The Composition And Indicative Function Of Carabid Beetles (Coleoptera: Carabidae) Community In Yeyahu Wetland Nature Reserve, Beijing

The wetland is an ecological landscape with the richest bio-diversity in nature and the most important natural resource that people depend,but characters of the wetland is degenerating at different degree because of human's disturbing,great attention has been paid to the issues of wetland environmental monitoring and restoration at home and abroad,and the effective and scientific index with high operability is urgently needed,to constitute the index system for wetland environmental quality assessment.The carabid beetle is one of the most important groups of Coleoptera,almost distributed over all of the terricolous system.It showed closely relationship to the environment,and was considered as bioindicator of environment.However, there is few investigation about carabid beetles in wetland at home.Carabid beetles from 32 sampling sites with five main vegetation types,two well-conserved ones and three degraded ones,were investigated in Yeyahu Wetland of Beijing by pitfall traps from April to December,2007.The results are as follows:(1) A total of 2535 carabid beetles belonging to 19 genera and 52 species were collected, Harpalus,Pterostichu and Chlaenius were the dominant genera,including 14,6 and 5 species respectively,and the dominant species were Harpalus griseus(Panzer),Harpalus pallidipennis Morawitz,Pterostichus eschscholtzii(Germar),Dolichus halensis Schaller and Harpalus capito Morawitz.(2) August was the fastigium with the total number of carabid beetles individuals in Yeyahu Wetland,and the individual in this month took up 48.4%of annual ones.There was no remarkable different in the total species number,which was the most in July.The seasonal dynamics of carabid beetles in different vegetation types made a great difference.The number of individual and species were more in June,July and August,except Hemarthria altissima transect.(3) The carabid beetles community diversity have significantly differences in different habitat.The community diversity of the well-conserved Phragmites communis and Cyperus glomeratus transects were higher than the three degraded ones;Salsola collina transect and Degradated Phragmites communis transect were better than Hemarthria altissima ones.The generic diversity was more significantly different between the well-conserved and degraded habitat.(4) The similarity of carabid beetles community was conducted by clustering analysis and component analysis(CA).The results presents that the component of carabid beetles in three degraded transects were similar.The number of individual and species in well-conserved Phragmites communis and Cyperus glomeratus transects were abundant,but there were relatively obvious difference in component,so they were classified into two types in component analysis.The composition of carabid beetles community was intimately correlated with the habitat of different vegetation types,which suggested that carabid beetles have closely relationship to the environment,furthermore,it showed the habitat selection of carabid beetles.(5) The result of CCA,based on individual number of carabid beetles and environment variables,presented community composition was influenced by many environment variables, and soil water content,plant biomass and coverage,the coverage,dry weight and plant thickness of litter were more prominent..(6) The analysis of habitat indicator value of species showed the indicator species of different habitats in Yeyahu Wetland,most of which had significantly differences and closely relationship to 6 main environment variables.Some indicator species were highly specific and thus restricted to a single ecological state,so we made the relative amount of Dolichus halensis Schaller and Harpalus pallidipennis Morawitz with moderate specificity and fidelity as an indicator index.(7) The total biomass and the mean individual biomass of carabid beetles community in well-conserved habitat were more than the degraded ones,however,the difference of the total biomass was more significance.Thus the total biomass maybe a more proper indicate index in Yeyahu Wetland.(8) According to the investigation of Yeyahu Wetland in 2007 and the elementary analysis, we tentatively proposed carabid beetles can be used as the bioindicator of ecological environment in Yeyahu Wetland.The indicator indexs included the number of individual,species and genes,Shannon-Wiener generic diversity index,indicator value,total biomass and the relative amount of Dolichus halensis Schaller and Harpalus pallidipennis Morawitz(Ratio of Dolichus halensis,RD),However,if the index was scientifically rational,it need to investigate deeply and collect more data to test,moreover,the concrete application and the applicable Range requires further research.