Distribution Characteristics Of Soil Arthropods In Farmland Landscape Of Typical County In Lower Liaohe River Plain Based On ESDA

In the agricultural landscape,the demand for arable land is increasing,non-cropped habitats are continuously declining,and habitat heterogeneity is declining,which in turn leads to a decline in biodiversity.The decline in farmland biodiversity is related to intensification of agriculture at multiple time and space scales.Habitat heterogeneity is associated with higher biodiversity in the farmed landscape,whether measured at a small or large scale.The more heterogeneity of landscape,the more biodiversity there is.Therefore,agricultural production methods,landscape heterogeneity and biodiversity have formed a closely interrelated mechanism of interaction.It is the basis for optimizing agricultural landscape configuration and composition that research on distribution and spatial autocorrelation pattern of arthropods in cropped and non-cropped habitats,at the same time,it is also a prerequisite for biodiversity conservation.To understand the distribution of soil arthropods in different habitats and the effect of different non-cropped habitats on the farmland habitat,this study conducted in Liaozhong County in the Lower Liaohe Plain,China.Arthropods were sampled in three sample areas which are 1km×1km grids with non-croped habitats proportion from 10% to 20% in summer and autumn.Community characteristics,distribution characteristics and seasonal dynamics of soil arthropods in different habitats can be obtained.Then,distribution of arthropods was analyzed and spatial autocorrelation of arthropods in global and local scale was analyzed based on ESDA.The results show that:(1)A total of 36477 soil arthropods were captured in this study.The soil arthropods captured belonged to 4 classes,15 orders,and 49 families.The dominant groups were Formicidae,Stepopodidae,and Acrididae,accounting for 83.39 %of the total.Of these,23097 were captured in summer and 13380 were captured in autumn.The number of soil arthropods captured in summer is significantly higher than in autumn.There are significant seasonal differences in the number of soil arthropods,and there is a certain similarity in the populations.The dominant groups of soil arthropods in the two seasons are the same,and the common groups are quite different.(2)There are differences in the average number and population quantity and diversity of arthropods in different habitats.There are the most individual number of arthropods in ditches.The individual number is decreasing from woodland,grassland,pond,hedge,farmland,country road to orchard.The population quantity of arthropods is decreasing from farmland,woodland,hedge,country road,ditch,grassland,pond to orchard.Compared to autumn,there are more soil arthropods in all habitat types in summer.The number of soil arthropods in farmland,woodland,hedges was significantly higher in summer than in autumn(P<0.05).The populations of soil arthropods in diferent habitat did not show seasonal dynamics.In addition,the diversity characteristics of soil arthropods in different habitat types are significantly different,and they are also affected by seasonal changes.(3)The global spatial autocorrelation of soil arthropod numbers indicates that: the spatial distribution of arthropods has significant spatial autocorrelation and aggregation status,this aggregation effect is stronger in summer than autumn.Using the Moran’s I scatter plot for local spatial autocorrelation analysis,the proportion of plots falling in the first and third quadrants totaled 77.27%,reflecting the positive interaction of soil arthropod numbers between adjacent habitat plots.According to local spatial analysis of different habitat types,grassland habitats all fall in the first quadrant,and 75%,70%,and 60% of woodlands,ditches,and hedges fall in the first quadrant.It showed that different habitat plots had different effects on the number of soil arthropods in their adjacent habitat plots.There is a "hot spots" with high-high aggregation of arthropods around the ditch,grassland,woodland and hedgerows,whereas there is a "cold spots" with low-low aggregation of arthropods around many farmland patches.However,there are no obvious high-high gather areas around rural roads and orchards.So,agricultural landscapes combined with ditches,grasslands,woodlands and hedges have positive effect on arthropods.