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.
MLRA notes
Major Land Resource Area (MLRA): 047X–Wasatch and Uinta Mountains
MLRA 47 occurs in Utah (86 percent), Wyoming (8 percent), Colorado (4 percent), and Idaho (2 percent). It encompasses approximately 23,825 square miles (61,740 square kilometers). The northern half of this area is in the Middle Rocky Mountains Province of the Rocky Mountain System. Parts of the western edge of this MLRA are in the Great Basin Section of the Basin and Range Province of the Intermontane Plateaus. The MLRA includes the Wasatch Mountains, which trend north and south. The steeply sloping, precipitous Wasatch Mountains have narrow crests and deep valleys. Active faulting and erosion are a dominant force in controlling the geomorphology of the area.
The mountains in this area are primarily fault blocks that have been tilted up. Alluvial fans at the base of the mountains are recharge zones for the basin fill aquifers. An ancient shoreline of historic Bonneville Lake is evident on the footslopes along the western edge of the area. Rocks exposed in the mountains are mostly Mesozoic and Paleozoic sediments.
The average precipitation is from 12 to 16 inches in the valleys and can range up to 73 inches in the mountains. Peak precipitation occurs in the winter months. The average annual temperature is 30 to 50 degrees Fahrenheit (-1 to 15 C). The freeze-free period averages 140 days and ranges from 60 to 220 days, generally decreasing in length with elevation.
The dominant soil orders in this MLRA are Entisols, Inceptisols, and Mollisols. The lower elevations are dominated by a frigid temperature regime, while the higher elevations experience cryic temperature regimes. The soil moisture regime is typically xeric. The minerology is generally mixed and the soils are very shallow to very deep, generally well drained, and loamy or loamy-skeletal.
LRU notes
This LRU includes the Wasatch Mountains which tend to run north and south. These steeply sloping, precipitous mountains have narrow crests and deep valleys. They are primarily fault blocks that have been tilted up. The alluvial fans located at the base of these mountains are important recharge zones for valley aquifers.
Ecological site concept
The soil of this site formed in colluvium and alluvium derived from shale and sandstone. They are moderately deep to deep, well-drained and moderately-slowly permeable. The available water-holding capacity ranges from 6.6 to 7.0 inches of water in the upper 40 inches of soil. Rock fragments are not common on the soil surface or throughout the profile. The soil moisture regime is aridic xeric and the soil temperature regime is frigid.
This site has a very similar plant community throughout. It is often hard to decipher the difference between early sagebrush and black sagebrush. In addition both communities are positioned on very similar landforms.
This site is found on south, west, and east-facing mountainsides at elevations between 6,000 and 7,200 feet. Slopes range from 4 to 50 percent. Runoff is medium to very high and neither flooding nor ponding occurs on this site.
Table 2. Representative physiographic features
Landforms
(1) Mountain slope (2) Hill
Flooding frequency
None
Ponding frequency
None
Elevation
6,000–7,200 ft
Slope
4–50%
Aspect
E, S, W
Climatic features
The climate of this site is characterized by cold, snowy winters and cool, dry summers. The average annual precipitation ranges from 14 to 17 inches, but in a few instances is as high as 20. June is commonly the driest month in precipitation. Annual distribution varies from 20 to 45 percent during the plant growth period, May to October. The effective moisture for plant growth is the 55 to 80 percent that falls during the plant dormant period.
Table 3. Representative climatic features
Frost-free period (average)
115 days
Freeze-free period (average)
149 days
Precipitation total (average)
17 in
Bar
Line
Figure 1. Monthly precipitation range
Bar
Line
Figure 2. Monthly average minimum and maximum temperature
Figure 3. Annual precipitation pattern
Figure 4. Annual average temperature pattern
Influencing water features
Due to its landscape position, this site is not typically influenced by streams or wetlands.
Wetland description
N/A
Soil features
The soil of this site formed in colluvium and alluvium derived from shale and sandstone. They are moderately deep to deep, well-drained and moderately-slowly permeable. The surface layer is a dark reddish-brown loam about 5 inches thick. The subsoil is a reddish-brown clay loam about 36 inches thick, over soft weathered sandstone. The available water-holding capacity ranges from 6.6 to 7.0 inches of water in the upper 40 inches of soil. Rock fragments are not common on the soil surface or throughout the profile. The soil moisture regime is aridic xeric and the soil temperature regime is frigid. This soil has been mapped in the Summit Area soil survey, Econ soil map unit.
