Vegetation Classification and Mapping Project Report, Colorado National Monument

Von Loh, J; Landgraf, K; Evenden, A; Owens, T; Blauer, S; Reid, M

The Northern Colorado Plateau Inventory and Monitoring Network (NCPN) cooperated with the U.S. Geological Survey (USGS) and National Park Service (NPS) Vegetation Mapping Program and NPS Fire Program to classify, describe, and map vegetation and fuels at Colorado National Monument (COLM). This collaborative project involved many partners, including engineering-environmental Management, Inc. (e²M), USGS Rocky Mountain Geographic Science Center (RMGSC), the Western Region office of NatureServe, and their cooperators.The total project mapping area is 12,685 hectares (31,344 acres), encompassing the monument and environs. Ecologists, botanists, and photo interpreters cooperated to identify plant associations for COLM and determine how best to map them using 1:12,000-scale, true color aerial photography. The team documented the project area’s vegetation by sampling 288 plots and 218 observation points. These data were analyzed and assigned to 67 associations of the National Vegetation Classification. Fuels data were collected for woodland and shrubland communities during sampling, but were not analyzed as part of this project. Fieldwork and mapping were completed between 2003 and 2005.Vegetation and land use were interpreted from high-resolution, true color digital orthoimageryand 9” x 9” stereo pairs of 1:12,000-scale true color photographs flown specifically for this project. Polygons representing vegetation or land use map classes defined by RMGSC, in consultation with other project partners, were delineated on orthophotos in a digital environment. With few exceptions, occurrences smaller than approximately 0.5 ha were not delineated.Vegetation within the monument boundary was mapped at as detailed a level as possible using a combination of computer modeling and aerial photo interpretation. A total of 4,359 map polygons were developed within the COLM mapping project area. Average polygon size is 2.9 ha (7.2 acres). Lands within the monument comprise 8,252 ha (20,391 acres), divided into 2,850 polygons representing natural and semi-natural vegetation map classes as well as geologic and developed land classes.The urbanized environs northeast of the monument were mapped using standardized land cover classes instead of the vegetation map classes used within COLM. One thousand five hundred and nine polygons totaling 4,428 ha (10,945 acres) of unvegetated, developed, and natural/seminatural vegetated map classes were delineated in the environs.Of the 38 map classes interpreted within the monument boundary, 20 occurred consistently in patches smaller than the minimum mapping unit of 0.5 ha and are represented by point data instead of polygons. Seventeen vascular and nonvascular map classes were delineated by landscape modeling techniques using ERDAS Imagine software, as were four unvegetated geologic types. Twenty-six vegetation map classes were interpreted and mapped using traditional photo interpretation methods and an on-screen digitizing process.Map accuracy was assessed within the COLM boundary only. Results from a thematic accuracy assessment of 23 vegetation map classes indicated an overall map accuracy of 68% (Kappa index = 64%). Several individual map classes exceeded the Vegetation Mapping Program standard of 80%. Other map classes did not meet the 80% accuracy standard, but were retained because of their value to monument managers. Twenty additional vegetation map classes were mapped as points directly from the field data; these are assumed to be 100% accurate.

Vegetation Classification and Mapping Project Report, Colorado National Monument

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