Is Ecological Risk Assessment Useful for Resolving Complex Ecological Problems?

Abstract

Risk assessment has been suggested as a tool to help manage Pacific salmon (Oncorhynchus spp.) and solve other complex ecological problems. Ecological risk assessment is usually defined as the process that evaluates the likelihood that adverse ecological effects are occurring, or may occur, as a result of exposure to one or more stressors. The basic concept, while straightforward, is difficult to apply to all but the simplest ecological problems. Strong reactions, both positive and negative, are often evoked by proposals to use risk assessment. Ecological problems that might be addressed by risk assessment include how to accomplish the following: (1) estimate objectively the condition or health of ecological resources such as Pacific salmon; (2) reduce the cost of regulations and policies; (3) focus public and private expenditures on solving the most important priorities; (4) describe and incorporate uncertainty in decision analysis and public choice; (5) provide technical information in ways that help move beyond political gridlock; and (6) democratize the decision-making process. When applied to relatively simple ecological problems (chemical toxicity being the most common), risk assessment is popular. There are many vigorous supporters, particularly among scientists, administrators, and politicians; however, there are also critics. The intellectual history of the risk assessment paradigm does not follow a neat, linear evolution. A formidable problem in many risk assessments, and especially for complex questions such as managing salmon, is selecting the ecological component or system that is considered at risk; this selection is entirely social and political, but estimating the actual risk is technical and scientific. Defining what is at risk must be resolved within the political decision-making framework or the results of the risk assessment will be of limited utility. Use of risk assessment for the Pacific salmon problem would be difficult politically unless the boundaries of the assessment were extremely narrow. However, narrowly defining the salmon problem would make the results of the risk assessment of limited relevance in decision making. For Pacific salmon, ecological risk assessment will be of limited use except for policy problems defined by fairly narrow technical boundaries or constrainèd by limited geographic scope.