The potential role of temperate Japanese regions as refugia for the coral Acropora hyacinthus in the face of climate change

As corals in tropical regions are threatened by increasing water temperatures, poleward range expansion of reef-building corals has been observed, and temperate regions are expected to serve as refugia in the face of climate change. To elucidate the important indicators of the sustainability of coral populations, we examined the genetic diversity and connectivity of the common reef-building coral Acropora hyacinthus along the Kuroshio Current, including recently expanded (<50 years) populations. Among the three cryptic lineages found, only one was distributed in temperate regions, which could indicate the presence of Kuroshio-associated larval dispersal barriers between temperate and subtropical regions, as shown by oceanographic simulations as well as differences in environmental factors. The level of genetic diversity gradually decreased towards the edge of the species distribution. This study provides an example of the reduced genetic diversity in recently expanded marginal popula...

由于热带海域珊瑚正遭受海水温度持续升高的威胁，已有研究观测到造礁珊瑚（reef-building corals）向极地扩张其分布范围，而温带海域有望成为气候变化背景下的珊瑚避难所。为阐明珊瑚种群可持续性的关键指示因子，本研究针对黑潮（Kuroshio Current）流域分布的常见造礁珊瑚鹿角杯形珊瑚（Acropora hyacinthus）开展了遗传多样性与连通性分析，样本涵盖形成时长不足50年的新近扩张种群。本次研究共发现3个隐存谱系（cryptic lineage），其中仅1个分布于温带海域，该结果暗示温带与亚热带海域间存在与黑潮相关的幼虫扩散障碍，这一推论得到了海洋学模拟结果与环境因子差异的佐证。遗传多样性水平随物种分布边缘逐渐降低。本研究为新近扩张的边缘种群遗传多样性降低提供了一个案例……