Natural Resources
Conservation Service
Ecological site R032XY212WY
Gravelly (Gr) 5-9” Wind River Basin Precipitation Zone
Accessed: 11/21/2024
General information
Provisional. A provisional ecological site description has undergone quality control and quality assurance review. It contains a working state and transition model and enough information to identify the ecological site.
Figure 1. Mapped extent
Areas shown in blue indicate the maximum mapped extent of this ecological site. Other ecological sites likely occur within the highlighted areas. It is also possible for this ecological site to occur outside of highlighted areas if detailed soil survey has not been completed or recently updated.
Associated sites
| R032XY222WY |
Loamy (Ly) 5-9” Wind River Basin Precipitation Zone |
|---|---|
| R032XY250WY |
Sandy (Sy) 5-9” Wind River Basin Precipitation Zone |
| R032XY262WY |
Shallow Loamy (SwLy) 5-9” Wind River Basin Precipitation Zone |
| R032XY266WY |
Shallow Sandy (SwSy) 5-9” Wind River Basin Precipitation Zone |
Similar sites
| R032XY312WY |
Gravelly (Gr) 10-14" East Precipitation Zone Gravelly 10-14" East P.Z. has higher production. |
|---|
Table 1. Dominant plant species
| Tree |
Not specified |
|---|---|
| Shrub |
Not specified |
| Herbaceous |
Not specified |
Physiographic features
This site occurs on nearly level to 50% slopes.
Table 2. Representative physiographic features
| Landforms |
(1)
Alluvial fan
(2) Hill (3) Plateau |
|---|---|
| Flooding frequency | None |
| Ponding frequency | None |
| Elevation | 4,500 – 6,600 ft |
| Slope | 50% |
| Ponding depth |
Not specified |
| Aspect | Aspect is not a significant factor |
Climatic features
Annual precipitation ranges from 5-9 inches per year. The normal precipitation pattern shows peaks in May and June and a secondary peak in September. This amounts to about 50% of the mean annual precipitation. Much of the moisture that falls in the latter part of the summer is lost by evaporation and much of the moisture that falls during the winter is lost by sublimation. Average snowfall is about 20 inches annually. Wide fluctuations may occur in yearly precipitation and result in more dry years than those with more than normal precipitation.
Temperatures show a wide range between summer and winter and between daily maximums and minimums, due to the high elevation and dry air, which permits rapid incoming and outgoing radiation. Cold air outbreaks from Canada in winter move rapidly from northwest to southeast and account for extreme minimum temperatures. Chinook winds may occur in winter and bring rapid rises in temperature. Extreme storms may occur during the winter, but most severely affect ranch operations during late winter and spring.
High winds are generally blocked from the basin by high mountains, but can occur in conjunction with an occasional thunderstorm.
Growth of native cool-season plants begins about April 1 and continues to about July 1. Cool weather and moisture in September may produce some green up of cool season plants that will continue to late October.
The following information is from the “Pavillion” climate station:
Minimum Maximum 5 yrs. out of 10 between
Frost-free period (days): 95 175 May 19 – September 19
Freeze-free period (days): 98 185 May 6 – October 3
Mean Annual Precipitation (inches): 2.50 12.54
Mean annual precipitation: 7.85 inches
Mean annual air temperature: 44.53 F (30.5 F Avg. Min. to 58.5 F Avg. Max.)
For detailed information visit the Natural Resources Conservation Service National Water and Climate Center at http://www.wcc.nrcs.usda.gov/ website. Other climate station(s) representative of this precipitation zone include” Riverton”, “Arminto”, and “Lost Cabin”.
Table 3. Representative climatic features
| Frost-free period (average) | 175 days |
|---|---|
| Freeze-free period (average) | 185 days |
| Precipitation total (average) | 9 in |
Influencing water features
Stream Type: None
Soil features
The soils of this site are moderately deep (greater than 20” to bedrock) to very deep, well to excessively well-drained soils that formed in alluvium or alluvium over residuum. These soils have moderately rapid, or rapid permeability. The surface soil will vary from 3 to 6 inches deep. The coarser topsoils may be included if underlain by finer textured subsoil. The soil characteristic most influential to the plant community is a high volume of coarse fragments on the surface and in the profile, which reduces plant density and available moisture.
