Department of Environmental Science, Policy, and Management, University of California-Berkeley, Berkeley, California, 94720, USA.
INIBIOMA, CONICET-Universidad Nacional Comahue, Bariloche, 8400, Argentina.
Ecology. 2019 Jul;100(7):e02724. doi: 10.1002/ecy.2724. Epub 2019 Jun 3.
The spatial relationship between predator and prey is often conceptualized as a behavioral response race, in which prey avoid predators while predators track prey. Limiting habitat types can create spatial anchors for prey or predators, influencing the likelihood that the predator or prey response will dominate. Joint spatial anchors emerge when predator and prey occupy similar feeding habitat domains and risk and reward become spatially conflated, confusing predictions of which player will win the space race. These spatial dynamics of risk-foraging trade-offs are often obscured by habitat heterogeneity and community complexity in large vertebrate systems, fueling ambiguity regarding the generality of predictions from predator-prey theory. To test how habitat distribution influences the predator-prey space race, we examine correlation in puma and vicuña habitat selection and space use at two sites, one of which generates a distinct risk-foraging trade-off at a joint spatial anchor. The distribution of vegetation, which serves as both forage for vicuñas and stalking cover for pumas, differs between the sites; the llano contains a single central meadow that acts as a joint spatial anchor, while the canyon is characterized by more heterogeneous vegetation. Puma-vicuña habitat selection correlation was positive in the llano and negative in the canyon, and similarly, utilization distributions were more strongly correlated in the llano than the canyon. Vicuña locations occurred at higher values of puma habitat selection and utilization in the llano than in the canyon. Similarly, puma locations in the llano occurred at higher values of vicuña habitat selection and utilization than in the canyon. Although pumas consistently selected for and utilized vegetative and topographic cover regardless of habitat distribution, vicuñas only selected against vegetation in the heterogeneous canyon site, reducing spatial correlation with pumas. Our work suggests a joint spatial anchor favors pumas in the space race due to the inability for vicuñas to avoid crucial foraging habitat. The outcome of the predator-prey space race appears to be strongly informed by the distribution of habitat, whereby corresponding predictability of predator and prey favors predators in the spatial game.
捕食者和猎物之间的空间关系通常被概念化为一种行为反应竞赛，其中猎物躲避捕食者，而捕食者追踪猎物。限制栖息地类型可以为猎物或捕食者创造空间锚点，影响捕食者或猎物反应占主导地位的可能性。当捕食者和猎物占据相似的觅食栖息地域并且风险和回报在空间上变得混淆时，就会出现联合空间锚点，这使得预测谁将赢得空间竞赛变得复杂。在大型脊椎动物系统中，栖息地异质性和群落复杂性常常掩盖了这种风险觅食权衡的空间动态，这使得捕食者-猎物理论的预测的普遍性存在模糊性。为了检验栖息地分布如何影响捕食者-猎物的空间竞赛，我们在两个地点检查美洲狮和骆马的栖息地选择和空间利用的相关性，其中一个地点在一个联合的空间锚点产生明显的风险觅食权衡。植被的分布作为骆马的饲料和美洲狮的 stalking 掩护，在两个地点都有所不同；llano 只有一个中央草地作为联合空间锚点，而峡谷则以更加异质的植被为特征。在 llano 中，美洲狮-骆马的栖息地选择相关性为正，而在峡谷中则为负，同样，利用分布在 llano 中比在峡谷中更强烈地相关。在 llano 中，骆马的位置比在峡谷中的美洲狮的栖息地选择和利用的位置更高。同样，在 llano 中，美洲狮的位置比在峡谷中的骆马的栖息地选择和利用的位置更高。尽管美洲狮始终选择植被和地形覆盖，无论栖息地分布如何，而骆马仅在异质峡谷地点选择不利用植被，从而降低了与美洲狮的空间相关性。我们的工作表明，由于骆马无法避免关键的觅食栖息地，联合空间锚点有利于空间竞赛中的美洲狮。捕食者-猎物空间竞赛的结果似乎强烈受到栖息地分布的影响，在空间游戏中，捕食者和猎物的对应可预测性有利于捕食者。
