干旱区生态环境知识资源中心

Enclosures around single-settlement sites are the products of the countryside rangeland contract system in China, and their recent establishment allows for the investigation of grazing gradients and corresponding rangeland degradation from single focal points. In the present study, which was conducted in an enclosure around a single settlement site in a semi-arid Leymus chinensis-dominated steppe area within the Xilingol Steppe, we analyzed vegetation changes at five distances (concentric half-circles at 250-m intervals that radiated out from the settlement). Our results show a clear trend in small-scale vegetation changes. Based on nonmetric multidimensional scaling (NMDS) and an analysis of similarities (ANOSIM), the five stages of vegetative degradation from the least to the most degraded were identified in the following order: L. chinensis, L. chinensis + S. grandis. L. chinensis + C. squarrosa (A. cristatum), P. acaulis + A. frigida and A. frigida. Based on indicator species and their above-ground biomass changes, the decreasing rates of the total above-ground biomass in the five stages were 51.5, 50.9, 41.6, 30.2 and 35.9%, respectively, in comparison to the baseline biomasses of selected non-degraded communities. These data indicate that the degradation gradient attenuated from medium to slight as the distance from the settlement in the enclosure increased. This research provides deeper insight into grazing and degradation patterns and processes in enclosures around single settlement sites and reveals that herder-related participatory recovery measures need to be implemented by local rangeland management departments to prevent further land deterioration or an acceleration of currently observed degradation patterns.