Technical Abstract: Rangeland ecosystems on public and private lands are subject to increasing pressures to meet multiple-use objectives, while managers and management techniques and plans on those same lands are subject to heightened public scrutiny. Innovative analytical and management tools, including simulation models and decision support systems, are needed to meet the multi-faceted challenges of analysis and management of heterogenous rangeland ecosystems. Simulation models have become important tools in the management of cultivated lands; by contrast, simulation models, while available, have not been widely employed in management of rangelands. Rangeland ecosystem process modeling has advanced from the pioneering Ecosystem Level Model (ELM) to a current high level of sophistication, applicability and utility. The question remains whether such models are now viable management tools which could or should be more widely employed. A symposium at the 50th Annual Meeting of the Society for Range Management addressed this question. This paper summarizes the symposium and provides a current reference for natural resources modeling activities associated with rangeland ecosystem management.