【摘要】 为了探讨土壤环境因子对植物群落物种数量、结构格局的影响 ,通过对岷江上游干旱河谷灌丛植被的大量群落学调查 ,采用了群落中 9个土壤特征指标 ,利用去势典范对应分析 (DCCA)排序方法 ,分析了不同群落类型中不同层次的物种数量结构的空间格局 ;定量分离了土壤、空间及其交互作用等因素对不同层次群落格局总体变异的影响。结果表明 :以水分为主导的多种环境因子耦合梯度决定着植物群落结构格局。环境因子对群落的影响程度在不同层次有差异 ,在灌木层中 ,单纯环境因子对植被格局的解释占 2 8.0 2 % ,环境 -空间耦合因子占 8.90 % ,空间因子独立占 10 .69% ,其他因子占 52 .3 9% ;而在草本层中 ,单纯环境因子对植被格局的解释占 2 0 .64% ,而环境 -空间耦合因子仅占 0 .83 % ,空间因子独立占 5.10 % ,其他因子占 73 .43 % ,草本的可解释性远远低于灌木。但无论是灌木层还是草本层 ,在诸多因子中 ,土壤水分始终在影响群落物种数量结构的空间格局分布中起着主导作用更多还原

【Abstract】 Minjiang river is an important branch of upper reach of the Yangtze River. The upper reach of Mingjiang river lies in the east margin of Qing-zang altiplano, a typical arid valley because of the special alpine canyon physiognomy, where the ecological security and the environment conservation is important for all of the Yangtze River valley. In this arid valley the mean annual precipitation is 493mm, the mean evaporation is 1332mm and the altitude 1300～2200m. The main plant communities are composed of xerophil plants. As the altitude increases, the special plant community’s spatial pattern, with corresponding soil environmental factors, is formed. The paper aims to explain the influence of soil factors on the species quantitative pattern in communities and give the reference for vegetation recovery, after the analysis on the relation between the environmental factors and the plant community spatial pattern along with the spatial variation in the arid valley. Based on the investigation of 53 plots in the arid valley, the parameters of soil (soil water, pH, soil organic matter, total N, available N, total K, available K, Total P, and available P), the parameters of plant communities (the coverage, number, height for different plant species, etc.) and the spatial parameters (longitude, latitude, etc.) were analyzed. The ordination based on the community plots and the quantitative classification is performed with the TWINSPAN (Two Way Indicator Species Analysis) method. The species quantitative pattern of shrub and herb layers of communities were analyzed with detrended canonical correspondence analysis (DCCA) ordination, and the influence of soil factors, spatial factors and their interaction with the total variance of plant species abundance pattern were quantitatively partitioned. The results showed, that the shrub layer of communities could be divided into 5 types and the herb layer could be divided into 7 types. The soil water as the most principal factor with other environmental factors plays important role in forming the distribution pattern of communities. However, the environmental factors in different layers of communities were different. In shrub layer, the contribution rate of the soil environmental factors was 28.02% solely; the contribution rate of the soil environment factors with spatial factors coupling function was 8.90%; the spatial factors was 10.69% solely and other undetermined factors constituted 52.39% for explaining the community distribution pattern forming. Whereas in herb layer, the contribution rates of the four aspects above-mentioned were 20.64%, 0.83%, 5.10% and 73.43% respectively. The other undetermined factors might be the biological factors and random factors. It is clear that the undetermined factor in the herb layer is much higher than in the shrub layer. Therefore, that the herb layer was influenced by environmental factors should be less than that in the shrub layer. Whether in the shrub layer or in the herb layer, among the many environmental factors, the soil water always plays the most important role in the forming of community distribution pattern or species abundance variation in the communities.更多还原