Norwegian Institute for Nature Research, FRAM-High North Research Centre for Climate and the Environment, 9296 Tromsø, Norway.
Proc Biol Sci. 2013 Aug 21;280(1769):20131483. doi: 10.1098/rspb.2013.1483. Print 2013 Oct 22.
In long-lived species, any negative effect of pollution on adult survival may pose serious hazards to breeding populations. In this study, we measured concentrations of various organochlorines (OCs) (polychlorinated biphenyl and OC pesticides) in the blood of a large number of adult glaucous gulls (Larus hyperboreus) breeding on Bjørnøya (Bear Island) in the Norwegian Arctic, and modelled their local survival using capture-recapture analysis. Survival was negatively associated with concentrations of OCs in the blood. The effect of OCs was nonlinear and evident only among birds with the highest concentrations (the uppermost deciles of contamination). The threshold for depressed survival differed between the sexes, with females being more sensitive to contamination. For birds with lower OC concentration, survival was very high, i.e. at the upper range of survival rates reported from glaucous and other large gull species in other, presumably less contaminated populations. We propose two non-exclusive explanations. First, at some threshold of OC concentration, parents (especially males) may abandon reproduction to maximize their own survival. Second, high contamination of OC may eliminate the most sensitive individuals from the population (especially among females), inducing a strong selection towards high-quality and less sensitive phenotypes.
在长寿物种中，污染对成年个体存活的任何负面影响都可能对繁殖种群造成严重危害。在这项研究中，我们测量了在挪威北极的比约恩岛（Bear Island）繁殖的大量成年大贼鸥（Larus hyperboreus）血液中的各种有机氯（OC）（多氯联苯和 OC 农药）的浓度，并使用捕获-再捕获分析对其当地存活率进行建模。存活率与血液中的 OC 浓度呈负相关。OC 的影响是非线性的，仅在浓度最高的鸟类（污染程度最高的十分位数）中明显。受抑制的存活率的阈值因性别而异，雌性对污染更敏感。对于 OC 浓度较低的鸟类，存活率非常高，即处于其他，据推测污染程度较低的群体中报告的大贼鸥和其他大型海鸥物种的存活率上限范围内。我们提出了两个非排他性的解释。首先，在 OC 浓度的某个阈值上，父母（尤其是雄性）可能会放弃繁殖以最大程度地提高自身的存活率。其次，OC 的高污染可能会使种群中最敏感的个体（尤其是雌性）灭绝，从而强烈地选择高质量和低敏感性的表型。
