2012-08-10_PERMIT FILE - C1981018A

• Permit No: C1981018A
• IBM Index Class Name: Permit File
• Doc Date: 8/10/2012
• Section_Exhibit Name: SECTION II.E & II.F Climatology Report & Vegetaton Studies
• Media Type: D
• Archive: Yes

ERO Resouroes
e. BIG SAGE9iUSHikEATGRASS TWE
l J
(11 Location and Distribution;
The big sagebrush-wheatgrass type is the most common vegetation type on
the permit area. This vegetation type occurs on a wide variety of terrain
including ridgetops, sidealopes and upland valleys and iraludes units 10
and 11 on the vegetation map (Table 4 and Maps 9 and 10, Pocketl. Pig
sagebrush-wheatgrass sites display an internal patchiness within the
overall mosaic. The two largest segments of this characteristic are
controlled by soils and by past and present land use. Variation in soils
alter the density characteristics of the sagebrush overstory and the herb
understory. Differences in the intensity of sheep utilization of areas
also contribute to the nature of the shrub overstory and herb layer. The
patchirwse can be described vegetationally by the amount of Colorado
wildrye in the herb understory versus western wheatgrass. The shrub
canopy in those areas where Colorado wildrye predominates is more closed,
whereas the western wheatgrass sites are marked by a more open shrub
• layer. Soils underlying the more dense sagebrush areas are primarily
coarse. Under the open sagebrush-western wheatgrass sites soil textural
turd more toward loamy and are more shallow. Although these units are
mapped separately, the dynamics of both are highly interrelated. In
addition, both units are the products of a sagebrush-wheatgrass type that
predominated on the site prior to overgrazing. As such, a single
discussion iraorporating both of the subtypes is appropriate to
understanding their interrelatedness and to explaining the effects of land
use on this type. This type accounts for 132.9 acres of the total
affected mine permit area (Table 5).
(2) Structure and Composition:
Ground cover values in the big sagebrush-wheatgrass sites sampled are
lichens and mosses - 1.7x, litter - 27,4x, rock 1.4X, soil - S7.3X and
woody species - 16.1X. In the refererae areas these values are lichens
and mosses - 1.0X, litter - 30.5X, rock 1.8X, coil - 56.5% and woody
• species - 17. 3X (Figure 4, Table 61.
II.F-34