三江平原典型沼泽湿地植物种群的生态位

采用Levins 公式，对三江平原典型沼泽湿地植物群落的优势种群生态位宽度和生态位重叠值进行了研究.结果表明：各湿地植物种的生态位宽度排序为漂筏苔草(0.907)>毛果苔草(0.864) >狭叶甜茅(0.855) >小叶章＝睡菜＝球尾花＝二歧银莲花(0.500).毛果苔草、漂筏苔草、睡菜与球尾花之间，以及狭叶甜茅、小叶章与二歧银莲花的生态位重叠值均较高，说明几种植物在同一资源位上出现的频率相近，利用资源的能力相似，在对资源利用上具有一定的竞争性.睡菜与小叶章和二歧银莲花，以及球尾花与小叶章和二歧银莲花的生态位重叠值均为0，表明几种植物适应环境的方式不同.水分是导致湿地植物生态适应性差异的主导因子，植物对环境生态位适应的程度是水分和营养状况等因素共同作用的结果.湿地植物的生态位特征能较好地表征各植物的生态适应性和分布幅度.

Niche characteristics of typical marsh wetland plant populations in Sanjiang Plain

Based on field investigation and by using Levins formulae, the niche breadth and niche overlap of dominant plant populations in Sanjiang Plain marsh wetland were studied. The results showed that the niche breadth of test marsh wetland plants decreased in the order of Carex pseudocuraica (0.907)>C. lasiocarpa (0.864)>Glyceria spiculosa (0.855)>Deyeuxia angustifolia (0.500)=Menyanthes trifotiata (0.500)=Naumburgia thyrsiflora (0.500)=Anemone dichotoma (0.500). The niche overlaps among C. lasiocarpa, C. pseudocuraica, M. trifotiata and N. thyrsiflora, and among G. spiculosa, D. angustifolia and A. dichotom were comparatively large, indicating an intense competition among them, while the niche overlap between M. trifotiata and N. thyrsiflora, and D. angustifolia and A. dichotoma was 0, suggesting their different manner of environmental adaptation. Soil water was the dominating environmental factor of wetland plant ecological adaptability. The niche fitness of plant to environment depended on the combined effect of soil water and nutrients. The niche characteristics of marsh wetland plants could better indicate their ecological adaptability and distribution range.