Threshold-based resource management: A framework for comprehensive ecosystem management

The problems posed by adaptive management for improved ecosystem health are reviewed. Other kinds of science-informed ecosystem management are needed for those regions of conflict between rapid human population growth, increa sed resource extraction. and the rising demand for better environmental ame nities, where large-scale experiments are not feasible. One new framework i s threshold-based resource management. Threshold-based resource management guides management choices among four major science and engineering approach es to achieve healthier ecosystems: self-sustaining ecosystem management, a daptive management, case-by-case resource management, and high-reliability management. As resource conflicts increase over a landscape (i.e., as the e cosystems in the landscape move through different thresholds), management o ptions change for the environmental decision-maker in terms of what can and cannot be attained by way of ecosystem health. The major policy and manage ment implication of the framework is that the exclusive use or recommendati on of any one management regime, be it seif-sustaining, adaptive, case-by-c ase, or high-reliability management, across all categories of ecosystems wi thin a heterogeneous landscape that is variably populated and extractively used is not only inappropriate, it is fatal to the goals of improved ecosys tem health. The article concludes with detailed proposals for environmental decision-makers to undertake "bandwidth management" in ways that blend the best of adaptive management and high-reliability management for improved e cosystem health while at the same time maintaining highly reliable flows of ecosystem services, such as water.