Population genetic structure of seagrass, Zostera marina, on the southern coasts of Korea (Jeju Island, South Sea): the cornerstone for its future conservation and restoration plans : 한국 두 연안(제주도, 남해)에 서식하는 잘피 거머리말 집단의 유전적 구조: 미래 보전과 복원을 위한 초석 연구

다국어 초록 (Multilingual Abstract)

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 status of this species on the southern coast of Korea by estimating the levels of genetic diversity and genetic structure of 10 geographically disconnected 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) = 2.15], which is located off the southernmost region of the Korean Peninsula, than for those in the South Sea (mean AR = 3.73), which is on the southern coast of the mainland. South Korea eelgrass populations were all substantially genetically divergent from one another, 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 each of the 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 highly significant species.

목차 (Table of Contents)

• Abstract 1
• Introduction 3
• Materials and Methods 8
• Sample collection 8
• DNA extraction, PCR, and microsatellite genotyping 12
• Statistical analyses 13
• Genetic diversity 13
• Population genetic structure 14
• Results 17
• Genetic diversity 17
• Population genetic structure 22
• Discussion 31
• Low level of genetic diversity 31
• Spatial and temporal genetic structure 35
• Genetic divergence by water depth 38
• Conservation implications 39
• Conclusions 41
• References 42
• Appendix 53
• Abstract (in Korean) 75