滇西北云南红豆杉群落物种生态位与种间联结

Niche and Interspecific Association of Species of Taxus yunnanensis Communities in Northwest Yunnan Province

在对滇西北云南红豆杉(Taxus yunnanensis)群落的野外调查基础上,采用生态位宽度、生态位重叠和基于2×2联列表的χ2检验、联结系数(AC)的方法,分析了群落种群间的相互关系。结果表明:物种的重要值与相对应的生态位宽度存在着极显著正相关;云南红豆杉、丽江铁杉(Tsuga forrestii)与青荚叶(Helwingia japonica)的生态位宽度大于其它种群;在1225个种对中有48.16%的生态位重叠值为0,同时χ2统计量中有4%为中性联结,说明群落中木本植物种群间资源利用性竞争较强。生态位宽度较大的种群间往往生态位重叠也较大;云南红豆杉与丽江铁杉之间的生态位重叠值要明显高于与其它种群的,Schoener指数为0.875。χ2检验表明云南红豆杉与其它种群之间表现为无联结。联结系数中显著负联结的种对要多于显著正联结,群落物种受到较大的外来干扰。联结系数与生态位重叠值之间存在极显著正相关,并能用Cubic指数建立回归方程模型。

Field data collection was based on 3200 m2 plots（including 8 subplots） in Taxus yunnanensis communities distributed in northwest Yunnan province.Methods including niche breadth,niche overlap,chi-square test,and association coefficient（AC） based on a 2× 2 contingency table were used for analyzing the interaction between the species population.Results showed significant positive correlation（p 0.001） between the importance value and corresponding niche breadth.The niche breadth of Taxus yunnanensis,Tsuga forrestii,and Helwingia japonica were larger than other populations.The niche overlap of 48.16% of species pairs was 0 in 1225 species pairs and 4% of species pairs showed neutral association in chi-square test,which indicated a stronger resource utilization competition on different populations.Simultaneously,niche breadth increased with niche overlap.The niche overlap of species pair of between Taxus yunnanensis and Tsuga forrestii was larger than species pairs between Taxus yunnanensis and other populations.The Schoener index was 0.875.Chi-square results showed that there was no association between Taxus yunnanensis and other populations.For AC,the proportion of negative association was more than positive association,which showed that the community had a larger external disturbance.There was a significant positive correlation between association coefficient and niche overlap and the model was Cubic index.