Effects Of Latitudes And Land Types On Communities Of Ground-Dwelling Arthropod In Cold Area

In terrestrial ecosystem,the ground-dwelling(GD)arthropods are charatcterized with small body size,high fertility,short life span,large number,wide distribution and diverse species.They are indispensable biological factors affecting matter circulation and energy flow in nature.Among them,agroforestry ecosystem plays a key role as foundation of human production and life providing essential materials.In China,the black soil area is one of the most important agroforestry ecosystem providing high quality food;however,currently it is experiencing rapid climate change and land use change.To study the structure differences of arthropods community in farmland at different latitudes is an important basis for predicting the impa cts of climate warming on agroforestry ecosystem services.It is also helpful for adjusting the strategic measures of agriculture and forestry management and maintaining the stability of agroforestry systems under global changes.This study consists of two surveys.Firstly,designed cropland and artificial wood-land at different latitudes were selected for investigation GD arthropod community in 2017;trapping method was used;GD arthropod community composition,diversity index and functional groups were calculated.Secondly,in both habitate types,GD arthropod community dynamics was monitored in Harbin in 2018 Relationship between GD arthropods community and soil environmental factors was analyzed,therefore,dominant factors influencing temporal changes o f GD arthropods community were also revealed.The results of influencing factors of temporal changes of arthropod s community on cropland and artificial wood-land were as follows:(1)Characteristics of arthropods community in cropland and artificial wood-land at different latitudesTotal of 12331 arthropod individuals were captured in farmland ecosystems at different latitudes,belonging to 3 classes,8 orders,30 families and 57 species.There is no common dominant species in the cropland system at three sampling sites,and there was no significant difference of arthropod abundance among different sites,but the difference for species richness arrived at significance.The species diversity index in Wangkui was larger,but the speices dominance was relatively lower.The species dominance in Changchun was higher and the diversity index was lowest among the three plots.Total of 2760 arthropods were captured in artificial wood-land at different latitudes,belonging to 4 classes,10 orders,41 families and 73 species.There were no dominant species in artificial wood-land at three latitudes.There were significant differences of species diversity indices among the three latitude plantations.Arthropod individuals in the artificial wood-land were less than that in the farmland but species number was more than the latter.While comparing characteristics of arthropod community in the artificial woodland and cropland at the same latitude the dominance index of cropland was higher,and the diversity was lower.Meanwhil e,species diversity of artificial woodland was higher and species distribution in this land type was more evenly distributed.Latitudes had no significant effects on the composition of arthropod functional groups,but had a significant impact on the species composition of individual functional groups.There were significant differences of omnivorous arthropods community composition among different latitudes.But no influence on the functional group composition by land types was observed.There were obvious differences of species distribution between artificial woodland and cropland.(2)Structure dynamics of arthropod community in cropland and artificial woodlandArthropod individuals decreased from July to October in 2018,highest in July and least in October.There was no obvious linear change of the species number,most species in September,individuals and species number collected in October was the lowest,and there were significant differences from other months.The species diversity index was the largest i n September,the lowest in October,and the middle in July and August.The dominance index and the diversity index posessed opposite trends.There were significant difference between arthropod individual number in July and August.Individuals in August were significantly lower,and there was no significant difference among other months.For the diversity of the community,the temporal variation trend of the species diversity was October>September>July>August.Between dominance and species diversity trends were opposite,where species uniformity in October was highest and species richness in July was highest.GD arthropod species and individual number in the farmland plots fluctuate d greatly temporally,and the plantation plots fluctuate less with time.It was a tendency to migrate over time for the arthropods.In the early cropping season,arthropods tended to enter cropland,and during crop maturity season,some species migrated from cropland to artificial woodland or other habitats.Analysis of environmental factors influencing arthropod community showed that Available-Phosphorous had a greater impact on arthropods in artificial woodland and cropland;moreover,effects of organic matter and total nitrogen were not negligible either.