Utilization is the percentage of forage that has been consumed or destroyed during a specific period. By comparing measured utilization with appropriate use levels for key forage plants, and by comparing utilization with actual use, climate, and trend data, short- and long-term stocking level adjustments can be made. Utilization monitoring provides an index to the amount of the current year’s standing crop that remains on the range following grazing. This standing crop helps maintain soil productivity, livestock diet quality, wildlife habitat, and forage plant vigor.
Use pattern mapping will be collected on scheduled allotments to provide an estimate of forage utilization on a pasture or allotment basis. On priority allotments, more detailed utilization data may be collected on key forage plants along permanent transects on existing or new, cooperatively established key areas.
Utilization will be measured on the standing vegetation in a pasture or allotment using Bureau of Land Management (BLM) approved methods. When practical, the times for measuring utilization will be agreed upon by the BLM and livestock grazing permittees, or otherwise will be consistent with federal regulations and BLM policy.
The utilization levels provided in Table W-1 are generally considered to be appropriate for the precipitation levels, vegetative communities, and grazing seasons encountered in the Planning Area. These utilization levels will be considered during the allotment monitoring, assessment, and evaluation process, as well as during activity plan development and the National Environmental Policy Act (NEPA) and permit/lease renewal process, and will be linked to climatic conditions and site-specific vegetative community information.
Although utilization levels may vary from year to year, utilization levels which consistently exceed the levels displayed in Table W-1 would not be expected to meet watershed and vegetation management objectives. Some exceptions may occur. Specialized grazing management may require utilization levels different than those cited.
Although the growing season varies by precipitation zone and from year to year, the growth curves described in the Natural Resources Conservation Service (NRCS) Ecological Site Technical Guides would be used as a guide to growing seasons.
Table W.1. Utilization Levels in the Planning Area
| On an allotment-by-allotment basis, the following utilization levels1 for key species and key areas would be established2 as appropriate in allotments not meeting or not making acceptable progress toward meeting rangeland health standards due to current livestock grazing use or not meeting allotment objectives under current prescribed grazing management3. | On an allotment-by-allotment basis, the following utilization levels1 for key species and key areas would be established2 as appropriate in allotments meeting or making acceptable progress toward meeting rangeland health standards under current livestock grazing use and/or meeting allotment objectives under current prescribed grazing management3. | ||
| Key grass species on key upland sites receiving 14 or less inches annual precipitation | 35% or less utilization of current standing crop during growing season4 50% or less utilization of current year’s growth during dormant season5 | Key grass species on key upland sites receiving 14 or less inches annual precipitation | 50% or less utilization of current standing crop during growing season4 60% or less utilization of current year’s growth during dormant season5 |
| Key grass species on key upland sites receiving greater than 14 inches annual precipitation | 45% or less utilization of current standing crop during growing season4 60% utilization of current year’s growth during dormant season5 | Key grass species on key upland sites receiving greater than 14 inches annual precipitation | 55% or less utilization of current standing crop during growing season4 65% utilization of current year’s growth during dormant season5 |
| Key grass species on all riparian sites | Less than 50% utilization of current year’s growth | Key grass species on all riparian sites | Less than 50% utilization of current year’s growth |
| Key shrub/woody species on all sites | Less than 35% utilization of current year’s growth | Key shrub/woody species on all sites | Less than 40% utilization of current year’s growth |
| 1In areas where extensive wildlife use occurs (crucial winter ranges for elk, bighorn sheep, pronghorn, and sage-grouse, and winter sage-grouse concentration areas or sage-grouse nesting habitat), utilization levels may need to be adjusted downward to ensure that total utilization of current year’s growth following the use period of wildlife does not exceed the prescribed level for dormant season use. 2Although levels may vary widely from year to year, utilization levels which consistently exceed these would not be expected to meet watershed and vegetation management objectives and would necessitate an adjustment in management. 3“Prescribed grazing” is defined as the controlled harvest of vegetation with grazing or browsing animals designed to meet rangeland health standards and allotment specific resource objectives. Prescribed grazing management is outlined in management agreements, allotment management plans, the terms and conditions of a permit or lease, etc. Grazing systems (rest rotation, deferred rotation, short duration, conservatively stocked season-long, etc.), range improvement projects, utilization standards, etc., are tools which could be used on an allotment specific basis to achieve resource objectives. 4Growing season in the 5-9 inch precipitation zone is generally considered to be April-June. Growing season in the 10-14 inch precipitation zone is generally considered to be May-July 15. Growing season in the 15-19 inch precipitation zone is generally considered to be May 15-August 1. 5Dormant season is defined as the period outside of growing season. | |||