Biodiversity and Conservation 5, 1143-1167 (1996) Uncertainty, ecology, sustainability and policy S.R. DOVERS*, T.W. NORTON Centre for Resource and Environmental Studies, Institute of Advanced Studies, The Australian National University, Canberra ACT 0200 Australia J.W. HANDMER Flood Hazard Research Centre, Middlesex University, Queensway, Enfield EN3 4SF UK Received 9 May 1995; revised and accepted 15 August 1995 Using an Australian focus to explore theoretical and policy issues of wider concern, this article examines linkages between public policy and the science of ecology. This is done within the broader framework of sustainability, emphasizing the problem of decision making in the face of 'uncertainty'. Insights from the ecological, risk, sustainability and policy literatures are used. The sustainability- uncertainty problem is characterized, and the adequacy of existing policy support techniques and approaches noted, particularly the precautionary principle. The problem is further defined using the notion of ignorance. The treatment of ignorance and uncertainty in ecology is discussed. We suggest that the science of ecology has had a limited influence on policy formulation and discuss the basis of this using biodiversity conservation and ecosystem management as examples. We conclude by considering challenges for handling risk, uncertainty and ignorance in ecological science for policy formulation. We emphasize the need for improved communication between the science and policy communities, greater recognition of the limits of quantitative techniques in addressing uncertainty, and contingency planning. Keywords: uncertainty; ecology; policy; sustainability; biodiversity. Introduction: the sustainability-uncertainty problem Ecosystem and environmental management are now, in principle, structured within the broader concept of sustainability. Following the World Commission on Environment and Development (WCED, 1987) and the subsequent 1992 UN Conference on Environment and Development and its outcomes (United Nations, 1992), the world is struggling with implementing the sustainability agenda. This seeks to integrate the traditional environmental issues of resource degradation and depletion, biodiversity, pollution and wastes with issues of security, economic development, poverty, and fairness to future generations. In Harrison's words, sustainable development is now, 'universally accepted as the prime goal of human progress' (Harrison, 1992, p. 315). Sustainability demands a balancing of the three 'legs' of ecological, social and economic concerns in decision making. (1) Ecological considerations: the maintenance of essential ecological processes and life support systems, and the protection of biodiversity. *To whomcorrespondenceshould be addressed. 0960-3115 © 1996 Chapman& Hall