Dissertation Research: Quantitative Interaction Strengths in Omnivorous Food Webs Across a Gradient in Primary Productivity

尽管杂食动物在自然界中无处不在，但人们对杂食动物影响其食物网的稳定性和功能的方式仍知之甚少。过去的研究主要采用两种方法：数学建模和观察摄食关系以定性重建食物网。这些方法产生了关于杂食动物重要性的相互矛盾的预测，以至于对杂食动物如何影响他们的社区的机械性理解仍然没有实现。然而，将食物网的功能与群落的生产力联系起来的开创性的生态学概念模型依赖于关于杂食动物所扮演角色的强有力的假设。这里提出的研究采用了一种基于观察的方法来量化新西兰潮间带食物网中沿着自然生产力梯度的物种相互作用的强度。因此，该项目将对杂食性物种影响其群落的机制的关键预测提供亟需的评估。除了在食物网生态学的理论和经验领域之间提供迫切需要的联系，这是为保护和资源利用实践所必需的，该研究项目还将极大地有助于我们对世界上这一未被研究的地区的自然历史知识。在这样做的过程中，它将与其他大陆更广泛研究的潮间带系统形成信息对比。

Despite their ubiquity in nature, the manner by which omnivores affect the stability and functioning of their food webs remains poorly understood. Two approaches have predominated past investigations: mathematical modeling, and the observation of feeding relationships to qualitatively reconstruct food webs. These approaches have produced conflicting predictions regarding the importance of omnivory such that a mechanistic understanding of how omnivores affect their communities remains unrealized. Seminal conceptual models of ecology that relate the functioning of food webs to the productivity of their communities rely on strong assumptions about the role that omnivores play however. The research proposed here employs an observation-based approach to quantify the strength of species interactions in food webs of the New Zealand intertidal along a natural productivity gradient. This project will thus provide a much needed assessment of key predictions concerning the mechanisms by which omnivorous species affect their communities.Aside from providing the much needed link between the theoretical and empirical realms of food web ecology that is necessary to inform conservation and resource-use practices, this research project will contribute greatly to our natural history knowledge of this understudied region of the world. In doing so, it will provide an informative contrast to the more extensively studied intertidal systems of other continents.