Major Soil Series correlated to this site include: Clifsand
Table 4. Representative soil features
| Surface texture |
(1) Fine sandy loam (2) Sandy loam (3) Loam |
|---|---|
| Family particle size |
(1) Loamy |
| Drainage class | Well drained to excessively drained |
| Permeability class | Moderately rapid to rapid |
| Soil depth | 20 – 60 in |
| Surface fragment cover <=3" | 15 – 50% |
| Surface fragment cover >3" | 10% |
| Available water capacity (0-40in) |
1.4 – 4.8 in |
| Calcium carbonate equivalent (0-40in) |
30% |
| Electrical conductivity (0-40in) |
4 mmhos/cm |
| Sodium adsorption ratio (0-40in) |
5 |
| Soil reaction (1:1 water) (0-40in) |
7.4 – 8.4 |
| Subsurface fragment volume <=3" (Depth not specified) |
5 – 35% |
| Subsurface fragment volume >3" (Depth not specified) |
10% |
Ecological dynamics
Potential vegetation on this site is dominated by mid cool-season perennial grasses. Other significant vegetation includes winterfat, big sagebrush, rubber and green rabbitbrush and a variety of forbs. The expected potential composition for this site is about 70% grasses, 15% forbs and 15% woody plants. The composition and production will vary naturally due to historical use, fluctuating precipitation and fire frequency.
As this site deteriorates, species such as threadleaf sedge, blue grama, big sagebrush, shadscale saltbush, and rubber rabbitbrush will increase. Weedy annuals will invade. Mid grasses such as bluebunch wheatgrass, needleandthread, Indian ricegrass, and rhizomatous wheatgrasses will decrease in frequency and production.
The Historic Climax Plant Community (description follows the plant community diagram) has been determined by study of rangeland relic areas, or areas protected from excessive disturbance. Trends in plant communities going from heavily grazed areas to lightly grazed areas, seasonal use pastures, and historical accounts have also been used.
The following is a State and Transition Model Diagram that illustrates the common plant communities (states) that can occur on the site and the transitions between these communities. The ecological processes will be discussed in more detail in the plant community narratives following the diagram.
State and transition model
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Click on state and transition labels to scroll to the respective text
State 1 submodel, plant communities
State 2 submodel, plant communities
State 3 submodel, plant communities
State 4 submodel, plant communities
State 1
Bluebunch wheatgrass/ Neadleandthread
Community 1.1
Bluebunch wheatgrass/ Neadleandthread
The interpretive plant community for this site is the Historic Climax Plant Community. This state evolved with grazing by large herbivores and periodic fires. Potential vegetation is about 70% grasses or grass-like plants, 15% forbs, and 15% woody plants. The state is a mix of warm and cool season midgrasses. The major grasses include bluebunch wheatgrass, needleandthread, rhizomatous wheatgrass, and Indian ricegrass. Other grasses and grass-likes occurring in the state include Sandberg bluegrass, bottlebrush squirreltail, red threeawn, blue grama, and threadleaf sedge. Winterfat, big sagebrush, shadscale saltbush, and rubber and green rabbitbrush are conspicuous components of this state. A variety of forbs also occurs in this state and plant diversity is high (see Plant Composition Table). The total annual production (air-dry weight) of this state is about 200 pounds per acre, but it can range from about 100 lbs./acre in unfavorable years to about 300 lbs./acre in above average years. The state is stable and well adapted to the Northern Great Plains climatic conditions. The diversity in plant species allows for high drought resistance. This is a sustainable plant community (site/soil stability, watershed function, and biologic integrity). Transitions or pathways leading to other plant communities are as follows: • Moderate, Continuous Season-Long grazing will convert the plant community to the Perennial Grass/Mixed Shrub Plant Community. Prolonged Drought will exacerbate this transition.
