EAGER: Explaining species coexistence from first principles of ecology

物种的共存长期以来一直吸引着生态学家。似乎有理由认为，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，然而，在自然界中并不总是如此。植物物种通常在自然系统中大量共存，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可能在我们发现它们的特定环境下共存，但没有一个能够直接从生态学的第一原则预测共存，即普遍支配生态系统功能的基本机制。为了预测地球仪周围的生态系统将如何对环境变异性作出反应，从而进一步影响环境变异性，我们需要在这一基本层面上了解它们。新的理论模型将被开发出来，并将依赖于扩展的生态学第一原理。这项研究将导致研究生的培训，以及在数学生态学博士后研究员。此外，该研究将参与并培训高中教师进行假设检验和研究。本研究将调查三种特定机制在产生物种共存中的作用：演替动态（由于干扰事件后植物群落的再生而引起的环境变化），植物-草食动物相互作用（植物与天敌的共同进化），以及进化优化的局限性（小样本和不断变化的环境使植物无法进化成适合特定环境的完美物种的现实）。该研究将建立植物相互作用及其环境的简单模型。这将只包含反映生态学第一原则的假设：（1）个体生长率和种群规模通常受到资源的限制，（2）资源对环境的输入率存在变化，（3）物种依赖于其他营养级，由强大的正生物反馈驱动，（4）物种有严格的物理和/或生理限制，（5）比邻居有更多后代的个体更接近后代的个体特征（基于个体的竞争或自然选择的进化）。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。该奖项反映了NSF的法定使命，并通过使用基金会的知识价值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.