统概念的预测相一致，表明河流已经受到了一定程度的人为干扰。

River continuum characteristics of Xiangxi River

The density of epilithic algae and concentration of chlorophyll a, Shannon-Wiener index and primary productivity were chosen to study the river continuum characteristics of Xiangxi River.The results showed that in general,the algal density,chlorophyll a concentration and Shannon-Wiener index tended to be increased with increasing stream order,but this trend was not very evident in the first three orders and even reversed. The primary productivity was also higher in the higher than that in the lower stream orders, and reached the maximum in the fourth order, then decreased slightly.The ratio of gross primary productivity to community respiration was the highest in the first stream orders, which means autochthonous productivity was dominant in the river. The results did not absolutely tally with the RCC forecast, therefore,we can conclude that Xiangxi River had been undergone anthropogenic influence.