| In the process of using semi-arid slopes,affected by policies and management,different types of utilization combinations have been formed,which have resulted in different landscape patterns.Soil animals,as consumers and decomposers that maintain energy flow and material circulation in the ecosystem,have a positive role in promoting the stability of the ecosystem.Stability of farmland ecosystems depends on the heterogeneity of its landscape structure.Highly heterogeneous landscapes can not only increase the connectivity of soil animal habitats,but also provide a carrier for its energy transport.Interference factors of slope farmland ecosystem are more complex,and land use types cannot fully reflect the differences of local habitats of soil animals,which make it necessary to study the impact of regional landscape patterns on soil animal diversity.In view of the above,this study takes the sloping land of the semi-arid small watershed in western Liaoning as the research area,and uses 3S technology and landscape index analysis method to analyze the landscape heterogeneity of different types of landscape combinations on the slopes in the region;and uses the trap method to obtain the data of the surface soil animals in each sample area;uses Pearson correlation analysis and multiple linear regression to analyze the relationship between the topsoil soil animal community feature index and landscape index,and then explores the impact of different landscape patterns on topsoil soil animals in semi-arid slope areas.The conclusions of the study are as follows:1.The overall landscape fragmentation degree of slope land in small watershed is relatively high.The landscape pattern differences among different landscape types are obvious.According to different land use types and their combinations,seven typical landscape combination are selected in this study area 20 samples,including type 1(orchard and terrace compound),2(orchard and slope farmland compound),type 3(forest land and slope farmland compound),type 4(forest land + orchard and slope farmland compound),type 5(forest land + terrace non-composite),type 6(forest land + slope farmland non-complex)and type 7(orchard + terrace non-complex).Due to the high precision of landscape refinement,the maximum PD value in the sample area at the landscape level reached 3933.078,the maximum LPI value was.143,and the maximum CONTAG value was 65.813.At the level of type,the patch density of farmland ridge is the highest,the degree of accumulation and dominance of farmland is the highest,and the shape of rural road is the most complex.The landscape patterns of the seven types of landscape combinations are not the same,the patch density of type 1,type 2,type 3 and type 6 is the highest,and the patch density of type 4,type 5 and type 7 is the highest on rural roads.2.There were significant differences in community characteristic indexes of topsoil soil animals.A total of 22,103 topsoil soil animals were captured in 20 sample areas,belonging to 56 families and 18 orders.The predominant species are two families of Carabidae and Formicidae.The common species are six families including Orthomorpha,Scutigeridae and Acrididae.The rare species includes forty-eight families.There were significant differences among the community characteristic indexes of all types of topsoil soil animals(P<0.01).The diversity and dominance index of type 1 topsoil soil animals were higher than other types,and the dominance index of type 3 was the highest and the diversity index was the lowest.The number of near surface soil animal species in compound landscape is higher than that in non-compound landscape.Diversity indexes of the four types of composite communities were significantly different from each other(P<0.01),while the diversity indexes of the three types of noncomposite communities were not significantly different from each other(P>0.05).3.There is a general correlation between topsoil soil animal community characteristics and landscape index.The community structure of topsoil soil animals was significantly affected by landscape pattern,and the evenness index(J)was significantly positively correlated with AREA_MN,and negatively correlated with LPI and PAFRAC.The richness index(E)was significantly negatively correlated with AREA_MN and positively correlated with LPI,PD and PRD.There was a significant positive correlation between the number of individuals and LPI.The number of species was positively correlated with PD,LPI and PAFRAC,positively correlated with PRD,and negatively correlated with AREA_MN.The more uneven the patch area distribution and the more abundant the patch types are,the more beneficial it is to increase the number of soil animals near the surface.The fragmentation degree of each patch was relatively high,and the more diverse the structure configuration of each small corridor was,the more abundant the topsoil soil animal species were.4.Different landscape combination types have different impacts on the characteristics of topsoil soil animal community.Landscape combination of seven types of topsoil soil animal community characteristic index and landscape index regression analysis,the results show that different combination is affected by the landscape index differences,such as type 1(orchard and terrace compound)the soil animal community diversity index and species from the effects of landscape index,while type 2(orchard and slope farmland compound)only species and individual number and species evenness index is affected by the landscape index;Same land use type the different combinations of topsoil soil animal community structure effect on landscape pattern of response degree also differ,for example,the landscape index of type 3(forest land and slope farmland compound)has obvious influence on the number of near surface soil animal species and species richness,while the landscape index of type 6(forest land + slope farmland non-complex)has certain influence on the number of near surface soil animal species,dominance,diversity and evenness index.In the process of land use in this research area and similar environmental conditions,the landscape layout should be adjusted according to different utilization conditions,so as to improve the farmland ecosystem service function suitable for the survival and reproduction of topsoil soil animals. |
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