The ecological communities guide contains accounts for three major types of ecological communities:
- Natural vegetation communities occurring in Montana as described under the National Vegetation Classification scheme at the Group level;
- Aquatic communities occurring in flowing (lotic) and standing (lentic) waters of different sizes, flow regimes and geographic regions;
- Areas recently disturbed by fire and insect outbreaks or that are heavily modified from natural vegetation communities by introduced vegetation or intensive human land uses such as crop agriculture and development of human structures.
