Effects Of Farmland Shelterbelt System On Diversity Of Soil Arthropods

Non-cropped habitat in agricultural landscape can provide the resources and environment for the survival of most species,and are conducive to the maintenance and protection of farmland landscape biological diversity.A systematic understanding of species distribution pattern and its influencing factors is important for realizing the optimization and rational layout of non-cropped habitat,as well as the protection of agricultural landscape biodiversity and various ecosystem services.As a specific type of non-cropped habitat,farmland shelterbelt is also an important part of the windbreak system in Three-North Area of China.In order to explore the strength of the biodiversity protection function of farmland shelterbelt,we taked Changtu County,Liaoning Province as an example,used GIS technology to select 8 farmland shelterbelt units as the research plots(each unit is a field).We used pitfall traps to investigate the distribution of soil arthropods at different distances(0m,50 m,100m,150 m,and 200m)in the farmland adjacent to different types of shelterbelt(complete,incomplete,and extinct).The vegetation community characteristics of farmland shelterbelt were also recorded.The methods of ANOVA and community ordination were used to analyze the effects of shelterbelt type,distance gradient and shelterbelt vegetation structure on the distribution of soil arthropods in the farmland.The main findings are as follows:1.A total of 12230 soil arthropods were captured.The captured soil arthropods belonged to 3 classes,8 orders,26 families,and 38 species.Among them,the dominant species were Teleogryllus emma,Harpalus sinicus,and Chlaenius junceus,a total of 9412 heads,accounting for 76.96% of the total catch.The common species were Chlaenius prostenus,Calosoma maximoviczi,Calosoma chinensis,Pyrrhocoris tibialis,Pholcidae and Trochanteriidae,with 2351 heads in total,accounting for 19.22% of the total catch.The rest 29 species were rare species,with a total of 467 heads,accounting for 3.82% of the total catch.2.Farmland shelterbelt could increase the abundance of soil arthropods in adjacent farmland significantly,however,no obvious effect on improving species diversity.The structure of soil arthropod community maintained by the farmland adjacent to shelterbelt was different from the extinct shelterbelt.Compared with the extinct shelterbelt,the abundance of soil arthropods maintained by the farmland adjacent to the complete and incomplete shelterbelt was significantly higher(P <0.05).The species number of soil arthropods was significantly higher in farmland adjacent to the incomplete shelterbelt(P <0.05).There was no significant difference in the Shannon-Wiener diversity and Simpson dominance of arthropods among various shelterbelt types(P> 0.05).The community structure of arthropods maintained by the farmland adjacent to the complete and incomplete shelterbelt was different from grassy fields boundary and bare fields boundary.3.With the increase of the distance from shelterbelt,the abundance of soil arthropods in the farmland adjacent to the shelterbelt showed a significant upward trend,while the species diversity showed a decreasing trend in all shelterbelt types,the edge effect was significant.With the increase of the distance from shelterbelt,the abundance of soil arthropods increased significantly in the farmland adjacent to the complete and incomplete shelterbelt,both showed significantly lower than other distance gradients at 0m(P <0.05).In the farmland adjacent to the extinct shelterbelt,the species abundance showed a trend of first decrease,then increase and then decrease,the difference between all distance gradients was not significant(P> 0.05).The Shannon-Wiener diversity of soil arthropods showed a decreasing trend in all shelterbelt types.The edge effect was more significantly in the farmland with vegetation boundaries.4.The diversity of soil arthropod community was closely related to the characteristics of shelterbelt vegetation structure.The abundance of soil arthropods was significantly positively related to the tree layer coverage,border width,herb layer species abundance and herb layer coverage.The species number of arthropods was significantly positively related to the abundance and richness of the herb layer.Shannon-Wiener diversity and Simpson dominance of arthropods were closely related to the width of the boundary and the species abundance of herb layer.5.The species abundance of herb layer and tree layer coverage in the shelterbelt were the main factors affecting the distribution of soil arthropod communities.Different arthropod species had different responses to the vegetation structure of the shelterbelt.Redundancy analysis showed that the effects of herb layer species abundance and tree layer coverage on the distribution of soil arthropod communities reached a significant level(P <0.05),which explained 35.4% of the arthropod community variability together.The responses of soil arthropods to the structure of shelterbelt vegetation community significantly differed with species.As the main natural enemies in the local agricultural landscape,carabid beetles and spiders were closely related to the above vegetation structure factors.The diversity of some common carabid species were positively associated with herb layer species abundance,while the diversity of common spider families were positively associated with tree layer coverage.