Abstract: To understand the effects of alpine meadow degradation on the composition and diversity of epigeic springtail and mite communities, we investigated epigeic springtail and mite communities in swampy meadow, grassland meadow, and moderately degraded meadow of Zoigê wetland using motor-sucking in July and October 2018. A total of 13640 springtail individuals, belonging to 4 orders, 11 families and 23 genera, were collected, with Sminthurinus and Desoria being the dominant taxon. A total of 5069 mite individuals, belonging to 3 suborders, 76 families and 98 genera (taxonomic groups), were collected, with Eupodidae as the dominant group. Results of principal component analysis showed that the taxonomic composition of springtail and mite communities differed remarkably among different habitats. With increasing degradation degree, the abundance and taxonomic richness of mites increased (P<0.05), the abundance of springtails increased significantly (P<0.05). The abundance and Simpson index of springtails were significantly higher in July than those in October (P<0.05) across the three habitats, while the opposite patterns were found for the taxonomic richness and Shannon index. Regarding to epigeic mites, the abundance and taxonomic richness were significantly higher in July than those in October (P<0.05), without seasonal variation in Shannon and Simpson dominance index (P>0.05). The results of redundancy analysis and multiple regression analysis showed that the taxonomic composition, abundances and diversity index of epigeic springtails and mites were mainly influenced by the specie richness and biomass of plant communities and soil bulk density, but the effects differed between springtails and mites. Our results demonstrated that degradation and seasonal changes had significant effects on the taxonomic composition, abundance and diversity index of epigeic springtail and mite communities. The springtails responded more sensitively to seasonal changes than mites, and the mites were more significantly affected by the degradation of alpine meadows than springtails.

Key words: microarthropods, diversity, community structure, Zoigê wetland