Climate change has myriad impacts on ecosystems, but the mechanisms by which it affects individual species can be difficult to pinpoint. One strategy to discover such mechanisms is to identify a specific ecological factor related to survival or reproduction and determine how that factor is affected by climate. Here we used Landsat imagery to calculate water clarity for 127 lakes in northern Wisconsin from 1995 to 2021 and thus investigate the effect of clarity on the body condition of an aquatic visual predator, the common loon (Gavia immer). In addition, we examined rainfall and temperature as potential predictors of water clarity. Body mass tracked July water clarity strongly in loon chicks, which grow chiefly in that month, but weakly in adult males and females. Long‐term mean water clarity was negatively related to chick mass but positively related to adult male mass, suggesting that loons foraging in generally clear lakes enjoy good foraging conditions in the long run but might be sensitive to perturbations in clarity during chick‐rearing. Finally, chick mass was positively related to the density of docks, perhaps because angling removes large fishes and thus boosts the abundance of the small fishes on which chicks depend. Water clarity itself declined strongly from 1995 to 2021, was negatively related to July rainfall, and was positively related to July air temperature. Our findings identified both long‐term and short‐term water clarity as strong predictors of loon foraging efficiency, and suggest that climate change, through water clarity, impacts freshwater ecosystems profoundly. Moreover, our results identified the recent decrease in water clarity as a likely cause of population decline in common loons.

中文翻译：

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与气候变化相关的水体透明度下降损害了普通潜鸟的进食

气候变化对生态系统有多种影响，但它影响单个物种的机制可能很难确定。发现此类机制的一种策略是识别与生存或繁殖相关的特定生态因素，并确定该因素如何受到气候的影响。在这里，我们使用 Landsat 图像计算了 1995 年至 2021 年间威斯康星州北部 127 个湖泊的水体清晰度，从而研究清晰度对水生视觉捕食者普通潜鸟身体状况的影响。加维亚·米尔）。此外，我们还研究了降雨量和温度作为水体透明度的潜在预测因素。潜鸟雏鸟的体重与七月水的透明度密切相关，潜鸟雏鸟主要在该月生长，但对成年雄性和雌性潜鸟的体重影响较弱。长期平均水体透明度与雏鸟质量呈负相关，但与成年雄性质量呈正相关，这表明在一般清澈的湖泊中觅食的潜鸟从长远来看享有良好的觅食条件，但可能对雏鸟饲养过程中透明度的扰动敏感。最后，雏鸡的质量与码头的密度呈正相关，这可能是因为钓鱼消除了大鱼，从而增加了雏​​鸡赖以生存的小鱼的数量。从 1995 年到 2021 年，水体透明度本身急剧下降，与 7 月降雨量呈负相关，与 7 月气温呈正相关。我们的研究结果表明，长期和短期水体透明度都是潜鸟觅食效率的有力预测因素，并表明气候变化通过水体透明度对淡水生态系统产生深远影响。此外，我们的研究结果表明，最近水体透明度的下降可能是普通潜鸟数量下降的原因。