Figure 2. Annual production by plant type (representative values) or group (midpoint values)
Figure 3. Plant community growth curve (percent production by month). WY0801, 5-9WR upland sites.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|---|---|---|---|---|
| J | F | M | A | M | J | J | A | S | O | N | D |
| 10 | 50 | 25 | 5 | 10 |
State 2
Perennial grass/mixed shrub
Community 2.1
Perennial grass/mixed shrub
Perennial Grass/ Mixed Shrub Plant Community Historically, this plant community evolved under grazing by large ungulates and a low fire frequency. Currently, it is found under moderate, season-long grazing by livestock, and will be exacerbated by prolonged drought conditions. In addition, the fire regime for this site has been modified and extended periods without fire is now common. Shrubs and forbs make up an increasingly significant portion of this plant community. Cool-season grasses make up the majority of the understory with the balance made up of short warm-season grasses. Dominant grasses and grass-likes include needleandthread, rhizomatous wheatgrasses, Sandberg bluegrass, red threeawn, threadleaf sedge, and blue grama. Forbs commonly found in this plant community include scarlet globemallow, Hood’s phlox, sulfur flower buckwheat, and lemon scurfpea. Sagebrush, rubber and green rabbitbrush and shadscale saltbush can make up to 25% of the total annual production. Plains pricklypear will also occur. When compared to the Historic Climax Plant Community, bluebunch wheatgrass and Indian ricegrass have decreased. Shrubs, particularly big sagebrush, rabbitbrush, and shadscale saltbush, and warm season species such as threadleaf sedge, blue grama, and red threeawn have increased. The total annual production (air-dry weight) of this state is about 150 pounds per acre, but it can range from about 75 lbs./acre in unfavorable years to about 200 lbs./acre in above average years. This plant community is resistant to change. The herbaceous species present are well adapted to grazing; however, species composition can be altered through long-term overgrazing. The herbaceous component is mostly intact and plant vigor and replacement capabilities are sufficient. Water flow patterns and litter movement may be occurring but only on steeper slopes. Incidence of pedestalling is minimal. Soils are mostly stable and the surface shows minimum soil loss. The watershed is functioning and the biotic community is intact. Transitions or pathways leading to other plant communities are as follows: • Prescribed grazing or possibly long-term prescribed grazing will convert this plant community to the HCPC. The probability of this occurring is high especially if rotational grazing along with short deferred grazing is implemented as part of a prescribed method of use. In addition, the removal of fire suppression will allow a somewhat natural fire regime to reoccur to more easily transition between this plant community and the HCPC. A prescribed fire treatment can be useful to hasten this transition if desired. • Frequent and severe grazing plus no fires will convert the plant community to the Mixed Shrub/ Bare Ground Vegetation State. The probability of this occurring is high. This is especially evident on areas where drought or heavy browsing does not adversely impact the shrub stand. • Frequent and severe grazing (yearlong) plus fire or Brush Management, will convert the plant community to a Threadleaf Sedge and Blue Grama Sod/ Bare Ground Vegetation State. The probability for this is high especially on areas were the shrubs have been heavily browsed or removed by natural or human causes. Drought can also exacerbate this transition.
