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边缘。我们准备解释捕食率的复杂决定因素，以及捕食者觅食行为和捕食者-捕食者相互作用等因素是如何驱动这些决定因素的，并阐述非消耗性捕食者效应(即感知捕食风险，PPR)对猎物生理、行为和种群动态的作用。在这个赠款周期中，我的团队将结合观测研究、野外和实验室实验以及建模练习，全面解决主要的知识差距，并为理解捕食者与猎物的相互作用建立新的基础。我们将在加拿大山猫、郊狼及其主要猎物(雪鞋兔)上使用基于卫星的遥测和加速测量来测试：1)捕食率是否取决于比率，以及这在捕食者和猎物物种之间有何不同；2)捕食者的运动是否符合流行的觅食理论，以及这如何随着野兔丰度的周期性波动而变化；3)捕食者的猎物切换是否对应于对猎物物种比例变化的主动选择与被动反应；以及4)野兔对捕食风险的实验和自然变化的生理行为反应。将通过较低的野兔种群来监测PPR增加对幼兔的母体影响，以确定成年和/或新招募人员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，在该系统中，我们将操纵捕食者-猎物的相互作用，并解决与捕食者的消耗效应有关的长期存在的问题，这些捕食者在该系统中具有很高的可驯性。重要的是，蜻蜓-蝌蚪系统还将用于评估在使用该系统的实验室研究中如此普遍的PPR反应是否可在现场复制。第二个捕食者-猎物模型系统(原生生物-藻类)将解决长期存在的谜团，即捕食者的非消耗性效应是否会影响捕食者-猎物的种群动态。这些研究将为该系统中捕食者的消耗性和非消耗性效应的种群模型的发展和参数化提供信息，该模型将扩展到捕食者(和PPR)对雪鞋兔种群周期的影响的相关模型。总的来说，这些努力将把理论和数据结合起来，以解释迄今为止尚未解决的支配捕食者-猎物相互作用的基本机制。这将为我们对捕食作为生态系统中的主导力量的理解取得重大突破奠定基础。这项工作还将培训HQP进行强有力的科学调查，并应用新的方法来解决以前难以解决的生态问题。

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.