Effectiveness of sand-fixing measures for restoration of vegetation and mitigation of wind erosion and deposition in a degraded sandy rangeland, northern China

Sand-fixing measures, including ground surface stabilization, have been implemented to restore sustainable productive activities on degraded sandy dunes. Wind erosion in dune areas with vegetation cover is generally assessed by vegetation cover. However, research in this area is limited due to the presence of varying thresholds of vegetation cover in different environments. Our objective was to investigate the factors influencing vegetation dynamics and the effect of vegetation on wind erosion and deposition mitigation through the evaluation of the application of dune stabilization measures. Vegetation and wind erosion surveys were conducted over four years on dunes where dune stabilization measures (fencing, installation of straw checkerboard, and seeding of two native plants) were applied by the local government in the Hulunbuir grasslands of China. The results showed that the straw checkerboard and sowing of native plants increased the vegetation cover and reduced the proportion of Amaranthaceae annual forbs, which are pioneer species on the sandy dunes. The seeded perennial grass Elymus spp. had a nursing effect after several years of construction and helped the growth of the seeded legume shrub Caragana microphylla. On the other hand, the growth of C. microphylla was affected by precipitation in the first few years after seeding, with different results depending on the year of seeding. Wind erosion was greatly mitigated where straw checkerboards were installed. The amount of ground surface variability showed a threshold relationship with vegetation cover, with wind erosion being significantly mitigated where vegetation cover was above about 5 %. The installation of straw checkerboards and the seeding of native plants were effective in stabilizing the ground surface on the dunes. However, the straw checkerboard decomposes 4-5 years after installation, suggesting that intensive management during the first few years after the application of sand fixing measures is important to sustain stabilized ground surfaces and restored vegetation.