State and transaction models (STMs) were conceived as a means to organize information about land potential and vegetation dynamics in rangelands to be used in their management. The basic idea is to describe the plant community states that can occur on a site and the causes of transitions between these states. STMs are not bound to any particular theory about how vegetation should change, so they are flexible and able to represent succession, event-driven change, and critical or abrupt transitions to alternative sites.  The diagrammatic and narrative portions of STMs synthesize various sources of knowledge about an ecosystem, including scientific results, historical anecdotes, and local knowledge to resent a set of explanations and predictions for how ecosystems can respond to natural events and management actions.