The Corps should encourage the explicit use of conceptual models to guide eco-system restoration planning and implementation. Conceptual models should be required as a first step in the planning process, as they provide a key link between early planning (e.g., an effective statement of problem, need, opportunity, and constraint) and later evaluation and implementation. Conceptual models are descriptions of the general functional relationships among essential com-ponents of an ecosystem. They tell the story of “how the system works ” and, in the case of eco-system restoration, how restoration actions aim to alter those processes or attributes for the betterment of the system. As such, conceptual models can provide the Ecosystem Restoration Team with: • a synthesis of the current understanding of how a system works • help in understanding and diagnosing the underlying problem • a basis for isolating cause and effect and simplifying complex systems • a common framework or “mental picture ” from which to develop alternatives • a tool for making qualitative predictions of ecosystem response