Species Diversity of Litter-layer Beetles in Northwest Yunnan Province,Southwest China

This paper studies litter-layer beetle species diversity and its changes in different habitats and local areas in the middle part of the Hengduan Range,a transition region between the east zones encircling the Pacific and the west zones of ancient Mediterranean,characterized by a series of paralleled mountain ranges and rivers from south to north,and with a sharp altitude differentiation.The study was conducted in Northwest Yunnan Province (E 99.0°-100.8°;N 26.7°-28.7°) and 33 plots were investigated to represent five different kinds of habitats,which located in six local areas,namely Mt.Daxue of Zhongdian County,Bitahai of Zhongdian County,Mt.Baimang of Deqin County,Shiguzhen of Lijiang County,Mt.Yulong Nature Reserve,Yongsheng County.Barber traps was employed.Totally,sixteen beetle families were found in the 2852 captured specimens,of which 41.3% was Staphylinidae and 25.9% was Carabidae;Scarabaeidae,Curculionidae and Tenebroinidae were each above 5%,and the other 11 families all together were less than 13%.There were no remarkable difference to be found in the values of species diversity (H),evenness (J) and richness (S),and individual number,if comparisons were made between local areas,but except for Yongsheng County and Bitahai of Zhongdian County.The former,characterizing by intensive farming,showed a relative low value of richness and individual number,whereas the latter,influenced by intensive herding and tourism,exhibited a low species diversity and richness.Computing the similarity coefficient (q) of beetle communities of the six local areas,we found that they tended to be less similar if geographic distances were longer between any two local sites,but it was true only when Yongsheng County was not included.Coniferous forests and meadows showed relatively higher abundance than the other habitats when we considered all beetles together,Carabidae only,or Scarabaeidae only;Staphylinidae was yet more abundant in broad-leaved forests and coniferous forests,Curculionidae in broadleaved forests and Tenebrionidae in shrubs.However,not all of these abundance differences among five different habitats showed statistic significance.If the whole scope of elevation from 1500 to 4500 m above the see level in the studied areas was divided into 6 intervals of 500 m,two peak values of diversity,richness and individual number corresponded to 2500-3000 m and 3500-4000 m respectively.Based on these results,we can conclude that geographic distances and habitat differences may influence species diversity and composition similarity of the litter-layer beetle communities in Northwest Yunnan Province;intensive activities of agriculture and tourism may disturb the natural patterns of changes of litter-layer beetle diversity in the studied region.