Figure 4. Plant community growth curve (percent production by month). WY0801, 5-9WR upland sites.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|---|---|---|---|---|
| J | F | M | A | M | J | J | A | S | O | N | D |
| 10 | 50 | 25 | 5 | 10 |
State 3
Mixed Shrub/ Bare Ground
Community 3.1
Mixed Shrub/ Bare Ground
This plant community is the result of frequent and severe grazing and protection from fire. Sagebrush, rabbitbrush, broom snakeweed, and Shadscale saltbush dominate this plant community as the annual production of shrubs is in excess of 25%. Shrubs, forbs, and warm season grass comprise the significant components of the plant community and the preferred cool season grasses have been eliminated or greatly reduced. The dominant grasses are Sandberg bluegrass, red threeawn, threadleaf sedge, and blue grama. Fringed sagewort, stemless goldenweed, basin rayless daisy, and sulfur flower buckwheat are some of the dominant forbs. Weedy annual species such as cheatgrass, kochia, Russian thistle, halogeton and a variety of mustards may occupy the site. Cactus has increased. Plant diversity is moderate to poor. The interspaces between plants have expanded leaving the amount of bare ground more prevalent. When compared with the HCPC or the Perennial Grass/ Mixed Shrub Plant Communities, the annual production is similar, as the shrub production compensates for the decline in the herbaceous production. The total annual production (air-dry weight) of this state is about 125 pounds per acre, but it can range from about 50 lbs./acre in unfavorable years to about 175 lbs./acre in above average years. This plant community is resistant to change as the stand becomes more decadent. These areas may actually be more resistant to fire as less fine fuels are available and the bare ground between the shrubs is increased. The herbaceous component is not as diverse and plant vigor and species regeneration capabilities of cool-season perennials are deficient. The removal of grazing does not seem to affect the plant composition or structure of the plant community. Soil erosion is accelerated because of increased bare ground. Water flow patterns and pedestalling are obvious. Infiltration is reduced and runoff is increased. Rill channels may be noticeable in the interspaces and gullies may be establishing where rills have concentrated down slope. Transitions or pathways leading to other plant communities are as follows: • Brush management, followed by prescribed grazing and seeding, will return this plant community to at or near the HCPC. If prescribed fire is used as a means to reduce or remove the shrubs, sufficient fine fuels will need to be present. This may require deferment from grazing prior to treatment. Post management is critical to ensure success. This can range from two or more years of rest to partial growing season deferment, depending on the condition of the understory at the time of treatment and the growing conditions following treatment. In the case of an intense wildfire that occurs when desirable plants are not completely dormant, the length of time required to reach the HCPC may be increased and seeding of natives is recommended. • Brush management, followed by frequent and severe grazing, will convert the plant community to a threadleaf Sedge and/or Blue Grama Sod/ Bare Ground Vegetation State. The probability of this occurring is high, because of the amount of bare ground exposed to weedy annuals and sod formers as the competition for space, has been removed.
Figure 5. Plant community growth curve (percent production by month). WY0801, 5-9WR upland sites.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|---|---|---|---|---|
| J | F | M | A | M | J | J | A | S | O | N | D |
| 10 | 50 | 25 | 5 | 10 |
State 4
Threadleaf Sedge and or Blue Grama sod/Bare Ground
Community 4.1
Threadleaf Sedge and or Blue Grama sod/Bare Ground
Threadleaf Sedge and/or Blue Grama Sod Bare Ground Plant Community This plant community is created when the Mixed Shrub/Perennial Grass Plant Community is subjected to severe heavy yearlong grazing and the shrub component has been removed by heavy browsing, wildfire or human means. Additionally, this plant community can occur as a result of the Shrub/Bare Ground Plant Community being subjected to fire or brush management and not followed by prescribed grazing. Weedy annuals, threadleaf sedge, and/or blue grama are the most dominate plants. Weedy annuals occupy any open bare ground areas, while threadleaf sedge and/or blue grama can form extensive sod patches. Rubber rabbitbrush may or may not be present on this site as this species may quickly re-establish the site after a fire. However, heavy browsing by large ungulates will significantly reduce or remove this shrub from this site. Shadscale saltbush can also remain on this site and become more prominent. Compared to the HCPC, weedy annual species are widespread and may include cheatgrass, kochia, Russian thistle, halogeton and a variety of mustards. Cactus and sageworts have increase significantly. Noxious weeds such as Russian knapweed, leafy spurge, or Canada thistle may invade the site if a seed source is available. Virtually all other cool-season mid-grasses are absent or severely decreased. Blue grama and threadleaf sedge have significantly increased from what is found in the HCPC. Shrubs have been removed with the exception of patches of rubber rabbitbrush and shadscale saltbush. Plant diversity is low. The total annual production (air-dry weight) of this state is about 50 pounds per acre, but it can range from about 25 lbs./acre in unfavorable years to about 75 lbs./acre in above average years. This plant community is relatively stable and resistant to overgrazing. Annuals and sod forming grasses are effectively competing against the establishment of perennial cool-season grasses. Plant diversity is greatly altered and the herbaceous component is not intact. Recruitment of perennial grasses is not occurring and the replacement potential is absent. The biotic integrity is missing. On areas with a well established sod plant community, water infiltration will be significantly affected. While this sod protects the area itself, adjacent on-site and off-site areas are impacted by excessive runoff that can cause rill channels and gully erosion. Water flow patterns and pedestalling are obvious. The watershed may or may not be functional. Transitions or pathways leading to other plant communities are as follows: • Grazing land mechanical treatment (chiseling, etc.) and pricklypear cactus control (if needed), followed by prescribed grazing, will return this plant community to near Historic Climax Plant Community condition. The sod areas are extremely resistant to change and will require grazing land mechanical treatments, such as chiseling to revert to a more preferred state. This may not be possible given the presence of cobbles or boulders on the soil surface, which can also exclude reseeding the area. If applicable, mechanical treatments and reseeding native plant species are recommended. This should be followed by proper grazing management to accelerate recovery where few desirable plants remain.