Table 4. Representative soil features
Parent material
(1) Alluvium–sandstone and shale
Surface texture
(1) Loam
Family particle size
(1) Clayey
Drainage class
Well drained
Permeability class
Moderately slow
Soil depth
40–60 in
Surface fragment cover <=3"
5%
Surface fragment cover >3"
Not specified
Available water capacity (0-40in)
6.6–7 in
Calcium carbonate equivalent (0-40in)
Not specified
Electrical conductivity (0-40in)
Not specified
Sodium adsorption ratio (0-40in)
Not specified
Soil reaction (1:1 water) (0-40in)
6.6–7.8
Subsurface fragment volume <=3" (Depth not specified)
4%
Subsurface fragment volume >3" (Depth not specified)
Not specified
Ecological dynamics
It is impossible to determine in any quantitative detail the Reference State for this ecological site because of the lack of direct historical documentation preceding all human influence. In some areas, the earliest reports of dominant plants include the cadastral survey conducted by the General Land Office, which began in the late 19th century for this area (Galatowitsch 1990). However, up to the 1870s the Shoshone Indians, prevalent in northern Utah and neighboring states, grazed horses and set fires to alter the vegetation for their needs (Parson 1996). In the 1860s, Europeans brought cattle and horses to the area, grazing large numbers of them on unfenced parcels year-long (Parson 1996). Itinerant and local sheep flocks followed, largely replacing cattle as the browse component increased.
Below is a State and Transition Model diagram to illustrate the “phases” (common plant communities), and “states” (aggregations of those plant communities) that can occur on the site. Differences between phases and states depend primarily upon observations of a range of disturbance histories in areas where this ESD is represented. These situations include grazing gradients to water sources, fence-line contrasts, patches with differing dates of fire, herbicide treatment, tillage, etc. Reference State 1 illustrates the common plant communities that probably existed just prior to European settlement.
The major successional pathways within states, (“community pathways”) are indicated by arrows between phases. “Transitions” are indicated by arrows between states. The drivers of these changes are indicated in codes decipherable by referring to the legend at the bottom of the page and by reading the detailed narratives that follow the diagram. The transition between Reference State 1 and State 2 is considered irreversible because of the naturalization of exotic species of both flora and fauna, possible extinction of native species, and climate change. There may have also been accelerated soil erosion.
When available, monitoring data (of various types) were employed to validate more subjective inferences made in this diagram. See the complete files in the office of the State Range Conservationist for more details.
The plant communities shown in this State and Transition Model may not represent every possibility, but are probably the most prevalent and recurring plant communities. As more monitoring data are collected, some phases or states may be revised, removed, or new ones may be added. None of these plant communities should necessarily be thought of as “Desired Plant Communities.” According to the USDA NRCS National Range & Pasture Handbook (USDA-NRCS 2003), Desired Plant Communities (DPC’s) will be determined by the decision-makers and will meet minimum quality criteria established by the NRCS. The main purpose for including descriptions of a plant community is to capture the current knowledge at the time of this revision.
State and transition model
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The Reference State is a description of this ecological site just prior to Euro-American settlement but long after the arrival of Native Americans. The description of the Reference State was determined by NRCS Soil Survey Type Site Location information and familiarity with rangeland relict areas where they exist. The Reference State for this site would have been a shrub steppe characterized by early sagebrush (Artemisia arbuscula spp. longiloba) and associated native perennial forbs and grasses. A more complete list of species by lifeform for the Reference State is available in the accompanying tables in the “Plant Community Composition by Weight and Percentage” section of this document.
Community 1.1 Reference State
Community Phase 1.1: early sagebrush/ native perennial herbs
This plant community would have been a shrub steppe characterized by early sagebrush and associated native perennial herbs. The primary perennial grasses would have included western wheatgrass (Pascopyrum smithii), bluebunch wheatgrass (Pseudoroegneria spicata), squirreltail (Elymus elymoides), Indian ricegrass (Achnatherum hymenoides), and needle-and-thread (Hesperostipa comata). Common forbs would have included shortstem buckwheat (Eriogonum brevicaule), Tolmie’s owl’s-clover (Orthocarpus tolmiei), Cushion phlox (Phlox spp.), and longleaf phlox (Phlox longifolia).
