Cool Loamy, threetip sagebrush
Scenario model
Current ecosystem state
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Management practices/drivers
Select a transition or restoration pathway
- Transition T1 More details
- Restoration pathway R1 More details
- Transition T2 More details
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No transition or restoration pathway between the selected states has been described
Target ecosystem state
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Description
State 1 Narrative:
State 1 represents sagebrush steppe with no invasive or exotic species. All the functional, structural groups have one or more species.
Reference State Community Phases:
1.1 Reference Idaho fescue-bluebunch wheatgrass / threetip sagebrush
1.2 Shrub Steppe Threetip sage / Idaho fescue-bluebunch wheatgrass
Communities 1.1 and 1.2 are stable with a high cover of Idaho fescue/bluebunch wheatgrass and low to moderate cover of threetip sage. Both communities have a minor amount of threadleaf sedge which is native, but also rhizomatous. But when the dominant bunchgrasses exhibit low vigor and decline, threadleaf sedge and threetip sage increase and Japanese brome colonizes the disturbed sites.
Dominate Reference State Species:
Threetip sagebrush, Idaho fescue, bluebunch wheatgrass
At-risk Communities:
• All communities in the reference state are at risk of invasive species. The seed source for Japanese brome or other invasive annual seed blows onto most sites annually.
• Any community becomes at-risk of moving to State 3 when Idaho fescue and bluebunch have low vigor the cover of threadleaf sedge is expanding, and Japanese brome has colonized the site
• Any community is at risk when fire kills the Idaho fescue plants. The holes could quickly be filled by threadleaf sedge or Japanese brome. The site should be inter-seeded that fall or early the following spring
Submodel
Description
State 2 Narrative:
State 2 represents a sedge-shrub community. Many native functional, structural groups have been altered or are missing. Annual grasses such as Japanese brome are present but secondary to the shrub and sedge components.
Community Phases for State 2:
2.1 Sedge-Shrub Threadleaf sedge-Threetip sage
In Community 2.1, sod-forming threadleaf sedge has expanded to a position of dominance. Threetip sage has increased but is quite variable. In some instances, threetip sage is co-dominant and in other instances is secondary to threadleaf sedge. But when the dominant bunchgrasses exhibit low vigor and decline, threadleaf sedge and threetip sage increase. Japanese brome or ventenata may colonize the disturbed sites. The loss of soil biological crusts contributes to the invasion by annual grasses.
Dominate Species in State 2:
Threadleaf sedge, threetip sagebrush
Submodel
Description
Narrative for State 3:
State 3 represents sites that have been seeded. The site was no longer productive for intended uses. So, a commitment was made to kill existing stand and seed more desirable species. Control of threadleaf sedge would be critical to success.
Community Phases for State 3:
3.1 Seeded grasses
3.2 Shrub – Seeded Grasses
Refer to narrative for R1
Dominate Species in State 2:
Desirable seeded grass species w/ or w/o legume
Submodel
Mechanism
T1 Transition from Reference State to State 2 (threadleaf sedge-threetip sagebrush). The Reference State has only a minor amount of threadleaf sedge and no invasive species. In State 2 threadleaf sedge makes a significant increase along with threetip sage.
Primary Trigger: Heavy grazing pressure (heavy grazing intensity, season long grazing or frequent late spring grazing) on Idaho fescue and bluebunch wheatgrass. Also, soil disturbances by rodents, badgers or rabbits allow annual grasses to colonize.
Ecological process. The cover of threadleaf sedge and threetip sagebrush increase as the cover of the dominant bunchgrasses decline. Japanese brome or other invasive annual grasses may colonize disturbed areas and later, expands as opportunity presents itself.
Indicators: increasing gaps between dominant bunchgrasses (Idaho fescue and bluebunch wheatgrass). Expanding cover of threadleaf sedge and threetip sage, and invasive species colonizing disturbed sites.
Mechanism
R1 Transition for State 3 annuals and State 4 seeded.
This restoration transition does not occur without significant time and inputs to control weeds, prepare a seedbed, seed desirable species, and post-seeding weed control and management. This requires a commitment of two years or more to kill threadleaf sedge and for weed control. Care must be taken to maintain soil structure so that the seedbed has many safe-sites for the seed. Seed placement must be managed to achieve seed-soil contact at very shallow depth (about 1/8 inch is desired). Proper grazing management is essential to maintain the stand post-seeding. Secar Snake River wheatgrass, thickspike wheatgrass, Sherman big bluegrass, Sandberg bluegrass, and crested or intermediate wheatgrass are typical species seeded on Cool Loamy ecological site.
The actual transition occurs when the seeded species have successfully established and are outcompeting the threadleaf sedge, shrubs and annual species for cover and dominance of resources.
Mechanism
T2 Transition from State 3 seeded grasses to State 2 threadleaf sedge – threetip sage.
Ecological process: Desirable seeded species have low vigor and are declining. The cover of threadleaf sedge, threetip sage and invasive annuals is expanding. The competitive edge
This transition occurs when the cover of dominant bunchgrasses drops to less than 10% threadleaf sedge has assumed a dominant position in the community.
Primary trigger: heavy grazing pressure (heavy grazing intensity, season long grazing or frequent late spring grazing) reduces the vigor of the desirable seeded species.
Indicators: Declining vigor and cover for the seeded species. Increasing canopy gaps between perennial species. Increasing cover of threadleaf sedge, threetip sage and cover of exotic species.
References:
Boling M., Frazier B., Busacca, A., General Soil Map of Washington, Washington State University, 1998
Daubenmire, R., Steppe Vegetation of Washington, EB1446, March 1968
Davies, Kirk, Medusahead Dispersal and Establishment in Sagebrush Steppe Plant Communities, Rangeland Ecology & Management, 2008
Environmental Protection Agency, map of Level III and IV Ecoregions of Washington, June 2010
Miller, Baisan, Rose and Pacioretty, “Pre and Post Settlement Fire regimes in mountain Sagebrush communities: The Northern Intermountain Region
Natural Resources Conservation Service, map of Common Resource Areas of Washington, 2003
Rapid Assessment Reference Condition Model for Wyoming sagebrush, LANDFIRE project, 2008
Rocchio, Joseph & Crawford, Rex C., Ecological Systems of Washington State. A Guide to Identification. Washington State Department of Natural Resources, October 2015. Pages 156-161 Inter-Mountain Basin Big Sagebrush
Rouse, Gerald, MLRA 8 Ecological Sites as referenced from Natural Resources Conservation Service-Washington FOTG, 2004
Soil Conservation Service, Range Sites for MLRA 8 from 1980s and 1990s
Tart, D., Kelley, P., and Schlafly, P., Rangeland Vegetation of the Yakima Indian reservation, August 1987, YIN Soil and Vegetation Survey
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