New perspectives on the consumptive and non-consumptive effects of predators

由于生态学理论、实验室和实地研究以及技术/分析工具的最新进展，我们现在正处于捕食者-猎物生态学重大突破的尖端。我们准备解释捕食率的复杂决定因素，以及这些因素是如何由捕食者觅食行为和捕食者-捕食者相互作用等因素驱动的，以及解决非消耗性捕食者效应（即感知捕食风险，PPR）在猎物生理，行为和种群动态中的作用。在这个拨款周期内，我的团队将结合观察研究、实地和实验室实验以及建模练习，全面解决主要的知识空白，并为理解捕食者-猎物相互作用建立新的基础。我们将在加拿大使用基于卫星的遥测和加速度计来测试猞猁、土狼和它们的主要猎物（雪鞋兔）：1)捕食率是否受比例依赖的影响，以及捕食者和猎物物种之间的差异；2)捕食者的运动是否符合流行的觅食理论，以及这种理论如何随着野兔丰度的周期性波动而变化；3)捕食者的猎物转换是否对应于对猎物种类比例变化的主动选择与被动反应；4)兔对实验和自然捕食风险变化的生理行为反应。小反刍兽疫增加对幼兔的母性影响将通过野兔种群低监测，以确定成年和/或新招募的野兔是否有助于种群恢复。这些研究工作将通过使用模型捕食者-猎物系统（即蜻蜓幼虫-蝌蚪）的实验来支持，在那里我们将操纵捕食者-猎物的相互作用，并解决与在该系统中具有高可驯服性的捕食者的消耗效应相关的长期问题。重要的是，蜻蜓-蝌蚪系统还将用于评估小反刍兽疫反应，这在使用该系统的实验室研究中如此普遍，是否可在现场复制。第二个捕食者-猎物模型系统（原生藻类）将解决长期存在的谜题，即捕食者的非消耗效应是否会单独影响捕食者-猎物种群动态。这些调查将为该系统中捕食者捕食和非捕食效应的种群模型的发展和参数化提供信息，并将其扩展到捕食（和PPR）对雪靴兔种群周期影响的相关模型。总的来说，这些努力将结合理论和数据来解释迄今为止尚未解决的控制捕食者-猎物相互作用的基本机制。这将为我们对捕食在生态系统中起主导作用的理解取得重大突破奠定基础。这项工作还将训练HQP在强大的科学调查和应用新方法来解决以前棘手的生态问题。

Owing to recent advances in ecological theory, lab and field studies, and technological/analytical tools, we are now at the cusp of major breakthroughs in predator-prey ecology. We are poised to explain the complex determinants of predation rate and how these are driven by factors like predator foraging behaviour and predator-predator interactions, as well as address the role of non-consumptive predator effects (i.e., perceived predation risk, PPR) on prey physiology, behaviour, and population dynamics. During this grant cycle my team will combine observational studies, field and lab experiments, and modelling exercises, to comprehensively address major knowledge gaps and establish a new basis for understanding predator-prey interactions. We will use satellite-based telemetry and accelerometry in Canada lynx, coyotes, and their primary prey (snowshoe hare) to test: 1) Whether predation rates are subject to ratio dependence and how this differs across predator and prey species; 2) If predator movements conform to prevailing foraging theory and how this varies with cyclic fluctuation in hare abundance; 3) If prey switching by predators corresponds to active choice vs. passive response to a change in prey species ratio; and 4) Physio-behavioural responses of hares to experimental and natural changes in predation risk. Maternal effects of increased PPR on juvenile hares will be monitored through a hare population low to determine whether adults and/or new recruits contribute to population recovery. These research efforts will be bolstered by experiments using a model predator-prey system (i.e., dragonfly larvae-tadpole), where we will manipulate predator-prey interactions and address longstanding questions related to consumptive effects of predators that have high tractability in this system. Importantly, the dragonfly-tadpole system also will serve to assess whether PPR responses, which are so prevalent in lab studies using this system, are replicable in the field. A second predator-prey model system (protist-alga), will address the longstanding enigma of whether non-consumptive effects of predators alone can affect predator-prey population dynamics. These investigations will inform the development and parameterization of a population model of the consumptive and non-consumptive effects of predators in this system, which will be extended to a related model of the effects of predation (and PPR) on the snowshoe hare population cycle. Collectively, these efforts will merge theory and data to explain fundamental mechanisms governing predator-prey interactions that to date have gone unresolved. This will set the stage for major breakthroughs in our understanding of predation as a dominant force in ecosystems. This work also will train HQP in robust scientific investigation and the application of novel approaches to address previously intractable ecological questions.