阿克苏河流域艾西曼湖湿地时空演变及对生态输水的响应

Spatio-temporal Evolution of Eichmann Lake Wetland in Aksu River Basin and Its Response to Ecological Water Transfer

及时了解和定量分析干旱半干旱地区天然生态系统的变化趋势及对生态输水过程的响应,对维护绿洲生态系统健康具有重要意义。论文结合遥感影像和生态输水监测数据,对阿克苏河流域艾西曼湖湿地的时空演变特征和生态输水的响应进行了研究。结果表明,艾西曼湖水域面积萎缩较严重,由1996年的61.57 km^(2)萎缩至2020年的27.76 km^(2),经历了快速下降、缓慢下降和缓慢恢复3个阶段,生态输水后水面面积出现明显的季相变化并伴随滞后现象,峰值出现在11月左右;生态输水对地下水位有明显的抬升作用,并受输水量、输水天数的影响,地下水位变动与生态输水的响应存在明显的滞后效应,时间约为1~2个月;不同的自然植被对生态输水的响应特征存在差异,胡杨对生态输水的响应明显且在距离输水口100~500 m的范围内长势最好,NDVI月度变化显示生态输水对自然植被生长的滞后时间为1个月左右。研究结果对阿克苏河流域天然植被恢复、区域水资源调配、生态需水调度等具有重要的指导价值。

Timely understanding and quantitatively analyzing the change trend of natural ecosystem and its response to ecological water transport process in arid and semi-arid areas is great significance to maintain the health of oasis ecosystem.Combined with remote sensing images and ecological water transfer monitoring data,this paper studied the temporal and spatial evolution characteristics of the Eichmann Lake wetland of Aksu River basin and its response to ecological water transfer.The results showed that the water area of Eichmann Lake shrunk seriously,from 61.57 km^(2) in 1996 to 27.76 km^(2) in 2020.The changes of water area experienced three stages,including rapid decline,slow decline and slow recovery.Water area of Eichmann Lake showed obvious seasonal change and lag effect after ecological water transfer,and the peak value appeared around November.Ecological water transfer had a significant lifting effect on the groundwater level,and was affected by water conveyance volume and water conveyance days.There was an obvious lag effect between the change of groundwater level and ecological water transfer,which was 1~2 months.The response characteristics of different natural vegetation to ecological water transfer were different.The response of Populus euphratica to ecological water transfer was more obvious.The growth of P.euphratica was the best in the range of 100~500 meters from the water delivery outlet.The monthly variation of NDVI showed that the lag time of ecological water conveyance on natural vegetation growth was about one month.This research could provide valuable reference fornatural restoration,regional water resources allocation and ecological water demand regulation in Aksu River Basin.