Sandy Claypan

Description

The Reference State (1.0) represents what is believed to show the natural range of variability that dominated the dynamics of the ecological site prior to European settlement. This site in the Reference State (1.0) is dominated by cool-season grasses with warm-season grasses subdominant. In pre-European times, the primary disturbance mechanisms included frequent fire and grazing by large herding ungulates. Timing of fires and grazing coupled with weather events dictated the dynamics that occurred within the natural range of variability. Taller cool-season wheatgrasses and needlegrasses would have declined and a corresponding increase in short statured grass and grass-like species would have occurred. Today, a similar state can be found on areas that are properly managed with grazing and sometimes on areas receiving occasional short periods of rest.

Dominant plant species

1. rose (Rosa), shrub

2. prairie sagewort (Artemisia frigida), shrub

3. silver sagebrush (Artemisia cana), shrub

4. western wheatgrass (Pascopyrum smithii), grass

5. needle and thread (Hesperostipa comata ssp. comata), grass

6. prairie sandreed (Calamovilfa longifolia), grass

7. green needlegrass (Nassella viridula), grass

8. sand bluestem (Andropogon hallii), grass

9. little bluestem (Schizachyrium scoparium), grass

10. blue grama (Bouteloua gracilis), grass

11. prairie Junegrass (Koeleria macrantha), grass

12. sedge (Carex), grass

13. white sagebrush (Artemisia ludoviciana), grass

14. dotted blazing star (Liatris punctata), grass

15. hairy false goldenaster (Heterotheca villosa), grass

16. prairie clover (Dalea), grass

17. scurfpea (Psoralidium), grass

Submodel

Description

The Shortgrass Sod State is dominated by shortgrass species, upland sedges and clubmoss. This State is the result of grazing management that did not provide adequate recovery time for cool-season wheatgrasses and needlegrass. The hydrologic function of this state is dramatically altered. Runoff is high and infiltration is low. This State is very resistant to change through grazing management alone.

Dominant plant species

1. blue grama (Bouteloua gracilis), grass

2. sedge (Carex), grass

3. Sandberg bluegrass (Poa secunda), grass

4. purple threeawn (Aristida purpurea), grass

5. needle and thread (Hesperostipa comata ssp. comata), grass

6. prairie Junegrass (Koeleria macrantha), grass

7. clubmoss (Lycopodiella), grass

8. white sagebrush (Artemisia ludoviciana), grass

9. tarragon (Artemisia dracunculus), grass

10. goldenrod (Solidago), grass

11. white prairie aster (Symphyotrichum falcatum), grass

12. scurfpea (Psoralidium), grass

Submodel

Description

The Early Successional State (3.0) is dominated by weedy annuals, threeawn, wheatgrass, and pricklypear cactus. This State is the result of heavy disturbance such as frequent and severe defoliation, heavy livestock concentrations coupled with grazing management that does not provide adequate recovery time for cool-season wheatgrasses and needlegrasses. The hydrologic function is also likely to be dramatically altered. Runoff is high and infiltration is low. This State is very resistant to change through grazing management alone.

Dominant plant species

1. threeawn (Aristida), grass

2. field brome (Bromus arvensis), grass

3. blue grama (Bouteloua gracilis), grass

4. sedge (Carex), grass

5. western wheatgrass (Pascopyrum smithii), grass

6. sixweeks fescue (Vulpia octoflora), grass

7. prairie sagewort (Artemisia frigida), grass

8. fetid marigold (Dyssodia papposa), grass

9. Cuman ragweed (Ambrosia psilostachya), grass

10. pussytoes (Antennaria), grass

11. prostrate verbena (Verbena officinalis var. prostrata), grass

Submodel

Description

This State is dominated by western wheatgrass, needle and thread, and non-native cool-season annual and perennial grasses. The Native/Invaded State (4.0) can resemble the Reference State (1.0) in species composition and vegetative production except that it is invaded by non-native cool-season grasses.

Dominant plant species

1. western wheatgrass (Pascopyrum smithii), grass

2. needle and thread (Hesperostipa comata ssp. comata), grass

3. field brome (Bromus arvensis), grass

4. blue grama (Bouteloua gracilis), grass

5. Kentucky bluegrass (Poa pratensis), grass

6. crested wheatgrass (Agropyron cristatum), grass

7. white sagebrush (Artemisia ludoviciana), grass

8. scarlet globemallow (Sphaeralcea coccinea), grass

9. common yarrow (Achillea millefolium), grass

10. scurfpea (Psoralidium), grass

Submodel

Description

Any plant community can transition to the Disturbed State (5.0). The two separate vegetative plant communities found in this State are highly variable in nature. They are derived through different management scenarios and are not related successionally. Infiltration, runoff, and soil erosion vary depending upon the vegetation present on the site.

Dominant plant species

1. broom snakeweed (Gutierrezia sarothrae), shrub

2. threeawn (Aristida), grass

3. dropseed (Sporobolus), grass

4. field brome (Bromus arvensis), grass

5. crested wheatgrass (Agropyron cristatum), grass

6. smooth brome (Bromus inermis), grass

7. western wheatgrass (Pascopyrum smithii), grass

8. foxtail barley (Hordeum jubatum), grass

9. sweetclover (Melilotus), grass

10. mountain deathcamas (Zigadenus elegans), grass

11. prickly lettuce (Lactuca serriola), grass

12. Canadian horseweed (Conyza canadensis), grass

13. forage kochia (Bassia prostrata), grass

14. common sunflower (Helianthus annuus), grass

Submodel