The Ecological Geographical Research Of Soil Macro-faunal Communities Along A Latitudinal Gradient In Farmland Of The Heilongjiang Province

Soil faunas are abundant and widely distribution,soil fauna communities are important decomposers of farmland ecosystem.They play important role in decomposing debris,changing soil physical and chemical properties,driving soil formation and development,promoting soil material circulation and energy conversion,and the ability to make rapid changes in the environment to respond.The spatial distribution of diversity,community characteristics and functional groups of soil macro-faunals of different latitudinal gradient of farmland,which is global climate change on the basis of the important foundation for the conservation of biological diversity.And it help to explore the underground ecosystem at a regional scale in our biodiversity features,while maintaining and management of the structure and function of farmland according to the main ecosystem to provide.We selected three representative mountain areas along the latitudinal gradient: the Maoer Mountains,Dailing and Tahe.Fieldwork was conducted in August 2011.In this study,we determined the composition,horizontal structure,vertical structure,diversity characteristics and functional groups of soil macro-faunal in farmland systems along a latitudinal gradient.The hand picking method of separation was used to determine the soil macro-faunal communities.Using bivariate correlation analysis and canonical correspondence analysis,we assessed the relationships between soil animal communities and environmental factors,to reveal the distribution characteristics and interference factors of soil macro-fauna community in different latitudinal gradient farmland in Heilongjiang Province.In total,2,339 individuals from 35 groups of soil animals were collected,which belonged to 2 phyla,6 classes,14 orders,and 35 families.Enchytraeidae,Lumbricidae,Carabidae,and Staphylinidae were dominant families,accounting for 58.84% of the total number of individuals.Formicidae,Araneidae,and Geophilomorpha were common groups,accounting for 32.79% of the total number of individuals.The results showed that:(1)In terms of horizontal distribution,individual density and numbers of groups at sites followed the order Dailing >Maoer Mountain > Tahe.Results of the one-way ANOVA revealed there were no significant differences in individual density or richness in the soil macro-faunal communities at different latitudes.The Shannon-Wiener diversity index(H)and Pielou evenness index(E)for sites followed the order Maoer Mountain > Dailing > Tahe.The Simpson dominance index(C)of Tahe and Dailing were higher than that of the Maoer Mountains,and the Margalef richness index(D)was greatest in Tahe,followed by the Maoer Mountains and Dailing.(2)In terms of vertical distribution,no significant differences were detected among the three different latitudinal areas for individual density or richness at the same vertical level(P < 0.05).Individual density and richness in soil macro-faunal communities decreased with increasing soil depth,except for soil macro-faunal communities from the Maoer Mountains at 5–10 cm,indicating an obvious surface aggregation.(3)Regarding the relationships between soil macro-faunal communities and soil environmental factors,the bivariate correlation analysis showed there were no significant correlations among numbers of groups,individual densities,diversity indices,evenness indices,richness indices,pH values,organic matter,total nitrogen,total phosphorus,and available phosphorus.Results of canonical correspondence analysis further indicated that the dominant and common groups were highly adaptable to environmental factors and the dominant and common groups were widely distributed in the three latitudinal areas.In this paper,the research on the functional groups of soil macro-faunal with different latitudes was carried out.Soil macro-faunals were divided into four functional groups,namely,predator,phytophage,saprozoic and omnivore soil faunas.Saprozoic soil animal biomass accounted for the absolute superiority,the biomass of Lumbricidae was the largest,and the density of predator and saprozoic soil faunas accounted for more than 80%,but the soil faunas of four functional groups did not depend on the spatial distribution shows a regular change.This study showed that the numbers of groups,individual densities,and diversity indices of the soil macro-faunal communities from the farmland ecosystem changed along a latitudinal gradient,but no significant changes were found in this study.Different soil animal groups at different latitudes are affected by environment variables.At the local scale,the influence of environmental factors on soil macro-fauna should not be ignored.The results of the study create a foundation for researching spatial patterns and mechanisms of biodiversity maintenance at regional scales.