Vegetation classification and mapping project report, Black Canyon of the Gunnison National Park [and associated files]

Coles, Janet; Tendick, Amy; Von Loh, Jim; Bradshaw, Ginger; Manis, Gerald; Wight, Aneth; Wakefield, Gery; Evenden, Angie

The Northern Colorado Plateau Inventory and Monitoring Network, with the support of the U.S. Geological Survey - National Park Service Vegetation Mapping Program undertook this project to describe and map vegetation at Black Canyon of the Gunnison National Park (BLCA). This collaborative effort involved many project partners, particularly BLCA natural resources staff, the Western Region office of NatureServe, engineering-environmental Management, Inc., and their cooperators.The mapping area is 22,989 hectares (56,807 acres), encompassing the entire park as well as environs of adjacent public and private lands. Ecologists and photo interpreters identified vegetation alliances and plant associations for BLCA and determined how best to map them using 1:12,000-scale, true color aerial photography and digital orthophotography. The team collected vegetation and environmental data from 112 classification plots and 16 observation points. Supplemental fuels data were collected during the project in Gambel oak, pinyon- juniper, ponderosa pine, Douglas-fir, and quaking aspen communities. Assessment of map accuracy entailed sampling of another 762 data points. Fieldwork and mapping were completed between 2001 and 2004. Analysis of the vegetation data revealed 77 National Vegetation Classification plant associations, vegetation alliances, or park special vegetation types within the park and environs, 56 of which are shared with the adjacent Curecanti National Recreation Area (CURE). Twenty-eight plant associations were documented exclusively from accuracy assessment data, the remainder from vegetation plots and observation points.Vegetation and land use were interpreted to as detailed a level as possible from high-resolution, 9” x 9” stereo pairs of 1:12,000-scale true color aerial photography. Polygons representing vegetation or land use map classes were delineated on Mylar overlays on paper plots of the orthophotographs and transferred to a spatial database where they were adjusted as necessary using on-screen digitizing techniques. The project used the program standard minimum mapping unit of 0.5 ha with few exceptions.Thirty-five (34 polygon and 1 point-based) map classes were developed for BLCA. The BLCA vegetation mapping project area was divided into 3,270 polygons. A total of 3,135 map polygons represent 24 natural and semi-natural vegetation map classes, and 11 land use map classes describe 135 other polygons within the mapping area. Average polygon size across all map classes is 7.0 ha (17.4 acres). Natural and semi-natural vegetation classes cover 22,220 ha (54,857 acres; 96.6% of the project area). Land use/land cover polygons, including roads, ranch developments and NPS facilities, total 788 ha (1,948 acres; 3.4% of the project area). The most common map class is Gambel Oak / Mixed Montane Shrubland (S-QUMX) with 554 polygons covering 28.6% of the mapping area. Map accuracy was assessed within the BLCA boundary only. Results from a thematic accuracy assessment of 24 vegetation map classes remaining after accuracy assessment analysis indicated an estimate of 83.8% overall map accuracy (Kappa statistic = 82.2%). Ten map classes did not meet the 80% standard for either producer’s or user’s accuracy, but were retained because of their relative rarity and/or value to Park managers. These map classes are described in the Accuracy Assessment section of this report, as is the justification for retention.

Vegetation classification and mapping project report, Black Canyon of the Gunnison National Park [and associated files]

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