Study on the Characteristics of the Vegetation in the Fenced Region of Ningxia in China

Fencing has been used as a main measure for rangeland and pasture rehabilitation all over the world. By quadrat method, the vegetation of Yanchi County of Ningxia Hui Autonomous Region has been investigated for the impacts of different fencing time on vegetation community structure and biomass. The result shows that it increases biodiversity and makes the vegetation community more stable. But long time fencing is not conducive to vegetation recovery. The Biodiversity Index in the edge areas and peripheral areas reached to highest level in the 4^th and 5^th year after fencing respectively. The Richness Index (R₁) and Comprehensive Diversity Index (D, H) of the edge areas are 22, 2.26, 6.18, and those in the peripheral areas reach to 13, 1.67 and 3.24. Then biodiversity index decreased as fencing time increases. Under different fencing measures, the Biodiversity Index in the core area is the highest. So fencing is an effective measure for vegetation restoration. The vegetation coverage and biomass in the peripheral areas are the largest. This shows that rational uses of grassland are beneficial to vegetation recovery. Strip tillage doesn't have obvious effects on vegetation recovery, and it suggested that grazing or cutting can be used in this region for rangeland and pasture rehabilitation.