Kazyak David C, Hilderbrand Robert H, King Tim L, Keller Stephen R, Chhatre Vikram E
University of Maryland Center for Environmental Science, Appalachian Laboratory, Frostburg, Maryland, United States of America.
U.S. Geological Survey, Leetown Science Center, Aquatic Ecology Branch, Kearneysville, West Virginia, United States of America.
PLoS One. 2016 Jan 5;11(1):e0146295. doi: 10.1371/journal.pone.0146295. eCollection 2016.
A fundamental issue in the management and conservation of biodiversity is how to define a population. Spatially contiguous fish occupying a stream network have often been considered to represent a single, homogenous population. However, they may also represent multiple discrete populations, a single population with genetic isolation-by-distance, or a metapopulation. We used microsatellite DNA and a large-scale mark-recapture study to assess population structure in a spatially contiguous sample of Brook Trout (Salvelinus fontinalis), a species of conservation concern. We found evidence for limited genetic exchange across small spatial scales and in the absence of barriers to physical movement. Mark-recapture and stationary passive integrated transponder antenna records demonstrated that fish from two tributaries very seldom moved into the opposite tributary, but movements between the tributaries and mainstem were more common. Using Bayesian genetic clustering, we identified two genetic groups that exhibited significantly different growth rates over three years of study, yet survival rates were very similar. Our study highlights the importance of considering the possibility of multiple genetically distinct populations occurring within spatially contiguous habitats, and suggests the existence of a cryptic metapopulation: a spatially continuous distribution of organisms exhibiting metapopulation-like behaviors.
生物多样性管理与保护中的一个基本问题是如何定义一个种群。占据溪流网络的空间上相邻的鱼类通常被认为代表一个单一的、同质的种群。然而，它们也可能代表多个离散的种群、一个具有距离隔离遗传的单一种群，或一个集合种群。我们使用微卫星DNA和大规模标记重捕研究来评估溪红点鲑（Salvelinus fontinalis）的一个空间上相邻样本中的种群结构，溪红点鲑是一种受保护的物种。我们发现，在小空间尺度上且不存在物理移动障碍的情况下，基因交流有限的证据。标记重捕和固定被动集成应答器天线记录表明，来自两条支流的鱼很少游入对面的支流，但支流与干流之间的移动更为常见。使用贝叶斯遗传聚类，我们识别出两个遗传组，在三年的研究中它们表现出显著不同的生长率，但存活率非常相似。我们的研究强调了考虑在空间上相邻的栖息地内出现多个遗传上不同的种群的可能性的重要性，并表明存在一个隐性集合种群：一种表现出类似集合种群行为的生物的空间连续分布。
