草原退化过程中植物群落的结构异质性分析——以家庭牧场为例

以内蒙古呼伦贝尔草原某家庭牧场作为研究尺度,以卧羊圈为中心沿辐射状将该家庭牧场划分为重牧区、中牧区、轻牧区和无牧区(围栏内),同时与村落自由放牧区(即过牧区)进行比较,开展植物群落结构空间异质性研究。结果表明:该家庭牧场植物群落种类较为丰富,多年生草本植物居多,一年生草本植物随放牧强度的减弱,比例也随之增加;轻牧条件下群落地上生物量最高,适度的放牧干扰有助于植物干物质的积累;轻牧区禾本科植物的重要值较大,说明轻度放牧干扰有利于群落发生恢复演替;重牧区和轻牧区Simpson集中性概率指数、Shannon-Wiener指数、均匀度指数高于过牧区,重牧区和轻牧区植物群落由于竞争达成了较稳定状态,群落较为集中,空间异质性高。

Analysis of Plant Community Structure Heterogeneity in The Process of Grassland Degradation---Taking Household Pasture for an Example

This study took a household pasture on the Hulunbeir grassland as research scale, and the method of space succession series instead of time series of succession series was used to analysis plant community structure heterogeneity. Setting the sheepfold as the center of the household pasture,we divided the household pasture into heavy grazing area, moderate grazing area, light grazing area and non-grazing area(fence inside), and at the same time setting a village free grazing area (i.e. over-grazing area) for comparison. The results showed that the household pasture had kinds of plant species, mostly plant species were perennial herbs, and the ratio of annual herbs increased with the grazing intensity reducing. The light grazing area had the highest aboveground biomass, thus, a light grazing disturbance could contribute to the increase of plant dry matter. Compared the household pasture with the over grazing area, the importance value of Poaceae plants in the light grazing area were higher than other areas, indicating that a light grazing disturbance conducived to the communities in restoration succession. Simpson index, Shannon-Wiener index and Pielou evenness index of heavy grazing area and light grazing area were higher than that of the over grazing area. Plant communities of the heavy grazing area and the light grazing area had reached a more stable state due to competition. The spatial heterogeneity of plant community was higher in more concentrated of plant communities.