Faculty of Agriculture and Marine Science, Kochi University, 200 Monobe, Nankoku, Kochi 783-8502, Japan.
National Institute for Environmental Studies, 16-2 Onogawa, Tsukuba, Ibaraki 305-8506, Japan.
Sci Rep. 2017 Mar 10;7:44375. doi: 10.1038/srep44375.
Natural disturbances often destroy local populations and can considerably affect the genetic properties of these populations. The 2011 Tohoku Earthquake Tsunami greatly damaged local populations of various coastal organisms, including the mud snail Batillaria attramentaria, which was an abundant macroinvertebrate on the tidal flats in the Tohoku region. To evaluate the impact of the tsunami on the ecology and population genetic properties of these snails, we monitored the density, shell size, and microsatellite DNA variation of B. attramentaria for more than ten years (2005-2015) throughout the disturbance event. We found that the density of snails declined immediately after the tsunami. Bayesian inference of the genetically effective population size (N) demonstrated that the N declined by 60-99% at the study sites exposed to the tsunami. However, we found that their genetic diversity was not significantly reduced after the tsunami. The maintenance of genetic diversity is essential for long-term survival of local populations, and thus, the observed genetic robustness could play a key role in the persistence of snail populations in this region which has been devastated by similar tsunamis every 500-800 years. Our findings have significant implications for understanding the sustainability of populations damaged by natural disturbances.
自然干扰常常会破坏局部种群，并可能极大地影响这些种群的遗传特性。2011 年的东日本大地震海啸对包括泥螺 Batillaria attramentaria 在内的各种沿海生物的当地种群造成了极大的破坏，泥螺是东北地区潮间带丰富的大型底栖动物。为了评估海啸对这些贝类的生态学和种群遗传特性的影响，我们在超过十年（2005-2015 年）的时间里，对整个干扰事件中泥螺的密度、壳大小和微卫星 DNA 变异进行了监测。我们发现，海啸过后，贝类的密度立即下降。贝叶斯推断遗传有效种群大小（N）表明，在暴露于海啸的研究地点，N 下降了 60-99%。然而，我们发现海啸后它们的遗传多样性并没有显著降低。遗传多样性的维持对于当地种群的长期生存至关重要，因此，观察到的遗传稳健性可能在该地区的贝类种群的持续存在中发挥关键作用，该地区每 500-800 年就会遭受类似的海啸破坏。我们的研究结果对理解受自然干扰破坏的种群的可持续性具有重要意义。
