Natural Resources
Conservation Service
Ecological site R047XA620UT
Subalpine Meadow (alpine timothy)
Accessed: 11/24/2024
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.
Classification relationships
Modal Soil: Cluff Family GR-L 2-8% — clayey-skeletal, montmorillonitic Mollic Cryoboralfs
Table 1. Dominant plant species
| Tree |
Not specified |
|---|---|
| Shrub |
Not specified |
| Herbaceous |
(1) Phleum alpinum |
Physiographic features
This site occurs on till plains of past-glaciated mountains at elevations between 9,800 and 11,000 feet. Slopes are gentle at 2 to 8 percent and runoff is medium. Flooding and ponding do not occur on these meadows and they do not have a seasonally high water table.
Table 2. Representative physiographic features
| Landforms |
(1)
Till plain
|
|---|---|
| Flooding frequency | None |
| Ponding frequency | None |
| Elevation | 2,987 – 3,353 m |
| Slope | 2 – 8% |
Climatic features
The climate is characterized by cool, moist summers and cold, snowy winters. Approximately 70 percent of the precipitation occurs as snow from October through May. On the average, June through August are the driest months and September through May are the wettest months.
Table 3. Representative climatic features
| Frost-free period (average) | 60 days |
|---|---|
| Freeze-free period (average) | 0 days |
| Precipitation total (average) | 1,016 mm |
Figure 2. Monthly average minimum and maximum temperature
Influencing water features
Due to its landscape position, this site is not typically influenced by streams or wetlands.
Soil features
The soils of this site formed in glacial till derived from sandstone and conglomerate rocks. They are moderately deep to deep over bedrock and have rock fragments on the soil surface and throughout the profile. These soils are well-drained with gravelly loam textures and moderate permeability. Available water holding capacity ranges from 3.8 to 5.0 inches of water in the upper 40 inches of soil. The soil moisture regime is xeric and the soil temperature regime is frigid. This site is correlated to the Crandall soil component of soil map unit 111 in the Summit Area soil survey (UT613).
Table 4. Representative soil features
| Surface texture |
(1) Gravelly loam |
|---|---|
| Family particle size |
(1) Loamy |
| Drainage class | Well drained |
| Permeability class | Moderate |
| Soil depth | 102 – 152 cm |
| Surface fragment cover <=3" | 20% |
| Surface fragment cover >3" | 11% |
| Available water capacity (0-101.6cm) |
9.65 – 12.7 cm |
| Calcium carbonate equivalent (0-101.6cm) |
0% |
| Electrical conductivity (0-101.6cm) |
0 mmhos/cm |
| Sodium adsorption ratio (0-101.6cm) |
0 |
| Soil reaction (1:1 water) (0-101.6cm) |
6.1 – 7.3 |
| Subsurface fragment volume <=3" (Depth not specified) |
22% |
| Subsurface fragment volume >3" (Depth not specified) |
19% |
Ecological dynamics
As this site deteriorates due to grazing pressure, alpine timothy decreases while sedges increase. When the potential natural plant community is burned, forbs decrease and grasses increase.
State and transition model
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Ecosystem states
State 1 submodel, plant communities
State 1
Reference State
Community 1.1
Reference State
The general view of this site is grass and forbs. The composition by air-dry weight is approximately 80 percent perennial grasses and grasslike plants and 20 percent forbs.
