Foraging ecology of great black-backed gulls and their impact on Atlantic puffin populations

在过去的30年里，许多种类的海鸟数量显著下降，气候变化被认为是主要原因。大西洋海雀是数量锐减的物种之一，这是一种高度保护的物种，最近被国际鸟盟重新列为“易危”物种。猎物（沙鳗）的减少被认为是减少的主要原因，然而，像大黑背鸥和大贼鸥这样的掠食性海鸟的捕食也可能起作用，特别是这些物种在许多地方显示出明显的增加。由于海鸟的捕食者和猎物都受到法律保护，这可能会导致野生动物冲突，特别是如果提出扑杀等管理措施。此外，对这两个物种的其他压力的影响将影响冲突，例如，大黑背鸥和海雀可能面临海上可再生能源设施（如风力发电场）的开发和[微]塑料的摄入的风险。因此，获取有关物种之间相互作用的详细信息是至关重要的，以便确定这种捕食者-猎物关系对种群动态的影响，并制定有效的管理策略来缓解这种野生动物冲突。博士将研究苏格兰东南部五月岛大黑背鸥数量显著增加对大西洋海雀数量的影响。在过去的十年里，梅岛上的大西洋海雀的数量减少了三分之一以上，而大黑背鸥的数量在同一时期增加了一倍多。过去在这个群体的工作表明，大部分捕食是由一群专业海鸥进行的，它们通常以幼海雀为目标[1,2]。然而，这种捕食对海雀种群水平的影响程度，以及这种影响是否会在未来发生变化，还没有经过测试。此外，由于对大黑背鸥的种群趋势和与当地海雀种群的相互作用程度的了解有限，目前尚不清楚对海雀的潜在影响是否更广泛。因此，该项目将包括对五月岛的重点研究和全国范围内的分析，以解决以下关键问题：a)单个海鸥的觅食专业化程度如何？b)早生海雀的年龄结构为何？c)海鸥的捕食对海雀种群的影响是什么？d)在五月岛和英国范围内，海雀和海鸥种群规模的预测变化与捕食者-猎物相互作用的未来变化有什么关系？e)多种驱动因素（包括近海可再生能源效应和海洋塑料的摄入）对这两个物种种群的预测变化是什么？解决这些问题将为保护管理者提供他们需要的证据，以选择缓解这种野生动物冲突的最佳选择。

Populations of many species of seabirds have declined significantly over the past 30 years, with climate change identified as a primary cause. One species undergoing large declines is the Atlantic puffin, a species of high conservation concern that has recently been re-classified as 'vulnerable' by BirdLife International. The reduction in availability of prey (sandeels) has been proposed as a principal cause for declines, however, predation by predatory seabirds such as the great black-backed gull and great skua may also play a role, especially as these species are showing marked increases in many locations. Since both seabird predator and prey are legally protected, this may lead to wildlife conflicts, especially if management measures such as culling are proposed. Furthermore, conflicts will be shaped by the effects of other pressures on both species e.g. great black-backed gulls and puffins are potentially at risk from the development of offshore renewable energy installations such as wind farms and from the ingestion of [micro]plastics. It is therefore vital that detailed information is available on the interactions between the species involved in order to ascertain the population dynamic consequences of this predator-prey relationship, and to devise effective management strategies to alleviate this wildlife conflict.The PhD would examine the consequences of the significant increase in the great black-backed gull population on the Isle of May, south-east Scotland, on the Atlantic puffin populations. Atlantic puffins on the Isle of May have declined by more than a third in the last decade, while the great black-backed gulls have more than doubled over the same period. Past work at this colony has demonstrated that the majority of predation is undertaken by a subset of specialist gulls that generally target juvenile puffins [1, 2]. However, the extent to which this predation has population-level effects on puffins, and whether this is predicted to change in the future, has not been tested. Further, it is not clear whether potential effects on puffins are apparent more widely, because of limited knowledge of the population trends of great black-backed gull and the extent of interactions with local puffin populations. Therefore the project would involve focussed research on the Isle of May and analyses at the national scale to address the following key questions: a) What is the degree of foraging specialism among individual gulls? b) What is the age structure of predated puffins? c) What are the population-level consequences of predation by gulls on the puffin population? d) What are the predicted changes in puffin and gull population sizes associated with future changes in predator-prey interactions on the Isle of May and at the UK scale? e) What are the predicted changes in populations of both species caused by multiple drivers including offshore renewable effects and ingestion of marine plastics? Addressing these questions would provide conservation managers with the evidence they need to select the best options for alleviating this wildlife conflict.