| Soil fauna are an essential component of soil biodiversity and often serve as biological indicators of ecosystem stability.Vegetation is the food source of soil faunas and plays an important role in the formation of soil fauna habitats.Vegetation mainly changes the diversity and abundance of soil fauna food resources by affecting soil physicochemical properties,biological characteristics and ecosystem nutrient cycling,thereby changing the composition and distribution of soil fauna communities.In recent years,studies on the relationship between vegetation-soil-soil fauna have received more and more attention in the field of soil ecology.Wuqi County,as a national demonstration county for the construction of forestry ecological projects such as returning farmland to forest(grass).At present,the research in this area mainly focuses on the influence of farmland abandonment period,plant community,and soil physicochemical properties on large soil faunas,and the research on the evolution characteristics and influencing factors of soil fauna community still lacks attention.Therefore,in 2021,this study took the soil fauna communities in the Hegou,Jinfoping,Mayaoxian and Zaocigou watersheds of Wuqi County as the research object to investigate the composition of soil fauna communities,the number of groups and the number of individuals under different vegetation types.Principal Component Analysis(PCA),Redundancy Analysis(RDA),Pearson Correlation Analysis and Structural Equation Modeling(SEM)and other methods.To study the structural characteristics,evolution law and influencing factors of soil fauna community between different vegetation types and the same vegetation type.To reveal the vegetation types in Wuqi small watershed on soil fauna community structure,evolution characteristics and its main influencing factors,to provide a scientific basis for evaluating the ecological effects of different vegetation types in Wuqi small watershed.The main results are as follows:(1)In different vegetation types,there are significant differences in the composition,quantity and characteristic index of soil fauna communities in different restoration years,which are mainly related to factors such as vegetation canopy density,herb biomass,herb diversity,number of herb species and soil p H.With the restoration of vegetation,the number and density of soil fauna community showed an overall trend of increasing first and then decreasing.The mixed forest community of Robinia pseudoacacia and Hippophae rhamnoides,the pure forest community of Robinia pseudoacacia and the pure forest community of Armeniaca sibirica were the key periods of vegetation restoration.The vegetation diversity in this period also reached a high level,and the composition and structure of soil fauna community were the most complex.(2)There were significant differences in the composition,quantity and characteristic index of soil fauna community in the pure Pinus tabuliformis forest with different planting years.The availability of soil resources was significantly improved after planting pine Pinus tabuliformis 11 a.With the increase of planting years,the overall soil fauna density showed a trend of first increasing and then decreasing.Planting 22 a pure Pinus tabuliformist can promote the improvement of soil fauna diversity and soil health,and the soil food web tends to be stable.In the process of restoration of Pinus tabuliformis pure forest,alkali-hydrolyzed nitrogen,herb density,herb diversity,number of herb species,electrical conductivity,total nitrogen and grass understory biomass are the main environmental factors affecting the composition,quantity and diversity of soil fauna communities.(3)In the process of vegetation restoration,soil fauna communities are mainly controlled by top-up resources,and changes in food resources and soil nutrients jointly drive the evolution of soil dominant order communities,thereby regulating the soil food web. |
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