Figure 3. Annual production by plant type (representative values) or group (midpoint values)
Table 5. Annual production by plant type
| Plant type | Low (kg/hectare) |
Representative value (kg/hectare) |
High (kg/hectare) |
|---|---|---|---|
| Grass/Grasslike | 1031 | 1390 | 1749 |
| Forb | 258 | 347 | 437 |
| Total | 1289 | 1737 | 2186 |
Table 6. Ground cover
| Tree foliar cover | 0% |
|---|---|
| Shrub/vine/liana foliar cover | 0% |
| Grass/grasslike foliar cover | 69-71% |
| Forb foliar cover | 14-16% |
| Non-vascular plants | 0% |
| Biological crusts | 0% |
| Litter | 0% |
| Surface fragments >0.25" and <=3" | 0% |
| Surface fragments >3" | 0% |
| Bedrock | 0% |
| Water | 0% |
| Bare ground | 0% |
Table 7. Canopy structure (% cover)
| Height Above Ground (m) | Tree | Shrub/Vine | Grass/ Grasslike |
Forb |
|---|---|---|---|---|
| <0.15 | – | – | – | – |
| >0.15 <= 0.3 | – | – | – | 14-16% |
| >0.3 <= 0.6 | – | – | 69-71% | – |
| >0.6 <= 1.4 | – | – | – | – |
| >1.4 <= 4 | – | – | – | – |
| >4 <= 12 | – | – | – | – |
| >12 <= 24 | – | – | – | – |
| >24 <= 37 | – | – | – | – |
| >37 | – | – | – | – |
Additional community tables
Table 8. Community 1.1 plant community composition
| Group | Common name | Symbol | Scientific name | Annual production (kg/hectare) | Foliar cover (%) | |
|---|---|---|---|---|---|---|
|
Grass/Grasslike
|
||||||
| 0 | Dominant Grasses | 915–1435 | ||||
| alpine timothy | PHAL2 | Phleum alpinum | 269–359 | – | ||
| mountain bentgrass | AGVA | Agrostis variabilis | 179–269 | – | ||
| tufted hairgrass | DECE | Deschampsia cespitosa | 179–269 | – | ||
| timber oatgrass | DAIN | Danthonia intermedia | 90–179 | – | ||
| fringed brome | BRCI2 | Bromus ciliatus | 90–179 | – | ||
| smallwing sedge | CAMI7 | Carex microptera | 54–90 | – | ||
| alpine bluegrass | POAL2 | Poa alpina | 54–90 | – | ||
| 1 | Sub-Dominant Grasses | 108–179 | ||||
| Grass, annual | 2GA | Grass, annual | 54–90 | – | ||
| Grass, perennial | 2GP | Grass, perennial | 54–90 | – | ||
|
Forb
|
||||||
| 2 | Sub-Dominant Forbs | 717–1076 | ||||
| Forb, annual | 2FA | Forb, annual | 269–359 | – | ||
| Forb, perennial | 2FP | Forb, perennial | 269–359 | – | ||
| sulphur-flower buckwheat | ERUMU2 | Eriogonum umbellatum var. umbellatum | 90–179 | – | ||
Interpretations
Animal community
This site provides grazing for cattle and sheep during the summer and fall.
Food and Cover
Wildlife using this site include moose, elk, mule deer, snowshoe hare, badger, grouse, and owl.
Hydrological functions
The soil series in in hydrologic group c. The hydrologic curve number is 74 when the vegetation is in good condition.
