Composition and spatio-temporal variation of soil arthropods in the wetland of the Daxia River on the Qinghai-Tibet Plateau

The Daxia River Basin on the eastern edge of the Chinese Qinghai-Tibetan Plateau is one of the typical distribution regions of alpine wetlands and a global biodiversity hotspot. The aim of this study is to analyze the composition and spatio-temporal distribution of the soil arthropods, and to use them as an indicator for the soil environment in the wetland. The soil arthropods of 32 taxa and 7706 individuals were collected from the soil samples at two soil layers (0–10 and 10–20 cm depth) in each habitat of six habitats along the Daxia River in cold season and warm season between 2016 and 2017. The habitat of Tumenguan had a greater arthropod abundance than all other habitats in both cold season and warm season. A significant seasonal variation was observed in the composition, abundance and diversity of the soil arthropod community in each habitat. In cold season the dominant groups were Chironomidae larvae, Sejidae and Trombidiidae. In warm season the dominant groups were Chironomidae larva, Onychiurus, Pygmephorus and Tullbergia. The soil arthopod communities exhibited significant differences among the habitats at the 0–10 and 10–20 cm depth. The multivariate tests with the linear model redundancy analysis (RDA) revealed the significant impact of soil physical and chemical factors on the seasonal change of soil arthropod community. The results demonstrate that soil arthropods in the study area respond more actively to temporal changes than to habitat changes.