Classification Distribution Vegetation Accuracy

Tree canopy is less than 10% (or absent), shrub cover is less than 25%, and herbaceous cover is greater than 25%. The dominant vegetation is emergent; semi-permanent or standing water is present. The class is comparable to the Viereck et al. (1992) hierarchical levels wet graminoid herbaceous (IIIA3), and wet forb herbaceous (IIIB3).

The wet herbaceous class occurs in small patches throughout the park’s boreal forest zone and at higher elevations dominated by low shrubs. The sites have standing or semi-permanent water dominated by hydrophilic vegetation. It most frequently occurs on lake edges, but also on saturated river terraces, the edge of ponds, sloughs, fens, other patterned ground, and occasionally in pools of hillside streams. The sites have little to no slope. Relative to other classes, the wet herbaceous class is generally small in size and patchy in distribution throughout Denali National Park and Preserve. The highest elevation, based on field data, is 824 meters (Table 3). It is uncommon in all ecoregions except the Kuskokwim-alluvial fans and flood plains ecoregion and the Kuskokwim-Minchumina Basin ecoregion (Tables 4a and 4b; Clark 1998). The class covers 0.6% (38,427 acres) of Denali National Park and Preserve (Table 5).

Herbaceous composition is highly variable and includes Menyanthes trifoliata, Potentilla palustris, Cnidium cnidiifolium, Eriophorum brachyantherum, E. vaginatum, Equisetum fluviatile, Carex rostrata, C. aquatilis and C. lasiocarpa. Each species may dominate a site. Low shrubs associated with the wet herbaceous class include Betula nana, Salix species, Potentilla fruticosa, Myrica gale, and Spirea beauverdiana. Sphagnum species sometimes form a floating mat interspersed with the emergent vascular species.

The producer’s accuracy for the wet herbaceous class is 68.7%, with a user’s accuracy of 89.7%. Errors of omission and commission are relatively small, but scattered with a number of different mapping classes (stunted spruce, willow, low shrub-sedge and water).