Kim Jae Hwan, Kang Ji Hyoun, Jang Ji Eun, Choi Sun Kyeong, Kim Min Ji, Park Sang Rul, Lee Hyuk Je
Molecular Ecology and Evolution Laboratory, Department of Biological Science, College of Science and Engineering, Sangji University, Wonju, Republic of Korea.
Korean Entomological Institute, Korea University, Seoul, Republic of Korea.
PLoS One. 2017 Mar 21;12(3):e0174105. doi: 10.1371/journal.pone.0174105. eCollection 2017.
Seagrasses provide numerous ecosystem services for coastal and estuarine environments, such as nursery functions, erosion protection, pollution filtration, and carbon sequestration. Zostera marina (common name "eelgrass") is one of the seagrass bed-forming species distributed widely in the northern hemisphere, including the Korean Peninsula. Recently, however, there has been a drastic decline in the population size of Z. marina worldwide, including Korea. We examined the current population genetic status of this species on the southern coast of Korea by estimating the levels of genetic diversity and genetic structure of 10 geographic populations using eight nuclear microsatellite markers. The level of genetic diversity was found to be significantly lower for populations on Jeju Island [mean allelic richness (AR) = 1.92, clonal diversity (R) = 0.51], which is located approximately 155 km off the southernmost region of the Korean Peninsula, than for those in the South Sea (mean AR = 2.69, R = 0.82), which is on the southern coast of the mainland. South Korean eelgrass populations were substantially genetically divergent from one another (FST = 0.061-0.573), suggesting that limited contemporary gene flow has been taking place among populations. We also found weak but detectable temporal variation in genetic structure within a site over 10 years. In additional depth comparisons, statistically significant genetic differentiation was observed between shallow (or middle) and deep zones in two of three sites tested. Depleted genetic diversity, small effective population sizes (Ne) and limited connectivity for populations on Jeju Island indicate that these populations may be vulnerable to local extinction under changing environmental conditions, especially given that Jeju Island is one of the fastest warming regions around the world. Overall, our work will inform conservation and restoration efforts, including transplantation for eelgrass populations at the southern tip of the Korean Peninsula, for this ecologically important species.
海草为沿海和河口环境提供了众多生态系统服务，如育苗功能、防侵蚀、污染过滤和碳固存。大叶藻（俗名“鳗草”）是广泛分布于北半球包括朝鲜半岛在内的海草床形成物种之一。然而，最近包括韩国在内，全球大叶藻的种群数量急剧下降。我们通过使用八个核微卫星标记估计10个地理种群的遗传多样性水平和遗传结构，研究了韩国南部海岸该物种当前的种群遗传状况。结果发现，位于朝鲜半岛最南端约155公里外的济州岛种群的遗传多样性水平[平均等位基因丰富度（AR）= 1.92，克隆多样性（R）= 0.51]显著低于韩国大陆南部海岸南海的种群（平均AR = 2.69，R = 0.82）。韩国鳗草种群在遗传上彼此差异很大（FST = 0.061 - 0.573），这表明种群间当代基因流有限。我们还发现一个地点在10年期间遗传结构存在微弱但可检测到的时间变化。在进一步的深度比较中，在三个测试地点中的两个，浅（或中）层和深层之间观察到了具有统计学意义的遗传分化。济州岛种群遗传多样性枯竭、有效种群规模小（Ne）以及连通性有限，这表明在不断变化的环境条件下，这些种群可能易受局部灭绝的影响，特别是考虑到济州岛是全球变暖最快的地区之一。总体而言，我们的工作将为这一具有重要生态意义的物种的保护和恢复工作提供信息，包括为朝鲜半岛南端的鳗草种群进行移植。
