Ecosystem models and environmental policy

Abstract
The use of models for guiding environmental policy should be distinguished from their use in imple menting management policies already decided upon. Ecosystem models are of potentially great value for guiding and informing incremental decisions regard ing environmental policy. They are unlikely to be used as a basis for comprehensive restructuring of programs. Their greatest use may lie in identifying points of leverage, where incremental policy changes will have the greatest long-term beneficial impact. For this reason, provision for formal sensitivity analysis is essential in models used to guide envi ronmental policy. Ecological models are more likely to influence policy decisions if they incorporate features which should be a part of any good model but which are often skimped: adequate documentation, reasonableness of prediction, explanation of limits and probable range of error, flexibility to deal with unanticipated problems, and effective presenta tion and display.