额济纳绿洲植物群落种间关系和生态位研究

根据61个天然植物群落样地的野外调查资料,采用生态位测度、方差比率法和基于2×2列联表的χ2检验、Ochiai关联指数、Pearson积矩相关系数和Spearman秩相关系数等方法,对额济纳绿洲植物群落主要物种进行了生态位和种间关联分析。结果表明：（1）胡杨（Populus euphratica）、柽柳（Tamarix ramosissima）、苦豆子（Sophora alopecuroide）生态位宽度值大,分别为该区的泛化种和乔木层、灌木层及草本层的优势种；（2）额济纳绿洲植物群落物种的总体联结性为不显著的正联结,大多数种对间呈中性联结（χ2<3.841,p>0.05）,物种趋向于独立分布。（3）种间联结系数（Ochiai指数）与生态位重叠之间极显著正相关,而生态位宽度与生态位重叠之间并无直接线性关系。

Interspecies Relationship and Niche Analysis on Phytocoenosium in the Ejina Oasis

Based on investigation data of 61 vegetation sample plots, we aimed to analyse interspecies relationship and species niche of 15 main species in the Ejina Oasis at the lower reaches of Heihe River. Based on 2×2 contingency table, Ochiai correlation index, Pearson correlation analysis and Spearman correlation test, we studied interspecies relationship and niche by means of calculating niche breadth, niche overlap, variance ratio, chisquare test. Important findings were as follows: (1) Populus euphratica, Tamarix ramosissima and Sophora alopecuroides were generalized and dominant species for arborous layer, shrub layer and herbaceous layer respectively; (2) General associativity of phytocoenosium in the Ejina Oasis was insignificantly positive correlation, most species pairs were neutral associated and all species tended to distribute independently; (3) Interspecies association coefficient and niche overlap showed significantly positive correlation, however, there was no direct linear correlation between niche breadth and overlap.