Wetlands of the Laurentian Great Lakes of North America (i.e., lakes Superior, Michigan, Huron, Erie, and Ontario) provide critical habitat for marsh birds. We used 11 years (2011–2021) of data collected by the Great Lakes Coastal Wetland Monitoring Program at 1,962 point-count locations in 792 wetlands to quantify the first-ever annual abundance indices and trends of 18 marsh-breeding bird species in coastal wetlands throughout the entire Great Lakes. Nine species (50%) increased by 8–37% per year across all of the Great Lakes combined, whereas none decreased. Twelve species (67%) increased by 5–50% per year in at least 1 of the 5 Great Lakes, whereas only 3 species (17%) decreased by 2–10% per year in at least 1 of the lakes. There were more positive trends among lakes and species (n = 34, 48%) than negative trends (n = 5, 7%). These large increases are welcomed because most of the species are of conservation concern in the Great Lakes. Trends were likely caused by long-term, cyclical fluctuations in Great Lakes water levels. Lake levels increased over most of the study, which inundated vegetation and increased open water-vegetation interspersion and open water extent, all of which are known to positively influence abundance of most of the increasing species and negatively influence abundance of all of the decreasing species. Coastal wetlands may be more important for marsh birds than once thought if they provide high-lake-level-induced population pulses for species of conservation concern. Coastal wetland protection and restoration are of utmost importance to safeguard this process. Future climate projections show increases in lake levels over the coming decades, which will cause “coastal squeeze” of many wetlands if they are unable to migrate landward fast enough to keep pace. If this happens, less habitat will be available to support periodic pulses in marsh bird abundance, which appear to be important for regional population dynamics. Actions that allow landward migration of coastal wetlands during increasing lake levels by removing or preventing barriers to movement, such as shoreline hardening, will be useful for maintaining marsh bird breeding habitat in the Great Lakes.

中文翻译：

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2011-2021 年五大湖沿海湿地沼泽鸟类数量增加，可能是由于水位上升造成的

北美劳伦森五大湖（即苏必利尔湖、密歇根湖、休伦湖、伊利湖和安大略湖）的湿地为沼泽鸟类提供了重要的栖息地。我们使用五大湖滨海湿地监测计划 11 年（2011-2021 年）在 792 个湿地 1,962 个点计数位置收集的数据，量化了滨海湿地 18 种沼泽繁殖鸟类的首次年度丰度指数和趋势遍及整个五大湖区。五大湖总共有 9 个物种 (50%) 每年增加 8-37%，但没有一个物种减少。在 5 个五大湖中至少有 1 个湖泊中，有 12 个物种 (67%) 每年增加 5-50%，而在至少 1 个湖泊中，只有 3 个物种 (17%) 每年减少 2-10%。湖泊和物种之间的积极趋势 (n = 34, 48%) 多于消极趋势 (n = 5, 7%)。这些大幅增加受到欢迎，因为大多数物种都受到五大湖保护的关注。这种趋势可能是由五大湖水位的长期周期性波动引起的。在研究的大部分时间里，湖泊水位上升，淹没了植被，增加了开放水域植被的散布和开放水域范围，众所周知，所有这些都会对大多数增加物种的丰度产生积极影响，并对所有减少物种的丰度产生负面影响。如果沿海湿地为受保护的物种提供高湖水位引起的种群数量，那么它们对沼泽鸟类的重要性可能比以前想象的更重要。沿海湿地的保护和恢复对于保障这一过程至关重要。未来的气候预测显示，未来几十年湖泊水位将会上升，如果许多湿地无法足够快地向陆地迁移以跟上步伐，这将导致许多湿地的“沿海挤压”。如果发生这种情况，可用于支持沼泽鸟类丰度周期性波动的栖息地将会减少，而这对于区域种群动态似乎很重要。通过消除或防止移动障碍（例如海岸线硬化），在湖泊水位上升期间允许沿海湿地向陆地迁移的行动，将有助于维持五大湖的沼泽鸟类繁殖栖息地。