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

accounted for little total cover. Native shrubs, with 15.7 percent of total vegetation cover,
were the next most abundant lifeform. Almost all of this measurable cover was attributable to •
alkali sagebrush (Seriphidium arbuscu/um ssp. /ongi/obum/ and mountain snowberry. Big
sagebrush (Seriphidium tridentatum and S. vaseyanuml is also frequently present in small
amounts. Introduced annual and biennial forbs accounted for 9.0 of total vegetation cover, the
bulk of which was attributable to twolabe speedwell (Poci//a bilobal. Other frequently
occurring species were prickly lettuce ILactuca serrio/al and salsify (Tragopopon dubiusl.
Native annual and biennial forbs totaled only 1.2 percent of total vegetation cover, most of
which was bigfruit willowherb. Linearleaf collomia was also commonly found. Introduced
annual grasses, primarily Japanese brome accounted for 1.7 percent of total vegetation cover.
Total vegetation cover in the portion of the Western Wheatgrass/Alkali Sagebrush type to be
affected by mining was 46.0 percent (Appendix 10E, Table Appendix t0E-1 ), while standing
dead, litter, bare soil, and rock were 0.1, 33.3, 20.3, and 0.3 percents, respectively. By
comparison, in the extended reference area portion of the Western Wheatgrass/Alkali
Sagebrush vegetation type, total vegetation cover was 60.4 percent (Appendix Appendix 10E,
Table 10E -21, while standing dead, litter, bare soil, and rock were 0.0, 25.5, 14.1, and 0.0
percents, respectively. Species density in the Western Wheatgrass/Alkali Sagebrush affected
areas was 23.1 species per 100 sq. m., while in the extended reference areas, it was 25.2
species per 100 sq. m.
Herbaceous biomass production averaged 1,667 pounds oven-dry per acre in the affected area •
(Appendix 10E, Table 10E-3) and 1,411 pounds oven-dry per acre in the extended reference
area (Appendix 10E, Table 10E-41. In this type, where normal summer drought would have
limited the productivity begun in spring, the rains of summer 1997 continually re-wet the
shallow root zone the seldom-realized highly productive nature of these clays made itself
apparent.
Shrub density in the Western wheatgrass/Alkali Sagebrush vegetation type affected area
averaged 4,290 stems per acre (Appendix 10E, Table 10E-51. In the affected area, where
cover data (Appendix 10-E, Table t0E-51 showed alkali sagebrush exceeding mountain
snowberry, the density data show over 3 times as many (small) snowberry individuals as alkali
sagebrush individuals (Appendix 10E, Table 10E-61. In the extended reference area, where
total shrub density averaged 2558 stems per acre (Appendix 10E, Table 10E-51, alkali
sagebrush were three times more numerous than mountain snowberry.
Mesic Drainage Vegetation Type (Photos 41 through 481
Native perennial cool season grasses and grasslikes dominated the Mesic Drainage Vegetation
Type, accounting for 45.5 percent of total vegetation cover (Appendix 10F, Table 10F-1 ). By
far the largest two contributors to this cover were beaked sedge (Carex utricu/ata/ and •
58 Revised 9/98
Nebraska sedge /Carex nebrascensisl. Other species making significant contributions to