Data_Sheet_1_Small Prey Animal Foraging Behaviors in Landscapes of Fear: Effects of Predator Presence and Human Activity Along an Urban Disturbance Gradient.pdf

Urban environments provide the only or best habitats that are left for wildlife in many areas, promoting increased interest in urban conservation and a need to understand how wildlife cope with urban stressors, such as altered predator activity and human disturbance. Here, we used filmed giving-up density experiments to investigate behavioral coping responses of foraging small prey animals at three sites (close, mid, and far) along an urban disturbance gradient. Our study design included “natural” and experimentally added stressor cues of predators and/or human disturbance. We observed small mammal foraging behaviors, particularly: the common brushtail possum (Trichosurus vulpecula), northern brown bandicoot (Isoodon macrourus), brown antechinus (Antechinus stuartii), black rat (Rattus rattus), and brown rat (Rattus norvegicus), and to a lesser degree several species of native birds. We found that at the close urban-edge environment, coping responses to human disturbances were most pronounced, and predator cues from the red fox (Vulpes vulpes) were perceived as least risky. However, at the mid environment, red fox cues were perceived as most risky, especially when combined with human disturbance. At the far environment, domestic cat (Felis catus) cues were perceived as most risky, again when combined with human disturbance. Impacts from the combined stressors of predator and human disturbance cues appeared to be additive, with higher risk being perceived with increasing distance from urban build-up. Behavioral adjustments were observed to be the primary response to stressors by small prey animals in the close environment. In the mid environment, slight temporal shifts in activity across the night were more evident. In the far environment, habitat components were likely being used differently as the primary coping response to stressors. As mostly the same species were observed along the disturbance gradient, our results suggest a level of response plasticity that is calibrated to the level of exposure to a stressor and the stressor type. To maximize conservation outcomes in urban habitats, we therefore propose that management should be sensitive to the level and history of human disturbance, as this affects the coping responses of wildlife that remain.

在诸多区域中，城市环境已成为野生动物仅剩的乃至最优的栖息生境，这推动了城市保护研究热度的提升，也使得人们亟需了解野生动物如何应对城市环境中的胁迫因子——如捕食者活动模式改变与人类活动干扰。本研究采用摄像记录式弃食密度（giving-up density）实验，探究沿城市干扰梯度设置的近、中、远三个样地中，觅食中的小型猎物动物的行为应对策略。本研究的实验设计包含两类胁迫线索：一是“自然”状态下的捕食者及人类干扰信号，二是实验人为添加的捕食者与/或人类干扰胁迫信号。

本研究观测到的小型哺乳动物觅食行为包括：刷尾负鼠（*Trichosurus vulpecula*）、北棕袋狸（*Isoodon macrourus*）、褐袋鼩（*Antechinus stuartii*）、黑鼠（*Rattus rattus*）与褐家鼠（*Rattus norvegicus*），同时也观测到少量本土鸟类类群的相关行为。研究结果显示：在紧邻城市建成区的生境中，小型动物对人类干扰的行为响应最为显著，而赤狐（*Vulpes vulpes*）的捕食者信号被判定为风险最低。而在中度干扰生境中，赤狐的捕食信号被视为风险最高的胁迫源，尤其是当该信号与人类干扰同时存在时。在远离城市建成区的生境中，家猫（*Felis catus*）的捕食信号被判定为风险最高的胁迫源，同样在与人类干扰叠加时风险感知最为强烈。

捕食者与人类干扰两类胁迫信号的叠加影响呈现加和效应，且动物对风险的感知强度随距城市建成区距离的增加而提升。在紧邻城市的生境中，小型猎物动物应对胁迫的主要策略为行为调整；在中度干扰生境中，动物夜间活动的时间小幅偏移现象更为普遍；而在远郊生境中，改变栖息地组分利用方式则成为应对胁迫的主要策略。由于沿城市干扰梯度观测到的物种类群基本一致，本研究结果表明，小型猎物动物具备与胁迫暴露程度及胁迫类型相匹配的响应可塑性。为最大化城市生境的保护成效，本研究建议城市管理工作应充分考量人类干扰的强度与历史背景——这会显著影响留存于城市生境中的野生动物的胁迫应对策略。