Figure 5. Annual production by plant type (representative values) or group (midpoint values)
Table 5. Annual production by plant type
Plant type
Low (lb/acre)
Representative value (lb/acre)
High (lb/acre)
Grass/Grasslike
350
425
550
Shrub/Vine
350
425
500
Forb
45
115
185
Total
745
965
1235
Table 6. Ground cover
Tree foliar cover
0%
Shrub/vine/liana foliar cover
35-40%
Grass/grasslike foliar cover
18-20%
Forb foliar cover
4-6%
Non-vascular plants
0%
Biological crusts
5-7%
Litter
8-10%
Surface fragments >0.25" and <=3"
0%
Surface fragments >3"
0%
Bedrock
0%
Water
0%
Bare ground
8-10%
Table 7. Canopy structure (% cover)
Height Above Ground (ft)
Tree
Shrub/Vine
Grass/ Grasslike
Forb
<0.5
–
–
–
–
>0.5 <= 1
–
–
–
4-6%
>1 <= 2
–
–
24-26%
–
>2 <= 4.5
–
34-36%
–
–
>4.5 <= 13
–
–
–
–
>13 <= 40
–
–
–
–
>40 <= 80
–
–
–
–
>80 <= 120
–
–
–
–
>120
–
–
–
–
State 2 Early Sagebrush/ Introduced Herb State
State 2 is very similar to State 1 in form and function, with the exception of the presence of exotic plants and animals, possible extinctions of native species, and a different climate. State 2 is a description of the ecological site shortly following Euro-American settlement. This state can be regarded as the current potential. State 2 is dominated by early sagebrush and associated native perennial herbs with a small component of introduced species such as cheatgrass (Bromus tectorum) and Russian thistle (Salsola spp). The primary perennial grasses include western wheatgrass (Pascopyrum smithii), bluebunch wheatgrass (Pseudoroegneria spicata), squirreltail (Elymus elymoides), Indian ricegrass (Achnatherum hymenoides), needle and thread (Hesperostipa comata), smooth brome (Bromus inermis), and Sandberg’s bluegrass (Poa secunda). Common forbs include short-stem buckwheat (Eriogonum brevicaule), Tolmie’s owl’s-clover (Orthocarpus tolmiei), and longleaf phlox (Phlox longifolia). The resiliency of this State is maintained by a healthy, productive, and diverse plant community that can provide native seed sources and promotes soil stability, water infiltration, and soil moisture retention. The resiliency of this state will be negatively impacted by continued heavy growing season livestock grazing. Mechanical or chemical shrub control or prescribed burning is not recommended because high soil erosion potential and poor biological and economic responses, especially on steep slopes. This site should be reseeded with native perennial herbs quickly after fire or mechanical disturbances.
Community 2.1 Early Sagebrush/ Introduced Herb State
Figure 6. State 2
Community Phase 2.1: early sagebrush/ bunch and rhizomatous grasses co-dominant
This plant community is characterized by early sagebrush and native perennial herbs. Some non-native herbaceous species such as cheatgrass may be present. The phase is fully functioning as it relates to soil & site stability, hydrologic function and biotic integrity. This phase represents a relatively equal abundance of rhizomatous and bunch grasses.
Community 2.2 Early sagebrush with depleted understory/rhizomatous grasses greater than bunch grasses
Community Phase 2.2: Early sagebrush with depleted understory/rhizomatous grasses greater than bunch grasses
This plant community is characterized by increasing dominance of larger, older shrubs, and rhizomatous grasses becoming more dominant than the bunch grasses due to the bunch grasses being more susceptible to grazing. Soil erosion is accelerated because of increased bare ground, water flow patterns and pedestals become more abundant. Although the overall functionality of the site is still intact, it is at risk with further degradation.
Community 2.3 Shrub-dominated Community
Community Phase 2.3: This plant community is characterized by increasing dominance of larger, older shrubs, and bunch grasses becoming more dominant than rhizomatous grasses. With the plant interspaces becoming larger from the reduction of rhizomatous grasses, soil erosion may accelerate because of the increased bare ground. Water flow patterns and pedestals become more abundant. Although the overall functionality of the site is still intact, it is at risk with further degradation.
Community 2.4 Herbaceous-dominated
Community Phase 2.4: This Phase will have a significantly reduced sagebrush composition that has shifted to a native or introduced herbaceous species dominated site. Depending on the health/vigor of the understory herbaceous species, a rangeland seeding may be necessary.
Pathway CP2.1-2.2 Community 2.1 to 2.2
Community Pathway 2.1-2.2: This pathway is triggered when the site is exposed to heavy continued season-long grazing by livestock and big game (elk).
Pathway CP2.1-2.3 Community 2.1 to 2.3
Community Pathway 2.1-2.3: This pathway is triggered when the site is protected from grazing and/or fire.
Pathway CP2.1-2.4 Community 2.1 to 2.4
Community Pathway 2.1-2.4: This pathway is triggered when the site has brush management applied (chemical, mechanical, or fire).
