人工封育区沙化草地植被生态位研究

采用样线和样方结合法对宁夏人工封育草原进行野外调查,运用重要值、Levins生态宽度指数和Pianka生态位重叠指数对封育外围区、边缘区、核心区3种不同措施下的植物生态位宽度及生态位重叠进行分析,以揭示人工封育区沙化草地植被生态位变化规律。结果表明：在整个人工封育区,重要值之和较大的为黑沙蒿（Artemisia ordosica Krasch.）和刺沙蓬（Salsolaruthenica IIjin.）,分别为689.53、455.83。外围区与边缘区生态位宽度最大的均为黑沙蒿,生态位宽度分别为0.846、0.790,核心区生态位宽度最大的是阿尔泰狗娃花（Heteropappus altaicus（Willd.）Novopokr.）,生态位宽度为0.640,是人工封育区的优势种。生态位重叠计测结果表明,植被的生态位宽度和生态位重叠并不存在直接的线性关系;生态位重叠度平均值和重叠对百分数表现为外围区〉核心区〉边缘区。不同封育措施间生态位宽度和生态位重叠度的差异表明适度封育有利于草地植被恢复,但随着封育时间延长,植物的再生和幼苗的形成会受到一定程度抑制。

The studies on sandy grassland vegetable niche of artificial fencing area

Using sample line and sample approaches for field survey in artificial fencing of Ningxia Hui Nationality Autonomous Region.In order to reveal the sandy grassland plants niche variation in three kinds of fencing measures including outside area,edge area and core area.The niche breadth and niche overlap were measured using important value,Levins index and Pianka index.The results showed that the biggest of important value were Artemisia ordosica Krasch.and Salsola ruthenica IIjin.,which were 689.53 and 455.83.The niche breadth of Artemisia ordosica Krasch.was both the biggest in the outside area and edge area,which were 0.846 and 0.790.In the core area,the niche breadth of Heteropappus altaicus（Willd.） Novopokr.was 0.640,It’s the dominant species in the artificial fencing.The results of niche overlap showed that the niche breadth didn’t have directly liner relation with niche overlap.The average value of niche overlap and percentage of overlap showed that outside areacore areaedge area.The difference of niche breadth and niche overlap in three kinds of fencing measures showed that moderate fencing was conducive to the recovery of vegetation,but with the fencing time extension,artificial fencing would inhibit plant regeneration and seedling formation.