Abstract: The Oribatida is the most abundant and diverse group of mites and one of the most abundant groups of invertebrates in soil, which is important for the decomposition of organic matter. In order to explore the effects of soil microhabitats on the structure and diversity of soil oribatid mite communities under extremely environment in arid land in Northwest China, soil samples were taken from each microhabitat from March, June, October to December in 2018, and were processed for Oribatida extraction in the modified Berlese-Tullgren extractor. A total of 11 752 adult soil oribatid mites were captured and classified into 44 genera, 34 families. Among them, Zygoribatula and Protoribates were the dominant groups, and accounted for 65.94% of the total collections. There were significant(P<0.05) differences in number of individuals, groups and diversity index of the soil Oribatida communities under different microhabitats. The order of individuals of the soil Oribatida in different microhabitats were SF>AG>AF>VY>VF>GL>FL, the order of groups quantity was SF>GL>AG>VY>AF>VF=FL and the order of diversity index was FL>VY>GL>SF>VF>AG>AF, respectively. The similarities among different microhabitats belonged to moderate dissimilarity (0.25-0.50). The results of MGP analysisⅠindicated that soil Oribatida communities in the area mainly belonged to O pattern, yet MGP analysisⅡindicated that soil Oribatida communities belonged to P pattern. In general, the soil microhabitats exerted an important impact on the ecological distribution of oribatid mite communities in the arid region.

Key words: Toksun County, microenvironment, soil oribatid mites, community diversity, MGP analysis