Responses of ground-active arthropod community in Caragana shrub plantations to grazing management in desertified region.

Abstract

We investigated the community structure of ground-active arthropods as well as vegetation and soil properties in Caragana shrub plantations under grazing and exclosure management across spring, summer and autumn in Yanchi County of Ningxia in northern China. The aim of this study was to uncover the responses of ground-active arthropods in shrub plantations to grazing management in desertified regions. The results showed that: 1) plant height, soil fine sand content, and soil electrical conductivity were significantly lower, whereas soil bulk density and coarse sand were significantly higher in shrub plantations under grazing than exclosure. 2) There were 40 families from 13 orders captured. The dominant groups included Formicidae and Tenebrionidae families, which comprised 68.75% of the total individuals. There were four common groups occupying 20.82% of the total individuals. The remaining 34 groups were relatively rare, only accounting for 10.44% of the total. Across the three seasons, the composition of ground-active arthropod community was significantly different between grazing and exclosure, which indicates the sensitivity and adaptability of ground-active arthropods to environmental changes including grazing management and seasonal changes. 3) There was a significant effect of grazing on total abundance of ground-active arthropods in shrub plantations, with significantly higher values under grazing than under exclosure. There was no significant effect of grazing management on group richness and diversity of ground-active arthropods in shrub plantations. 4) There was a correlation of total abundance, evenness index and the Simpson index with plant abundance, vegetation height, soil moisture, soil pH and electrical conductivity. There was a significant correlation of the Shannon index with vegetation height, soil moisture and soil fine sand. Plant density, and soil pH, soil moisture and soil temperature were the key factors driving the structure of ground-active arthropod communities in shrub plantations under gra-zing management across seasons based on the partial RDA results. It was concluded that the variations of plant height, soil pH, soil moisture and soil temperature under grazing management could result in different ground-active arthropod taxon to changing habitats. The conservation effect of shrub on ground-active arthropod could reduce the negative impacts of grazing. Spring grazing could enhance ground-active arthropod abundances in shrub plantations. It was necessary to pay attention to prevention of insects which are caused by spring grazing in shrub plantations.