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: Geosciences >> Geography submitted time 2023-02-02 Cooperative journals: 《干旱区地理》
Abstract：生态输水是塔里木河流域退化胡杨林生态恢复的主要措施，及时监测和准确评估其恢复成效是优化输水策略、完善胡杨林修复体系的关键。以2013年以来8个胡杨林区为研究对象，基于中高分辨率遥感数据监测不同胡杨林区生态输水前后植被面积、长势及植被覆盖度的时序变化，探讨胡杨林恢复与生态输水的关系。结果表明：（1）2016 年以来整个流域累计漫溢水面为2172.96 km2，占林区总面积的4.39%，主要分布在输水通道两侧及末端10 km范围内。（2）输水前后林区植被整体呈现由退化到恢复的转变，林区生态恢复水平与年最大漫溢面积显著正相关。（3）生态恢复成效评估表明，生态恢复最显著的区域是塔里木河中上游和叶尔羌河下游的夏马勒林场，但整个流域远离输水通道的胡杨林仍有退化趋势。合理规划输水通道建设，扩大胡杨林区的受水范围是退化胡杨林生态恢复的关键。
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