We have a good conceptual definition of rangelands
"Land on which the indigenous vegetation (climax or natural potential) is predominantly grasses, grass-like plants, forbs, or shrubs and is managed as a natural ecosystem. If plants are introduced, they are managed similarly. Rangelands included natural grasslands, savannas, shrublands, many deserts, tundras, alpine communities, marshes and meadows” - Society for Range Management
The Federal Geographic Data Committee (FGDC) can help reach agreement on definitions.
"The agreement on definitions.Federal Geographic Data Committee coordinates the development of the National Spatial Data Infrastructure (NSDI). The NSDI encompasses policies, standards, and procedures for organizations to cooperatively produce and share geographic data. The 17 federal agencies that make up the FGDC are developing the NSDI in cooperation with organizations from state, local and tribal governments, the academic community, and the private sector."
FGDC Sustainable Forest Data Working Group agreement on definitions.
The MOU states that "Agencies will work together to resolve data issues that are beyond the means or jurisdiction of any single agency, avoid future inconsistencies and incompleteness in data coverage, and otherwise coordinate data activities as appropriate to their missions and consistent with their statutory responsibilities."