宁夏蝗虫地理分布格局的聚类分析

根据宁夏的自然环境和行政区划将宁夏分为22个分布区域。为方便聚类分析，根据分布范围将宁夏蝗虫分为全布种(22个区域有分布)、多布种(2～21区域有分布)和独布种(只分布在1个区域)3类。在以分布区域为特征做聚类分析的基础上，把多布种分组并确定重叠的分布格局，共分为14个组。各组蝗虫在宁夏的自然分布作为其分布格局。结果表明：宁夏蝗虫的多布种多呈不连续分布；分布格局与国内外基本相似；贺兰山是宁夏蝗虫分布的热点。不连续的环境是造成宁夏蝗虫多布种不连续分布的主要原因。

Cluster Analysis on the Distribution Patterns of Grasshopper in Ningxia

Ningxia was divided into 22 area units based on the environment and regionalism.To facilitate the cluster analysis,the grasshopper species in Ningxia were divided into three groups.1)all-area-distributed species (distributed in all the 22 areas),2)more-area-distributed species(distributed in more than one area),3)one-area-distributed species (distributed only in one area).The more-area-distributed species were clustered based on distributions,and then grouped into 14 groups.The distributive areas of each grasshopper group were taken as their distribution pattern.The results show that:The distribution of more-area-distributed grasshopper species in Ningxia is in disconnected,the grasshopper species sharing the same distribution patterns in Ningxia have the similar distribution pattern in China,Helanshan is the hotspot of grasshopper distribution.The fragmented environment is the reason for the unconnected-distribution of more-area-distributed grasshopper species in Ningxia.