Ecological sciences and the policy sciences have essential commonalities that open crucial opportunities for collaboration. Ecology represents the best of inter-disciplinary natural-science systems theory. The policy sciences merge understanding of the policy process with a framework for discovering how to maximize values. As Garry Brewer (1998) has pointed out, ecology and the policy sciences are problem-oriented, value-committed, contextual, process-oriented, multi-method, and holistic. They are, in many ways, reflections of one another across the divide between the natural and social sciences. Their common commitment to the principles and premises enumerated above make their practitioners natural allies in efforts to secure conservation and sustainable development. Linking natural sciences with the policy sciences is an extraordinarily fruitful and exciting undertaking. Therefore this paper searches for deeper divergences between ecology and the policy sciences that lurk beneath the broad areas of agreement. The broad agreements are found in: appreciation of the need for a normative commitment; appreciation of process, including various forms of adaptation and evolution; appreciation of complexity growing out of contextuality and the process orientation. We will show, however, that subtle differences exist in how ecology and the policy sciences approach normative commitment, evolutionary implications, and complexity. After outlining these differences, we will focus on what ecology and the policy sciences can learn from one another regarding six topics of practical relevance to conservation and sustainable development: 1. incorporating environmental considerations in cost-benefit analysis; 2. use of complex models; 3. ecosystem management vs. local strategies; 4. scope of environmental standards; 5. sustainability criteria for science and resource management; 6. balancing user rights and environmental rights.
