DISSERTATION RESEARCH: Mechanisms of compensatory dynamics in natural systems

了解生态稳定性的机制，例如为什么像初级生产力这样的属性在某些群落中是稳定的，而在其他群落中是可变的，长期以来一直是生态学的中心焦点。环境条件和物种动态之间的相互作用通常被认为是长期以来群落一级稳定性的关键决定因素。在多变的环境中，环境-物种相互作用可能产生补偿动态，当种群水平的异步波动缓冲群落水平的波动时发生。例如，降水是草地生产力的强有力的控制因素，在降水变化大的草地上，植物物种往往会随着时间的推移而权衡取舍，因为有些物种更能忍受干旱年份，而其他物种在湿润年份更具竞争力。该项目将表明在降水量可变的环境中补偿动态的稳定作用是否取决于1）物种对降水量的反应和2）物种对生产力的影响。 研究人员将在加州草原上进行实验，通过操纵降水变化和物种相互作用来验证这一点。结果将产生一个第一个机制，基于实地的测试如何补偿动态形状communitystability.This研究是重要的社会，因为许多人依赖于稳定的自然资源来源，但全球变化很可能会增加降雨和温度的变化。例如，加州的牧场主依赖草地作为饲料，但这种生态系统服务的可靠性受到气候变化的威胁。结果将通过中央海岸牧场联盟和加州博物学家和牧场等管理人员阅读的出版物传播给这些土地管理人员，项目的数据集将向公众提供。该项目还将培养一名博士。学生和本科生，其中五人已开发的荣誉论文项目有关的研究。

Understanding the mechanisms governing ecological stability, such as why a property such as primary productivity is stable in some communities while variable in others, has long been a central focus of ecology. Interactions between environmental conditions and species dynamics are generally thought to be key determinants of stability at the community level over time. In variable environments, environment-species interactions may generate compensatory dynamics, which occur when asynchronous fluctuations at the population level buffer against fluctuation at the community level. For example, precipitation is a strong control of grassland productivity, and in grasslands characterized by high precipitation variability plant species tend to tradeoff over time because some species better tolerate drought years, whereas other species are more competitive in wet years. This project will show whether the stabilizing effect of compensatory dynamics in environments with variable precipitation depends on 1) the responses of species to precipitation and 2) the effects of species on productivity. Researchers will test this with experiments in California grasslands, where species tradeoffs are frequent, by manipulating precipitation variability and species interactions. Results will yield one of the first mechanistic, field-based tests of how compensatory dynamics shape community stability.This research is important to society because many people rely on stable sources of natural resources, but global change is likely to increase variability in rainfall and temperature. For example, ranchers in California depend upon grasslands for forage, but the reliability of this ecosystem service is threatened by climate change. Results will be disseminated to such land managers via the Central Coast Rangeland Coalition and through publications read by managers such as the California Naturalist and Rangelands, and the sets of data from the project will be made available to the public. The project will also train a Ph.D. student and undergraduates, five of whom have developed honors thesis projects related to the research.