Reversing long-term experiments to understand regime shifts

生态系统的一个组成部分的变化有时会导致整个系统发生重大的、相对快速的、看似永久性的变化。这个项目提供了一个难得的机会，以严格的方式研究这种戏剧性的生态变化的可逆性。该项目将使用在奇瓦瓦沙漠进行的一项长期实验，在该实验中，选择性地将主要食种啮齿动物排除在外，导致动植物物种的丰度以及土壤养分水平发生了急剧变化。这些排除将被逆转，并在五年内测量对植物、动物和土壤的影响。该项目的更广泛影响包括培训两名研究生，并通过建设一个科学研究交流网站向公众广泛宣传。此外，更好地了解特定因素如何导致生态系统的重大变化，将有助于土地管理者和政策制定者避免自然资源管理的意外后果。

Changes in one component of an ecological system can sometimes cause major, relatively rapid, and seemingly permanent changes in the system as a whole. This project offers a rare opportunity to study the reversibility of such dramatic ecological changes in a rigorous way. The project will use a long-term experiment in the Chihuahuan Desert in which selective exclusions of rodents that are major seed eaters has produced sharp changes in the abundances of plant and animal species and in levels of soil nutrients. These exclusions will be reversed, and the effects on plants, animals, and soils measured over five years. The broader impacts of this project include the training of two graduate students and broad outreach to the public through construction of a website for the communication of scientific research. In addition, better understanding of how specific factors can cause major shifts in ecological systems will help land managers and policy makers avoid unintended consequences of natural resource management.