Site Fidelity and Individual Variation in Winter Location in Partially Migratory European Shags
Site Fidelity and Individual Variation in Winter Location in Partially Migratory European Shags
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DOI：
10.1371/journal.pone.0098562
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发表时间：
2014-06-03
期刊：
影响因子：
3.7
通讯作者：
Reid, Jane M.
中科院分区：
文献类型：
--
作者：
Grist, Hannah;Daunt, Francis;Reid, Jane M.
在部分迁徙的种群中，来自单一繁殖区的个体在非繁殖期经历了一系列的环境。如果个体在年内或年内对特定地点表现出高度的忠诚，则任何年度环境对个体生活史的影响都可能被加强，从而导致大量的人口异质性。因此，量化非繁殖季节位置的个体内部和个体之间的变异和可重复性是预测部分迁徙种群动态的大范围环境影响的关键。我们对已知在苏格兰五月岛繁殖的带色环的成年欧洲长尾鹬进行了实地观察，以量化连续三个冬季内和冬季位置的个体差异和可重复性。在包括五月岛在内的622公里海岸线上，总共记录了3797次，882只个体的回归。这些个体占已知繁殖种群的50%以上，并且包括年龄和性别的代表性分布。从五月岛到个体在冬季被重新发现的距离有很大的不同，北到486公里，南到136公里，包括五月岛上的繁殖地。然而，重视距离在个体内高度可重复；在整个9 - 3月的观测期内，冬内和冬间的重复度分别为>.72和>.59，在更有限的冬中期，重复度分别为>.95和>.79。无论是冬季内还是冬季间，雄性和雌性之间或不同年龄组之间的重复性无显著差异。这些数据表明，焦点长毛象种群是部分迁移的，此外，个体在冬季位置和连续冬季的迁移策略上表现出高度可重复的变化。如此高的个体间变异和个体内可重复性，无论是在冬季内还是在冬季之间，都可能导致大量的生活史变异，从而影响种群动态和未来的保护管理策略。
In partially migratory populations, individuals from a single breeding area experience a range of environments during the non-breeding season. If individuals show high within-and among-year fidelity to specific locations, any annual environmental effect on individual life histories could be reinforced, causing substantial demographic heterogeneity. Quantifying within-and among-individual variation and repeatability in non-breeding season location is therefore key to predicting broad-scale environmental impacts on the dynamics of partially migratory populations. We used field resightings of colour-ringed adult European shags known to have bred on the Isle of May, Scotland, to quantify individual variation and repeatability in winter location within and among three consecutive winters. In total, 3797 resightings of 882 individuals were recorded over 622 km of coastline, including the Isle of May. These individuals comprised over 50% of the known breeding population, and encompassed representative distributions of ages and sexes. The distances from the Isle of May at which individuals were resighted during winter varied substantially, up to 486 km and 136 km north and south respectively and including the breeding colony on the Isle of May. However, resighting distances were highly repeatable within individuals; within-and among-winter repeatabilities were >0.72 and >0.59 respectively across the full September-March observation period, and >0.95 and >0.79 respectively across more restricted mid-winter periods. Repeatability did not differ significantly between males and females or among different age classes, either within or among winters. These data demonstrate that the focal shag population is partially migratory, and moreover that individuals show highly repeatable variation in winter location and hence migration strategy across consecutive winters. Such high among-individual variation and within-individual repeatability, both within and among winters, could lead to substantial life history variation, and therefore influence population dynamics and future conservation management strategies.