2018-08-30_PERMIT FILE - C1982057 ‎(2)‎

• Permit No: C1982057
• IBM Index Class Name: Permit File
• Doc Date: 8/30/2018
• Section_Exhibit Name: Tab 10 Vegetation
• Media Type: D
• Archive: No

Average herbaceous canopy cover was estimated to be 32 percent on the original reference •
area and 17.5 percent on the mine study area. Fo rbs were sparse, contributing an average
of 15 and 4,5 percent cover in the reference and mine study areas, respectively. No one
species ryas strongly dominant, but the more frequently encountered species were western
yarrow, nettleleaf gianthy ssop, American vetch (Vicia ameri cana), and Oregon fleabane
(Erigeron speciosus). Grasses contributed about 17 percent cover in the reference area
and 13 percent in the affected area, also with no single species being dominant. The more
frequently encountered species included fowl bluegrass (Poa palustris) and bl uebunch
wheatgrass (Agropy ron spicatum) on the original reference area and elk sedge and fowl
bluegrass on the mine study area.
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Herbaceous productivity for the original reference area and mine area was 103.1 g/m (920
lb/acre) and 109.1 g/m2 (974 lblacre) respectively (Tables 3-17 and 3-18). Herbaceous
production data from the Mixed Brush vegetation type show that graminoids provided nearly
twice as much annual production as forbs. Kentucky bluegrass and New Mexico bluegrass
(Poa tracyi) provided the bulk of the grami noid production. The four species which
provided most of the rest of the graminoid production were slender wheatgrass (Agropyron
trachy caulum), elk sedge, mountain brome, and basin wi ldrye (Elymus cinereus). The •
contribution of the latter was very sporadic but large where it does occur. Among the
forbs, perennial native forbs comprised the bulk of the production. Important among the
perennial native forbs were western yarrow, nettleleaf gianthyssop, Oregon fleabane,
lupines (Lupinus spp.), and common yampa (Perideridia g_airdneri ).
Estimated average shrub density on the mine study area was 63.0 stems/SOm2 (5,163
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stems/acre), reference area average density was estimated to be 62,5 stems/SOm (5,163
stems/acre). Composition and relative density of different species is highly similar
between the reference and mine study area samples (Tables 3-19 and 3-20).
The number of species sampled in the Mixed Brush type was nearly equal to that of the
Aspen type. Shrubs, especially snowberry, contributed the majority of the canopy cover
and production in this type.
Sagebrush. Tables 4-21 and 4-22 in Appendix 10-4 list cover data collected in the
Sagebrush vegetation type from the mine site and associated reference area. Tables 4-25
and 4-26 include shrub density data. Tables 4-23 and 4-24 present herbaceous production. •
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