Ferreira Clara Mendes, Dammhahn Melanie, Eccard Jana A
Animal Ecology, Institute for Biochemistry and Biology University of Potsdam Potsdam Germany.
Behavioural Biology, Institute for Neuro- and Behavioural Biology University of Münster Münster Germany.
Ecol Evol. 2023 Jul 26;13(7):e10330. doi: 10.1002/ece3.10330. eCollection 2023 Jul.
Spatial and temporal variation in perceived predation risk is an important determinant of movement and foraging activity of animals. Foraging in this landscape of fear, individuals need to decide where and when to move, and what resources to choose. Foraging theory predicts the outcome of these decisions based on energetic trade-offs, but complex interactions between perceived predation risk and preferences of foragers for certain functional traits of their resources are rarely considered. Here, we studied the interactive effects of perceived predation risk on food trait preferences and foraging behavior in bank voles () in experimental landscapes. Individuals ( = 19) were subjected for periods of 24 h to two extreme, risk-uniform landscapes (either risky or safe), containing 25 discrete food patches, filled with seeds of four plant species in even amounts. Seeds varied in functional traits: size, nutrients, and shape. We evaluated whether and how risk modifies forager preference for functional traits. We also investigated whether perceived risk and distance from shelter affected giving-up density (GUD), time in patches, and number of patch visits. In safe landscapes, individuals increased time spent in patches, lowered GUD and visited distant patches more often compared to risky landscapes. Individuals preferred bigger seeds independent of risk, but in the safe treatment they preferred fat-rich over carb-rich seeds. Thus, higher densities of resource levels remained in risky landscapes, while in safe landscapes resource density was lower and less diverse due to selective foraging. Our results suggest that the interaction of perceived risk and dietary preference adds an additional layer to the cascading effects of a landscape of fear which affects biodiversity at resource level.
感知到的捕食风险的时空变化是动物运动和觅食活动的重要决定因素。在这种充满恐惧的环境中觅食时，个体需要决定何时何地移动以及选择何种资源。觅食理论基于能量权衡预测这些决策的结果，但很少考虑感知到的捕食风险与觅食者对其资源某些功能特征的偏好之间的复杂相互作用。在这里，我们在实验环境中研究了感知到的捕食风险对银行田鼠食物特征偏好和觅食行为的交互作用。19只个体在24小时内被置于两种极端的、风险一致的环境中（要么有风险，要么安全），环境中有25个离散的食物斑块，均匀地填充着四种植物物种的种子。种子在功能特征上有所不同：大小、营养成分和形状。我们评估了风险是否以及如何改变觅食者对功能特征的偏好。我们还研究了感知到的风险和与庇护所的距离是否会影响放弃密度（GUD）、在斑块中的停留时间以及斑块访问次数。与有风险的环境相比，在安全的环境中，个体在斑块中停留的时间增加，GUD降低，并且更频繁地访问较远的斑块。个体无论风险如何都更喜欢较大的种子，但在安全处理中，它们更喜欢富含脂肪的种子而不是富含碳水化合物的种子。因此，在有风险的环境中资源水平的密度更高，而在安全的环境中，由于选择性觅食，资源密度更低且多样性更少。我们的结果表明，感知到的风险和饮食偏好的相互作用为影响资源水平生物多样性的恐惧景观的级联效应增加了额外的一层。
