PERMFILE41090

• Permit No: C1981021
• IBM Index Class Name: Permit File
• Doc Date: 12/11/2001
• Section_Exhibit Name: APPENDIX B VEGETATION STUDIES
• Media Type: D
• Archive: No

for 15 percent of the total biomass. Idaho fescue and needlegrass were the most
productive species with 5.61 and 4.34 grams per square meter, respectively. Eight
~rcent of the total biomass was attributable to fortis. 5nakeweed, the only
semi-shrub, accounted for 4 percent of the total biomass.
The mean total shrub density in the affected area big sagebrush community
was 45,467 individuals per hectare (18,408/acre) (Table 10). The most abundant
species was big sagebrush with 42,133 individuals per hectare (17,058/acre).
Fifty-nine percent of this total was in the first height class, 36 percent were
~ , ;;
in the second height class and 5 percent in the third height class. Three species of
rabbitbrush, (Chrysotizamizus nauseosus,)., (Chrysothanmus, viscidif'Zorus) and
(Chrysotha~mzus parryi) vrere the next most abundant species with 1,533 (621/acre),
767 (311/acre) and 733 (297/acre) individuals per hectare, respectively. Black
sage (Artemisia nova) and horsebrush (Tetradymia canescens) were the least
abundant species with 267 (108/acre) and 33 (13/acre) individuals per hectare,
~spectively. Big sagebrush had the highest mean cover value with 27.2 percent.
All other species had cover values less than 2 percent.
The reference area big sagebrush community had a similar mean total shrub
density with 47,867 individuals per hectare (19,379/acre) (Table 11). Big
sagebrush, the most abundant species, had 46,567 (18,853/acre) individuals per
hectare. Sixty-three percent of those individuals were in the first height
class, 32 percent in the second and 5 percent in the third height rlass. Two
species of rabbitbrush, (Chrysothamnus parryi) and (Chrysotharmzus viscidiflorus)
were the next most abundant species with 667 (270/acre) and 567 (230/acre)
individuals per hectare, respectively. Horsebrush and rubber rabbitbrush
(Chrysotharmils nauseosus) were the least abundant species v:ith 33 (13/acre)
individuals per hectare each. Big sagebrush had the highest mean cover value
~th 24.8 percent.
The affected areas and reference area for the big sagebrush community were
also evaluated using t-tests. There were no significant differences between the
control and reference areas for the total vegetation cover, total production, and