New Vegetation Map

For the first time in almost 20 years, Rocky Mountain National Park has a new vegetation map* as of 2005. The four year project started in 2001 and was a cooperative effort among the U.S. Bureau of Reclamation, U.S. Geological Survey, Colorado Natural Heritage Program, NatureServe, and the National Park Service. Based on the NatureServe U.S. National Vegetation Classification system, authors identified plant associations known or suspected from the park. Each of these plant associations was then further defined by the slope and aspect on which it occurred, and density of plants within it.

Mappers started by drawing lines around areas of ground cover that looked uniform on aerial photos. They could discriminate among these different areas because they had different colors or textures in the photos. Field crews visited 632 vegetation characterization plots in the park to help mappers understand what plant associations corresponded to the areas mappers could delineate. Mappers then had to relate the 172 plant associations known from the field work to the areas they could identify on the aerial photos. This resulted in 46 actual map units that can be displayed on printed maps (12 map units identify unvegetated areas such as rock). Finally, the field crews went back into the park and examined 1219 new plots to determine how accurate the map was. The map was accurate 86% of the time, and when inaccurate, usually identified the area as something quite similar to the actual vegetation on the ground. The new map is about thee times more detailed (22,065 polygons versus 7,141 polygons) than any previous vegetation map of the park.

Field crews did extensive documentation of each site, including a vegetation survey, and took several photographs. This information is available to park managers and to researchers in the form of a database. The database links photos to specific points on the ground via maps. While the database is quite complex and contains extensive information, the park staff expect that it will be very useful for future projects designed to monitor changes in vegetation, whether they be due to plant growth, fires, or insect damage.

* Sallas, David, Joe Stevens, and Keith Schulz. 2005. Rocky Mountain National Park, Colorado: 2001-2005 Vegetation Classification and Mapping. Technical Memorandum 8260-05-02, Remote Sensing and GIS Group, Technical Service Center, Bureau of Reclamation, Denver, CO.