Department of Marine Biology and Environmental Sciences, University of Miyazaki, Faculty of Agriculture, Gakuen- kibanadai-nishi-1-1, Miyazaki, 889-2192, Japan.
R&D Center for Submarine Resource, Japan Agency for Marine-Earth Science and Technology, 2-15, Natsushima-cho, Yokosuka-city, Kanagawa, 237-0061, Japan.
Sci Rep. 2019 Feb 13;9(1):1892. doi: 10.1038/s41598-018-38333-5.
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 populations, thus indicating the possible vulnerability of these populations to environmental changes. This finding underpins the importance of assessing the genetic diversity of newly colonized populations associated with climate change for conservation purposes. In addition, this study highlights the importance of pre-existing temperate regions as coral refugia, which has been rather underappreciated in local coastal management.
由于热带地区的珊瑚受到水温升高的威胁，造礁珊瑚的分布范围已经向两极方向扩展，预计在气候变化面前，温带地区将成为珊瑚的避难所。为了阐明珊瑚种群可持续性的重要指标，我们研究了黑潮中的常见造礁珊瑚鹿角珊瑚的遗传多样性和连通性，包括最近（<50 年）扩展的种群。在发现的三个隐生谱系中，只有一个分布在温带地区，这可能表明在温带和亚热带地区之间存在与黑潮相关的幼虫扩散障碍，这一点得到了海洋学模拟以及环境因素差异的证实。遗传多样性的水平逐渐向物种分布的边缘降低。本研究为最近扩展的边缘种群遗传多样性降低提供了一个实例，这表明这些种群可能容易受到环境变化的影响。这一发现强调了评估与气候变化相关的新殖民化种群遗传多样性的重要性，以实现保护目的。此外，本研究还强调了预先存在的温带地区作为珊瑚避难所的重要性，而这一点在当地沿海管理中往往被低估。
