Key Laboratory of Watershed Geographic Sciences, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, PR China.
Key Laboratory of Watershed Geographic Sciences, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, PR China; University of Chinese Academy of Sciences, Beijing 100049, PR China; College of Nanjing, University of Chinese Academy of Sciences, Nanjing 211135, PR China.
Sci Total Environ. 2022 Aug 15;834:154936. doi: 10.1016/j.scitotenv.2022.154936. Epub 2022 Apr 1.
Poyang Lake, the largest freshwater lake in China, serves critical ecosystem function for water regulation and biodiversity conservation. However, it experienced dramatic changes in lake inundation due to recent climate change and human activities, causing ecological and economic problems. Here, we applied a multiple-index water detection rule to integrated Landsat and MODIS products to reconstruct surface water series at 30-m and 8-day resolutions and quantified the spatio-temporal inundation dynamics in Poyang Lake over the past 20 years (2000-2019). Furthermore, their influences on habitat suitability for herbivorous birds were also assessed from the perspectives of hydroperiod and vegetation growth threshold. The significant declining trend (-26.66 km yr, p < 0.001) for the annual minimum water areas throughout the 20 years implied that Poyang Lake was undergoing a continuous shrinkage in the low-water season. On the monthly scale, inundation frequency (IF) decreases were more significant in September-January, most of which occurred in the alluvial delta zones near the lake center. The altered water regime after the Three Gorges Dam (TGD) might be the dominant contributor responsible for the continuous lake shrinkage during the recent low-water period. The sub-lakes suffered from spring drought rather than winter drought, triggering vegetation successions regarding the reversed trend of the well-documented xerophilization in Poyang Lake. The recent earlier and prolonged dry seasons caused an increase of suitable habitat for herbivorous birds (13.92 km year, p < 0.1), but triggered a potential risk of food quality degradation when the migratory waterbirds peaked in December. These results provide a clear reference for optimizing the hydrologic management and biodiversity conservation of Poyang Lake.
鄱阳湖是中国最大的淡水湖，对水调节和生物多样性保护具有关键的生态系统功能。然而，由于最近的气候变化和人类活动，鄱阳湖的湖泊淹没面积发生了巨大变化，造成了生态和经济问题。在这里，我们应用了一种多指标水检测规则，综合使用 Landsat 和 MODIS 产品，以 30 米和 8 天的分辨率重建了过去 20 年（2000-2019 年）的地表水系列，并量化了鄱阳湖的时空淹没动态。此外，我们还从水期和植被生长阈值的角度评估了它们对食草鸟类生境适宜性的影响。过去 20 年中，年最小水域面积呈显著下降趋势（-26.66kmyr，p<0.001），这意味着鄱阳湖在枯水季节持续萎缩。在月度尺度上，9 月至 1 月的淹没频率（IF）下降更为显著，其中大部分发生在湖泊中心附近的冲积三角洲地区。三峡大坝（TGD）后改变的水情可能是导致近期枯水期持续湖泊萎缩的主要因素。子湖区春季干旱而非冬季干旱，引发了植被演替，与鄱阳湖有据可查的旱化趋势相反。最近旱季提前且延长，增加了食草鸟类的适宜栖息地（13.92kmyear，p<0.1），但在 12 月候鸟高峰期时，可能会引发食物质量下降的潜在风险。这些结果为优化鄱阳湖的水文管理和生物多样性保护提供了明确的参考。
