Department of Ecosystem and Conservation Sciences, College of Forestry and Conservation, Wildlife Biology Program, University of Montana, Missoula, MT 59812, USA.
Proc Biol Sci. 2012 Nov 22;279(1747):4626-33. doi: 10.1098/rspb.2012.1698. Epub 2012 Sep 12.
Predation risk is an important driver of ecosystems, and local spatial variation in risk can have population-level consequences by affecting multiple components of the predation process. I use resource selection and proportional hazard time-to-event modelling to assess the spatial drivers of two key components of risk--the search rate (i.e. aggregative response) and predation efficiency rate (i.e. functional response)--imposed by wolves (Canis lupus) in a multi-prey system. In my study area, both components of risk increased according to topographic variation, but anthropogenic features affected only the search rate. Predicted models of the cumulative hazard, or risk of a kill, underlying wolf search paths validated well with broad-scale variation in kill rates, suggesting that spatial hazard models provide a means of scaling up from local heterogeneity in predation risk to population-level dynamics in predator-prey systems. Additionally, I estimated an integrated model of relative spatial predation risk as the product of the search and efficiency rates, combining the distinct contributions of spatial heterogeneity to each component of risk.
捕食风险是生态系统的一个重要驱动因素，风险的局部空间变化通过影响捕食过程的多个组成部分，可能对种群水平产生后果。我使用资源选择和比例风险时间事件建模来评估狼（Canis lupus）在多猎物系统中施加的两个关键风险组成部分的空间驱动因素 - 搜索率（即聚集反应）和捕食效率（即功能反应）。在我的研究区域中，风险的两个组成部分都随着地形变化而增加，但人为特征仅影响搜索率。预测的累积风险（即捕杀的风险）模型，或狼搜索路径的风险，与捕杀率的广泛变化吻合良好，这表明空间风险模型为从捕食风险的局部异质性扩展到捕食者-猎物系统的种群水平动态提供了一种手段。此外，我估计了相对空间捕食风险的综合模型，将搜索率和效率率相乘，将空间异质性对每个风险组成部分的独特贡献结合在一起。
