Data from: Phantoms of the forest: legacy risk effects of a regionally extinct large carnivore

The increased abundance of large carnivores in Europe is a conservation success, but the impact on the behavior and population dynamics of prey species is generally unknown. In Europe, the recolonization of large carnivores often occurs in areas where humans have greatly modified the landscape through forestry or agriculture. Currently, we poorly understand the effects of recolonizing large carnivores on extant prey species in anthropogenic landscapes. Here, we investigated if ungulate prey species showed innate responses to the scent of a regionally exterminated but native large carnivore, and whether the responses were affected by human-induced habitat openness. We experimentally introduced brown bear Ursus arctos scent to artificial feeding sites and used camera traps to document the responses of three sympatric ungulate species. In addition to controls without scent, reindeer scent Rangifer tarandus was used as a noncarnivore, novel control scent. Fallow deer Dama dama strongly avoided areas with bear scent. In the presence of bear scent, all ungulate species generally used open sites more than closed sites, whereas the opposite was observed at sites with reindeer scent or without scent. The opening of forest habitat by human practices, such as forestry and agriculture, creates a larger gradient in habitat openness than available in relatively unaffected closed forest systems, which may create opportunities for prey to alter their habitat selection and reduce predation risk in human-modified systems that do not exist in more natural forest systems. Increased knowledge about antipredator responses in areas subjected to anthropogenic change is important because these responses may affect prey population dynamics, lower trophic levels, and attitudes toward large carnivores. These aspects may be of particular relevance in the light of the increasing wildlife populations across much of Europe.

欧洲大型食肉动物（large carnivores）种群丰度的提升是一项保护领域的成功案例，但其对猎物种群行为与种群动态的影响目前普遍尚不明确。在欧洲，大型食肉动物的重新定居往往发生在人类通过林业或农业活动极大改造了景观的区域。当前，我们对重新定居的大型食肉动物在人为景观中对现存猎物种群产生的影响仍知之甚少。本研究旨在探究有蹄类猎物（ungulate prey）是否会对区域性灭绝但本土原生的大型食肉动物的气味展现出先天防御反应，以及此类反应是否会受到人类活动导致的栖息地开阔度的影响。我们通过实验将棕熊（Ursus arctos）的气味投放至人工投喂点，并利用相机陷阱（camera traps）记录三种同域分布的有蹄类动物的反应。除无气味对照组外，我们还使用了驯鹿（Rangifer tarandus）的气味作为非食肉动物的新奇对照气味。黇鹿（Dama dama）会显著规避带有熊气味的区域。当存在熊气味时，所有有蹄类动物相较于封闭生境，更倾向于利用开阔生境；而在驯鹿气味组或无气味对照组中，观测到的结果恰好相反。人类通过林业、农业等活动对森林生境的开垦，使得栖息地开阔度的梯度相较于未受显著干扰的封闭森林系统更为显著，这为猎物提供了改变栖息地选择的机会，从而在人类改造的生态系统中降低被捕食风险——这类风险规避策略在更为天然的森林系统中并不存在。增强对受人为活动影响区域内猎物反捕食反应的认知至关重要，因为此类反应可能会影响猎物种群动态、低营养级生物群落，以及公众对大型食肉动物的态度。考虑到欧洲大部分地区的野生动物种群正持续增长，上述研究议题的相关意义尤为突出。