School of Biological Sciences, University of Auckland, Auckland 1010, New Zealand.
Scottish Oceans Institute and School of Biology, University of St Andrews, St Andrews, UK.
Proc Biol Sci. 2020 Jun 10;287(1928):20200318. doi: 10.1098/rspb.2020.0318. Epub 2020 Jun 3.
Metapopulation theory assumes a balance between local decays/extinctions and local growth/new colonisations. Here we investigate whether recent population declines across part of the UK harbour seal range represent normal metapopulation dynamics or are indicative of perturbations potentially threatening the metapopulation viability, using 20 years of population trends, location tracking data ( = 380), and UK-wide, multi-generational population genetic data ( = 269). First, we use microsatellite data to show that two genetic groups previously identified are distinct metapopulations: northern and southern. Then, we characterize the northern metapopulation dynamics in two different periods, before and after the start of regional declines (pre-/peri-perturbation). We identify source-sink dynamics across the northern metapopulation, with two putative source populations apparently supporting three likely sink populations, and a recent metapopulation-wide disruption of migration coincident with the perturbation. The northern metapopulation appears to be in decay, highlighting that changes in local populations can lead to radical alterations in the overall metapopulation's persistence and dynamics.
复合种群理论假设局部衰减/灭绝与局部增长/新殖民之间的平衡。在这里，我们利用 20 年的种群趋势、位置跟踪数据（=380）和英国范围内的多世代种群遗传数据（=269），研究了英国海豹部分种群范围的近期种群下降是否代表正常的复合种群动态，还是表明存在可能威胁复合种群生存能力的干扰。首先，我们使用微卫星数据表明，之前确定的两个遗传群体是不同的复合种群：北部和南部。然后，我们在区域下降开始之前和之后的两个不同时期描述了北部复合种群的动态（前/扰动期）。我们发现北部复合种群存在源-汇动态，两个假定的源种群显然支持三个可能的汇种群，并且最近一次与干扰同时发生的整个复合种群范围的迁徙中断。北部复合种群似乎正在衰减，这表明局部种群的变化可能导致整个复合种群的持久性和动态发生根本性变化。
