Functional traits and the mechanisms of species coexistence in an annual plant community

生态学的一个基本目标是了解维持群落内物种多样性的过程。虽然生物学家早就知道，物种之间在诸如鸟喙形状或植物生根深度等性状上的差异可以通过促进专业化和减少竞争来维持群落的多样性，但这一假设的普遍性尚未得到广泛的检验。本研究的目的是评估植物性状，如叶和果实的大小，作为预测的过程，可以导致物种共存或排除物种，通过竞争。该研究将在适应加州特定土壤的植物群落中进行。测试这些性状和共存之间的联系是否可以预测自然群落中性状变异的模式，可以推动生态学领域的发展，因为它将把最近开发的理解物种共存的理论方法与我们对植物功能性状的理解联系起来。 这项研究将有助于预测全球变化对生物多样性的影响，教育和推广活动将改善国家的科学人力资源。该项目将评估植物功能性状如何预测加州蛇纹石土壤上一年生植物群落的竞争结果。 它将在物种相互作用的局部尺度上这样做，也将在环境异质性可能对共存产生重大影响的更广泛的空间和时间尺度上这样做。空间分布的去除和共同的花园实验和观察将用于参数化模型和测试假设的特点（例如，比叶面积、叶氮含量和综合水分利用效率）和适合度。 邻里相互作用实验将在数学模型中参数化竞争系数，这将是使用与零模型的比较进行进一步假设检验的基础。在更广泛的空间尺度上，人口过程（例如，种子生产、发芽和存活）和植物功能性状将在一系列生物和非生物梯度上进行测量。 对这些观察结果和相互作用实验结果的分析将评估该模型在环境异质性的自然条件下的适用程度;统计分析将在多个尺度上使用零模型进行性状分散模式。 从理论上讲，这项研究将把性状与稳定的生态位差异和平均适应度差异联系起来，这些差异实际上推动了共存、竞争排斥和社区模式。该项目代表了一个显着的进步，在以前的研究中，坚定地将功能性状纳入物种共存的框架，一个框架，适用于广泛的问题，在社区生态。该项目将支持培训和指导一名博士后研究员和一名研究生;促进学生之间的国际合作;加强本科教育;并为早期职业科学家开展外联活动。

A fundamental aim of ecology is to understand the processes that maintain species diversity within communities. While biologists have long understood that differences between species in traits such as a bird's bill shape or the rooting depth of plants can maintain diversity in communities by promoting specialization and reducing competition, the generality of this assumption has not been widely tested. The goal of this research is to evaluate plant traits, such as leaf and fruit sizes, as predictors of the processes that can lead to either species coexistence or the exclusion of species though competition. The research will be conducted in a plant community adapted to specific soils in California. Testing if the links between such traits and coexistence can predict patterns of trait variation in natural communities can advance the field of ecology because it will link recently developed theoretical approaches for understanding species coexistence with advances in our understanding of plant functional traits. This research will help to anticipate the effects of global changes on biodiversity, and education and outreach activities will improve the nation's scientific human resources.The project will evaluate how plant functional traits predict competitive outcomes in annual plant communities on serpentine soils in California. It will do so at the local scales of species interaction and also at broader spatial and temporal scales where environmental heterogeneity can substantially influence coexistence. Spatially distributed removal and common garden experiments and observations will be used to parameterize models and test hypotheses on traits (e.g., specific leaf area, leaf N content, and integrated water use efficiency) and fitness at multiple scales. A neighborhood interaction experiment will parameterize competition coefficients in a mathematical model, which will be a basis for further hypothesis testing using comparisons to null models. At a broader spatial scale, population processes (e.g., seed production, germination, and survival) and plant functional traits will be measured across a range of biotic and abiotic gradients. Analyses of both these observations and the results of the interaction experiments will evaluate how well the model applies to natural conditions of environmental heterogeneity; the statistical analyses will use null models for trait dispersion patterns at multiple scales. Theoretically, the study will connect traits to the stabilizing niche differences and average fitness differences that actually drive coexistence, competitive exclusion, and community pattern. The project represents a significant advance over previous studies by firmly incorporating functional traits into the species coexistence framework, a framework that applies to a wide range of problems in community ecology. This project will support the training and mentoring of one postdoctoral researcher and one graduate student; foster international collaboration between students; augment undergraduate education; and develop outreach for early career scientists.