SG: Identifying patterns of trait variation that arise from competitive interactions

对稀缺资源的竞争是地球生命的一个基本方面。陆生植物争夺光、水和土壤养分。许多鸟类为了食物和筑巢地点而竞争，在潮间带，贝类为了附着在岩石基底上而竞争。经典生态学理论预测，当竞争很重要时，物种可以通过具有将其资源需求与竞争对手区分开来的特征与其他物种共存。反过来，这一预测导致了这样的假设，即当社区包括分化良好的物种时，竞争必须是一个主导过程。不幸的是，这一假设并不支持现代共存理论的关键方面，该理论已经证明，如果竞争优势很小，即使非常相似的竞争物种也可以共存。该项目将通过开发一个种内竞争的一般生态进化数学模型来解决这一科学争议，在该模型中，竞争与物种特征明确相关，并确定进化稳定的群落。最终，这项工作将导致更好地了解自然群落中生物的分布和丰度，并解决经典和现代理论中的这些差异。此外，本研究将为一名博士后研究人员和一名本科生提供研究培训。理论生态学的教学模块也将为本科生和研究生开发。大多数关于竞争相互作用产生的特征分布的理论工作都假设单个特征（或至多一对特征）决定了竞争者之间的生态位重叠和任何适合度差异。 在这种假设下，顶极群落的特征分布通常表现出过度分散;然而，也有人指出，当它们的适应性差异很小时，相似物种的集群可以在中间的时间尺度上形成（称为“涌现中性”）。该项目将采用竞争的数学模型来比较现代共存理论下出现的性状变异模式与从自然社区收集的数据。该项目将纳入更大程度的生物现实主义比以前的方法，通过调节的程度，生态位差异和健身差异控制相同的性状或不同的性状。生态进化框架内的Lotka-Volterra竞争模型的数值模拟将被用来确定进化稳定的社区。发展的性状分散的模式将使用各种指标进行总结，以展示当性状对适应性有不同程度的控制时，顶极群落的模式和机制。该奖项反映了NSF的法定使命，并被认为值得通过使用基金会的智力价值和更广泛的影响审查标准进行评估来支持。

Competition for scarce resources is a fundamental aspect of life on earth. Terrestrial plants compete for light, water and soil nutrients. Many birds compete for access to food and nesting sites, and in the intertidal zone, shellfish compete for rocky substrate on which to attach themselves. Classic ecological theory predicts that when competition is important, species can coexist with others by having traits that differentiate their resource needs from those of their competitors. In turn, this prediction has led to the hypothesis that when communities comprise well differentiated species, competition must be a dominant process. Unfortunately, this hypothesis does not support key aspects of modern coexistence theory, which has demonstrated that even very similar competing species can coexist if the competitive advantage is small. This project will address this scientific controversy by developing a general eco-evolutionary mathematical model of intraspecific competition in which competition is explicitly linked to species traits and evolutionarily stable communities are identified. Ultimately, this work will lead to a better understanding of the distribution and abundance of organisms in natural communities and resolve these discrepancies in classic and modern theory. Additionally, this research will provide research training for a postdoctoral researcher and an undergraduate student. A teaching module in theoretical ecology will also be developed for undergraduate and graduate students.Most of the theoretical work on trait distributions arising from competitive interactions has assumed that a single trait (or at most a pair of traits) determines both the niche overlap and any fitness differences among competitors. Under this assumption, trait distributions of climax communities generally demonstrate over-dispersion; however, it has also been shown that clumps of similar species can form at intermediate time-scales when their fitness differences are small (termed "emergent neutrality"). This project will employ mathematical models of competition to compare patterns of trait variation that emerge under modern coexistence theory to data collected from natural communities. This project will incorporate a greater degree of biological realism than previous approaches, by modulating the extent to which niche differences and fitness differences are controlled by the same trait or different traits. Numerical simulations of a Lotka-Volterra competition model within an eco-evolutionary framework will be used to identify evolutionarily stable communities. The patterns of trait dispersion that develop will be summarized using a variety of metrics to demonstrate the patterns and mechanisms that underlie climax communities when traits have varying degrees of control over fitness.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.