Predation risk and habitat selection in culturally significant herbivores of the boreal forest

这项建议涉及一项关于食物链结构的研究，通过将安大略省北方狼占主导地位的地区的食草动物觅食和行为与纽芬兰地区的食草动物觅食和行为进行对比，在纽芬兰地区，狼不存在，郊狼是最近到达的。被选为研究对象的食草动物，驼鹿和海狸，是北方森林生态系统中的主导动物，也具有重要的文化意义，例如狩猎和诱捕资源。这项研究强调了在北方森林中自上而下(捕食者)影响的问题，自然和人为干扰在改变捕食者-捕食者动态中的作用以及在植被和土壤中明显的持久的自上而下的影响。例如，一个关键的假设是，海狸和驼鹿的选择性觅食改变了土壤养分的可获得性，间接限制了植物的生长，在没有其他干扰的情况下，特别是在没有捕食者的情况下，这种间接影响通过改变土壤过程对食草动物本身变得有限。捕食者的存在调节了这种影响，而驼鹿和海狸通过栖息地的变化从长期来看是间接的竞争者。通过地区之间的比较，验证这些假设可能会填补资源管理方面的知识空白。这项研究建议让四名学生参与土壤调查、植被调查、无线电跟踪和现有GPS遥测数据的分析，以及基本发现的问题。这项建议的一个基本前提是，捕食者和食草动物之间通过特征调节的相互作用是足够的，但作为潜在的自上而下的陆地生态系统影响，这种相互作用还没有得到充分的探索。这种相互作用将包括在捕食者存在的情况下觅食行为的变化，这些捕食者的进化使得食草动物的密度低于仅靠捕食限制种群的情况。此外，这项研究还比较了捕食、诱捕和森林干扰在特定地区的相对影响，在这些地区，海狸群体的持久性和种群动态将被探索。

This proposal involves a study of how food chains are structured, by contrasting herbivore foraging and behaviour in areas of the Northern Boreal Initiative (a development frontier) in Ontario, where wolves dominate, to areas of Newfoundland, where wolves are absent and coyotes are recent arrivals.  The herbivores chosen for study, moose and beaver, are dominants in the boreal forest ecosystem and also culturally significant, for example, as hunting and trapping resources.  This study emphasizes questions of the case for top-down (predator) effects in the boreal forest, the role for natural and anthropogenic disturbances in changing predator-prey dynamics, and enduring top-down effects evident in vegetation and in soils.  A key hypothesis, for example, is that selective foraging by beavers and moose alters soil nutrient availability, indirectly limiting plant growth, and that in the absence of other disturbances and especially in the absence of predators, this indirect effect becomes limiting to the herbivores themselves via changes to soil processes.  The presence of predators regulates this effect, while moose and beavers are indirect competitors over the long term via changes to habitat.  Testing these hypotheses potentially fills a knowledge gap in resource management through comparisons among regions. This study proposes to engage four students in soil survey, vegetation survey, analysis of radio-tracking and existing GPS telemetry data, as well as in questions of fundamental discovery.  A basic premise of this proposal is that trait-mediated interactions among predators and herbivores are sufficient yet under-explored as potential top-down terrestrial ecosystem effects.  Such interactions would include changes in foraging behaviour in the presence of predators that evolve such that herbivore density is lower than it would be if predation alone were limiting populations.  This study also contrasts the relative effects of predation, trapping and forest disturbances in specific areas where persistence and population dynamics of beaver colonies will be explored.