中文摘要：

采用Smith生态位宽度公式、Pianka生态位重叠指数公式和冗余分析（RDA）对古夫河22种优势种进行生态位计算和分析。结果表明,古夫河春夏季着生藻类优势种以硅藻门和蓝藻门的种类居多。根据不同月份的生态位宽度将古夫河着生藻类优势种分为5类,第一类优势种具有最宽的生态位且它们与蓝藻类优势种的重叠性指数最大。古夫河着生藻类优势种的分布受总氮、酸碱度、氨氮的影响较大。第一类优势种可反映古夫河总体水质情况,第五类优势种反映古夫河水体中某一个或几个水质因子的变化;生态位重叠值大小可反映古夫河水质是否受到外来因素干扰;结合RDA排序图和优势藻类种群变化可判断古夫河水体中总氮、氨氮及酸碱度含量的变化。

英文摘要：

The concept of niche is one of the most important fundamental researches of modem ecology and it has percolated into many fields besides ecology. Niche mainly involves three aspects： niche breadth, niche overlap and niche differentiation. Based on the analysis of dominant periphytic algae＇s niche in the Gufu River, this paper explored the interactions among periphytic algae and their utilization of resources in mountain river. There were many reports about the niche of algae, which mostly focused on lakes or reservoirs. On the contrary, few reports were found focusing on mountain rivers. The Gufu River chosen as the research subject is a near-natural river which has little human disturbance and a mountain river located in Shennongjia Forest District. In this paper, 22 dominant species of periphytic algae in spring and summer were firstly figured out by Mcnaughton dominance index in the Gufu River. Next, the niche breadth and niche overlap of these dominant species were respectively determined by using modified Smith and Pianka formulae, and niche differentiation was studied by Redundancy Analysis （RDA）. The results showed that the most species of the dominant species were diatom and phytoplankton, but the number of diatom was far less than that of phytoplankton, and green algae＇s number was the least. The niche breadth and niche overlap of these dominant species were different in different periods. Based on their niche breadth in each month, the dominant species in the Gufu River could be classified into 5 groups, among which, Phorrnidiurn foveolarum, Achnanthes linearis and Aphanocapsa rivularis had broadest niche; the broader niche a dominant species had, the more resource it would occupy, conversely one with narrower niche. The niche overlap indices were the biggest between three dominant species above and phytoplankton, followed by diatom and green algae; the niche overlap indices between these three dominant species and the rest dominant species were roughly the same in the spring months, yet that