关键词: 典型草原, 放牧, 粪金龟子群落, 指示值法, 功能群, 内蒙古

Abstract:  From May to September 2004, choosing grasslands under different grazing pressure (i.e., ungrazed grassland, moderately grazed grassland and overgrazed grassland) as sampling plots in a typical steppe in Inner Mongolia, and collecting dung beetles by pitfall trap method, we analyzed the influences of grazing activity on dung beetle assemblages in order to clarify the effects of grazing activity on dung beetle assemblage. The results indicated that a total of 60 839 dung beetles belonging to 3 families, 5 genera and 24 species were captured. As grazing pressure increased, the changes of the number of individuals, biomass and species number of dung beetle assemblages were significantly different. Different dung beetles showed distinct sensitivity to grazing activity. All above indices of dung beetle assemblages had obviously seasonal characteristics. The Pearson corelation analysis showed that the individual number, biomass and species number of dung beetle assemblages as well as the numbers of individuals of Aphodius comma and Aphodius subterraneus had significant negative correlation with the increase of grazing pressure in spring. Moreover, the species number of dung beetle assemblage and the number of individuals of Ceratophyus polyceros had significant negative correlation with grazing pressure in summer. But in autumn, the biomass and species number of dung beete assemblages as well as the numbers of individuals of Ceratophyus fischeri, Gymnopleurus mopsus and Onthophagus gibbulus had significant positive correlation with the increase of grazing pressure. Based on body length, body weight and behavioral characteristics of dung beetles, four functional groups were classified. Grazing activity had greater influences on functional group Ⅲ and Ⅳ, whose body size were relative small. The results caculated with the IndVals method showed that C. fischeri, Aphodius scofa and A. subterraneus could be used as the indicator species to define grasslands under different grazing pressure in typical steppes in Innner Mongolia.

Key words: Typical steppe, grazing activity, dung beetle assemblage, IndVals method, functional group, Inner Mongolia