Assessing the ecological impacts of non-native gamebird release on reptiles in the UK

背景和理由：英国有着将环颈雉（Phasianus colchicus）和红腿凤头鹦鹉（Alecleum rufa）（以下简称为“猎鸟”）释放到乡村进行拍摄的悠久历史（Madden & Sage 2020）。自1960年以来，在射击场释放的猎鸟数量一直在增加，1960年至2014年期间，每个地点释放的鸟类密度每年增加4.3%（Robertson et al. 2017），自2004年以来，鸟类数量增加了38%（Aebischer 2019）。尽管如此，被射杀的猎鸟数量保持相对稳定，这导致了后方释放效率的降低（Mason等人，2020）。在5700万只鸟，这一最新估计的年度大规模释放的游戏鸟超过任何其他游戏鸟释放在欧洲或北美（Mason等人，2020年），在秋季释放点，估计猎鸟代表了所有英国本土繁殖鸟类春季生物量的两倍以上（Blackburn and Gaston 2018; Aebischer 2019）在英国释放的猎鸟数量越来越多，引发了环保主义者，政策制定者和射击社区本身对这种广泛活动的生态影响的担忧（Mason et al. 2020）。有证据表明，狩猎场管理可以间接地使生物多样性受益，例如通过林地保护和维护（Oldfield等人，2003年）和树篱网络（Draycott等人，2012年）。然而，人们担心，非本地猎鸟的数量和密度通过一系列直接压力对生态产生广泛的负面影响。（捕食，浏览，栖息地改造）和间接压力（对通才捕食者的影响，资源竞争，非法迫害和铅弹药中毒）。传闻证据表明，释放猎鸟可能会对英国爬行动物种群产生负面影响（埃德加等人，2015;加德纳等人，2019;梅森等人，2020）。最近的评论建议紧急研究野生鸟类对爬行动物的直接影响（Madden和Sage 2020; Mason等人2020），因为缺乏关于野生鸟类的影响及其对爬行动物种群的潜在有害影响的信息。在英国本土物种减少的背景下（Hayhow et al. 2019），了解大规模释放猎鸟的影响是一个重大挑战。因此，有强有力的理由进行研究，旨在产生经验证据的关系，猎鸟和爬行动物。

Background and Rationale:Britain has a long history of releasing ring-necked pheasant (Phasianus colchicus) and red-legged partridge (Alectoris rufa), hereafter referred to as "gamebirds", into the countryside for the shoot (Madden & Sage 2020). The number of gamebirds released on shooting estates has been increasing since 1960, with a 4.3% annual increase in the density of birds released per site between 1960 and 2014 (Robertson et al. 2017), and a 38% increase in the number of birds since 2004 (Aebischer 2019). Despite this, the numbers of gamebirds shot have remained relatively stable, which has led to a reduction in rear-releasing efficiency (Mason et al. 2020). At 57 million birds, this latest estimate for the annual large-scale release of gamebirds exceeds any other gamebird release in Europe or North America (Mason et al. 2020), and at the Autumn point of release it is estimated that gamebirds represent more than twice the spring biomass of all native UK breeding birds combined (Blackburn and Gaston 2018; Aebischer 2019).The increasing number of gamebirds released in the UK has triggered concerns about the ecological impacts of this widespread activity amongst conservationists, policymakers and within the shooting community itself (Mason et al. 2020). There is evidence that game estate management can indirectly benefit biodiversity, for example through woodland protection and maintenance (Oldfield et al. 2003) and on hedgerow networks (Draycott et al. 2012). However, concerns have been raised that the numbers and densities of non-native gamebirds are having widespread negative ecological impacts through a range of direct pressures (predation, browsing, habitat modification) and indirect pressures (impacts on generalist predators, resource competition, illegal persecution and lead ammunition poisoning).Anecdotal evidence suggests that gamebird release may be having a negative impact on UK reptile populations (Edgar et al. 2015; Gardner et al. 2019; Mason et al. 2020). Recent reviews recommend urgent research examining the direct impacts of gamebirds on reptiles (Madden and Sage 2020; Mason et al. 2020) as information is lacking on the effect of gamebirds and their potentially detrimental effects on reptile populations. Against a backdrop of native species decline in the UK (Hayhow et al. 2019), understanding the impacts of large-scale releases of gamebirds represents a major challenge. There is therefore strong justification for studies that aim to produce empirical evidence on the relationship between gamebirds and reptiles.