Alkali Terrace
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 Alkali Terrace with no invasive or exotic species. All the functional, structural groups have one or more species.
By cover saltgrass dominates the Reference Community
By weight basin wildrye dominates the Reference Community
Reference State Community Phases:
1.1 Reference Basin wildrye – Saltgrass
1.2 Rhizomatous Saltgrass – Basin wildrye
Dominate Reference State Species:
Basin wildrye, saltgrass
At-risk Communities:
• All communities in the reference state are at risk of invasive species. Annual or biennial weeds and annual grass seeds blow onto most sites annually
Submodel
Description
State 2 Narrative:
State 2 represents Alkali Terrace where invasive broadleaf weeds and/or invasive annual grasses have prominence. Basin wildrye is all but missing and saltgrass remains as a patchwork of spots and clumps.
State 2 can have two variations, both with or without rabbitbrush:
1. Broadleaf annual or biennial weeds w/ saltgrass patches
2. Annual grasses w/ saltgrass patches
Community Phases for State 2:
Invasive broadleaf annual or biennial weeds with patches of saltgrass
Invasive annual grasses with patches of saltgrass
Some Invasive Species in State 2:
cheatgrass slender cinquefoil rabbitsfoot grass
foxtail barley perennial pepperweed
Description
State 3 Narrative:
State 3 represents a site that has been seeded to desirable grasses such as basin wildrye, beardless wildrye, tall wheatgrass, or western wheatgrass.
Community Phases for State 3:
3.1 Seeded Grass
3.2 Shrub – Seeded Grass
Submodel
Mechanism
T1 Result: Shift from Reference State to State 2 with invasive species
Primary Trigger: Grazing pressure (heavy intensity, season long grazing, frequent late spring grazing) to basin wildrye.
Ecological process: with consistent grazing pressure basin wildrye has poor vigor, shrinking crowns and mortality. Initially, saltgrass increases but then declines with further grazing pressure. Invasive species colonize and as the deterioration continues, eventually dominate the site.
Indicators: Increasing gaps between basin wildrye plants, decreasing cover of saltgrass and increasing cover of invasive species.
Mechanism
R1 Transition from State 2, a community dominated by invasive annual species, to State 3, which is predominately desirable seeded grasses. Species selection for the seeding is critical as the site is moderately saline-sodic.
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. It may take two years or longer to kill invasive annual species and remaining saltgrass, and to exhaust the seedbank of invasive weed seeds. 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 a very shallow depth (about 1/8 inch is desired). Species that can tolerate the saline-sodic conditions include basin wildrye, beardless wildrye, tall wheatgrass, and western wheatgrass. Proper grazing management is essential to maintain the stand post-seeding.
The actual transition occurs when the seeded species have successfully established and are outcompeting the annual species for cover and dominance of resources.
Mechanism
T2 Result: Shift from State 3 seeded grasses to State 2 with invasive species
Primary Trigger: Grazing pressure (heavy intensity, season long grazing, frequent late spring grazing) to desirable seeded grasses.
Ecological Process: with consistent grazing pressure desirable grasses have poor vigor, shrinking crowns and mortality. This allows invasive species to colonize and then expand to a position of dominance.
Indicators: increasing gaps between basin wildrye plants, increasing cover of invasive 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
Model keys
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