Data from: Depth as an organizing force in Pocillopora damicornis: intra-reef genetic architecture

Relative to terrestrial plants, and despite similarities in life history characteristics, the potential for corals to exhibit intra-reef local adaptation in the form of genetic differentiation along an environmental gradient has received little attention. The potential for natural selection to act on such small scales is likely increased by the ability of coral larval dispersal and settlement to be influenced by environmental cues. Here, we combine genetic, spatial, and environmental data for a single patch reef in Kāne‘ohe Bay, O‘ahu, Hawai‘i, USA in a landscape genetics framework to uncover environmental drivers of intra-reef genetic structuring. The genetic dataset consists of near-exhaustive sampling (n = 2352) of the coral, Pocillopora damicornis at our study site and six microsatellite genotypes. In addition, three environmental parameters – depth and two depth-independent temperature indices – were collected on a 4 m grid across 85 locations throughout the reef. We use ordinary kriging to spatially interpolate our environmental data and estimate the three environmental parameters for each colony. Partial Mantel tests indicate a significant correlation between genetic relatedness and depth while controlling for space. These results are also supported by multi-model inference. Furthermore, spatial Principle Component Analysis indicates a statistically significant genetic cline along a depth gradient. Binning the genetic dataset based on size-class revealed that the correlation between genetic relatedness and depth was significant for new recruits and increased for larger size classes, suggesting a possible role of larval habitat selection as well as selective mortality in structuring intra-reef genetic diversity. That both pre- and post-recruitment processes may be involved points to the adaptive role of larval habitat selection in increasing adult survival. The conservation importance of uncovering intra-reef patterns of genetic diversity is discussed.

尽管珊瑚与陆生植物具有相似的生活史特征，但相较于后者，珊瑚沿环境梯度以遗传分化形式展现礁内局部适应的潜力，迄今仍未受到足够关注。珊瑚幼虫的扩散与定居可受环境信号调控，这一特性大概率会提升自然选择在如此精细尺度上发挥作用的潜力。本研究以美国夏威夷州瓦胡岛卡内奥赫湾内的一处斑礁为研究对象，借助景观遗传学（landscape genetics）框架整合遗传、空间与环境数据，旨在揭示礁内遗传结构形成的环境驱动因子。本研究的遗传数据集源自对研究区域内指形鹿角珊瑚（Pocillopora damicornis）的近乎全面采样（样本量n=2352），以及基于6个微卫星基因型（microsatellite genotypes）获得的分型数据。此外，本研究在全礁85个采样点以4米为网格间隔采集了三类环境参数：水深以及两个与水深无关的温度指标。本研究采用普通克里金（ordinary kriging）法对环境数据进行空间插值，以此估算每株珊瑚对应的三类环境参数。偏曼特尔检验（Partial Mantel tests）结果显示，在控制空间效应的前提下，遗传亲缘关系与水深之间存在显著相关性。多模型推断（multi-model inference）分析也验证了上述结果。此外，空间主成分分析（spatial Principle Component Analysis）结果显示，沿水深梯度存在具有统计学显著性的遗传渐变群。基于体型等级对遗传数据集进行分组分析后发现，遗传亲缘关系与水深的相关性在新补充个体中显著存在，且随体型等级增大而增强，这表明幼虫栖息地选择与选择性死亡可能共同参与了礁内遗传多样性的塑造过程。既然补充前与补充后过程均可能参与其中，这说明幼虫栖息地选择在提升成体存活率方面具有适应性意义。本研究最后讨论了揭示礁内遗传多样性格局的保育学重要性。