黑河下游胡杨种群的点格局分析

Point pattern analysis of Populus euphratica population in the lower reaches of Heihe River

采用空间点格局分析方法中的Ripley K函数,将宏观的地理环境与微观的点格局相结合,分析了不同尺度下黑河下游胡杨种群的空间分布格局.结果表明：胡杨种群密度随离河距离增大而减小,且东河胡杨种群密度整体上高于西河;胡杨种群分布格局随空间尺度的变化而变化,主要在中尺度5~12 m呈聚集分布,在小尺度0~2 m和大尺度38~40 m呈随机分布,极少呈均匀分布;胡杨种群在不同离河距离主要呈聚集分布,且聚集强度随离河距离的增大呈增大趋势,而胡杨种群在离河距离较远的地段有扩散趋势,转为随机分布.表明胡杨种群内部的生态联系对空间尺度具有很强的依赖性,胡杨种群空间分布主要受表层土壤含水量和地下水埋深的影响.

Taking Populus euphratica population in the lower reaches of Heihe River as the research object, through field investigation, using spatial point pattern analysis method of Ripley＇s K func- tion, and combined the macro geographical environment with micro point pattern, we analyzed the spatial distribution pattern of P. euphratica population at different scales. The results showed that P. euphratica density decreased with the increasing distance away from the river, and its density was higher along the East River than along the West River on the whole. The distribution pattern of P. euphratica population varied with spatial scale which was mainly aggregated at mesoscale of 5- 12 m, randomly distributed at small-scale of 0-2 m and large-scale of 38-40 m, and very few was evenly distributed. P. euphratica populations were mainly aggregated away from the fiver, and the aggregation intensity tended to increase with the distance, while it tended to spread and turned into a random distribution at the farther distance. Research showed that the ecological linkages of P. eu- phratica populations strongly depended on space scale, and the surface soil moisture and groundwa- ter depth were the main factors influencing the spatial distribution of P. euphratica populations.