Comparative landscape genetic analysis of three Pacific salmon species from subarctic North America

We examined the assumption that landscape heterogeneity similarly influences the spatial distribution of genetic diversity in closely related and geographically overlapping species. Accordingly, we evaluated the influence of watershed affiliation and nine habitat variables from four categories (spatial isolation, habitat size, climate, and ecology) on population divergence in three species of Pacific salmon (Oncorhynchus tshawytscha, O. kisutch, and O. keta) from three contiguous watersheds in subarctic North America. By incorporating spatial data we found that the three watersheds did not form the first level of hierarchical population structure as predicted. Instead, each species exhibited a broadly similar spatial pattern: a single coastal group with populations from all watersheds and one or more inland groups primarily in the largest watershed. These results imply that the spatial scale of conservation should extend across watersheds rather than at the watershed level which is the ...

本研究旨在检验如下假说：景观异质性（landscape heterogeneity）对亲缘关系相近且地理分布重叠的物种的遗传多样性（genetic diversity）空间分布具有相似影响。据此，我们评估了流域归属（watershed affiliation）以及四类（空间隔离（spatial isolation）、生境面积（habitat size）、气候（climate）与生态（ecology））共9种生境变量（habitat variables），对北美亚北极区域（subarctic North America）三个相邻流域内的三种太平洋鲑（Pacific salmon）——大鳞大麻哈鱼（Oncorhynchus tshawytscha）、银大麻哈鱼（O. kisutch）与狗鲑（O. keta）——的种群分化（population divergence）的影响。通过整合空间数据（spatial data），本研究发现该三个流域并未如预期那样构成等级种群结构（hierarchical population structure）的第一层级。相反，各物种均呈现出大致相似的空间分布模式：存在一个涵盖所有流域种群的沿海类群，以及一个或多个主要分布于最大流域的内陆类群。上述结果表明，保护工作的空间尺度应跨流域展开，而非局限于流域层级，这一...