|
(61-01) The Western Frontier-The future of risk prediction and the management of ecological systems. Landis, Wayne*,1, 1 Western Washington University, Bellingham, USA ABSTRACT- Dated constructs such as the reference site and biological integrity must give way to approaches that recognize the inherent properties of ecological structures without assumptions about ideal states, inherent equilibrium conditions, and fallacious indices. The key to the prediction of the impacts of xenobiotics and other stressors is the realization that ecological systems are complex in the sense of Prigogine, Kaufman and Gell-Mann. Complex systems are non-equilibrium, dynamic and historical structures with stochastic and deterministic features. A complex system can have components exhibiting a constrained equilibrium, simple dynamics and chaos all at the same time. Modeling efforts clearly illustrate the critical nature of patch dynamics in predicting the outcomes of toxicant exposure within a landscape. Our research goal is to develop tools for risk assessment and management that recognize these properties. One applicable regional risk assessment tool is the relative risk model (RRM) of Wiegers and Landis that has been used at 7 different sites. This methodology explicitly recognizes that there are multiple stressors originating from multiple sources, and that the stressor-effect relationship is mediated by habitat. The sources, habitats, and effects are mapped using Geographical Information Systems (GIS), and GIS is used as an important analysis tool. The output of the RRM inherently produces testable hypotheses about patterns within the area of concern. We have tested these hypotheses against fish and macroinvertebrate community structure in Codorus Creek, Pennsylvania, USA, and confirmed patterns predicted by the risk assessment. Finally, the RRM can be used to examine management alternatives for the change in risk within a geographic region. Different management scenarios can be examined to predict potential changes to risk patterns within the landscape. In conclusion, it is now possible to tie the properties of ecological systems and stressors to testable predictions of risk when making management decisions. Key words: Complex systems, risk assessment, relative risk model |
