岷江上游干旱河谷区植被多样性与环境因子的相关性研究

对岷江上游干旱河谷区植被多样性与环境因子相关研究表明：1）阴、阳坡灌、草丛植物群落物种α多样性指标均随海拔升高表现出明显的增加趋势，阳坡呈现出中间低两头高的海拔梯度格局；阴坡总体呈现直线上升的趋势。2）该区土壤肥力总体水平高低表现为：中上部〉中部〉下部〉中下部、阴坡〉阳坡。低海拔地区土壤破碎，土壤含水量和土壤肥力极低，高海拔地区的土壤水分含量和土壤肥力都相对较高，立地条件也较适宜植物的生长。3）植被多样性与环境因子的相关分析表明，海拔、坡向、坡度、土壤含水量、速效N、速效K、有机质、全N、全K与灌丛群落多样性和生物量均呈正相关关系，而pH值、速效P、全P、全Ca与多样性和生物量呈负相关关系。通过逐步回归分析和主成分分析筛选出环境主导因子为全N、速效P、土壤含水量和速效N。

A Study of the Relatedness between Species Diversity and Environment Factors of the Arid Valleys in the Upper Minjiang River

This research work focused on the relationship of species diversity and environment factors of the arid valleys in the upper Minjiang River. The results showed that the α diversity of shrub and herb increased with the rising of elevation both on north facing slope（nfs） and south facing slope（sfs）. The capacity of soil fertility showed the upper part 〉 central part 〉 lower part, and nfs 〉 sfs. Because of the broken soil there was a poor soil fertility and a low soil moisture at lower elevations. However, soil fertility and soil moisture were better at high elevations which fitted the growth of plants. The result of correlation anal- ysis between species diversity and environment factors indicated that there were positive correlations among environment factors （ elevation, exposure, slope, soil moisture, available N, available K, organic matter, total N, total K） and species diversity. And there were negative correlations among environment factors （ph Value,available P,total P and total Ca） and species diversity or biomass. The results of step-regress analysis and principal component analysis indicated that environment factors were synthetically affected by total N, available P, soli moisture and available N.