Abstract
Alpine revegetated dunes have been barely researched in terms of morphological change and migration within its regional aeolian environments.To reveal the sand-fixing and land-reforming mechanisms of artificial vegetation,we observed the morphology and migration of four dunes with four revegetated types(Hippophae rhamnoides Linn.,Salix cheilophila Schneid.,Populus simonii Carr.,and Artemisia desertorum Spreng.)using unpiloted aerial vehicle images and GPS(global positioning system)mapping in 2009 and 2018.Spatial analysis of GIS(geographic information system)revealed that the revegetated dunes exhibited a steady progression from barchan dune shapes to dome or ribbons shapes mainly through knap planation,wing amplification,and slope symmetrization.Generally,conditions of northern aspects,smaller slope degree,and larger altitude of unvegetated dunes would suffer more serious wind erosion.The southward movement of dune wings with a migration speed of 2.0–5.0 m/a and the alternating motion of sand ridges in eastwestern directions led greater stability in revegetated dunes.The moving distances of revegetated dunes remarkably changed in patterns of quadratic or linear function with depositional depth.Compared with unvegetated dunes,the near-surface wind velocity of revegetated dunes decreased by 20%–30%,which led to heavy accumulation in low-flat dunes and erosion in high-steep dunes,but all vegetation species produced obvious sand-fixing benefits(100%–450%and 3%–140%in the lower and higher dune scales of revegetated dunes,respectively)with decreasing sand transport rates and increasing coverages.In practice,the four vegetation species effectively anchored mobile dunes by adapting to regional aeolian environment.However,future revegetation efforts should consider optimizing dune morphology by utilizing H.rhamnoides as a pioneer plant,S.cheilophila and P.microphylla in windward and northward dune positions,and A.desertorum in a sand accumulative southward position.Also,we should adjust afforestation structure and replant some shrub or herbs in the higher revegetated dunes to prevent fixed dune activation and southward expansion.
基金项目
Jiangxi Provincial Natural Science Foundation(20202BABL213028)
Open Project of the State Key Laboratory of Plateau Ecology and Agriculture,Qinghai University,China(2022-KF-07)
Doctoral Scientific Research Foundation of East China University of Technology(2019052)
Doctoral Scientific Research Foundation of East China University of Technology(2019045)
国家科技期刊平台
NSTL
维普
万方数据