Aeolian Activities and Protective Effects of Artificial Plants in Re-vegetated Sandy Land of Qinghai Lake, China

作者 Wu Wangyang; Zhang Dengshan; Tian Lihui; Zhang Hongwei

期刊 CHINESE GEOGRAPHICAL SCIENCE , DEC 2020,6:30

摘要 Land desertification and aeolian activity are currently the greatest threats to alpine ecological environments and are also the primary challenges of desertification control and ecological restoration projects. Afforestation of sandy lands around the Qinghai Lake in China has effectively controlled the desertification of this watershed. However, certain issues remain which challenge its overall success, including lack of diverse biological species and poor theoretical understanding of aeolian processes, such as controlling wind-sand flow in relation to complex alpine ecological factors. Therefore, to help improving afforestation techniques, this research focused on Hippophae rhamnoides, Salix cheilophila, Pinus sylvestris, Populus simonii and Artemisia desertorum vegetation implanted in the mobile dunes on the eastern shore of Qinghai Lake. Aeolian transport characteristics and annual changes to community ecological factors from 2010-2016 were monitored in comparison with uncontrolled sand dunes. Based on simultaneous observations using gradient anemometers and sand samplers, it was found that the aeolian activities exhibited the following features: 1) In re-vegetated lands, the logarithmic growth of wind speed was disrupted by the wind speed amplification in the middle and high layers and wind speed reduction in the low layers, while vegetation had significant wind-breaking (> 37%) and sand-fixing (> 85%) effects in 2016. 2) Wind speeds in re-vegetated lands and mobile dunes showed a linear correlation, especially in lower layers of H. rhamnoides and S. cheilophila, while sand transport in re-vegetated land increased linearly or exponentially with increasing wind speed. 3) The four artificial shrubs and forests had greater sand deposition with intensities of 280-860 t/(ha center dot yr), largely concentrated during winter and spring which accounted for 60%-85% of the annual cycle, while A. desertorum experienced significant root undercutting; and 4) Intensity of aeolian activity in re-vegetated lands, except for A. desertorum, was significantly negative with respect to plant growth structure, community cover, topsoil moisture, and regional precipitation. Overall, these five sand-binding species produced optimistic wind-sand protection effects for the alpine sandy lands, which relied on the plants'' physical disturbance of wind-sand flow during the early stages of community development. In comparison, H. rhamnoides and S. cheilophila individually maintained stable wind-sand protection effects, while P. sylvestris and P. simonii were better in mixing with other shrubs and herbs to achieve a comprehensive ecological system for future control of aeolian activity.

涉及物种 沙蒿 Artemisia desertorum 乌柳 Salix cheilophila 小叶杨 Populus simonii 中国沙棘（亚种） Hippophae rhamnoides