State 1
Historic Climax Plant Community

Community 1.1
Historic Climax Plant Community

State Containing the Historic Climax Plant Community Grassland State: The historic plant community is dominated by western wheatgrass. Other important grasses that typically appear on this site include, alkali sacaton, blue grama, galleta, vine mesquite and spike muhly. Fourwing saltbush is the dominant shrub. Rabbitbrush, broom snakeweed, and winterfat may also be sparsely scattered across the site. Continuous heavy grazing will cause a decrease in western wheatgrass and vine mesquite. A community dominated by alkali sacaton or blue grama and galleta with western wheatgrass as the subdominant may result. In other instances, especially on the heavier textured clay soils, a sparse, less productive, near monotypic stand of western wheatgrass may persist. Diagnosis: Grass cover is uniform with few large bare areas present. Shrubs are scattered with canopy cover averaging five percent. Evidence of erosion such as pedestalling of grasses, rills and gullies is infrequent.

State 2
Dry Grassland

Community 2.1
Dry Grassland

Additional States: Dry Grassland: This site is characterized by decreased available soil moisture. Typically alkali sacaton or blue grama is the dominant grass species. Alkali sacaton is generally found in clumps or tussocks with interconnected bare areas between plants. Blue grama occurs as low vigor sod like patches with frequent large bare areas present. Diagnosis: Grass cover is patchy with large interconnected bare areas present. Alkali sacaton or blue grama are the dominant grass species. Rills, gullies, or obstructions to overland flow are present. Transition to Dry Grassland (1a): Soil drying due to blocked or redirected flow of run-on water, loss of grass cover, or gullying are thought to initiate this transition. Water retention or diversion structures, sediment deposition, or roads may block or divert water that would naturally run-on to the site. Roads or trails may concentrate water during high flow periods and facilitate gully formation. Loss of adequate grass cover due to overgrazing can decrease infiltration, increase runoff rates, and initiate gullying. Key indicators of approach to transition: *Reduction in western wheatgrass cover and increase in size and frequency of bare patches. *Increase in cover of blue grama, galleta, ring muhly and mat muhly. *The formation of trails, gullies, barriers or other features that disrupts natural overland flow Transition back to Grassland (1b) The natural hydrology of the site must be restored. Erosion control structures, shaping or filling gullies, culverts, turnouts, or moving or re-routing obstructions may be necessary to restore natural run-on flow patterns. Prescribed grazing will help restore and maintain adequate grass cover.

State 3
Bare State

Community 3.1
Bare State

Bare State: Extensive areas of bare ground characterize this site. Surface soils in most bare areas are sealed over with physical crusts. Herbaceous cover consists mainly of annuals. If perennial grasses are present they occur only in isolated patches. Diagnosis: Annuals are the dominant herbaceous vegetation. Extensive interconnected bare areas are common with scattered or no grass plants. Evidence of erosion such as rills and gullies are present. Transition to Bare State (4a) The continued loss of remaining grass cover due to overgrazing or soil drying may cause this transition. The subsequent sealing of the soil surface by physical crusts can inhibit grass reestablishment.4 Additionally, heavy use by livestock during periods when the soils are saturated can cause trampling damage and soil compaction. Soil compaction decreases infiltration limiting grass reestablishment. Transition back to Grassland (4b) The hydrology of the site must be restored first (see 1b). Seeding is necessary to reestablish Bottomland grasses. Prescribed grazing will help ensure adequate rest and proper forage utilization following grass establishment. The degree to which this site is capable of recovery depends on the restoration of hydrology, the extent of degradation to soil resources, and adequate rainfall necessary to establish grasses.

State 4
Shrub-Dominated

Community 4.1
Shrub-Dominated

Shrub-Dominated: This state is characterized by the predominance of shrubs, especially rabbitbrush, and in some instances fourwing saltbush. Blue grama, galleta, or sparse western wheatgrass are typically the dominant grass species. Diagnosis: Rabbitbrush or fourwing saltbush is found at increased densities relative to the Grassland state. Grass cover is patchy with large bare areas present. Evidence of erosion such as pedestalling of plants, elongated water flow patterns, litter dams, and rills or gullies is common. Transition to Shrub-Dominated (2, 3a) Loss of grass cover and resulting decreased competition by grasses are believed to initiate this transition. The loss of grass cover may be due to a change in hydrology, overgrazing, or other disturbance such as fire. Rabbitbrush is believed to increase under heavy grazing pressure6, and after 1-3 years following fire7. Fourwing saltbush is a highly palatable shrub and typically decreases in response to heavy browsing.2 Resource competition by grasses is reported to negatively affect the establishment of fourwing saltbush.3 It may be possible that fourwing saltbush increases in response to a loss of grass cover and reduced competition, due to causes other than heavy grazing. Key indicators of approach to transition: * Change in composition or distribution of grass cover. * Increase in size and frequency of bare patches. * Increase in amount of shrub seedlings. Transition back to Grassland (3b) Brush control may be necessary to initiate the transition back to the grassland state. Chemical control has been shown to be effective in controlling 12 rabbitbrush.1, 5 Root plowing and other mechanical methods that sever the plant below the root crown may reduce rabbitbrush densities, however follow up treatment may be necessary. Prescribed grazing will help ensure adequate rest following brush control and will assist in the establishment and maintenance of grass cover. In addition the natural hydrology of the site must be restored if the transition pathway was from Dry Grassland to Shrub-Dominated (2). See Transition Back to Grassland (1b).