The value of coastal saltpans for migratory shorebirds: conservation insights from a stable isotope approach based on feeding guild and body size
The value of coastal saltpans for migratory shorebirds: conservation insights from a stable isotope approach based on feeding guild and body size
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沿海盐田对迁徙滨鸟的价值：基于摄食行会和体型的稳定同位素方法的保护见解
DOI：
10.1111/acv.12717
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发表时间：
2021-07-16
影响因子：
3.4
通讯作者：
Piersma, Theunis
中科院分区：
文献类型：
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作者：
Lei, Weipan;Masero, Jose A.;Piersma, Theunis
候鸟是最受威胁的鸟类之一。在繁殖季节之外，它们依赖于自然的潮间带栖息地，但在一定程度上已经适应了使用人工栖息地。在这里，我们评估了沿海盐田——一种人为湿地——在候鸟沿着东亚-澳大拉西亚迁徙路线（EAAF）向北迁徙期间为其提供食物的重要性。结合滦南滨海湿地复合体潮间带和盐滩附近的低潮计数和基于稳定同位素的贝叶斯混合模型分析（bmm），评估了沿海盐滩与自然潮间带栖息地作为迁徙物种觅食地的相对重要性。我们将24种滨鸟按摄食方向和体型进行分组，发现两者都解释了退潮时滨鸟在盐田觅食的大范围模式。水面觅食物种（如高跷和avocets），与身体大小无关，主要在盐田中觅食，而中小型视觉（如鸻）和触觉表面（如矶鹞）觅食物种在该栖息地消耗了很大一部分食物。相比之下，大多数大型触觉表面觅食物种在退潮时很少在盐田觅食。BMMs显示，与传统的退潮时每个栖息地觅食鸟类的数量相比，滨鸟对盐田的依赖程度更高。盐碱地食物富含必需脂肪酸，因此盐碱地对滨鸟饮食的贡献不应只考虑绝对值，还应考虑这种贡献的质量。因此，盐田如果管理得当——例如通过控制水位——可能有助于保护日益减少的滨鸟，以服务于依赖它们的特定喂养行业。虽然我们的重点是在EAAF，但这些发现与其他飞行路线和其他非潮汐人工湿地有关。
Migratory shorebirds are among the most threatened groups of birds. They rely on natural intertidal habitats outside the breeding season, but, to some extent have adjusted to using man-made habitats. Here, we assessed the importance of coastal saltpans - a type of anthropogenic wetland - for feeding in migratory shorebirds during their northward migration along the East Asian-Australasian Flyway (EAAF). We combined low tide counts on intertidal flats and nearby saltpans at the Luannan coastal wetland complex (Bohai Bay, China) with Bayesian mixing model analyses (BMMs) based on stable isotopes to evaluate the relative importance of coastal saltpans versus natural intertidal habitats as foraging grounds for migrating species. We grouped shorebird species (n = 24) according to feeding guild and body size, and found that both predictors explained the broad-scale patterns of foraging use of saltpans by shorebirds at low tide. The guild of water-surface foraging species (e.g. stilts and avocets), independently of body size, mostly fed in saltpans, and the small-medium visual (e.g. plovers) and tactile-surface (e.g. sandpipers) foraging species consumed a significant portion of their diet in this habitat. In contrast, most large tactile-surface foraging species barely foraged in saltpans at low tide. BMMs showed that shorebirds had a greater reliance on saltpans than did traditional counts of foraging birds in each habitat at low tide. Saltpan food is rich in essential fatty acids, so the contribution of saltpans to the diet of shorebirds should not be considered only in absolute values, but also in the quality of this contribution. Saltpans may therefore help conserve declining shorebirds if properly managed - for example by controlling water levels - to serve the specific feeding guilds that rely on them. While our focus is in the EAAF, the findings are relevant for other flyways and other non-tidal anthropogenic wetlands.