Abstract: A field survey was undertaken to investigate the community composition and spatial distribution of arthropods in the desertified steppe of Ningxia. The pitfall traps were used to collect specimens in spring, summer and autumn of 2011. (1) The traps captured 32 taxonomical groups belonging to 31 families, 9 orders and 2 classes. These taxonomical groups were classified into predator, herbivore, sapropages, and omnivore. The two dominant groups were the Tenebrionidae and Formicidae families, together making up 71.97% of total ground-dwelling arthropods. There were 8 common groups, accounting for 19.72% of total individuals, and 22 rare groups making up 8.30% of total individuals. (2) The results indicated remarkable changes in the community composition and their abundances of arthropods between shrub microhabitat along with seasonal changes. In spring, the shrub microhabitats harbored the dominant group, common group and rare group, while in the summerthe shrub microhabitats only harbored the dominant group, without common group in the open space and without rare group in either shrub microhabitats. (3) The number of shared groups between shrub microhabitats was low in summer, which was followed by the autumn, whereas in the spring there were a considerably greater number of shared groups between shrub microhabitats. The order of Sorenson index was found to be followed as:spring > autumn > summer. (4) In both spring and autumn, there were no significant (P>0.05) differences in total abundance, richness and Shannon index between shrub microhabitats, whereas in the summer, a markedly (P<0.05) greater richness and Shannon index was found beneath the shrub cover relative to the open spaces. (5) In spring, only the abundance and richness of sapropages was found to indicate markedly (P<0.05) greater values beneath the shrub cover relative to the open spaces. In summer, only the taxa richness of predator was found to indicate markedly (P<0.05) greater values beneath the shrub cover relative to the open spaces. In autumn, however, there were no significant (P>0.05) differences in the abundance and richness of functional groups between shrub microhabitats. (6) It was concluded that the spatial distribution of arthropod community between shrub microhabitats was correlated with both the ecological attributes of shrub plants and the seasonal changes of rainfall and temperature.

Key words: desertified steppe, seasonal changes, arthropod community, spatial distribution, community structure, shrub microhabitats