Data from: Evidence for nonconsumptive effects from a large predator in an ungulate prey?

Pedators can indirectly affect prey survival and reproduction by evoking costly anti-predator responses. Such non-consumptive effects may be as strong or stronger than consumptive predator effects. However, evidence for this in large terrestrial vertebrate systems is equivocal and few studies quantify the actual fitness costs of non-consumptive effects. Here we investigated whether non-consumptive effects elicited by Eurasian lynx (Lynx lynx), a large terrestrial predator, reduced survival in an ungulate prey, the European roe deer (Capreolus capreolus). To reveal the behavioral processes underlying non-consumptive effects, we distinguished between proactive risk avoidance of areas with high lynx encounter probability, and reactive risk avoidance in response to actual lynx encounters and analyzed these responses using step selection functions. We also quantified the consequences of these behaviors for deer survival. Deer reacted differently at day and at night, but avoided high-risk areas proactively during the day and at night in the summer. During a predator encounter, deer increased avoidance of high-risk areas at night but not during the day. Thus, roe deer exhibited a behavioral response race that involved temporally and spatially varying tradeoffs with environmental constraints. We found evidence that non-consumptive effects of lynx predation risk reduced deer survival and that survival was more sensitive to variation in non-consumptive effects of lynx than to variation in human proximity. Our findings highlight that non-consumptive effects may depend on the spatiotemporal distribution of risks and the environmental context, and we discuss how human factors contribute to predator-prey dynamics in human dominated landscapes.

捕食者可通过触发代价高昂的反捕食响应，间接影响猎物的存活与繁殖。此类非消耗效应（non-consumptive effects）的强度可与消耗性捕食效应相当，甚至更强。但目前针对大型陆生脊椎动物系统的相关研究证据尚不明确，且鲜有研究量化非消耗效应的实际适合度代价（fitness costs）。本研究聚焦大型陆生捕食者欧亚猞猁（Lynx lynx），旨在探究其引发的非消耗效应是否会降低其有蹄类猎物——欧洲狍（Capreolus capreolus）的存活概率。为揭示非消耗效应背后的行为机制，我们将风险规避行为划分为两类：一是主动规避猞猁遭遇概率较高的区域，二是针对实际遭遇猞猁的反应性风险规避，并通过步选择函数（step selection functions）对上述两类行为响应进行分析。此外，我们还量化了这些行为对狍存活状况的影响。研究发现，狍在昼夜间的行为响应存在显著差异：夏季无论昼夜，狍均会主动规避高风险区域；而在实际遭遇捕食者时，狍仅在夜间会进一步强化对高风险区域的规避，日间则无此类变化。由此可见，欧洲狍展现出一种随时间与空间动态调整的行为响应权衡策略，需平衡各类环境约束。本研究证实，猞猁捕食风险带来的非消耗效应会降低狍的存活概率，且狍的存活对猞猁非消耗效应变化的敏感度，高于其对人类活动临近程度变化的敏感度。我们的研究结果凸显了非消耗效应可能依赖于风险的时空分布与环境背景，并讨论了在人类主导的景观中，人类活动因素如何调控捕食者-猎物动态关系。