2010-03-12_REPORT - C1981019 ‎(8)‎

• Permit No: C1981019
• IBM Index Class Name: REPORT
• Doc Date: 3/12/2010
• Doc Name: 2009 AHR & ARR Section 9 ‎(2009 Revegetation Monitoring Report)‎
• From: Colowyo Coal Company
• To: DRMS
• Annual Report Year: 2009
• Permit Index Doc Type: Hydrology Report
• Email Name: JRS
• Media Type: D
• Archive: No

2.4 Reference Areas
2.4.1 Mountain Shrub Reference Area
The Mountain Shrub Reference Area is; comprised of approximately 18 acres of gently to
moderately sloping vegetation that has a predominately northwesterly aspect (mesic) and easterly aspect
(xeric) (see Plate 1). The Mountain Shrub Reference Area was expanded in 2005 to include the east-
facing slope of the ridge to provide representation from the xeric subtype of the Mountain Shrub
community. The purpose of this inclusion is to provide a better representation of the distribution of
Mountain Shrub communities located on and around Colowyo properties. The xeric exposure tends to
exhibit more elevated herbaceous parameters given a modest reduction in the overstory. This reference
area is located on the undisturbed ridge immediately west of the West Pit Area (see Map 1). A total of 28
plant taxa were observed in this reference area (see Table AB-1). Current annual herbaceous production
across the area averaged 630 pounds per acre in 2009 with perennial grasses the dominant category
(see Table 1). Ground cover in the Mountain Shrub Reference Area (Table AB-2 and Chart AB-1)
consisted of 61.3% live vegetation, 0.7% rock, 33.2% litter, and bare soil exposure of 4.9%. Perennial
cover across the unit averaged 54.7% with annual and biennial cover averaging 6.7%. Dominant taxa
were big sagebrush, bluegrass (Poa agasizensis), mountain snowberry, slender wheatgrass (Agropyron
trachycaulum), and Japanese brome with 10.6 %, 8.6%, 7.5%, 6.3%, and 5.1% average cover,
respectively. With regard to diversity, the Mountain Shrub Reference Area exhibited five perennial
grasses with between 3% and 50% relative cover and relative forb cover of 9.1% (excluding noxious
weeds).
2.4.2 Sagebrush Reference Area
The Sagebrush Reference Area is comprised of approximately 4.7 acres of gently to moderately
sloping vegetation that has a predominately northerly aspect (see Plate 2). This reference area is
located on a gently sloping ridge north of the Administration / Facilities Area (see Map 1). A total of 27
plant taxa were observed in this reference area (see Table AB-1). Current annual herbaceous production
across the area averaged 760 pounds per acre in 2009 with perennial grasses and annual grasses the
dominant categories (see Table 1). Ground cover in the Sagebrush Reference Area (Table AB-2 and
Chart AB-1) consisted of 48.4% live vegetation, 2.55% rock, 37.2% litter, and bare soil exposure of
11.9%. Perennial cover across the unit averaged 39.6% with annual and biennial cover averaging 8.8%.
Dominant taxa were Griffiths wheatgrass (Agropyron albicans), big sagebrush, cheatgrass, prairie
junegrass (Koeleria macrantha), Japanese brome and bluegrass, with 11.1%, 9.7%, 6.0%, 4.3%, 2.5%
and 2.5% average cover, respectively. With regard to diversity, the Sagebrush Reference Area exhibited
three perennial grasses with between 3% and 50% relative cover and relative forb cover of 4.7%
(excluding noxious weeds).
CEDAR CREEK ASSOCIATES, Inc. Page 24 Colowyo Mine
2009 Revegetation Monitoring Report