Vegetation Classification and Mapping Project Report - USGS

B32 Torrey’s Jointfir – Bigelow’s Sagebrush Sparse Vegetation
Location: Torrey’s Jointfir – Bigelow’s Sagebrush Sparse Vegetation occurred widely throughout the park,
with the greatest concentration of map units located on the tops of sandstone mesas and plateaus.
Photosignature: Artemisia bigelovii, a gray green dwarf shrub, had a uniform, gray green, smooth speckled
signature. It tended to occur in a regular pattern. In some areas it was difficult to identify Artemisia
bigelovii; however, the bedrock striations of the sandstone tended to indicate this map class. It also tended
to occur on the lighter white-to-gray clay soils. Ephedra torreyana does not have a strong signature and
was not reliably identified on the aerial photos.
G35
Figure.G63..Ground.photo.for.map.class.B32,.
Torrey’s.Jointfir.–.Bigelow’s.Sagebrush.Sparse.
Vegetation.
Figure.G64..Photosignature.for.map.class.B32.
Torrey’s.Jointfir.–.Bigelow’s.Sagebrush.Sparse.
Vegetation.
Plant communities
Ephedra torreyana – Artemisia bigelovii Sparse Vegetation
Group map class
Inter-Mountain Basins Semi-Desert Shrub Steppe (1 of
5)
Management map class Vegetated Rim Complex (1 of 4)
Macrogroup map class
Inter-Mountain Basins Semi-Desert Grassland and
Steppe (1 of 17)
Number of map units in park 516
Number of map units in park & environs 668
Number of map units less than 0.5 ha 236 (1.8% of total map class area)
Area of map class in park
2119 ha / 5237 ac
Total area of map class
3227 ha / 7975 ac
Proportion of land cover in park 66%
Proportion of map class in project environs 34%
Base map class accuracy user 56.7 (41.9 – 70.4), producer 17.9 (9.0 – 32.4)
Group map class accuracy user 41.8 (34.7 – 49.2), producer 38.1 (31.5 – 45.1)
Management map class accuracy user 72.4 (63.9 - 79.5), producer 77.8 (69.0 - 84.2)
Macrogroup map class accuracy user 93.0 (90.1 - 95.0), producer 77.2 (73.3 - 80.6)
Documentation for base map class
12 2003 relevés, 12 1996 relevés, 38 AA observation
sites
Appendix G: Map Class summaries