干旱区生态环境知识资源中心

Over-grazing by livestock in semiarid ecosystems is one of the main causes of desertification. Although over-grazing contributes to global environmental challenge, only a few studies have investigated grazing impacts on the composition of species and functional groups of seedling bank. In this study, we determined whether the composition of seedling species and functional groups, as well as the correlations between the seedlings of sparse-elm (Ulmus pumila var. sabulosa or U.pumila) and other species changed under three grazing intensities in the degraded sparse-elm grassland in the Horqin Sandy Land, China. Species composition and abundance of established seedlings were surveyed and the relationships between seedlings of U.pumila and other species were analyzed. The results showed that plant communities under moderate grazing were more stable than the other two grazing intensities due to higher seedling density, higher species richness, and higher number of perennial herbs. Seedlings of U.pumila could even prevent noxious seedlings growth under moderate grazing. We concluded that moderate grazing could benefit the recovery of this sparse-elm grassland in the Horqin Sandy Land.