This booklet is about making decisions that affect conservation of biodiversity. Often these decisions target a select group of species and the habitats on which they depend—for example, How can we manage our forests to produce more quail coveys? Other times, the decisions address the entire suite of species—How do we provide for all the species that inhabit old-growth forests? Forest managers on both public and private lands make such decisions regularly, and this publication has the goal of helping them improve their own ability, and that of the groups that advise them, to make these complex decisions in the context of their many other objectives. How do we make those decisions? When can detailed analysis help? Both of these questions will be addressed generally, and then in relation to conservation of forest biodiversity.

Much of the time, the combination of intuitive decision processes and informal decision rules can suffice. Sometimes, though, we may want to take a deeper, more systematic look. Our approach poses complexity in at least two dimensions: (1) the social dimension asks how many players and how complicated and contentious are their relationships, and (2) the informational dimension asks to what degree available data and relationships must be organized. Our experience suggests that, as either or both of these dimensions increase in complexity, the need and call for systematic, transparent analysis will also increase.

Decision support systems (DSS). are tools that help evaluate alternative options or scenarios (decision), deal with complexity (support), and have a clear, reproducible protocol (system). More specifically, DSS is the name often given to computerized decision aids to help with complex decisions. Committing to DSS can have significant ramifications for decision effectiveness, ranging from exhilarating to disastrous, so whether to use a decision support system is a major decision in its own right. In addition, it would be a mistake to think of DSS merely as models into which you feed data and the answer to your biodiversity problems pops out the other end. Rather, we believe they should be seen as a possible component in the decision process, a set of specified tools that can be useful to enhance deliberation in certain circumstances.