UNSUSTAINABILITY

In natural resource management, wise decisions must result in desired ecosystem conditions that are sustained over indefinitely long periods. Thus, the concept of sustainability is an important consideration in management decisions. In many cases, our understanding of whether or not sustainable conditions will result from a management decision is based on long-term projections from computer models. Although these models are theoretically based and statistically calibrated, they usually fail to account for uncertainty in the underlying assumptions, in the statistical calibration, and in the values used to initiate projections. Moreover, given our current level of knowledge of ecosystem behavior, results from even our best models may appear to indicate sustainable conditions, but cannot measure or incorporate probabilities of increasing stochasticity, critical threshold or extreme value events and surprises, or chaotic (dynamical) system behavior. For now, this unanticipated uncertainty can be adequately managed by accurately discounting present resource values, analyzing activities at appropriate temporal and spacial scales, maintaining biological diversity, and avoiding extreme impacts that can create overcompensating feedbacks.