Figure 6. Plant community growth curve (percent production by month). WY0801, 5-9WR upland sites.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|---|---|---|---|---|
| J | F | M | A | M | J | J | A | S | O | N | D |
| 10 | 50 | 25 | 5 | 10 |
Additional community tables
Table 5. Community 1.1 plant community composition
| Group | Common name | Symbol | Scientific name | Annual production (lb/acre) | Foliar cover (%) | |
|---|---|---|---|---|---|---|
|
Grass/Grasslike
|
||||||
| 1 | 40–80 | |||||
| Montana wheatgrass | ELAL7 | Elymus albicans | 40–80 | – | ||
| bluebunch wheatgrass | PSSP6 | Pseudoroegneria spicata | 40–80 | – | ||
| 2 | 20–40 | |||||
| western wheatgrass | PASM | Pascopyrum smithii | 20–40 | – | ||
| 3 | 20–40 | |||||
| Indian ricegrass | ACHY | Achnatherum hymenoides | 20–40 | – | ||
| 4 | 10–20 | |||||
| needle and thread | HECO26 | Hesperostipa comata | 10–20 | – | ||
| 5 | 10–30 | |||||
| Grass, perennial | 2GP | Grass, perennial | 0–10 | – | ||
| Fendler threeawn | ARPUL | Aristida purpurea var. longiseta | 0–10 | – | ||
| blue grama | BOGR2 | Bouteloua gracilis | 0–10 | – | ||
| threadleaf sedge | CAFI | Carex filifolia | 0–10 | – | ||
| squirreltail | ELELE | Elymus elymoides ssp. elymoides | 0–10 | – | ||
| prairie Junegrass | KOMA | Koeleria macrantha | 0–10 | – | ||
| Sandberg bluegrass | POSE | Poa secunda | 0–10 | – | ||
|
Forb
|
||||||
| 6 | 20–30 | |||||
| Forb, perennial | 2FP | Forb, perennial | 0–10 | – | ||
| Franklin's sandwort | ARFR | Arenaria franklinii | 0–10 | – | ||
| prairie sagewort | ARFR4 | Artemisia frigida | 0–10 | – | ||
| woollypod milkvetch | ASPU9 | Astragalus purshii | 0–10 | – | ||
| wavyleaf Indian paintbrush | CAAPM | Castilleja applegatei ssp. martinii | 0–10 | – | ||
| miner's candle | CRVI4 | Cryptantha virgata | 0–10 | – | ||
| little larkspur | DEBI | Delphinium bicolor | 0–10 | – | ||
| cutleaf daisy | ERCO4 | Erigeron compositus | 0–10 | – | ||
| fleabane | ERIGE2 | Erigeron | 0–10 | – | ||
| sulphur-flower buckwheat | ERUM | Eriogonum umbellatum | 0–10 | – | ||
| plains pricklypear | OPPO | Opuntia polyacantha | 0–10 | – | ||
| nailwort | PARON | Paronychia | 0–10 | – | ||
| fuzzytongue penstemon | PEER | Penstemon eriantherus | 0–10 | – | ||
| waxleaf penstemon | PENI3 | Penstemon nitidus | 0–10 | – | ||
| spiny phlox | PHHO | Phlox hoodii | 0–10 | – | ||
| lemon scurfpea | PSLA3 | Psoralidium lanceolatum | 0–10 | – | ||
| scarlet globemallow | SPCO | Sphaeralcea coccinea | 0–10 | – | ||
| thrift mock goldenweed | STARA | Stenotus armerioides var. armerioides | 0–10 | – | ||
|
Shrub/Vine
|
||||||
| 7 | 0–10 | |||||
| Wyoming big sagebrush | ARTRW8 | Artemisia tridentata ssp. wyomingensis | 0–10 | – | ||
| 8 | 0–10 | |||||
| winterfat | KRASC | Krascheninnikovia | 0–10 | – | ||
| 9 | 20–40 | |||||
| Shrub (>.5m) | 2SHRUB | Shrub (>.5m) | 0–10 | – | ||
| shadscale saltbush | ATCO | Atriplex confertifolia | 0–10 | – | ||
| yellow rabbitbrush | CHVI8 | Chrysothamnus viscidiflorus | 0–10 | – | ||
| rubber rabbitbrush | ERNA10 | Ericameria nauseosa | 0–10 | – | ||
| soapweed yucca | YUGL | Yucca glauca | 0–10 | – | ||
Interpretations
Animal community
