Abstract: Along a latitudinal gradient from Changchun, Harbin, to Suihua, we investigated the community composition and diversity of ground-dwelling arthropods in farmlands and plantation forests by pitfall trap, and analyzed their relationship with environmental factors. A total of 15001 individuals of ground-dwelling arthropods belonging to 83 species were captured, belonging to 4 classes, 8 orders, and 44 families. On the latitude gradient, the individual number of ground-dwelling arthropod in farmlands and the species number of ground-dwelling arthropod in planted forests were gradually decreased from low latitude to high latitude. The individual number of ground-dwelling arthropods in farmlands was significantly higher than that in planted forests, while the number of species in planted forests was higher than that in farmlands. In the three sites, Shannon index, Pielou index and Margalef index of ground-dwelling arthropods in plantation forests were higher than those in farmlands, while Simpson index in farmlands was higher than that of plantation forests. The diversity of ground-dwelling arthropods in farmlands gradually increased from low to high latitude, and the dominance gradually decreased. In plantation forests, Changchun had the highest Shannon index and low Simpson index, Harbin had the highest Simpson index and the lowest Shannon index, and Suihua was in the middle. Regarding the relationships between the ground-dwelling arthropod communities and environmental factors, soil pH value, total nitrogen and soil organic matter, water content and temperature were significantly correlated with the individual number of soil arthropods in Harbin farmland (P<0.05), with soil water content having the greatest impact. In other plots, ground-dwelling arthropods were relatively less affected by environmental factors. The results of redundancy analysis were consistent with those of bivariate correlation analysis. The dominant groups in various plots were highly adaptable to environmental factors and were widely distributed in the study plots. However, the impact of environmental factors on the individual number of ground-dwelling arthropods did not show obvious pattern with latitude. Our results laid a foundation for understanding spatial variations of soil animals in farmlands and forests and ecosystem stability in the black soil region.

Key words: ground-dwelling arthropod, community structure, diversity, latitudinal gradient