Plant-Environment Relationships in an Anthropogenic World

我的研究项目测试了生物和非生物机制如何相互作用来影响草原的多样性和功能，以及这些机制是如何因人类环境变化而改变的。在最简单的层面上，所有陆地系统，包括草原，都受到营养、水和光等资源的可用性的调节。人类通过极大地改变这些资源的可获得性来影响多样性和功能，但这是以复杂的方式实现的，因为气候变化、氮污染、物种引进、栖息地丧失和营养崩溃等因素往往同时发生。我们的实验室使用基于现场和统计的方法，从本地到全球，研究这些问题，目标是基础理论及其在管理中的应用。在接下来的五年里，我的实验室将专注于三个项目：多样性如何与人类影响的非生物过程相互作用，以调节草原的入侵抗性；种内(种内多样性)和种间(种间多样性)的特征变化如何影响植物群落对环境变化的反应；以及气候变化和氮污染如何结合在一起改变草原上的尖叫昆虫动态。这三个目标的一个共同主题是解开与物种相互作用和多样性有关的生物过程与与环境变化有关的非生物过程如何改变有限资源的可获得性和对生态系统功能的影响。资源的调节是所有物种共存模式的核心原则，无论是从生态学的角度，还是作为具有特征置换的进化因素。多样性通过生态位差异(即不同物种在不同环境中茁壮成长)影响资源，最大限度地吸收并因此生产，同时减少入侵物种的可获得性(例如，生物抵抗力)。非生物因素以一系列方式影响资源，最重要的是当供应超过植物群落的需求(例如，氮污染)或无法满足需求(例如，严重干旱，限制可用水)。影响环境的多样性(通过对资源的需求)和影响多样性的环境(通过资源的供应)之间的这种互惠关系捕捉到了决定植物群落中物种相互作用结果的许多基本机制。它还应该预测以人类为基础的环境变化如何影响这些过程，这是我的研究计划的核心主题。

My research program tests how biotic and abiotic mechanisms interact to influence the diversity and functioning of grasslands, and how those mechanisms are transformed by human-based environmental change. At the simplest level, all terrestrial systems, including grasslands, are regulated by the availability of resources such as nutrients, water, and light. Humans affect diversity and function by dramatically altering the availability of these resources, but do so in complicated ways because factors such as climate change, nitrogen pollution, species introductions, habitat loss, and trophic collapse often occur simultaneously. Our lab uses field-based and statistical approaches, at scales from local to global, to investigate these issues, targeting both fundamental theory and its application to management. For the next five years, my lab will be focusing on three projects: how diversity interacts with human-influenced abiotic processes to regulate invasion resistance in grasslands, how trait variation within-species (intraspecific diversity) versus among-species (interspecific diversity) influences responses to environmental change in plant communities, and how climate change and nitrogen pollution combine to transform plaint-insect dynamics in grasslands. A shared theme of these three objectives is untangling how biotic processes relating to species interactions and diversity versus abiotic processes relating to environmental change, transform the availability of limiting resources and the implications for ecosystem function. The regulation of resources is a central tenet of all models of species coexistence, in both ecological terms and as an evolutionary factor with character displacement. Diversity affects resources via niche differences (i.e., different species thriving in different environments), maximizing uptake and thus production, while reducing availability for invading species (e.g., biotic resistance). Abiotic factors affect resources in a range of ways, most importantly when supply exceeds the demand of the plant community (e.g., nitrogen pollution) or fails to meet it (e.g., intense drought, limiting water availability). This reciprocal relationship between diversity affecting the environment (via the demand for resources) and the environment affecting diversity (via the supply of resources) captures many of the fundamental mechanisms that determine the outcome of species interactions in plant communities. It should also predict how human-based environmental change affects these processes, a theme that is central to my research program.