Reynolds L K, Stachowicz J J, Hughes A R, Kamel S J, Ort B S, Grosberg R K
Department of Evolution and Ecology, University of California, Davis, Davis, CA, USA.
Marine Science Center, Northeastern University, Nahant, MA, USA.
Heredity (Edinb). 2017 Apr;118(4):404-412. doi: 10.1038/hdy.2016.114. Epub 2016 Dec 28.
Genetic diversity and population structure reflect complex interactions among a diverse set of processes that may vary temporally, limiting their potential to predict ecological and evolutionary outcomes. Yet, the stability of these patterns is rarely tested. We resampled eelgrass (Zostera marina) meadows from published studies to determine variability in genetic diversity and structure within and between meadows over 5-12 years. The meadows sampled (San Francisco, Tomales and Bodega Bays in California and the Virginia coastal bays) represent a range of life histories (annual vs perennial), age (well-established vs restored) and environments (rural vs urbanized). In all of these systems, neither diversity nor differentiation (F) changed over time. Differences among tidal heights within Bodega Bay were also remarkably consistent, with the high intertidal being more diverse than the subtidal, and tidal height differentiation being modest but significant at both time points. Historical studies used only a few microsatellite loci; therefore, our temporal comparisons were based on 4-5 loci. However, analysis of the current data using a set of 12 loci show that 4-5 loci are sufficient to describe diversity and differentiation patterns in this system. This temporal consistency was not because of the resampling of large clones, underscoring the feasibility and relevance of understanding drivers of the differences. Because seagrasses are declining at rapid rates, restoration and conservation are increasingly a coastal management priority. Our results argue that surveys of eelgrass genetic structure and diversity at decadal scales can provide accurate depictions of populations, increasing the utility of published genetic data for restoration and designing networks of reserves.
遗传多样性和种群结构反映了一系列不同过程之间复杂的相互作用，这些过程可能随时间变化，限制了它们预测生态和进化结果的潜力。然而，这些模式的稳定性很少得到检验。我们对已发表研究中的鳗草（大叶藻）草甸进行了重新采样，以确定5至12年内草甸内部和之间遗传多样性和结构的变异性。采样的草甸（加利福尼亚州的旧金山湾、托马莱斯湾和博德加湾以及弗吉尼亚沿海湾）代表了一系列生活史（一年生与多年生）、年龄（成熟与恢复）和环境（农村与城市化）。在所有这些系统中，多样性和分化（F）都没有随时间变化。博德加湾内不同潮位之间的差异也非常一致，高潮间带比低潮间带更加多样，并且在两个时间点潮位分化都较小但显著。历史研究仅使用了少数微卫星位点；因此，我们的时间比较基于4至5个位点。然而，使用一组12个位点对当前数据进行分析表明，4至5个位点足以描述该系统中的多样性和分化模式。这种时间上的一致性并非由于对大型克隆的重新采样，这突出了理解差异驱动因素的可行性和相关性。由于海草正在迅速衰退，恢复和保护日益成为沿海管理的优先事项。我们的结果表明，在十年尺度上对鳗草遗传结构和多样性进行调查可以提供种群的准确描述，提高已发表遗传数据在恢复和设计保护区网络方面的实用性。
