Hoey Jennifer A, Fodrie F Joel, Walker Quentin A, Hilton Eric J, Kellison G Todd, Targett Timothy E, Taylor J Christopher, Able Kenneth W, Pinsky Malin L
Ecology, Evolution, & Natural Resources, Rutgers University, New Brunswick, NJ, USA.
Institute of Marine Sciences, University of North Carolina at Chapel Hill, Morehead City, NC, USA.
Mol Ecol. 2020 Apr;29(8):1421-1435. doi: 10.1111/mec.15414. Epub 2020 Apr 13.
Dispersal sets the fundamental scales of ecological and evolutionary dynamics and has important implications for population persistence. Patterns of marine dispersal remain poorly understood, partly because dispersal may vary through time and often homogenizes allele frequencies. However, combining multiple types of natural tags can provide more precise dispersal estimates, and biological collections can help to reconstruct dispersal patterns through time. We used single nucleotide polymorphism genotypes and otolith core microchemistry from archived collections of larval summer flounder (Paralichthys dentatus, n = 411) captured between 1989 and 2012 at five locations along the US East coast to reconstruct dispersal patterns through time. Neither genotypes nor otolith microchemistry alone were sufficient to identify the source of larval fish. However, microchemistry identified clusters of larvae (n = 3-33 larvae per cluster) that originated in the same location, and genetic assignment of clusters could be made with substantially more confidence. We found that most larvae probably originated near a biogeographical break (Cape Hatteras) and that larvae were transported in both directions across this break. Larval sources did not shift north through time, despite the northward shift of adult populations in recent decades. Our novel approach demonstrates that summer flounder dispersal is widespread throughout their range, on both intra- and intergenerational timescales, and may be a particularly important process for synchronizing population dynamics and maintaining genetic diversity during an era of rapid environmental change. Broadly, our results reveal the value of archived collections and of combining multiple natural tags to understand the magnitude and directionality of dispersal in species with extensive gene flow.
扩散设定了生态和进化动态的基本尺度，对种群的持续存在具有重要意义。海洋扩散模式仍知之甚少，部分原因是扩散可能随时间变化，且常常使等位基因频率趋于同质化。然而，结合多种类型的天然标记可以提供更精确的扩散估计，生物样本库有助于重建随时间变化的扩散模式。我们利用1989年至2012年间在美国东海岸五个地点捕获的存档夏季牙鲆（Paralichthys dentatus，n = 411）幼体样本的单核苷酸多态性基因型和耳石核心微化学来重建随时间变化的扩散模式。单独的基因型或耳石微化学都不足以确定幼鱼的来源。然而，微化学识别出了起源于同一地点的幼体集群（每个集群有3 - 33条幼体），并且可以更有信心地对集群进行遗传归属。我们发现，大多数幼体可能起源于一个生物地理分界线（哈特拉斯角）附近，并且幼体在这个分界线两侧双向运输。尽管近几十年来成年种群向北移动，但幼体来源并没有随时间向北转移。我们的新方法表明，夏季牙鲆的扩散在其整个分布范围内广泛存在，在代内和代际时间尺度上都是如此，并且在快速环境变化的时代，这可能是同步种群动态和维持遗传多样性的一个特别重要的过程。总体而言，我们的结果揭示了存档样本库以及结合多种天然标记对于理解具有广泛基因流动的物种扩散的规模和方向性的价值。
