Variations And Influencing Factors Of Carabine Diversity In Temperate Forests Of China

Due to the interferences of human activities and the impacts of climate change,the composition of forest vegetation-has undergone great changes.Original forests in temperate forest-ecosystems have suffered serious damages,and-are gradually being replaced by artificial-and secondary forests.The effect of temperate forests dominated by artificial and secondary forests on biodiversity has received extensive attention.Albeit domestic and foreign scholars have carried out indepth research on the biological role of temperate forests in biodiversity conservation,insects are usually being ignored due to their small body size and their biodiversity is easily overlooked.The ground beetles(Carabidae)were one of the most abundant taxons in forest ecosystems,most species were predatory which character plays an important role in maintaining the stability of ecosystems.Carabid is an indicator of environment change because their behavioral and physiological heterogeneity.Studying the impact of forest changes on the carabid diversity is conducive to understand the forest ecosystem functions indepth,and provide a theoretical basis for biodiversity conservation and ecosystem restoration in temperate forests.This study was conducted in the temperate forests of nine locations,which are:Dongling Mountain of Beijing,Bashang area of Hebei Province,Liaoheyuan of Hebei Province,Yiwulv Mountain of Liaoning Province,Zhanggutai of Liaoning Province,Baishilazi of Liaoning Province,Changbai Mountain of Jilin Province,Zhangguangcailing of Heilongjiang Province and Laoyeling of Heilongjiang Province.We used traps to collect carabids in the research areas.The objectives of this study were to understand the effect of vegetation composition on the diversity and functional groups of carabids,explore the impacts of climate change on the diversity and turnover rate of carabids,and master the effect of landscape structure changes on the diversity and community composition of carabids.We also investigated the vegetation diversity and structure,climatic characteristics of the carabid habitat and forest landscape patterns.The main research results and conclusions are as follows:(1)In the nine areas,we-installed 159 quadrats and 512 traps for 579 capturing days.A total of 162 species with 30685 individuals were sampled.The species richness and abundance of carabids showed a fluctuating trend from Dongling Mountain in the north of China to Maoer Mountain in the northeast of China.Comparing with other areas,the Maoer Mountain harbored the highest species diversity while the Zhanggutai area had the least species diversity.The fluctuating trend was significantly correlated with the primary forest in the northeast forest area.The results showed that the conservation of the primary forests was important to carabid protection.RDA analysis of carabids and vegetation structure and the rarefaction and extrapolation curves showed that the diversity of carabids could be elevated by increasing forest canopy,tree species richness and herbaceous diversity.(2)To understand the effects of herb community structure on the functional group of the carabid,we built the herbaceous phylogenetic community structure and calculated the phylogenetic community structure index for herbaceous plants in each sample plot of the study area.The results of correlation analysis between herbaceous phylogenetic community structure index and carabids functional group index showed that the number of predatory and small individuals increased with nearest taxon index,the number of large,predatory and omnivorous individuals increased with net relatedness index,the number of large and predatory individuals decreased-when PD index increased,and the number of small,omnivorous and phytophagous-carabids increased with PD index.(3)Carabid richness and abundance-generally had a positive correlation with temperature and rainfall,but rare species mainly occurred in areas with low temperature and limited rainfall.Carabid abundance in different seasons was mainly affected by high temperature,and the richness was mainly affected by rainfall.However,the positive effects of high temperature and rainfall on the abundance and richness of the carabids were shown in specific altitudes,latitudes and longitudes confirming that species might migrate to cope with the effects of climate change.The lower turnover rate of-carabids in Northeast China in response to climate change was related to the longer seasons in North China than Northeast China.The low turnover rate allowed species with different life history characteristics to coexist,and species behaviors with different life history characteristics promoted species replacement.The low turnover rate of the carabid in Northeast China in response to climate change was related to the weaker diffusion capacity of species.(4)We explored the influence of landscape structure on the composition of the carabid at the scale of 18.378km radius.The result showed the richness of carabid increased with-habitat area and land types,so ensuring adequate habitat was critical to-maintain species diversity.The richness of the specialist species increased with the decrease of landscape fragmentation and the increase of the habitat area,so the reduction of specialist species was caused by landscape fragmentation from human disturbances.The extent of diffusion of the generalist species was strongly influenced by the landscape pattern,with a positive correlation to landscape plaque homogeneity and the degree of isolation).The pattern of species dominance in habitat was closely related to the landscape pattern,which the higher landscape fragmentation and lower connectivity was related to greater number of dominant species individuals.