Saline lakes are threatened globally and provide critical habitat for a diverse array of migratory and breeding waterbirds. The ability of large numbers of waterbirds to profitably use saline lakes is primarily dependent upon concentrations of invertebrate fauna that are only present within a narrow range of salinities. Additionally, waterbirds themselves can incur steep physiological costs as their salt loads increase, meaning that they are especially sensitive to changes in salinity. Nonetheless, relatively little is known about ecosystem function within natural saline lakes or how birds will respond to fluctuations in salinity across time, hindering efforts to maintain ecologically functional saline ecosystems. To help address this gap, we coupled data from waterbird surveys undertaken across 25 years at Lake Abert, Oregon, USA with data on lake area (a proxy for salinity) and invertebrate abundance to document how waterbird numbers changed in response to variation in lake area and the presence of their invertebrate prey. We found that as the area of Lake Abert decreased and salinity increased, both invertebrate and waterbird numbers declined, with especially high salinities associated with the presence of few waterbirds and invertebrates. However, we also found that at high lake levels and low salinities the abundance of most waterbirds and invertebrates either plateaued or declined as well. Our study reinforces physiological studies showing that both invertebrates and waterbirds can only tolerate a narrow range of salinities, and is among the first to document the effects of this tolerance range at the ecosystem level. As anthropogenic water usage increases and snowfall decreases in the coming century, Great Basin saline lakes are projected to increasingly face water shortages and high salinities. Conserving saline lake ecosystems thus requires mitigating these losses and maintaining water levels and salinities within the normal range of inter-annual variation. When conditions outside of this range occur too frequently or persist too long, they can result in dysfunctional ecosystems with deleterious consequences for the species that rely on them.

中文翻译：

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压力下的盐湖：大盆地盐湖鸟类、水位和无脊椎动物之间的关系

盐湖在全球范围内受到威胁，为各种迁徙和繁殖水鸟提供了重要的栖息地。大量水鸟利用盐湖获利的能力主要取决于仅存在于狭窄盐度范围内的无脊椎动物群的浓度。此外，随着盐负荷的增加，水鸟本身可能会产生急剧的生理成本，这意味着它们对盐度的变化特别敏感。尽管如此，人们对天然盐湖内的生态系统功能或鸟类如何响应盐度随时间的波动知之甚少，这阻碍了维持具有生态功能的盐湖生态系统的努力。为了帮助解决这一差距，我们将 25 年来在美国俄勒冈州阿伯特湖进行的水鸟调查数据与湖泊面积（盐度的代表）和无脊椎动物丰度数据相结合，记录水鸟数量如何随湖泊面积变化而变化以及它们的无脊椎动物猎物的存在。我们发现，随着阿伯特湖面积的减小和盐度的增加，无脊椎动物和水鸟的数量都减少了，特别是盐度很高与水鸟和无脊椎动物的数量很少有关。然而，我们还发现，在高湖水位和低盐度下，大多数水鸟和无脊椎动物的丰度要么趋于稳定，要么下降。我们的研究强化了生理学研究，表明无脊椎动物和水鸟只能耐受狭窄的盐度范围，并且是最早记录该耐受范围在生态系统水平上的影响的研究之一。随着下一世纪人为用水量的增加和降雪量的减少，大盆地盐湖预计将日益面临缺水和高盐度的问题。因此，保护​​盐湖生态系统需要减轻这些损失，并将水位和盐度维持在正常的年际变化范围内。当超出此范围的条件发生得太频繁或持续太久时，可能会导致生态系统功能失调，对依赖它们的物种产生有害后果。