EAGER: Explaining species coexistence from first principles of ecology

物种共存长期以来一直令生态学家着迷。认为一个物种应该比其他物种更善于在环境中发挥作用并成为优势物种似乎是合理的，然而，在自然界中并不总是如此。植物物种通常大量共存于自然系统中，这种多样性有助于许多重要的生态系统服务，包括土壤保持、附近作物的授粉和碳储存。我们预测物种共存的能力是有限的。已经发展了许多理论来解释为什么植物物种在我们所处的特定环境下可能共存，但没有一个能够直接从生态学的基本原理，即支配生态系统普遍功能的基本机制来预测共存。为了预测全球生态系统将如何对环境变异性做出反应，从而进一步影响环境变异性，我们需要在这个基本层面上了解它们。将开发新的理论模型，并将依赖于扩展的生态学第一原理。这项研究将培养数学生态学方面的研究生和博士后研究员。此外，这项研究将在假设检验和研究方面吸引高中教师并对其进行培训。这项研究将调查三种特定机制在产生物种共存中的作用：演替动力学(由于干扰事件后植物群落重新生长而导致的环境变化)，植物-食草动物相互作用(植物及其天敌的共同进化)，以及进化优化的限制(小样本和环境变化的现实，使植物无法进化成适合特定环境的完美物种)。这项研究将建立植物之间及其环境之间相互作用的简单模型。这将只包含反映生态学第一原理的假设：(1)个体增长率和种群规模通常受到资源的限制，(2)资源对环境的投入速率存在差异，(3)物种本身依赖于其他营养水平，受到强大的正生物反馈的驱动，(4)物种受到严格的物理和/或生理约束，以及(5)后代比邻居多的个体更像后代个体的特征(基于个体的竞争或自然选择进化)。这项研究将测试物种共存是否以及如何从这些原则中产生。共存的具体预测将尽可能与数据进行比较。这一奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

The coexistence of species has long fascinated ecologists. It seems reasonable to think that one species should be better at functioning in the environment than others and become dominant, however, this is not always the case in nature. Plant species commonly coexist in natural systems in large numbers, and this diversity contributes to many important ecosystem services, including soil retention, the pollination of nearby crops, and carbon storage. Our ability to predict species coexistence is limited. Many theories have been developed to explain why plant species might coexist under the particular circumstances we find them in, but none is able to predict that coexistence directly from first principles of ecology, i.e. the fundamental mechanisms that govern ecosystem function universally. In order to predict how ecosystems around the globe will react to, and thus further affect, environmental variability, we need to understand them on this fundamental level. New theoretical models will be developed, and will rely on expanded first principles of ecology. The research will result in the training of graduate students as well as a postdoctoral researcher in mathematical ecology. Additionally, the research will engage and train high school teachers in hypothesis testing and research.This research will investigate the role of three specific mechanisms in generating species coexistence: successional dynamics (the changing environment due to regrowth of a plant community that follows a disturbance event), plant-herbivore interactions (the co-evolution of plants and their natural enemies), and limitations to evolutionary optimization (the reality of small sample sizes and changing environments that keep plants from evolving into the perfect species for a specific environment). The research will build simple models of plant interactions with one another and their environment. This will incorporate only assumptions that reflect the first principles of ecology: (1) that individual growth rates and population sizes are generally limited by resources, (2) that there is variation in the input rate of resources to environments, (3) that species depend on other trophic levels, driven in their own right by strong positive biological feedbacks, (4) that there are hard physical and/or physiological constraints on species, and (5) that individuals that have more offspring than their neighbors better resemble the traits of individuals in future generations (individual-based competition or evolution by natural selection). The research will test whether and how species coexistence may arise from these principles. Specific predictions of coexistence will be compared with data wherever possible.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.