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11A

Ecological site DX032X01B150

Sandy (Sy) Big Horn Basin Rim

Home / Esd catalog / MLRA 032X / Ecological site DX032X01B150
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T 1-2 - Frequent or high-intensity herbivory on a community weakens the ability for the grasses to persist, especially during prolonged drought. Low vigor in grasses and lack of fire shifts the composition to a more pronounced sagebrush community. In time, sagebrush will increase in density (lack of perennial grass cover), preventing the recovery without intervention.
T 1-3 - Long duration, high-intensity grazing reduces the bunchgrass component and encourages threadleaf sedge and blue grama. Prolonged drought stresses the plants, opening the canopy, and allows these short-statured sod-forming grasses to fill in the interspaces. The shallow, dense root mats will continue to spread over time. The removal of sagebrush with animal impacts, fire or brush management aids in establishing this sod-former community.
R 2-1 - Removal or thinning of the sagebrush by mechanical or chemical means, or by fire, leaving remnant populations of desired native perennial grass species allows the recovery to the Reference State, if climatic variables cooperate and rest occurs for seed development and seedling establishment.
T 2-3 - Sod-forming species such as threadleaf sedge and blue grama can tolerate high levels of use and will maintain as other native species decline. This decline creates a sagebrush–sod-former community that is resistant to change with management. Impacts to sagebrush by disease or insect damage will shift this to the secondary community phase.
T 2-4 - Seed sources are prevalent for cheatgrass, knapweed, and other invasive species. Stress to the native community from drought; events such as wildfire (prescribed burning) and other forms of brush management; or ground/soil disturbance, including impacts by grazing large herbivores or recreation creates a niche for invasive or undesirable weeds. This invasion will start small and spread each year if not addressed immediately.
T 3-4 - The interstitial spaces within the patchy canopy of sod-formers leaves areas for weedy species to establish, especially with disturbance or within high traffic areas.
R 4-5 - Integrated pest management plan or other intense weed control program with seeding will be necessary to overcome a severe weed infestation. Preparing the seedbed and using improved varieties, native seed, or introduced species suited for the management use intended may be the only way to overcome some invasive species.
T 5-4 - In the reclamation or restoration process, or after land disturbance, if no management is put into place to prevent a reoccurrence or a new infestation of weeds, the community will revert back or transition to an invaded state. Wildfire, prescribed burning, drought, or frequent and severe overutilization can be a disturbance that either opens the canopy or introduces the species to the location.
CP 1.1-1.2 - Historic use patterns, drought, and climatic shifts have attributed to the decline in needle and thread and Indian ricegrass. As bare ground increases, species such as prairie Junegrass, blue grama, and threadleaf sedge increase as well as the canopy of sagebrush.
CP 1.2-1.1 - Removal of the historic use patterns in favor of a rest rotation system, and the implementation of wildlife management programs has helped to reduce the grazing pressure and allow rest for recovery. The use of dormant season grazing to thin sagebrush, by reducing overall canopy and encouraging rejuvenation of growth. This also allows grasses the opportunity to spread out from the crown of the sagebrush plant and increase in density within the interspaces.

State 2 submodel, plant communities

CP 3.1-3.2 - In a sod-dominant community, the hydrology has been altered drying the soils and reducing the potential for seedling establishment by many native grasses and shrubs. Once sagebrush is removed from this community by intense grazing pressure, drought or insect damage and disease, the community will move towards a complete sod community. Cactus increases in this transition due to the open interspaces between patches of sod-formers.
CP 4.1-4.2 - The competition for limited resources by invasive species, coupled with the weakening of natives with continued drought stress or grazing pressure, will allow the invasive species to become dominant on the site, leaving only remnant populations of natives. Non-use allows soils to become loose and vulnerable to invasive species in these stressed conditions, allowing expansion as the natives decline.
CP 4.1-4.3 - Removal of sagebrush by fire, drought, or overuse opens the potential for invasion by weedy species, especially by cheatgrass following a fire. Continued overutilization or continued drought will further stress the native grasses, opening the canopy to the threat of invasive species.
CP 4.2-4.1 - The integration of a pest management and weed control plan to reduce competition in conjunction with intensive grazing management over time will encourage the remnant populations of native species protected within the crown of the sagebrush to expand their footprint in the community. In some instances, it may be natives from surrounding communities that will creep back into a weed dominated site. Eradication of the invasive species may not be possible, but it is possible to encourage natives to persist on the site.
CP 4.2-4.3 - A catastrophic disturbance (intense or large-scale fire) resulting in the loss of sagebrush and native grasses opens the potential for invasion by weedy species, especially by cheatgrass following a fire.
CP 5.1-5.2 - Rangeland seeding, and mechanical treatments, can be used to establish native species back to the community. With integrated pest management and intensive weed control and management this site can be maintained.
CP 5.2-5.1 - Abandoned sites or heavily impacted areas will become weedy quickly. If a reclaimed site is not managed properly, abused or left unused, the community will degrade back to early successional or other invasive weedy species.