Effects of fencing project on wind erosion reduction in Alpine grassland and its impact on the development of climbing dunes in southern Tibetan Plateau

Abstract

Alpine grassland in the Tibetan Plateau (TP) of China is one of the most susceptible regions to wind erosion in recent decades. The fencing project, grassland enclosure using fencing, has been a common strategy for land degradation counteraction in the TP. However, the wind erosion reduction effects of fencing project remain largely unclear, especially in the regions lacking continuous observations such as Southern TP. In this study, a sand source area with fencing protection (fencing land, a mainly eroded grazing grassland before being fenced) and a near‐source climbing dune were selected to illustrate the effect of fencing project on wind erosion using 137Cs and 210Pbex tracing techniques. An adjacent perennial grazing land was selected for comparison. The results showed that the wind erosion rate in sand source area was 17.18 t·ha−1·year−1 before the implementation of project, while that was −6.67 t·ha−1·year−1 since fencing. The wind erosion rates in perennial grazing land were 24.91 t·ha−1·year−1 for 20 years ago to 1963 and 24.33 t·ha−1·year−1 for almost 20 years. The normalized difference vegetation index (NDVI) of sand source area increased from 0.098 before fencing to 0.137 after fencing; the latter was 1.63 times higher than that of grazing land during the same period. After the implementation of fencing project in sand source area, it was found that the sand supply to the climbing dune was mainly reduced, thus stabilizing it and promoting NDVI increase, especially in the middle‐lower part of the climbing dune. These results would benefit the evaluation of grassland restoration effectiveness in the TP.