Recovery of the elkhorn coral Acropora palmata is critical to reversing coral reef ecosystem collapse in the western Atlantic, but the species is severely threatened. To gauge potential for the species’ restoration in Florida, USA, we conducted an assisted migration experiment where 50 coral fragments of 5 nursery-raised genetic strains (genets) from the upper Florida Keys were moved to 5 sites across 350 km of the offshore reef. Additionally, 4 fragments from the 1 remaining colony of A. palmata in Dry Tortugas National Park (DRTO) were added to the 2 DRTO experimental sites to test for local adaptation. To measure coral performance, we tracked coral survival, calcification, growth, and condition from May 2018 to October 2019. All 24 corals relocated to the DRTO sites survived and calcified ~85% faster than the fewer surviving corals transplanted to the 2 upper Keys sites. While coral survival across the entire experiment did not depend on genet, there was a weak but statistically significant genetic effect on calcification rate among the corals relocated to DRTO. The DRTO native genet was among the fastest growing genets, but it was not the fastest, suggesting a lack of local adaptation at this scale. Our results indicate that DRTO, a remote reef system inhabited by the species during the Holocene and located at the nexus of major ocean currents, may be a prime location for reestablishing A. palmata. Assisted migration of A. palmata to DRTO could restore a sexually reproducing population in <10 yr, thereby promoting the species’ regional recovery.

中文翻译：

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重建受威胁珊瑚 Acropora palmata 的垫脚石种群，以帮助区域恢复

鹿角珊瑚 Acropora palmata 的恢复对于扭转西大西洋珊瑚礁生态系统的崩溃至关重要，但该物种受到严重威胁。为了评估该物种在美国佛罗里达州的恢复潜力，我们进行了一项辅助迁移实验，将来自佛罗里达礁岛上游的 5 个苗圃培育的遗传品系（基因）的 50 个珊瑚碎片移至 350 公里近海珊瑚礁的 5 个地点. 此外，来自干龟岛国家公园 (DRTO) 的 1 个剩余 A. palmata 菌落的 4 个片段被添加到 2 个 DRTO 实验地点，以测试本地适应性。为了衡量珊瑚的表现，我们跟踪了 2018 年 5 月至 2019 年 10 月的珊瑚存活、钙化、生长和状况。迁移到 DRTO 站点的所有 24 种珊瑚存活和钙化的速度比移植到 2 个上部 Keys 站点的少数存活珊瑚快约 85%。虽然整个实验中珊瑚的存活率不依赖于基因，但在重新安置到 DRTO 的珊瑚中，对钙化率的遗传影响微弱但具有统计学意义。DRTO 本地基因是生长最快的基因之一，但不是最快的，表明在这种规模上缺乏局部适应。我们的结果表明，DRTO 是全新世期间该物种居住的一个偏远珊瑚礁系统，位于主要洋流的连接处，可能是重建掌叶海棠的主要地点。A. palmata 向 DRTO 的辅助迁移可以在 <10 年内恢复有性繁殖种群，从而促进该物种的区域恢复。