Vegetation classification and mapping project report, Canyonlands National Park

Tendick, Amy; Coles, Janet; Decker, Karin; Hall, Mark; Von Loh, Jim; Belote, Travis; Wight, Aneth; Wakefield, Gery; Evenden, Angie

The Northern Colorado Plateau Inventory and Monitoring Network (NCPN) worked with the support of the U.S. Geological Survey - National Park Service (USGS-NPS) Vegetation Mapping Program to describe and map vegetation at Canyonlands National Park (CANY). This collaborative effort involved many project partners, particularly the Rocky Mountain Mapping Center of the USGS, the Western Region office of NatureServe, engineering-environmental Management, Inc. (e2M), and their cooperators. The mapping area is approximately 170,618 hectares (421,605 acres), encompassing the entire park as well as an environs of adjacent public and private lands. Ecologists and photointerpreters identified plant associations for CANY 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 914 vegetation classification plots and 373 observation points between 2003 and 2004 to prepare the initial classification and vegetation map. Assessment of map accuracy entailed sampling an additional 2,043 data plots from spring of 2007 to late winter of 2009. Analysis of the classification plot and accuracy assessment plot data revealed 164 National Vegetation Classification Standard (NVC) plant associations, alliances, or park special vegetation types within the park and environs. Twenty-six 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 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 directly on-screen through heads-up digitizing using ArcGIS editing tools and transferred to a spatial database. The project used the program standard minimum mapping unit of 0.5 ha with few exceptions. Fifty-four map classes represented by 31,497 polygons were developed for CANY. A total of 30,329 polygons represent 41 natural or semi-natural vegetation map classes covering 94.8% of the mapping project area. One map class was documented as point locations only. Twelve additional land use/land cover and geologic map classes describe 1,168 polygons (3.7% of polygons and 5.2% of the area). Average polygon size across all map classes is 9.9 ha (24.4 acres). Lands within CANY make up 135,204 ha (334,096 acres) or 79.2% of the total project area. Blackbrush Shrubland had the highest number of polygons (3600) polygons covering 9.4% of the mapping area. The Potholed and Jointed Sandstone Woodland Complex is the most common map class, delineated on 30,495 ha (75,354 acres) or 17.9% of the project area. Map accuracy was assessed within the CANY boundary only. Primary analyses of the field data were presented and evaluated at an accuracy assessment (AA) meeting held from August 18-19, 2010. Results from a thematic AA of 41 vegetation map classes remaining following AA analysis indicated an estimate of 86.3% overall map accuracy (Kappa statistic = 85.8%). Fourteen vegetation 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, Canyonlands National Park

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