水分梯度下荒漠植物多样性与稳定性对土壤因子的响应

荒漠生态系统多样性的研究对维持荒漠区群落稳定性有着重要意义。以艾比湖流域荒漠植物群落为研究对象，基于野外样方调查数据及实验分析，探讨不同水分梯度下植物多样性与稳定性的变化规律及土壤因子对二者的影响。结果表明：（1）随土壤水分含量下降，Shannon-Wiener多样性指数（H）、Simpson多样性指数（D）、Pielou均匀度指数（J）、Margalef丰富度指数（R）和种群密度稳定性（ICV）指数均呈下降趋势，且当土壤含水量低于4.65%时，荒漠植物多样性与群落稳定性总体显著降低（P<0.05）；（2）不同水分梯度下影响艾比湖流域植物多样性的土壤因子具有差异性，高水梯度为硝态氮与有机质，中水梯度下影响植物多样性的因子为pH，低水梯度为全氮和有机质；（3）仅在环境适宜的情况下，土壤因子（土壤含盐量与有机质）才能对群落稳定性产生显著影响（P<0.01）；（4）三种梯度下，物种多样性均对群落稳定性有显著性影响（P<0.001），植物多样性与群落稳定性存在正相关关系。

Response of desert plant diversity and stability to soil factors based on water gradient

Study of desert ecosystem diversity is of great significance for maintaining the stability of desert communities. As an important component of biodiversity, plant diversity plays an important role in maintaining the function and stability of community ecosystem. In arid and semi-arid areas, the increase in drought will have an important impact on plant diversity, which in turn will affect the stability of the community. Therefore, soil water content is a key factor affecting the diversity and community stability of desert plant. We studied the changes of plant diversity, community stability and other soil factors along the soil water gradient in Ebinur Lake basin. From July to August in 2017, a 30 m×3600 m transect was established north of the Aqikesu River and divided into sixty 30 m×30 m quadrats. In each plot, plant abundance, height, and diameter at breast height were recorded. Soil characteristics were analyzed, including water content(WC), soil pH(pH), soil salinity (SA), soil organic matter(SOM), total nitrogen(TN), total phosphorus(TP), available phosphorus(AP), and nitrate nitrogen(NN). Firstly, the sampling plots were divided into three water gradients by cluster analysis and included high water (W1), middle water (W2), and low water(W3) gradients. Secondly, we studied the changes of plant diversity, community stability and other soil factors along the soil water gradient. Finally, we screened the soil factors and added them to the structural equation model(SEM) to discuss the main soil factors affecting plant diversity and community stability under different water gradients. The results showed that:(1) with the decrease of soil water content, Shannon-Wiener index (H), Simpson index (D), Pielou index (J), Margalef index (R) and Inverse coefficient of population density variation (ICV) all showed a downward trend. Moreover, when the soil water content was lower than 4.65%, the overall diversity and community stability of desert plants decreased significantly (P<0.05); (2) There are differences in soil factors affecting plant diversity under different water gradients. The high water gradients were soil nitrate nitrogen and soil organic matter, medium water gradients were soil pH, and low water gradients were soil total nitrogen and soil organic matter; (3) Soil factors (soil salinity and organic matter) have a significant impact on community stability only the soil environment is appropriate (P<0.01); (4) Species diversity has significant effects on community stability under three gradients (P<0.001). There was a positive correlation between plant diversity and community stability. The research results are of great significance to the restoration of vegetation diversity and community stability in the study area.