Collaborative research: Measuring and modeling the ecological consequences of associational effects

该项目将研究害虫如何在不同植物物种组合的背景下影响单个植物种群。当昆虫寻找吃的植物时，它们会受到周围植物的外观和气味的影响。相邻植物既可以增加也可以减少昆虫对植物的伤害，这种现象被称为关联效应（associational effects， AE）。虽然很明显，关联效应可以在单个植物的水平上发生，但对于这些效应是否重要到足以改变自然界中的植物种群，或者它们在多大程度上影响农田中的作物产量，人们知之甚少。该项目将使用短期实验结合数学模型来推断关联效应如何影响本地植物种群。本项目开发的方法也可用于确定如何利用关联效应使作物产量最大化。该项目将为本科生、研究生和博士后学生以及一名学士后技术员提供STEM培训，研究人员将与K-12教师合作，开发利用学校花园和羽衣甘蓝和芥菜等作物之间的关联效应教授科学的活动。该项目将结合数学模型和实验来研究关联效应是否以及如何影响旧田系统中植物种间竞争（共存和/或相对丰度）的结果，并以卡罗莱纳马属植物（Solanum carolinense）和一枝黄花（Solidago altissima）为焦点物种。该项目将从经验上解决三个问题：1)声发射在该系统中的空间尺度是什么？（采用Nelder风机设计现场实验）2)多物种声发射是如何组合的？（使用单种、双种和三种不同密度的实验）和3)关联效应如何影响竞争（使用之前有和没有食草动物的竞争实验的数据）。空间隐式和显式模型将解决植物空间结构和频率依赖形式如何改变声发射对植物种群的预测效应。研究人员将使用来自实证研究的数据来参数化模型，以测试关联效应如何扩大到人口水平。总体而言，该项目将首次直接量化关联效应如何影响植物竞争，并为理解不同形式的关联效应如何影响不同类型消费者-资源系统中的种群水平过程提供一个总体框架。该项目还将建议如何最好地操纵农业中的关联效应，以最大限度地提高作物产量。

This project will study how insect pests affect individual plant populations within the context of diverse assemblages of plant species. When insects search for plants to eat, they can be influenced by the look and smell of surrounding plants. Neighboring plants can both increase and decrease insect damage to plants, and the term for this is associational effects (AE). Although it is clear that associational effects can occur at the level of individual plants, little is known about whether these effects are important enough to alter plant populations in nature, or to what degree they contribute to affecting crop yield in agricultural fields. This project will use short-term experiments in combination with mathematical models to infer how associational effects influence populations of native plants. The methods developed in this project can also be used to determine how to use associational effects to maximize crop yields. The project will provide STEM training for undergraduate, graduate and postdoctoral students and a post-baccalaureate technician, and the researchers will partner with K-12 teachers to develop activities for teaching science using school gardens and associational effects between crops such as collards and mustards. This project will combine mathematical models and experiments to address whether and how associational effects influence the outcome of plant interspecific competition (coexistence and/or relative abundance) in an old-field system, using Solanum carolinense (Carolina horsenettle) and Solidago altissima (goldenrod) as focal species. The project will address three questions empirically: 1) What is the spatial scale of AE in this system? (using a Nelder fan design field experiment) 2) How do AE from multiple species combine? (using an experiment with monocultures, bicultures, and tricultures at two different densities) and 3) how do associational effects influence competition (using data from a previous competition experiment with and without herbivores). Spatially implicit and explicit models will address how plant spatial structure and the form of frequency dependence alter predicted effects of AE on plant populations. The researchers will parameterize models using data from the empirical studies to test how associational effects scale up to the population level. Overall, this project will quantify directly for the first time how associational effects influence plant competition and provide a general framework for understanding how different forms of associational effects influence population-level processes across different types of consumer-resource systems. This project will also suggest how best to manipulate associational effects in agriculture, in order to maximize crop yields.