Causes and Consequences of Variable Recruitment in the AcornBarnacle, Semibalanus Balanoides

虽然人们普遍认为，不同的招募方式(将新的个体引入一个种群)会影响海洋种群的结构和动态，但对于任何有浮游幼体的物种来说，可变招募的具体原因和后果知之甚少。目前的证据表明，橡子藤壶的招募受到海洋特征的强烈影响，这些特征决定了幼虫的供应。此外，由此产生的补充变异可能会以先前意想不到的方式强烈影响藤壶种群的分布、丰度、人口学和遗传结构。在这些初步数据的基础上，三位年轻的科学家Gaines、Berness和Geyer博士将启动一项地区性研究，以考察特定的沿海海洋学特征(蓄水时间)、水柱幼虫丰度、底栖动物补充变化和半条鱼种群过程之间的联系。具体地说，这项调查将：1)检验这样一种假设，即在受保护的海湾之间和不同年份之间冲洗率的变化会导致幼虫丰度和海岸线沉降率的变化，2)通过实验评估这种区域和时间上的补充变化对藤壶种群的分布、丰度和人口统计学的相对重要性，3)检验这样一种假设，即避风港间幼虫滞留率的变化可以通过改变基因流动的速度来预测藤壶种群的局部适应程度。这项工作将解决我们对具有复杂生活史的物种的生态和进化的理解中至关重要的问题。

While it is widely believed that variation in recruitment (the introduction of new individuals to a population) can influence the structure and dynamics of marine populations, the specific causes and consequences of variable recruitment are poorly known for any species with planktonic larvae. The present evidence suggests that recruitment of the acorn barnacle, Semibalanus balanoides, is strongly influenced by oceanographic features that dictate larval supply. Moreover, the resulting recruitment variation hypothetically can strongly influence the distribution, abundance, demography, and genetic structure of barnacle populations in previously unsuspected ways. On the basis of these preliminary data three young scientists Drs. Gaines, Bertness and Geyer will initiate a regional study to examine the links between a specific coastal oceanographic feature (embayment flushing time), water column larval abundance, benthic recruitment variation, and population processes in Semibalanus balanoides. Specifically, this investigation will: 1) examine the hypothesis that variation in flushing rates among sheltered bays and among years generates variation in larval abundance and shoreline settlement rates, 2) evaluate experimentally the relative importance of this regional and temporal variation in recruitment to the distribution, abundance, and demography of barnacle populations, and, 3) test the hypothesis that variation in larval retention among sheltered bays predictably affects the degree of local adaptation of barnacle populations by altering rates of gene flow. This work will address critically important issues in our understanding of the ecology and evolution of species with complex life histories.