Recreational uses
Hiking and hunting
Wood products
None
Supporting information
Contributors
Darryl Trickler, David Somerville
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) | V. Keith Wadman, NRCS Retired. |
|---|---|
| Contact for lead author | shane.green@ut.usda.gov |
| Date | 10/15/2012 |
| Approved by | Shane A. Green |
| Approval date | |
| Composition (Indicators 10 and 12) based on | Annual Production |
Indicators
-
Number and extent of rills:
None. A very slight amount of rill development may be observed following large storm events or spring runoff periods, but they should heal within the following growing season. Slight rill development may also be observed where the site is adjacent to ecological sites that produce large amounts of runoff (i.e. steeper sites, slickrock, etc.). -
Presence of water flow patterns:
None to rare. Any flow patterns present should be sinuous and wind around perennial plant bases. They should be short (5 to 10 feet), < one foot wide, and spaced from 20 to 30 feet apart. They should be stable with only minor evidence of deposition. Flooding and ponding do not occur on these high elevation meadows and they do not have a seasonally high water table. -
Number and height of erosional pedestals or terracettes:
None to rare. A few plants may show very minor pedestalling where they are adjacent to any water flow patterns present, but there will be no exposed roots. Terracettes are not present. -
Bare ground from Ecological Site Description or other studies (rock, litter, lichen, moss, plant canopy are not bare ground):
10 to 20% bare ground. Any bare ground openings present should be < 1 foot in size and should not be connected. -
Number of gullies and erosion associated with gullies:
None to Very Slight. Some slight gully development may be evident following significant weather events or where they convey runoff from higher elevation sites and/or rocky or naturally eroding areas. -
Extent of wind scoured, blowouts and/or depositional areas:
No evidence of wind generated soil movement. Wind scoured (blowouts) and depositional areas are not present. -
Amount of litter movement (describe size and distance expected to travel):
The majority of litter accumulates in place at the base of plant canopies. Slight movement of the finest material (< 1/4 inch) may move 1 to 2 feet downslope when transported by water. Little accumulation is observed behind obstructions. -
Soil surface (top few mm) resistance to erosion (stability values are averages - most sites will show a range of values):
This site should have a soil stability rating of 5 to 6 under plant canopies and a rating of 4 to 5 in any interspaces present. The average should be 5. Surface textures typically vary from sandy loams to loams. -
Soil surface structure and SOM content (include type of structure and A-horizon color and thickness):
(Crandall) Soil surface is typically 0 to 5 inches deep. Surface texture is a gravelly loam, and structure is weak fine granular. The A-horizon color is brown, (7.5YR 4/3). Soils have an Mollic epipedon that extends 10 to 16 inches into the soil profile. Use the specific information for the soil you are assessing found in the published soil survey to supplement this description. -
Effect of community phase composition (relative proportion of different functional groups) and spatial distribution on infiltration and runoff:
Perennial vegetation breaks raindrop impact and reduces splash erosion. Dense distribution of plants slows runoff by obstructing surface flows, allowing time for increased infiltration. -
Presence and thickness of compaction layer (usually none; describe soil profile features which may be mistaken for compaction on this site):
None. This site will normally have textural changes within its' profile. These should not be mistaken for compaction layers. -
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:
Perennial Grasses (alpine timothy, tufted hairgrass, bentgrasses) > Perennial Forbs (Sulphurflower wild buckwheat).Sub-dominant:
Sprouting Shrubs (silver sage, woods rose > Rhizomatous Grasses and grasslikes (arctic rush, alpine bluegrass)Other:
Functional/structural groups may appropriately contain non-native species if their ecological function is the same as the native species in the reference state. Biological soil crust is variable in its' expression where present on this site and is measured as a component of ground cover. Perennial and annual forbs can be expected to vary widely in their expression in the plant community based upon departures from average growing conditions.Additional:
Disturbance regimes include insects and infrequent . Temporal variability can be caused by fires, droughts, insects, etc. Spatial variability can be caused by runoff, soil pH, and topography. -
Amount of plant mortality and decadence (include which functional groups are expected to show mortality or decadence):
During years with average to above average precipitation, there should be no mortality or decadence in either perennial grasses or grasslikes. During severe (multi-year) droughts that affect groundwater levels, up to 10% of the perennial plants may die. There may be partial mortality of individual grasses and grasslikes during less severe droughts. -
Average percent litter cover (%) and depth ( in):
Litter cover ranges from 40 to 60%. Depth should be 1 inch thickness in any interspaces 2 inches under perennial plant canopies. -
Expected annual annual-production (this is TOTAL above-ground annual-production, not just forage annual-production):
Annual production in air-dry herbage should be approximately 1500 to 1600 pounds per acre on an average year. Production could vary from 1100 to 2000 pounds per acre during drought or above-average years. -
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:
Black medic, Canada thistle, curlycup gumweed, whitetop and other non-native forbs and grasses. -
Perennial plant reproductive capability:
All perennial plants should have the ability to reproduce sexually or asexually in most years, except in drought years.
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