Effects of disaster prevention facilities on the persistence of semi-terrestrial crab populations along the Tohoku coast: analysis of population genetic structure

2021 Fiscal Year Final Research Report

• Project/Area Number: 19K20488
• Research Category: Grant-in-Aid for Early-Career Scientists
• Allocation Type: Multi-year Fund
• Review Section: Basic Section 64040:Social-ecological systems-related
• Research Institution: Tohoku University
• Principal Investigator: Yuhara Takeshi 東北大学, 生命科学研究科, 学術研究員 (90772369)
• Project Period (FY): 2019-04-01 – 2022-03-31
• Keywords: 個体群存続機構 / 集団遺伝構造 / 半陸生ガニ / 遺伝的分化 / 震災復興工事

Outline of Final Research Achievements

The common semi-terrestrial brachyuran crabs, such as Orisarma dehaani, Chiromantes haematocheir, and Helice tridens, inhabited the terrestrial area and spawned in the coastal area, requiring a continuous habitat to maintain their populations. After the seawall construction associated with reconstruction after the Great East Japan Earthquake, the terrestrial and coastal areas were fragmented, making analysis of the population genetic structure of the these crabs an urgent issue. Therefore, this study aimed to clarify the possibility of genetic differentiation of local populations of these crabs in the Japanese archipelago. Among the three crabs, only O. dehaani showed gene flow restriction between the Tohoku Pacific coast and the other Japanese coasts. Therefore, it is necessary to ensure the continuous habitats in order to conserve the crab populations in the Tohoku Pacific coast.

Free Research Field

海洋保全生態学

Academic Significance and Societal Importance of the Research Achievements

日本各地の沿岸域に生息しているクロベンケイガニにおいて，東北地方太平洋沿岸の地域集団の遺伝的孤立が示唆された．東日本大震災の津波被害が大きかった東北地方から房総半島にかけての太平洋沿岸では，震災後に多くの防潮堤や護岸が建設されている．したがって，これらの集団を保全するためには，陸域と海域の移動のための継続的な生息地を確保するために，防潮堤のセットバック，アンダーパスやエコロードの建設などの積極的な対策も必要であろう．