【作者】 吴汪洋； 田丽慧； 张登山； 张明远； 周鑫； 汪海娇； 王俏雨；

【Author】 WU Wang-yang;TIAN Li-hui;ZHANG Deng-shan;ZHANG Ming-yuan;ZHOU Xin;Key Laboratory of Environmental Changes and Natural Disaster, Ministry of Education, School of Geography;Qinghai Academy of Agricultural Forestry Sciences;State Key Laboratory of Plateau Ecology and Agriculture, Qinghai University;

【机构】 环境演变与自然灾害教育部重点实验室北京师范大学地理科学学部； 青海大学农林科学院； 青海大学省部共建三江源生态和高原农牧业国家重点实验室；

【摘要】 固沙植物沙堆的形态特征是高寒植物生态适应性与防治效益的重要体现,对幼龄人工植被沙堆的形态研究有益于探索植被与风沙的相互关系,指导生物治沙工作。通过对青海湖东岸主要固沙植物沙堆的形态拟合与蚀积监测发现:(1)强堆积型的沙棘与沙蒿沙堆在堆积高度、面积与体积上均大于弱堆积型或弱侵蚀型的樟子松与小叶杨沙堆,这主要受株高、冠幅等植物生长因子及其交互作用的影响;(2)根据8方位蚀积断面观测,各沙堆堆积部位主要在NE-E-SE方位带,沙蒿、乌柳沙堆的蚀积强度具有显著的方位差异,这与同方位输沙强度呈现显著的负相关性(P<0.05)。在W、NW、SE等方位,沙堆间的物种差异显著;(3)根据各植物沙堆的固沙强度和林下地表输沙强度分析,沙棘、乌柳、樟子松、小叶杨与沙蒿年均固沙效益分别为40.45%、15.53%、4.69%、4.20%与62.72%,沙棘、乌柳与沙蒿均为典型优良的固沙树种。更多还原

【Abstract】 Morphology of plant sandpiles was an important reflection of ecological suitability and sand-fixing benefits of different artificial plants.Under explorations of sandpiles forming features and causes,the plant erosion and deposition effects could be instinctively compared to provide some basic reasons for sand-fixing species selection.It was also vital to reveal the relationships between alpine vegetation growth and wind-sand activities.Five typical sand-fixing plants afforested in the Ketu sand land on the eastern shore of Qinghai Lake,were focused on their primary sandpiles.Based on the methods of morphological fitting and sand-deposition monitoring,three-dimensional morphology of vegetation sandpiles were simulated and analyzed with the vegetation investigations and wind-sand observations in the year of 2015~2016.Under the statistics of total and sectional deposition depth,intensity and causing factors,we found that:(1)Hippophae rhamnoides,Salix cheilophila,Pinus sylvestris,Simon poplar and Artemisia desertorum,all sandpiles were formed with conical,hemispherical or linear shapes.H.rhamnoides and A.desertorum sandpiles were strongly accumulated with larger depth,projected area and three-dimensional volume than the other three light-erosive or light-depositional plant sandpiles.(2)Considering the eight directional sections,the main deposition parts of the sandpiles changed among the northeast-east-southeast directions.In consequence of significant negative correlations between depositional intensity and sediment transport rate in the same directions,all vegetation sandpiles show remarkable direction differences in depositional intensity,especially for the S.cheilophila,S.poplar and A.desertorum.In addition,the deposition depth and intensity changed significantly in the directions of northwest,east and southeast.(3)The morphology differences of plant sandpiles were mainly affected by vegetation growth features,the depositional depth of H.rhamnoides and S.poplar sandpiles increased with height,canopy and soil crust,especially with their coupling effects.P.sylvestris and S.poplar sandpiles were seriously controlled by the basal diameter and clear bole length.Furthermore,the strong winter wind with the west-northwest-north direction belt gave impetus to the sandpile erosion,it was also verified by the significantly negative correlations between the directional accumulated depth and sand transport intensity,especially for the S.cheilophila and A.desertorum.Calculated by the sand-fixing intensity and surface sediment transport intensity,we could predict the sand accumulation modulus of the five forest dunes,the H.rhamnoides and S.cheilophila forests prevented the sand most with the amount of 400~1100 t/ha because of their high afforesting density and surviving rates.In general,H.rhamnoides,S.cheilophila and A.desertorum could be chosen as adaptive and efficient sand-control vegetation species with sand-fixing benefits of 40.45%,15.53%and 62.72%respectively,while the other artificial species demand afforesting conservation and structure optimization for their low sand-prevention effects which were lower than 5%.更多还原