Dissertation Research: Examining Anti-predator Cascades Over Four Trophic Levels

捕食者可以以复杂的方式影响猎物种群。例如，捕食食草动物的捕食者可以通过直接消耗食草动物或通过所谓的“非消耗效应”间接减少食草动物对植物群落的压力。 非消耗性效应通常发生在捕食者的存在导致被捕食物种减少进食活动以避免被吃掉的时候。这种反捕食行为对食草动物的生存有重要影响，并可能对植物产生影响，否则这些植物将被食草动物吃掉。由于许多掠食者是杂食性的，既吃植物也吃动物，因此对植物的这种影响更加复杂。这个项目研究了吃种子的地面甲虫和吃种子和地面甲虫的老鼠如何相互影响，并影响一种共同植物（藜）的丰度，它们消耗种子。由于藜是一种重要的农业杂草，这项研究的结果对农民的杂草管理有直接的影响。该项目将为一名研究生提供跨学科培训，并将涉及一名本科生研究员的指导。该项目的概念和结果正在被纳入普渡大学的教学课程，并将在科学会议上提出，以及在农民为重点的农业会议。这项工作也将解释为公众在各种外展活动，包括农场图尔斯，硕士园丁课程，和教育webinars.More具体来说，这个项目将使用一个种子捕食者食物网，以检查环境和行为因素，驱动复杂的捕食者-猎物的相互作用，在多个营养水平。初步数据表明，捕食者介导的啮齿动物使用避难所干扰甲虫的活动和种子去除。甲虫在小鼠存在下的种子去除减少可归因于行会内捕食（消耗效应）或反捕食者警惕（非消耗效应; NCE）。这两个不同的，但不相互排斥的营养途径对植物种群动态有不同的长期影响。这个项目将建立在这些概念的基础上，对种子采集者对捕食风险的反应进行实验。 它将解决三个具体的问题：1）种子捕食受内公会捕食者的NCE？ 2)结构避难所介导的NCE对种子捕食？3)避难栖息地是否影响脊椎动物/无脊椎动物捕食事件的频率？ 该实验将研究granivore觅食行为的种子的quarterters是如何影响的捕食者的存在和可用性的保护覆盖。

Predators can affect prey populations in complex ways. Predators that eat herbivores, for example, can reduce herbivore pressure on plant communities directly by consuming the herbivores or indirectly through what is known as "non-consumptive effects". Non-consumptive effects often occur when the mere presence of a predator causes prey species to reduce feeding activity to avoid being eaten, themselves. This anti-predator behavior has important impacts on herbivore survival and likely on the plants that would otherwise be eaten by the herbivores. Such effects on plants are further complicated by the fact that many predators are omnivorous, feeding on both plants and animals. This project examines how ground beetles, which eat seeds, and mice, which eat both seeds and ground beetles, influence each other and affect the abundance of a common plant (lambsquarters), whose seeds they consume. Because lambsquarters is a weed species of agricultural importance, results of this study have direct implications for weed management by farmers. This project will provide interdisciplinary training for a graduate student and will involve mentorship of an undergraduate researcher. Concepts and results of this project are being integrated into Purdue's teaching curriculum, and will be presented at scientific conferences, as well as at farmer-focused agricultural conferences. This work will also be interpreted for the public at various outreach events including farm tours, Master Gardener courses, and educational webinars.More specifically, this project will use a seed predator food web to examine the environmental and behavioral factors that drive complex predator-prey interactions over multiple trophic levels. Preliminary data suggest that predator-mediated use of refuge by rodents interferes with beetle activity and seed removal. Reductions in seed removal by beetles in the presence of mice could be attributed to intra-guild predation (consumptive effects) or anti-predator vigilance (non-consumptive effects; NCEs). These two distinct, but non-mutually exclusive trophic pathways have different long-term implications for plant population dynamics. This project will build on these concepts with an experiment on seed-foragers' responses to predation risk. It will address three specific questions: 1) Is seed predation affected by NCEs of intra-guild predators? 2) Do structural refuges mediate NCEs on seed predation? 3) Does refuge habitat affect the frequency of vertebrate/invertebrate predation events? The experiment will examine how granivore foraging behavior on seeds of lambsquarters is impacted by the presence of predators and the availability of protective cover.