Shrub-steppe landscape. Photo courtesy of Wyoming BLM.Ecosystem change results from multiple, interacting factors, and many of those factors may be human-influenced such as climate, grazing, fire, flood, and land-use. Non-native species are one factor in ecosystem change that interacts with all other factors and provides a model system for not only monitoring ecosystem change but also for forecasting components of ecosystem change such as changes in species composition and structure, which, in turn, alter habitat and disturbance processes. Non-native or exotic species are generally defined as species that were not present in the US prior to European settlement, and these species are considered invasive when they cause, or have the potential to cause, economic or environmental harm or harm to human health. Because of their impacts on ecosystems ranging from wilderness to agricultural to societal (e.g., via disease organisms such as avian influenza), significant resources are focused on management of non-native species. The USGS Invasive Species Program includes goals of early detection, rapid response and monitoring. Several on-going research projects of the USGS Northern Rocky Mountain Science Center highlight non-native species interactions with other factors that result in ecosystem change. The unifying components of these projects include interdisciplinary research teams, standardized inventory and monitoring approaches and the use of vegetation composition and structure as an indicator of change. Principal collaborators include all USGS disciplines, Colorado State University, the Bureau of Land Management, US Fish and Wildlife Service, US Forest Service, Wyoming Game and Fish, and other agencies and organizations. NoRock scientists are actively cultivating relationships with management agencies to promote the use of comparable vegetation monitoring methods to facilitate ecosystem-level analyses of ecosystem change.