2013—2020年塔里木河流域胡杨林生态恢复成效评估

Effectiveness assessment of ecological restoration of Populus euphratica forest in the Tarim River Basin during 2013—2020

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 km^(2),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。

As the main constructive species of desert riparian forest in Xinjiang of western China,the Populus euphratica forest is of great importance to ecological balance maintenance,desertification control and biodiversity protection.Ecological water conveyance is the main way to promote ecological restoration of degraded Populus euphratica in the Tarim River Basin.Ecological monitoring and assessment are critical to optimizing water conveyance strategy and improving ecological restoration systems.In this study,the changes in vegetation area,NDVI and vegetation coverage in eight key Populus euphratica forests in the Tarim River Basin were monitored based on medium-high resolution time-series remote sensing,and the relation between ecological restoration level and ecological water conveyance areas was discussed.The results show that the accumulative maximum water conveyance area was 2172.96 km~2 in the Populus euphratica forest of the Tarim River Basin since 2016,accounting for 4.39%of the total forest area,mainly distributed within 10 km from both sides and the end of water conveyance channels.During 2013—2020,the vegetation in the forest showed a trend from degradation to restoration before and after water conveyance,and the restoration degree was significantly positively correlated with the annual maximum water conveyance area.The comprehensive assessment of vegetation restoration in different forest regions showed that the cumulative water conveyance area and the perfection of water conveyance channels are the determinants of ecological restoration degree in the degraded Populus euphratica forest regions.For example,the most significant restoration regions were the middle and upper reaches of the Tarim River and the Xiamal forest farm at the lower reaches of the Yarkand River.However,the Populus euphratica far away from water conveyance channels is still degraded.It is crucial for ecological restoration of Populus euphratica forest far away from the water conveyance channels to plan rationally the construction of ecological water conveyance channels and increase the water conveyance area of damaged Populus euphratica forest.