Data from: Testing the prey-trap hypothesis at two wildlife conservancies in Kenya

Protecting an endangered and highly poached species can conflict with providing an open and ecologically connected landscape for coexisting species. In Kenya, about half of the black rhino (Diceros bicornis) live in electrically fenced private conservancies. Purpose-built fence-gaps permit some landscape connectivity for elephant while restricting rhino from escaping. We monitored the usage patterns at these gaps by motion-triggered cameras and found high traffic volumes and predictable patterns of prey movement. The prey-trap hypothesis (PTH) proposes that predators exploit this predictable prey movement. We tested the PTH at two semi-porous reserves using two different methods: a spatial analysis and a temporal analysis. Using spatial analysis, we mapped the location of predation events with GPS and looked for concentration of kill sites near the gaps as well as conducting clustering and hot spot analysis to determine areas of statistically significant predation clustering. Using temporal analysis, we examined the time lapse between the passage of prey and predator and searched for evidence of active prey seeking and/or predator avoidance. We found no support for the PTH and conclude that the design of the fence-gaps is well suited to promoting connectivity in these types of conservancies.

保护濒危且遭大肆偷猎的物种，可能与为共存物种打造开放且生态连通的景观的目标产生冲突。在肯尼亚，约有一半的黑犀牛（Diceros bicornis）栖息于带有电网围栏的私人保护区内。专门设置的围栏缺口，既为大象保留了一定的景观连通性，又能防止黑犀牛逃脱。我们通过红外触发相机（motion-triggered cameras）监测了这些围栏缺口的使用模式，发现此处动物通行量颇高，且猎物移动呈现出可预测的规律。猎物陷阱假说（prey-trap hypothesis, PTH）提出，捕食者会利用这种可预测的猎物移动模式。我们在两处半渗透性保护区内，通过空间分析与时间分析两种不同方法对该假说进行了验证：在空间分析环节，我们借助GPS记录捕食事件的发生位置，检视围栏缺口附近是否存在猎杀位点聚集现象，并通过聚类分析与热点分析，确定具有统计学显著性的捕食聚集区域；在时间分析环节，我们考察了猎物与捕食者通过缺口的时间间隔，并搜寻捕食者主动追踪猎物，抑或猎物规避捕食者的相关证据。本研究未发现支持该假说的证据，并据此认为，此类围栏缺口的设计十分适合在这类保护区中提升景观连通性。