The following table lists suggested stocking rates for cattle under continuous season-long grazing under normal growing conditions. These are conservative estimates that should be used only as guidelines in the initial stages of the conservation planning process. Often, the current plant composition does not entirely match any particular plant community (as described in this ecological site description). Because of this, a field visit is recommended, in all cases, to document plant composition and production. More precise carrying capacity estimates should eventually be calculated using this information along with animal preference data, particularly when grazers other than cattle are involved. Under more intensive grazing management, improved harvest efficiencies can result in an increased carrying capacity. If distribution problems occur, stocking rates must be reduced to maintain plant health and vigor.
Plant Community Production Carrying Capacity*
(lb./ac) (AUM/ac)
Historic Climax Plant Community 100-300 .08
Perennial Grass/Mixed Shrub 75-200 .06
Mixed Shrub/Bare Ground 50-175 .03
Threadleaf Sedge &/or B. Grama Sod/ B.G. 25-75 .02
* - Continuous, season-long grazing by cattle under average growing conditions.
Grazing by domestic livestock is one of the major income-producing industries in the area. Rangeland in this area may provide yearlong forage for cattle, sheep, or horses. During the dormant period, the forage for livestock use needs to be supplemented with protein because the quality does not meet minimum livestock requirements.
Hydrological functions
Water is the principal factor limiting forage production on this site. This site is dominated by soils in hydrologic group B, with localized areas in hydrologic group C. Infiltration potential for this site varies from moderately rapid to rapid depending on soil hydrologic group and ground cover. Runoff varies from low to moderate. In many cases, areas with greater than 75% ground cover have the greatest potential for high infiltration and lower runoff. An example of an exception would be where short-grasses form a strong sod and dominate the site. Areas where ground cover is less than 50% have the greatest potential to have reduced infiltration and higher runoff (refer to Part 630, NRCS National Engineering Handbook for detailed hydrology information).
Rills and gullies should not typically be present. Water flow patterns should be barely distinguishable if at all present. Pedestals are only slightly present in association with bunchgrasses. Litter typically falls in place, and signs of movement are not common. Chemical and physical crusts are rare to non-existent. Cryptogamic crusts are present, but only cover 1-2% of the soil surface.
Recreational uses
Recreational Uses
This site provides hunting opportunities for upland game species. The wide variety of plants which bloom from spring until fall have an esthetic value that appeals to visitors.
Wood products
No appreciable wood products are present on the site.
Other products
None noted.
Supporting information
Inventory data references
Information presented here has been derived from NRCS inventory data. Field observations from range trained personnel were also used. Those involved in developing this site include: Chris Krassin, Range Management Specialist, NRCS and Everet Bainter, Range Management Specialist, NRCS. Other sources used as references include USDA NRCS Water and Climate Center, USDA NRCS National Range and Pasture Handbook, USDI and USDA Interpreting Indicators of Rangeland Health Version 3, and USDA NRCS Soil Surveys from various counties.
