What Stabilizes Population Dynamics in Nature? A New Framework for Quantifying the in situ Strength and Nonlinearity of Species Interactions

生态学中的一个基本问题是，物种之间的相互作用(如捕食者-被捕食者)如何导致一些物种随着时间的推移表现出周期性的种群波动，而对于其他物种则不是。为了预测物种及其生态系统将如何应对环境扰动，包括栖息地丧失和气候变化，有必要了解这些机制。这项研究项目将开发新的方法和统计分析，将应用于太平洋西北部的河流群落。研究人员将测试有关物种种群何时会大量循环的假设。目前的理论只能解释最简单的情况，即专业捕食者物种只以一个或几个猎物物种为食。然而，自然界中的大多数物种都是嵌入到物种相互作用的复杂网络中的多面手。这一限制被广泛认为是资源管理和养护做法发展中的一个重大问题。这项工作有望推动一般生态学理论的发展，并解决自然界中捕食者-猎物相互作用的稳定性这个长期存在的难题。该项目的结果将提高我们预测物种对环境干扰的反应的能力，这在野生动物管理和保护中非常重要。该项目还将支持本科生和研究生以及一名博士后研究员的指导和研究培训。通过与俄勒冈州立大学小学伙伴计划的广泛合作，将实现与俄勒冈当地社区的更广泛参与。该计划为小学生提供科学和数学方面的丰富知识，并为他们的教师提供专业发展，以增加在科学、数学、健康、工程和教育领域继续追求职业生涯的未被充分代表和教育不足的学生的数量。这项研究将开发一类新的观察方法，用于评估物种丰富的系统中捕食者与猎物相互作用的强度。在安德鲁斯实验森林长期生态研究场地的溪流群落中，该方法的观测和实验实施将被用来定量比较依赖猎物、依赖消费者和适应觅食的过程对相互作用非线性的经验水平的贡献程度。来自经验的见解将被整合到抽象的数学模型中，以开发关于专家和多面手消费者的动态的一般理论。这项研究有望在我们对捕食者-猎物相互作用调节物种丰富群落动态的机制的概念和应用理解方面取得重大进展。这里将要开发的观测方法的新颖、简单和广泛的适用性承诺了一种连接数学理论和经验数据的变革性新方法。

A fundamental question in ecology is how interactions among species (e.g. predator-prey) cause some species to exhibit cyclic population fluctuations over time while for other species they do not. An understanding of these mechanisms is necessary in order to forecast how species and their ecosystems will respond to environmental perturbations, including habitat loss and climate change. This research project will develop new methods and statistical analyses that will be applied to stream communities of the Pacific Northwest. The investigators will test hypotheses regarding when species populations will cycle in abundance. Current theory can explain only the most simplistic case of specialist predator species that feed on only one or a few prey species. However, most species in nature are generalists embedded in complex networks of species interactions. This limitation is widely acknowledged as a significant problem in the development of resource management and conservation practices. This work promises to advance general ecological theory and resolve a long standing puzzle concerning stability of predator-prey interactions in nature. Results of this project will improve our ability to forecast species responses to environmental disturbances, which is important in wildlife management and conservation. This project also will support the mentoring, and research training of undergraduate and graduate students, and a postdoctoral researcher. Broader involvement with Oregon's local communities will be achieved through an extensive collaboration with Oregon State University's elementary school partnership program, which provides science and math enrichment for elementary school students and professional development for their teachers in order to increase the number of underrepresented and educationally underserved students that go on to pursue careers in science, math, health, engineering, and education.This research will develop a new class of observational methods for estimating the strength of predator-prey interactions in species-rich systems. Observational and experimental implementations of the approach in stream communities of the Andrews Experimental Forest Long Term Ecological Research site will be used to quantitatively compare the degree to which prey-dependent, consumer-dependent and adaptive-foraging processes contribute to empirical levels of interaction nonlinearity. Empirically-derived insights will be integrated into abstracted mathematical models to develop general theory regarding the dynamics of specialist and generalist consumers. This research promises significant advances in our conceptual and applied understanding of the mechanisms by which predator-prey interactions regulate the dynamics of species-rich communities. The novel simplicity and broad applicability of the observational approach to be developed here promises a transformative new way to bridge mathematical theory and empirical data.