Dynamic Monitoring and Ecological Risk Analysis of Lake Inundation Areas in Tibetan Plateau

Lake inundation is one of the most important hydrological factors affecting lake ecosystems. In order to accurately and timely grasp the spatio-temporal pattern of the lake inundation area, and reveal the ecological evolution of the lake landscape, this paper quantifies the inundation dynamics of lakes on the Tibetan Plateau in the past 20 years and analyzes the spatio-temporal characteristics of the inundation area from four aspects: the region, type, altitude and recharge mode of the lake. Combined with the water inundation frequency, the landscape inundation frequency index is constructed and applied to the landscape ecological risk index to explore the spatio-temporal dynamic changes of landscape ecological risk in the inundation area. The results show that the change of the lake-inundated area first decreases and then increases in 2000–2020, the salt lakes and low-altitude lakes have the largest inundation areas, accounting for 83.2% and 55.6% of the total inundated area, respectively; the change intensity of lake inundation frequency is relatively large, and the alternate changes of the lake water–land junction area are enhanced, and the area of permanent lake increases; inundation has the greatest impact on bare land and grassy landscapes; the study area is dominated by lower-risk and lowest-risk areas, accounting for 84.9% of the total area of risk areas, but most areas are transformed from lower-lowest risk to medium-higher risk. This study provides a case of dynamic monitoring of lake inundation areas, which is helpful to formulate ecological restoration and risk prevention measures in lake inundation areas, and can also be used for ecological risk research in similar areas.