基于物种生存域的干旱半干旱区地下水与植被关系研究

土壤水分和盐分是干旱半干旱区植被生态最直接和最主要的环境因子，是地下水与植被相互作用关系的关键纽带。以宁夏回族自治区盐池县的地下水浅埋区为研究对象，通过野外生态地质调查，获取了每个调查点的植被类型及土壤水分和盐分含量，并以土壤含水率和含盐量为变量，圈划了5个优势物种的生存域，并根据不同物种生存域范围叠加图，分析了地下水位下降对植被的影响。生存域叠加图分析表明，地下水位的下降将导致研究区植被类型出现以盐蒿—芨芨草—苦豆子—骆驼蓬—沙蒿等优势种为代表的盐生—湿生—旱生—沙生植被类型演替趋势。研究表明，以土壤水盐为变量绘制物种生存域范围图，能形象地刻画干旱半干旱区不同植被物种的适生环境，并可用来预测地下水位变化后植被物种的演替趋势。

Study on Relationship between Groundwater and Vegetation in Arid and Semiarid Region Based on Survival Regions of Plant Species

Soil moisture and salinity are the most direct and important ecological environmental factors for vegetation in arid and semiarid region, which are critical links of interactions between groundwater and vegetation. Ecological and hydrogeological survey was conducted in field with shallow water table in Yanchi County of Ningxia Hui Autonomous Region. The data of vegetation types and moisture and soil salinity at each investigation point were obtained. Then, moisture and salinity of soil were selected as the variables, survival regions of five dominant species were determined. Survival regions of five dominant species were mapped in a coordinate system to analyze the impact of decline of groundwater table on vegetation. The result indicates that the decline of groundwater table will bring about succession of vegetation types according to the order of halophytic, hygrophilous, xerophytic to sandy vegetation. The result shows that the map of survival regions of plant species is good at describing suitable environment of different vegetation species in arid and semi-arid region. Furthermore, survival regions of plant species can be used to predict the trend of vegetation succession species due to groundwater level change.