科尔沁沙地草地植被恢复演替进程中群落优势种群空间分布格局研究

通过对处于流动沙地、半固定沙地和固定沙地等不同恢复演替阶段的群落的取样调查 ,研究了科尔沁沙地草地植被恢复进程中群落优势种群的空间分布格局及其动态变化。运用扩散系数、聚集指数、平均拥挤度、聚块性指数、Green指数、聚集强度、Poisson分布和负二项分布的 χ2 拟合检验等 7项指标 ,对群落优势种群的分布格局的研究结果基本一致 ,大多数物种的空间分布呈显著的聚集分布。在演替进程中种群格局强度的变化和群落总体聚集程度的变化与种群动态和群落结构的空间异质性相对应 ,较高的聚集程度是种群分布斑块化和群落结构的空间异质性的反映 ,随着演替进展 ,优势种的种群数量扩展 ,但种群分布的聚集强度下降 ,群落结构的空间异质性降低。在 7种测定分布格局的指标中 ,聚块性指数、Green指数和聚集强度是无量纲的指标 ,其大小不受种群大小的影响 ,其变化可以较好地指示格局强度本身的变化 ,并与种群动态和群落结构变化相联系

Spatial patterns of main species of the grassland community in the recovering succession in Horqin sandy land

In this paper, spatial patterns of main species in grassland community in the recovering succession were measured with 7 indexes, such as dispersion index, clump index, mean crowding intensity, patchiness index, Green's index, the clump intensity index, the Chi-test for Poisson distribution and negative binomial distribution. Almost all of the spatial patterns of the main species of the grassland community in Horqin sandy land were clump. Clump distribution had the good advantage of promoting population invasion and inhabitation, promoting community formation and promoting vegetation restoration. In the process of community succession, the intensity of distribution pattern changed. This change could indicate population dynamics and pattern intensity which can be a measurement for spatial heterogeneity of community structure. The results of 7 measurements were the same, but the patchiness index, Green's index ,and the clump intensity index were more preferrable than the others.