Effectiveness of afforested shrub plantation on ground-active arthropod communities and trophic structure in desertified regions

Abstract

In desertified regions, the mobile sand land, and afforested shrubland of different ages (i.e., 6, 15, 24 and 36years) in addition to the naturally restored grassland were selected in order to evaluate their consequences on taxonomic and trophic structures, and the diversity of ground-active arthropods. The taxa-specific responses to the land conversion were found within functional groups. The activity density of predator Labiduridae and Carabidae, and herbivore Tenebrionidae decreased, while that of herbivore Melolonthidae and omnivore Formicidae increased markedly (p<0.05) from the mobile sand land to the afforested shrubland, regardless of shrubland ages. The taxa richness of herbivores also increased markedly (p<0.05) from the mobile sand land to the afforested shrubland, regardless of shrubland ages. However, there was little effect of land conversion on the activity density and richness of detritivores due to the lack of litter on the surface of soils. Different functional groups of ground-active arthropods responded in a different way to the land conversion. The total density and Simpson index decreased, while the taxa richness and Shannon index increased markedly (p<0.05) from the mobile sand land to afforested shrubland, regardless of shrubland ages. It was suggested that the afforested shrub plantations of different ages had similar implications on the trophic structure and diversity indices as was close to the naturally restored grassland (except for Shannon index). The Shannon index in the grazed afforested shrubland of 24years that was close to the naturally restored grassland was markedly (p<0.05) lower compared with the other afforested plantations. In conclusion, the afforested shrubland was an option for the stabilization of mobile sand land and biodiversity recovery of degraded ecosystems, regardless of shrub ages. Furthermore, the grazing management on afforested shrubland could improve the effectiveness of this recovery process.