新疆塔里木河下游土壤特性及其对物种多样性的影响

结合塔河下游大西海子至台特玛湖区段的8个地下水监测断面、31个土壤剖面的217个土样分析数据,利用非参数检验、单因素方差分析和灰色关联方法,分析了塔河下游土壤特性及其对物种多样性变化的影响.研究结果表明,塔河下游土壤除全磷外,有机质等指标存在垂直分布差异,出现显著差异的土层深度为50cm.塔河下游上段的土壤养分含量相对较高,下段较低;物种多样性指数自上段至下段的下降趋势与有机质等的变化相同,而植物群落退化则表现为从复合群落到单一群落的演变趋势,即从乔(胡杨为主)、灌(柽柳为主)、草复合群落演变到单一的柽柳灌丛群落.灰色关联分析表明塔河下游上层(0～50cm)土壤有机质、全氮、全磷、全钾含量与物种多样性的相关性较高.塔河下游土壤有机质、全氮、全磷、全钾等在一定程度上对物种多样性变化有一定影响.

Soil properties and theiri mpacts on changes in species diversity in the lower reaches of Tarim River, Xinjiang, China

Based on the data of soil physical and chemical characteristics from 217 soil samples collected from 31soil profiles located in eight monitoring sections in the lower reaches of Tarim River,southern Xinjiang,we analyzed the spatial patternsof soil properties usingnon-parametric method or ANOVA,and examined the differences in soil quality between monitoring sections by cluster analysis.The relationship between plant species diversity and soil factors was also examined by using grey correlation analysis.Results indicate that the measured soil properties,including the organic matter,total N,and total K varied vertically among different soil layers with exception of the total P,with significant differentiation at 50cm soil depth.Based onsoil quality,the lower reaches of Tarim River aregenerally differentiated between the upper sections and the lower sections,withthe content of nutrientsin soils of the upper parts being greater than in the lower parts.Along the environmental gradients of the different monitoring sections located 150m away from the river course of the lower reaches of Tarim River(namely from upper to the lower sections),plant species diversity indices displayed the same pattern of descending gradient as soil organic matter.Moreover,plant communities showed a change from mixed-species communities to single-species community corresponding to the changes of plant species diversity indices,i.e.from the communities composed of arbor(Populus euphratica),shrub(Tamarix spp.) and mixture of herbage to pure Tamarix community.Grey correlation analysis indicates that there exist significant relationships of plant species diversity with soil organic matter,total N,total P,and total K in the 0-50cm soil layer,suggesting that changes in these soil factors could reflect changes in plant species diversity to certain extentin the lower reaches of Tarim River.