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.