Hosack Geoffrey R, Hayes Keith R, Dambacher Jeffrey M
Department of Fisheries and Wildlife, Oregon State University, 104 Nash Hall, Corvallis, Oregon 97331, USA.
Ecol Appl. 2008 Jun;18(4):1070-82. doi: 10.1890/07-0482.1.
Ecological predictions and management strategies are sensitive to variability in model parameters as well as uncertainty in model structure. Systematic analysis of the effect of alternative model structures, however, is often beyond the resources typically available to ecologists, ecological risk practitioners, and natural resource managers. Many of these practitioners are also using Bayesian belief networks based on expert opinion to fill gaps in empirical information. The practical application of this approach can be limited by the need to populate large conditional probability tables and the complexity associated with ecological feedback cycles. In this paper, we describe a modeling approach that helps solve these problems by embedding a qualitative analysis of sign directed graphs into the probabilistic framework of a Bayesian belief network. Our approach incorporates the effects of feedback on the model's response to a sustained change in one or more of its parameters, provides an efficient means to explore the effect of alternative model structures, mitigates the cognitive bias in expert opinion, and is amenable to stakeholder input. We demonstrate our approach by examining two published case studies: a host-parasitoid community centered on a nonnative, agricultural pest of citrus cultivars and the response of an experimental lake mesocosm to nutrient input. Observations drawn from these case studies are used to diagnose alternative model structures and to predict the system's response following management intervention.
生态预测和管理策略对模型参数的变异性以及模型结构的不确定性很敏感。然而，对替代模型结构的影响进行系统分析，通常超出了生态学家、生态风险从业者和自然资源管理者通常可利用的资源范围。这些从业者中的许多人也在使用基于专家意见的贝叶斯信念网络来填补经验信息的空白。这种方法的实际应用可能会受到填充大型条件概率表的需求以及与生态反馈循环相关的复杂性的限制。在本文中，我们描述了一种建模方法，该方法通过将符号有向图的定性分析嵌入到贝叶斯信念网络的概率框架中来帮助解决这些问题。我们的方法纳入了反馈对模型对其一个或多个参数持续变化的响应的影响，提供了一种探索替代模型结构影响的有效手段，减轻了专家意见中的认知偏差，并且适合利益相关者的参与。我们通过研究两个已发表的案例研究来展示我们的方法：一个以柑橘品种的外来农业害虫为中心的寄主-寄生蜂群落，以及一个实验湖泊中试生态系统对养分输入的响应。从这些案例研究中得出的观察结果用于诊断替代模型结构，并预测管理干预后系统的响应。
