滹沱河流域湿地植被优势种群生态位研究

采用Shannon-Wiener生态位宽度指数和Petraitis生态位重叠指数测定了滹沱河流域湿地植被20个优势种群的生态位宽度和生态位重叠.结果表明,浮叶眼子菜、莎草、藨草等占据较窄的生态位,生态位发生明显特化.苔草、海乳草、黄花蒿、赖草等占据较宽的生态位,生态位泛化比较明显.根据生态位宽度指数将湿地植物分为4个生态类群.在20个优势种群构成的380个种对中,有71个种对间表现出生态位重叠,占整个种对的18.68%.说明优势种群间生态位重叠现象并不普遍,各种群间生态位明显分离,因此不同种群利用资源的方式具有较为显著的差异性.图1表3参15

Niche of Dominant Species of Wetland Vegetation In the Hutuo River Valley

Seventy four quadrats are classified into seven formations in the Hutuo River valley, Shanxi using TWINSPAN, and it is clear that the ecological types of wetland vegetation have changed gradually from mesophytes to hygrophytes and hydrophytes, showing obvious environmental gradient. Niche breadths of twenty dominant species were analyzed using Shannon-Wiener niche breadth index, and the dominant species were classified into four ecological groups. It was found that the dominant species with high frequency produced a broad niche, while those with low frequency produced a relatively narrow niche. Based on the correlation analysis of the niche breadths of dominant species and the moisture gradient of soil, the soil moisture was shown increasing, but the niche breadths of dominant species decreasing. The results from analysis of the niche breadths of dominant species in each formation indicated that the dominant species showed a clear advantage in adaptation. They could not only adapt themselves well among microhabitats, but also had strong competition for resources in those microhabitats. The Petraitis niche overlap index indicated there were only 71 species counterparts having niche overlaps, accounting for 18.68% of the total 380. This indicated that the dominant species did not have complete and popular niche overlaps, and the niches of different populations were separated distinctly, owing to their different ways of using resources. Fig 1, Tab 3, Ref 15