Data from: Isolation by environment in the highly mobile olive ridley turtle (Lepidochelys olivacea) in the eastern Pacific

Spatial and temporal scales at which processes modulate genetic diversity over the landscape are usually overlooked, impacting the design of conservation management practices for widely distributed species. We examine processes shaping population divergence in highly mobile species by re-assessing the case of panmixia in the iconic olive ridley turtle from the eastern Pacific. We implemented a biophysical model of connectivity and a seascape genetic analysis based on nuclear DNA variation of 634 samples collected from 27 nesting areas. Two genetically distinct populations largely isolated during reproductive migrations and mating were detected, each composed of multiple nesting sites linked by high connectivity. This pattern was strongly associated with a steep environmental gradient and also influenced by ocean currents. These findings relate to meso-scales features of a dynamic oceanographic interface in the eastern tropical Pacific (ETP) region, a scenario that possibly provides different cost-benefit solutions and selective pressures for sea turtles during both the mating and migration periods. We reject panmixia and propose a new paradigm for olive ridley turtles where reproductive isolation due to assortative mating is linked to its environment. Our study demonstrates the relevance of integrative approaches for assessing the role of environmental gradients and oceanographic currents as drivers of genetic differentiation in widely distributed marine species. This is relevant for the conservation management of species of highly mobile behaviour; and assists the planning and development of large-scale conservation strategies for the threatened olive ridley turtles in the ETP.

调控景观尺度下遗传多样性的生态过程所对应的空间与时间尺度，往往未得到足够重视，这一疏漏会对广布物种的保护管理实践设计造成负面影响。本研究通过重新审视东太平洋标志性物种榄蠵龟（olive ridley turtle）的泛交（panmixia）现象，解析高流动性物种种群分化的驱动过程。本研究基于27个产卵场采集的634份样本的核DNA变异数据，构建了连通性生物物理模型，并开展了海洋景观遗传学分析。研究检测到两个遗传分化显著的种群，二者在生殖洄游与交配过程中存在显著隔离；每个种群均包含多个通过高连通性相连的产卵场。该遗传分化格局与陡峭的环境梯度密切相关，同时也受海流作用的影响。上述研究结果与东热带太平洋（ETP）区域动态海洋学界面的中尺度特征密切相关，该场景可能为海龟在交配与洄游阶段提供了差异化的成本收益策略与选择压力。本研究否定了泛交假说，并提出榄蠵龟种群的全新范式：由选型交配（assortative mating）导致的生殖隔离与其生存环境紧密相关。本研究证明了整合研究方法的重要性，该方法可用于解析环境梯度与海流作为广布海洋物种种群遗传分化驱动因子的作用机制。该研究结果对高流动性物种的保护管理具有重要参考价值，同时可为东热带太平洋区域受威胁的榄蠵龟制定大规模保护策略提供辅助支持。