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measurable cover included meadow barley /Criterion brachyantheruml, common spiketush
<br />• /E/eocharis pe/ustris/, slender wheatgra55, tall :mannagrass /Glyceria a/ate/, and Agassiz
<br />bluegrass. Introduced perennial cool season grasses were the second most abundant lifeform
<br />group with 15.8 percent of total vegetation cover, almost all of which was attributable to
<br />redtop /A~r rostis gipanfeal. Though offering little cover, common timothy was also fairly
<br />common. Native perennial forbs accounted for 14.8 percent of total vegetation cover. The
<br />only large individual contribution to this cover was by cutleaf coneflower /Rudbeckia amp/al.
<br />Other species with common occurrence, and minor cover extent, included western yarrow,
<br />bracted aster, Hall willowherb /Epi/obium ha//eanuml, flichardson geranium /Geranium
<br />richardsoniil, bigleaf evens lGeum macrophylluml, duckweed lLemna ct. minusculal, few-
<br />flowered false Solomon's seal /Maianthemum sfe/latuml, fieldmint (Menthe arvensisl, common
<br />Yampa, Gmelin crowfoot (Ranuncu/us ome/iniil, willow dock (Rumex trianqu/iva/visl, white
<br />checkermallow /Side/cea candidal, stinging nettle /Urtica dioica ssp. raci/isl, cornlily /Veratrum
<br />tenuipeta/uml, American speedwell (Veronica americanal, and Pacific aster. Introduced
<br />perennial forbs accounted for 10.4 percent of total vegetation cover, almost ell of which was
<br />the noxious weed Canada thistle IBreea arvensis, aka Cirsium arvensel. Common plantain
<br />(P/antaoo ma/or) and common dandelion (Terexecum ollicina/e/ were also frequently
<br />encountered. Shrubs were a relatively minor component of these areas, with 3.8 percent of
<br />total vegetation cover. Contributions to this total were fairly evenly distributed between
<br />twinberry /DisfeCia invo/ucratal, black chokecherry, common gooseberry, Woods' rose,
<br />• Drummond willow /Salix drummondianal, silver sagebrush, big sagebrush, and mountain
<br />snowberry. Quaking aspen were also marginal components of this type and accounted for 1.8
<br />percent of total vegetation cover. Vascular cryptogamic species, almost entirely field horsetail
<br />lfguisetum arvensel, accounted for 4.8 percent of total vegetation cover. Annual and biennial
<br />forbs were a minor component of the sampled Mesic Drainage communities in the area to be
<br />affected. Native annual and biennial forbs were only 0.5 percent of total vegetation cover,
<br />most of which was bigfruit willowherb. Introduced annual and biennial forbs amounted to 2.4
<br />percent of total vegetation cover, the bulk of which was houndstongue. Bull thistle /Cirsium
<br />vu/ are/ and tarweed /Media Clomeratal were also fairly commonly encountered.
<br />Total vegetation cover in the portion of the Mesic Drainage vegetation type to be affected by
<br />mining was 83.6 percent (Appendix 10F, Table tOF-11, while standing dead, litter, bare soil,
<br />and open water were O.O, 7.5, 7.3, and 1.6 percents, respectively. By comparison, in the
<br />extended reference area portion of the Mesic Drainage vegetation type, total vegetation cover
<br />was 84.6 percent (Appendix tOF, Table tOF-21, while standing dead, litter, bare soil, and rock
<br />were 0.0, 6.0, 5.3, and 3.9 percents, respectively. Species density in the Mesic Drainage
<br />affected areas was 37.6 species per 100 sq. m. (Appendix 10F, Table 10F-11, while in the
<br />extended reference areas, it was 38.6 species per 100 sq. m.
<br />Herbaceous biomass production averaged 3,612 pounds oven-dry per acre in the affected area
<br />(Appendix 10F, Table 10F-31 and 3,137 pounds oven-dry per acre in the extended reference
<br />59 Revised 9/96
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