Subjects: Biology >> Ecology submitted time 2023-02-27 Cooperative journals: 《干旱区地理》
Abstract： Ecological water conveyance is an important measure in the special action of Populus euphratica forest protection, and the analysis of the effect of submerged irrigation on the restoration of P. euphratica forest is critical for evaluating the effect of ecological restoration. We select the National Nature Reserve of P. euphratica in Tarim Basin, Xinjiang, China, as the study area. Based on dense time-series remote sensing data, NDWI threshold segmentation and human-computer interaction were used to extract the overflowing surface of ecological water conveyance, and the modified maximal gradient difference model was used to retrieve the vegetation coverage of the P. euphratica forest. Geographical information system spatial analysis and regression analysis were used to dynamically monitor the ecological water conveyance since the implementation of the special action for P. euphratica forest protection in 2016 and quantitatively analyze the impact of the submerged irrigation area and frequency on the restoration of the P. euphratica forest vegetation coverage. The results are as follows: (1) The submerged irrigation area is mainly rising from the end of July to the beginning of August, reaching the maximum overflow area in September. In 2017, the area of ecological water conveyance was the largest, reaching 246.7 km2 , and the ecological water conveyance force in 2018—2021 was reduced compared with the previous two years. The smallest area in 2020 was 70.5 km2 . There is a tendency for the spatial distribution to be more in the north and less in the south and for downstream to be greater than upstream. (2) The vegetation coverage of the National Nature Reserve of P. euphratica in Tarim, increased from 18.88% to 19.61% from 2016 to 2021. The north side of the Tarim River with a greater submerged irrigation area shows an increasing trend, whereas the P. euphratica forest on the south side of the Tarim River with less ecological water conveyance still exhibits a degradation trend. (3) The restoration degree of vegetation coverage of the P. euphratica forest increased significantly with an increase in the ecological water submerged irrigation frequency. When the submerged irrigation frequency exceeded three times, the growth rate of vegetation coverage of the P. euphratica forest was approximately 0.93%·a-1 -1.11%·a-1 , which was 4-5 times higher than that of the nonecological water conveyance overflow area. This study provides a new idea for the evaluation of ecological water conveyance benefits of the P. euphratica forest and is of great significance for evaluating the effectiveness of the special action of P. euphratica forest protection and developing a more rational water transport strategy.
Subjects: Environmental Sciences, Resource Sciences >> Basic Disciplines of Environmental Science and Technology submitted time 2020-07-14 Cooperative journals: 《干旱区研究》
Abstract：荒漠河岸带植被在维护极端干旱区生态稳定起着极其重要的作用，研究干旱区荒漠河岸带植被对生态输水的响应及其变化过程，对生态保育恢复及输水政策制定具有重要意义。本文以塔里木河下游流域内的荒漠河岸带植被为研究对象，利用Landsat8 OLI、Sentinel-2A等数据构建植被覆被数据与典型监测断面植被指数时序数据，分析2013—2018年荒漠河岸带植被时空变化特征，并结合地下水位数据分析荒漠河岸带植被对生态输水的响应。结果表明：2013—2018年间，塔里木河下游植被面积呈持续的增加趋势，其中灌木面积恢复最大。胡杨和草本距离河岸较近，沿河岸带植被恢复的区域分布位于距离河道1.0km和2.5km的范围，而灌木林恢复区域在双通道输水措施和地下水上升的影响下，沿河岸11km范围内的灌木均呈现不同程度增加。通过对不同生态断面的3种主要植被的长势分析表明，当地下水埋深大于-5.75m时，塔里木河下游植被出现明显改善。
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