College of Civil and Transportation Engineering, Hohai University, Nanjing 210098, China.
College of Computer and Information Engineering, Hohai University, Jiangsu, Nanjing 210098, China.
Sci Total Environ. 2021 Dec 10;799:149256. doi: 10.1016/j.scitotenv.2021.149256. Epub 2021 Jul 24.
Lakes and vegetation are important components of the hydro-ecological environment and sensitive indicators of anthropogenic climate change and human activities. For the first time, the lake area, vegetation cover change (obtained from Landsat satellite images), terrestrial water storage (TWS; estimated from the gravity recovery and climate experiment), and hydrochemistry, stable isotopes of different waterbodies were combined to analyze the long-term evolution and controlling factors of lake area and vegetation cover in the Nenjiang River basin, China. Between 1985 and 1999, the lake area experienced natural shrinkage due to climatic and hydrological changes, whereas artificial shrinkage related to increased human activities dominated during 2000-2019. The normalized difference vegetation index (NDVI) increased during 1988-1999 and was affected by hydrometeorological factors in the same year and lake area in the previous year. The rate of increase in the NDVI accelerated during 2000-2012 owing to the impact of human activities which is reflected by GDP, and the related artificial shrinkage of the lake area. The main hydrochemical type of lake water changed from Ca-HCO before 2000, which was similar to that of river water, to Na-HCO after 2000, which was the main hydrochemical type of groundwater. In addition, most of the lake water and groundwater samples were rich in HSiO, and a strong correlation between the TWS and lake area for the period 2003-2019 indicated that lake water was strongly affected by groundwater, which was related to deep circulation. Therefore, the decreased river water recharge owing to human activities made groundwater contribute more to lake water. This study can substantially improve the decision-making support for environmental protection and water resource management in ecologically diverse areas, specifically in arid and semi-arid areas.
湖泊和植被是水生态环境的重要组成部分，也是人为气候变化和人类活动的敏感指标。本研究首次将湖泊面积、植被覆盖变化（来自陆地卫星图像）、陆地水储量（由重力恢复和气候实验估计）以及不同水体的水化学和稳定同位素结合起来，分析中国嫩江流域湖泊面积和植被覆盖的长期演变及其控制因素。1985 年至 1999 年，由于气候和水文变化，湖泊面积自然萎缩，而 2000 年至 2019 年，人为活动导致的萎缩占主导地位。归一化植被指数（NDVI）在 1988 年至 1999 年期间增加，受当年水文气象因素和前一年湖泊面积的影响。2000 年至 2012 年，由于 GDP 等人类活动的影响，NDVI 增加速度加快，这反映了湖泊面积的人为萎缩。湖泊水的主要水化学类型在 2000 年之前为 Ca-HCO，与河水相似，2000 年之后为 Na-HCO，为地下水的主要水化学类型。此外，大部分湖泊水和地下水样品富含 HSiO，2003 年至 2019 年期间 TWS 与湖泊面积之间存在很强的相关性，表明湖泊水受到地下水的强烈影响，这与深部循环有关。因此，由于人类活动导致的河流来水减少，地下水对湖泊水的贡献更大。本研究可为环境保护和水资源管理提供决策支持，特别是在生态多样化的干旱和半干旱地区。
