摘要:全球气候变化对生态系统功能的影响决定着种群地位和群落演替，由于干旱区的特殊性成为研究生物响应环境变化的热点地区。为探索艾比湖流域荒漠区植物生态位对土壤水盐梯度的响应，在研究水、盐含量和植物生态位特征的基础上，应用变系数模型，分析了土壤水盐梯度下的群落组成和生态位响应趋势。结果显示：（1）随土壤水盐梯度的降低，艾比湖流域群落的物种组成呈倒"V"型分布，说明土壤水盐交互作用影响着植被分布和群落类型。（2）高水盐环境下，胡杨（Populus euphratica）、琵琶柴（Reaumuria soongorica）和梭梭（Haloxylon ammodendron）等生态位宽度值（B_i）较大，柽柳（Tamarix ramosissima）、骆驼刺（Alhagi sparsifolia）和甘草（Glycyrrhiza uralensis）等B_i较小；中水盐环境下，白刺（Nitraria schoberi）和琵琶柴的B_i较大，铃铛刺（Halimodendron halodendron）、甘草和盐节木（Halocnemum strobilaceum）的B_i较小；低水盐环境下，梭梭、花花柴（Karelinia caspica）和琵琶柴等B_i较大，盐节木的B_i较小；说明土壤水盐环境和物种生态学特性是影响B_i的重要因素。（3）物种水平上，B_i较大的种群与其他物种的生态位重叠（O_ij）一般较大，但B_i较小的物种间的O_ij不一定小（例如：高水盐土壤环境下柽柳和骆驼刺的O_ij为1）；群落水平上，B_i与O_ij具有一定的正相关性；说明由于资源纬度的相似性增大了低B_i物种间的O_ij，并且B_i和O_ij由物种向群落尺度转换时，两者之间的关系存在冗余。（4）土壤水盐梯度与群落生态幅呈现一种非线性相关特征，高水盐格局对群落B_i有一定的促进效应，而低水盐模式对B_i具有一定的限制作用，表明土壤水盐的协同效应影响着物种在群落的地位，并在一定程度上决定了群落向正负两极演替的方向。



Abstract:The impact of global climate change on ecosystem function determines the status of population and community succession, and since arid areas are unique, they have become a hot spot for studying biological responses to environmental change. We used a sample plot method investigation to explore the response of plant niche to the soil water and salt gradient of the Ebinur Lake Basin. Based on a study of moisture, salt content, and plant niche characteristics for arid desert areas, the changes in community composition and niche responses to soil water and salt at different gradients were analyzed. The results showed the species composition of communities had a reverse "V" pattern along the water and salt environmental factor gradient (from high to low); these phenomena indicate that the interaction of water and salt concentration was the main reason the distribution of vegetation types was restricted. The niche breadth of Populus euphratica, Reaumuria soongorica, and Haloxylon ammodendron were larger than those of Tamarix ramosissima, Alhagi sparsifolia, and Glycyrrhiza uralensis at high saltwater soil environments. The niche breadth of Nitraria schoberi and Reaumuria soongorica were larger than those of Halimodendron halodendron, Glycyrrhiza uralensis, and Halocnemum strobilaceum at moderate saltwater soil environments. The niche breadth of Haloxylon ammodendron, Karelinia capsica, and Reaumuria soongorica were larger than those of Halocnemum strobilaceum at low saltwater soil environments. These phenomena indicate that the ecological niche of a population was not only determined by soil moisture and salinity, but also the ecological characteristics of the species in the desert area. At the species level, the niche overlap of the populations with large niche breadth between other species was generally large, but the niche overlap with smaller niche breadth species was not necessarily small; however, at the community level, there was a positive correlation between niche breadth and niche overlap. These phenomena indicate that a similarity in resource latitudes increased the niche overlap between the low niche breadth species, and the relationship between them was redundant when there was a transformation of niche breadth and niche overlap from the species to the community scale. The soil water and salt gradient showed a nonlinear correlation with community ecological amplitude. The distribution pattern of high water and salt in the soil had a certain promoting effect on the niche breadth of the community, while the distribution pattern of low water and low salt had a limited effect on niche breadth. The synergistic effect of soil water and salt determined the status of species in the community and determined the direction of community succession to the positive and negative poles.





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