The inundation areas of floodplains are crucial to wetland ecosystems, especially in supporting biodiversity. Accurately identifying the spatial and temporal patterns of inundation areas is important for understanding floodplain ecosystem processes. Here, lakes in the Yangtze River Floodplain were divided into two types according to hydrological conditions: the natural connected lakes (Dongting Lake and Poyang Lake) with natural water level fluctuations and the isolated lakes (lakes in Jianghan Plain) with stable water levels. We established a method to identify inundation areas using multi-sources remote sensing data based on the Google Earth Engine. The dynamics of inundation areas were determined, and the relative indices were calculated in common year (2017) and a drought year (2018). The differences between the connected lakes and the isolated lakes were analyzed, and impacts of hydrological fluctuations on inundation area and habitat quality were evaluated. The results show that lakes with natural hydrological fluctuations have a greater regulative flexibility, with both patch density (PD) and submerged elasticity index (SEI) values higher than that of isolated lakes. The trend of the vegetation index in the connected lakes and in the isolated lakes is also different. The mean EVI in Dongting Lake and Poyang Lake showed a U-shaped trend which is similar to the shape of the trend of PD. The trend of mean enhanced vegetation index (EVI) in the isolated lakes is the opposite and has a lower range of variation over a year. This study provides new indicators and rapid methods for habitat quality assessment in floodplains, as well as presenting scientific information useful for improving wetland management in the middle and lower Yangtze River.

中文翻译：

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大型洪泛区水文孤立湖和连通湖调节灵活性的差异：从淹没动态和景观异质性的洞察

洪泛区的淹没区对湿地生态系统至关重要，尤其是在支持生物多样性方面。准确识别淹没区的时空格局对于理解洪泛区生态系统过程非常重要。在这里，长江漫滩湖泊根据水文条件分为两种：天然水位波动的天然连通湖（洞庭湖和鄱阳湖）和水位稳定的孤立湖（江汉平原湖泊）。我们建立了一种基于谷歌地球引擎的多源遥感数据识别淹没区的方法。确定了淹没区的动态，并计算了共同年（2017年）和干旱年（2018年）的相对指数。分析了连通湖与孤立湖的差异，评价了水文波动对淹没面积和生境质量的影响。结果表明，具有自然水文波动的湖泊具有更大的调节灵活性，斑块密度（PD）和淹没弹性指数（SEI）值均高于孤立湖泊。连通湖和孤立湖的植被指数变化趋势也不同。洞庭湖和鄱阳湖的EVI均值呈U型趋势，与PD的趋势形状相似。孤立湖泊中平均增强植被指数（EVI）的趋势相反，一年内变化范围较小。该研究为洪泛区栖息地质量评估提供了新的指标和快速方法，