"Resistance, resilience, and vulnerability of boreal forests to environmental change"

地球目前正在经历一段大范围的环境变化时期；其中许多变化在高纬度地区发生得特别快。在北方森林中，我们希望看到生态系统对环境变化的多个维度做出反应，包括气候变化、干扰和物种组成。在许多森林系统中，强大的稳定反馈和高生态惯性或阻力意味着这些生态反应不太可能以渐进的方式发生。相反，我们可以预料到由干扰或其他生态阈值触发的生态系统状态的突然、非线性变化。我们预测和管理森林生态系统的复原力，或其从干扰或压力源中恢复的能力，将取决于我们对塑造森林动态的潜在机制的理解。这项研究建议侧重于与火和气候有关的几个关键过程，我们认为这些过程影响了北方森林对变化的复原力和脆弱性：a)火或其他干扰在创造快速门槛变化机会方面的作用，例如新物种的入侵；b)物种变化对森林生态系统结构及其生长和发展方式的影响；c)树木生长对气候的响应模式，这可能预示着森林类型即将发生变化；以及d)小斑块和大景观之间的相互作用，影响森林地貌变化和应对环境变化的方式。研究结果将告诉我们北方森林最容易受到变化的影响，从而开发我们预测、管理和适应下个世纪生态变化的潜力。

The earth is currently experiencing a period of widespread environmental change; many of these changes are occurring particularly rapidly at high latitudes. In the boreal forest, we expect to see ecosystems responding to multiple dimensions of environmental change, including altered climate, disturbance, and species composition. Strong stabilizing feedbacks and high ecological inertia, or resistance, in many forest systems mean that these ecological responses are unlikely to occur in a gradual, incremental way. Instead, we can expect sudden, non-linear changes in ecosystem states that are triggered by disturbance or other ecological thresholds. Our ability to predict and manage the resilience of forest ecosystems, or their capacity to rebound from disturbance or stressors, will depend on our understanding of the underlying mechanisms that shape forest dynamics. This research proposal focuses on several key processes related to fire and climate that we think influence the resilience and vulnerability of boreal forests to change: a) the role of fire or other disturbance in creating opportunities for rapid, threshold changes, such as the invasion of new species; b) the impacts of species change on the structure of forest ecosystems and they way they grow and develop; c) patterns of tree growth responses to climate that may predict an impending switch in forest type; and d) interactions between small patches and large landscapes that affect the way in which forest landscapes will shift and respond to environmental change. Research results will teach us about where boreal forests are most likely to be vulnerable to change, thus developing our potential to anticipate, manage, and adapt to ecological changes in the coming century.