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RULE 2 PERMITS <br /> <br />South Taylor – Rule 2, Page 34 Revision Date: 7/21/25 <br /> Revision No.: MR-267 <br />where: nmin = the minimum number of observations needed <br />t = the distribution value at a given confidence level (CL); i.e. 1.64 (90% CL) for <br />grassland communities and 1.282 (80% CL) for shrubland communities <br /> s2 = the sample variance <br /> d2 = 10% level of accuracy, or 0.1 <br /> x = the sample mean <br />An adequate sample for each parameter (cover and production) was determined in each vegetation type <br />by exceeding the nmin requirement obtained from the equation with a minimum of 15 samples. <br />Data Analyses - Cover data were summarized by determining the mean percent cover, relative percent <br />cover, and standard deviation for each species, lifeform group, rock, litter, and bare ground within each <br />vegetation type sampled. Above ground standing biomass of species (production) was determined as the <br />mean dry weight of all species in all plots within each vegetation type sampled. Production was <br />expressed in grams per square meter and pounds per acre for each type. Shrub density was computed as <br />the mean number of plants per 50 square meters and the mean number of plants per 0.1 acre for all <br />species. Tree density was computed as the mean number of plants per 100 square meters and the mean <br />number of plants per 0.1 acre for all species. Species diversity was computed as the mean number of <br />different species encountered by vegetation hits along the 50-meter cover transect. <br />Statistical Equivalency of Reference Areas - The statistical equivalency of each reference area with the <br />study area was determined for vegetation cover, production and species density in each vegetation type <br />according to the following equation (OSM 1980): <br />(x 1 −x 2 )<or >t (s 21 /n1 )+(s2 2 /n 2 ) <br />Where: x = sample mean <br />s2 = sample variance <br />t = t table value for 90% confidence level <br />n = sample size <br />Livestock Carrying Capacity - Livestock carrying capacity of each vegetation type was determined by <br />considering the nutritional requirements of cattle and sheep (Stoddart et al, 1975) according to the <br />following assumptions. A cow and calf (cattle animal unit) consumes 900 pounds of air-dry forage per <br />month and a ewe and lamb (sheep animal unit) consumes 150 pounds of air-dry forage per month. The <br />conversion of oven dry weight to air-dry weight is 1.11. The ideal utilization factor for forage grazing is <br />50 percent. The livestock carrying capacity was determined by the following: <br />LCC = (1.11 x FA x .5) / FC <br />where: LCC = Livestock Carrying Capacity (AUM per acre) <br /> FA = Forage Available (oven-dry lbs/acre) <br /> FC = Forage Consumption Requirement (900 lbs for cattle AUM, 150 lbs for sheep <br />AUM) <br />Results - The vegetation of the Danforth study area is typical of northwestern Colorado. Hillsides are <br />covered with a mixture of mountain shrub and aspen forests at upper elevations while sagebrush <br />dominates the lower elevations. Valley bottoms are dominated by a mixture of grassy meadows and <br />sagebrush. The valley bottoms are used more intensively for grazing than upland areas. Hay is produced