Statistical Methods for Regime Shifts

该项目将开发和评估正式的统计方法，以追溯确定生态系统中相互作用的种群丰富度的时间序列数据中的制度转变。它将进一步发展和评估正式的统计方法，以确定这种生态系统是否具有反应性(即，系统的动态是否会放大扰动)。将应用公认的统计原则，并以相互作用的人口系统的动态的一般模型为基础。这些方法的性能将通过一系列模拟实验以及它们在以前公布的数据集上的应用来评估。扰动可能会导致自然生态系统经历制度转变(即从一个局部稳定的稳定状态突然转变到另一个稳定状态)，这对管理具有重要意义。为了理解真实系统中的这一现象，有必要区分制度变迁和其他类型的可变性。这个项目的第一个目标是提供这样的方法，如果没有这些方法，就很难取得支持这一领域管理的科学进展。该项目的第二个目标是开发确定系统是否具有反应性(即能够放大扰动)的方法。这一点很重要，因为反应性代表着一种可能的“政权更迭之路”。因此，对于寻求避免政权更迭的经理人来说，了解一个系统是否具有反应性是很重要的。这项工作将有助于为渔业管理和养护决策提供信息。该项目的结果将发表在同行评议的科学文献中，并将免费提供应用这些方法的MatLab例程。

This project will develop and assess formal statistical methods for the retrospective identification of a regime shift in time series data of the abundances of interacting populations in an ecosystem. It will further develop and assess formal statistical methods for determining whether such an ecosystem is reactive (i.e., whether the dynamics of the system would amplify a perturbation). Well-established principles of statistics will be applied and based on a general model of the dynamics of a system of interacting populations. The performance of these methods will be assessed through a series of simulation experiments and with their application to previously published data sets. The possibility that a perturbation can cause a natural ecosystem to undergo a regime shift (i.e., an abrupt shift from one locally stable steady state to another) has important implications for management. To develop an understanding of this phenomenon in real systems, it is necessary to be able to distinguish between regime shifts and other types of variability. The first objective of this project is to provide such methods, without which scientific progress in support of management in this area is difficult. The second objective of the project is to develop methods for determining whether a system is reactive (i.e., capable of amplifying a perturbation). This is important because reactivity represents one possible "route to regime shift." Knowing whether a system is reactive is therefore important to managers seeking to avoid a regime shift. This work will help inform decision-making in fisheries management and conservation. The results of this project will be published in the peer-reviewed scientific literature and MATLAB routines for applying the methods will be made freely available.