Inventory Data References
Ocular field estimations observed by trained personnel.
Contributors
C. Krassin
Rangeland health reference sheet
Interpreting Indicators of Rangeland Health is a qualitative assessment protocol used to determine ecosystem condition based on benchmark characteristics described in the Reference Sheet. A suite of 17 (or more) indicators are typically considered in an assessment. The ecological site(s) representative of an assessment location must be known prior to applying the protocol and must be verified based on soils and climate. Current plant community cannot be used to identify the ecological site.
| Author(s)/participant(s) | |
|---|---|
| Contact for lead author | |
| Date | 07/01/2005 |
| Approved by | E. Bainter |
| Approval date | |
| Composition (Indicators 10 and 12) based on | Annual Production |
Indicators
-
Number and extent of rills:
Due to the wide slope range associated with this site, the number and extent of rills will vary from none on slope < 9% to common on slopes > 25% -
Presence of water flow patterns:
Due to the wide slope range associated with this site, water flow patterns vary from barely observable on slopes of < 9% from broken and irregular in appearance to continuous on slopes > 25% -
Number and height of erosional pedestals or terracettes:
Not evident on slopes < 9% present on slopes > 9% -
Bare ground from Ecological Site Description or other studies (rock, litter, lichen, moss, plant canopy are not bare ground):
Bare ground is 10-20%. 20-50% of soil surface is coarse fragments -
Number of gullies and erosion associated with gullies:
Active gullies restricted to concentrated water flow patterns on steeper slopes -
Extent of wind scoured, blowouts and/or depositional areas:
None -
Amount of litter movement (describe size and distance expected to travel):
Little to no plant litter movement on slopes < 9%. Litter movement does occur on slopes > 9% -
Soil surface (top few mm) resistance to erosion (stability values are averages - most sites will show a range of values):
Plant cover and litter is at 40% or greater of soil surface and maintains soil surface integrity. Soil Stability class is anticipated to be 4 or greater. -
Soil surface structure and SOM content (include type of structure and A-horizon color and thickness):
Use Soil Series description for depth and color of A-horizon -
Effect of community phase composition (relative proportion of different functional groups) and spatial distribution on infiltration and runoff:
Grass canopy and basal cover should reduce raindrop impact and slow overland flow providing increased time for infiltration to occur. Infiltration varies with soil texture from moderately rapid to rapid. -
Presence and thickness of compaction layer (usually none; describe soil profile features which may be mistaken for compaction on this site):
No compaction layer or soil surface crusting should be present. -
Functional/Structural Groups (list in order of descending dominance by above-ground annual-production or live foliar cover using symbols: >>, >, = to indicate much greater than, greater than, and equal to):
Dominant:
Sub-dominant:
Other:
Additional:
Mid stature Bunch Grasses > mid stature rhizomatous & short grasses > Shrubs > Forbs > -
Amount of plant mortality and decadence (include which functional groups are expected to show mortality or decadence):
Some plant mortality and decadence is expected -
Average percent litter cover (%) and depth ( in):
Average litter cover is 10-15% with depths of 0.10 to 0.25 inches -
Expected annual annual-production (this is TOTAL above-ground annual-production, not just forage annual-production):
200 lbs/ac -
Potential invasive (including noxious) species (native and non-native). List species which BOTH characterize degraded states and have the potential to become a dominant or co-dominant species on the ecological site if their future establishment and growth is not actively controlled by management interventions. Species that become dominant for only one to several years (e.g., short-term response to drought or wildfire) are not invasive plants. Note that unlike other indicators, we are describing what is NOT expected in the reference state for the ecological site:
Threadleaf sedge, blue grama, big sagebrush, shadscale saltbush, rubber rabbitbrush, annuals, exotics, and Species found on Noxious Weed List -
Perennial plant reproductive capability:
May be Limited due to effective moisture and seed to soil contact
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