Species Diversity of Litter-layer Beetles in Four Forest Types in Eastern Hengduan Mountain Region|
YU Xiao-dong LUO Tian-hong ZHOU Hong-zhang
Using pitfall traps, we build up 20 plots in the Eastern Hengduan Mountain Region, Southwest China, to compare the composition and distribution of litter-layer beetle communities among managed secondary forests (MSF) of planation after clear-cutting, unmanaged secondary forests (USF) surrounding by farmland after clear-cutting, contiguous natural Abies forests (NAF), and contiguous natural Rhododendron elfin forests (NRF). Based on principal component analysis (PCA) and cluster analysis of species and individuals of litter-layer beetles, we discussed the effects of clear-cutting and management practices. A total of 4 292 individuals representing 24 families wer collected between July 8 and July 14, 2004. Of these, individuals of the family Carabidae take 46.8% of the total, Agyridae 13.1%, Staphylinidae 11.4%, and Scarabaeidae, Curculionidae and Tenebrionidae each more then 5%. These six families can be considered as common groups in the study area. The individuals of Carabidae were significantly more abundant in NRF than those in the other forests, and significanly sparser in USF then those in the other forests. Agrytidae was found more frequently in two uncut natural forests than in two secondary forests after clear-cutting. More individuals of Tenebrionidae were found in NRF than those in other forests. Significantly more individuals of Cantharidae were trapped in NAF and MST than in USF. Elateridae was found significantly more frequently in USF then in MSF and NAF. The individuals of Curculionidae were more aboundant in MSF and NRF than in USF. More individuals of Chrysomelidae were trapped in NRF then in USF. Beetle capture per 100 traps per day was gradually increased from USF, MSF, NAF to NRF, but eveness was opposite. MSF had the higest species richness and diversity values. USF and NRF had the lowest values of richness and diversity, respectively. Principal component analysis and cluster analysis showed that beetle community of USF was different from those of the other forest tyupes; although the beetle community of MSF was similar to two uncut natural forests,the similarity between MSF and NAF was much low.Based on these results,we conclude managed plantation after clear-cutting contribute to the re-establishment of the diversity of litter-layer beetle assemblages in Eastern Hengduan Mountain Region.
Litter-layer beetles; Clear-cutting; Diversity; Eastern Hengduan Mountain Region