Connectivity and gene flow in a dominant reef-building coral

许多水生和海洋生物在其生活史上都有一个浮游期，它们生命的头几天或几周都是在浮游生物中度过的。浮游生物可能会被洋流带到很远的地方，使新的区域得以殖民，并在显然相当遥远的种群之间交换基因。毫不奇怪，浮游生活期的出现强烈影响着许多进化和生态过程，包括物种的全球分布、新物种的创造和个体种群的持续存在。后者对于自然保护尤为重要。例如，古巴的龙虾可能会将它们的后代放入浮游生物中，然后浮游生物到达佛罗里达州。在这种情况下，佛罗里达州的龙虾数量可能高度依赖于古巴的成年龙虾数量，而且种群需要大规模管理。了解幼虫交换水平对于生物多样性养护和渔业管理至关重要，但可获得的数据很少。通常采用两种方法来推断幼虫的连接性水平。第一个使用详细的海洋模型来预测“虚拟幼虫”在海洋和沿海洋流中的扩散。第二种方法检查种群的遗传结构，并确定幼虫交流较少的规模(即相对孤立的种群)。这两种方法很少被结合在一起，这主要是因为在相关空间尺度上对生物体进行采样的挑战，以及创建空间上真实的循环模型的计算复杂性。然而，将这两种方法结合起来是非常可取的，因为它们提供了巨大的协同效应。在这项提案中，我们将遗传结构的大规模采样与最先进的幼虫传播模型(今年早些时候发表在我们的合作者在《科学》杂志上发表)相结合。我们研究了遍布加勒比海的大型环状珊瑚Montastraea Cirularis的遗传结构和幼虫连通性。与这种珊瑚合作有很多好处。也许最重要的是，它的自然历史相对容易建模，这有助于对幼虫的扩散进行建模。因此，我们能够进行最清晰的测试之一，以确定模拟的幼虫扩散和观察到的遗传多样性之间的一致性。我们已经对整个加勒比海的环状支原体的遗传多样性进行了采样，并将观察到的基因流模式与预测的幼虫连接性水平进行比较。该项目的洞察力还将支持正在进行的活动，以模拟这一重要珊瑚的集合种群动态，并为选择海洋保护区网络设计更适当的算法。

Many aquatic and marine organisms have a planktonic phase in their life history and spend the first days or weeks of their life drifting in plankton. Plankton may be carried great distances by ocean currents and enable new areas to be colonised and genes to be exchanged between apparently quite distant populations. Not surprisingly, the occurrence of a planktonic life phase strongly influences many evolutionary and ecological processes including the global distribution of species, the creation of new species, and the persistence of individual populations. The latter is particularly important for conservation. For example, lobsters in Cuba may launch their offspring into the plankton which later arrive in Florida. In this case, the number of lobsters in Florida may be highly dependent on the number of adult lobsters in Cuba and the populations require management at large scales. Understanding levels of larval exchange is vital for biodiversity conservation and fisheries management but few data are available. Two approaches are usually taken to infer levels of larval connectivity. The first uses detailed oceanographic models to predict the dispersal of 'virtual larvae' in ocean and coastal currents. The second examines the genetic structure of populations and identifies scales where little larval exchange occurs (i.e. relatively isolated populations). Rarely have both approaches been integrated, largely because of the challenges in sampling organisms across relevant spatial scales and the computational complexity of creating spatially-realistic models of circulation. However, it is highly desible to combine both approaches as they offer great synergy. In this proposal, we combine large-scale sampling of genetic structure with a state-of-the-art model of larval dispersal (published by our collaborators in Science earlier this year). We examine the genetic structure and larval connectivity of the massive coral Montastraea annularis which is found throughout the Caribbean Sea. Working with this coral has a number of advantages. Perhaps most importantly, its natural history is relatively easy to model which lends itself to modelling larval dispersal. Therefore, we are able to perform one of the clearest tests possible for agreement between modelled larval dispersal and observed genetic diversity. We have sampled the genetic diversity of M. annularis throughout the Caribbean Sea and will compare the observed patterns of gene flow to predicted levels of larval connectivity. Insight from this project will also support on-going activities to model the metapopulation dynamics of this important coral and design more appropriate algorithms for the selection of marine reserve networks.