Pathway CP2.2-2.1 Community 2.2 to 2.1
Community Pathway 2.2-2.1: This pathway is triggered when the site is restored due to the implementation of prescribed grazing.
Pathway CP2.3-2.1 Community 2.3 to 2.1
Community Pathway 2.3-2.1: This pathway is triggered when the site is restored due to the implementation of prescribed grazing and prescribed burns to manage brush.
Pathway CP2.4-2.1 Community 2.4 to 2.1
Community Pathway 2.4-2.1: This Phase (2.4) will be re-invaded by sagebrush at a rate dependent upon levels of grazing use and climatic conditions.
State 3 Disturbed State
State 3: Disturbed State
Due to extent of the disturbance, this site has become extremely susceptible to accelerated erosion due to the complete loss of the vegetative community.
Community 3.1 Reclaimed Phase
Figure 7. State 3
Community Phase 3.1: This Phase is dominated by native and/or introduced grasses and forbs that used in the reclamation process.
Community 3.2 Recovered Phase
Community Phase 3.2: This Phase occurs on sites that overtime have sagebrush moving back into them. The Phase is characterized by still being dominated by perennial herbaceous vegetation with a minor component of early sagebrush recolonizing the site.
Pathway CP3.1-3.2 Community 3.1 to 3.2
Community Pathway 3.1-3.2: This Pathway occurs in this State when over time through natural succession along with utilizing prescribed grazing or non-use.
Pathway CP3.2-3.1 Community 3.2 to 3.1
Community Pathway 3.2-3.1: By implementing brush management or through natural or prescribed fire, this Phase (3.2) will return to Phase 3.1.
Transition T1.1-2.1 State 1 to 2
T1.1-2.1: Transition from State 1 to State 2 (Reference State to Early Sagebrush/ Introduced Herb State)
The simultaneous introduction of exotic species, both plants and animals, and possible extinctions of native flora and fauna, along with climate change, has caused State 1 to transition to State 2. Reversal of such historic changes (i.e. a return pathway) back to State 1 is not practical.
Transition T2-3.1 State 2 to 3
T2-3.1: Transition from State 2 to State 3 (Early Sagebrush/Introduced Herbaceous Species/Disturbed State)
This transition occurs when the site experiences a disturbance such as the use of excavation equipment.
Additional community tables
Table 8. Community 1.1 plant community composition
This site provides well-balanced nutritious forage for livestock during spring, summer, and fall.
The potential is very poor for openland habitat, fair for woodland habitat, very poor for wetland habitat, and fair for rangeland habitat.
Hydrological functions
The soils in this site are in b and c hydrologic groups. When the vegetation is in good condition the hydrologic curves are 74 to 61.
Recreational uses
This site has fair values for aesthetics and natural beauty. Hunting is fair for deer, antelope, upland game, and rabbits.
Wood products
None, except for some firewood for campfires.
Supporting information
Inventory data references
Information presented here has been derived from NRCS clipping data and other inventory data. Field observations from range trained personnel were also used.
Other references
Galatowitsch, S.M. 1990. Using the original land survey notes to reconstruct pre-settlement landscapes in the American West. Great Basin Naturalist: 50(2): 181-191. Keywords: [Western U.S., conservation, history, human impact]
Parson, R. E. 1996. A History of Rich County. Utah State Historical Society, County Commission, Rich County, Utah. Keywords: [Rich County, Utah, Historic land use, European settlements]
USDA-NRCS. 2003. National Range and Pasture Handbook. in USDA, editor, USDA-Natural Resources Conservation Service-Grazing Lands Technology Institute. Keywords: [Western US, Federal guidelines, Range pasture management]
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), Shane A. Green (NRCS)
Contact for lead author
shane.green@ut.usda.gov
Date
10/17/2012
Approved by
Approval date
Composition (Indicators 10 and 12) based on
Annual Production
Indicators
Number and extent of rills:
None to very few. Some very minor rill development may occur on steeper slopes (>15%) or on areas located below exposed bedrock or other water shedding areas where increased runoff may occur. Any rills present should be <1 inch deep, fairly short (<6 feet long) and somewhat widely spaced (8-10 feet). Minor rill development may be observed following major thunderstorm or spring runoff events, but they should heal during the next growing season.
Presence of water flow patterns:
Slight. Some very minor evidence of water flow patterns may be found around perennial plant bases. They show little evidence of current erosion. They are expected to be somewhat short (3-6 feet), stable, sinuous and not connected. There may also be very minor evidence of deposition. Evidence of water flow may increase somewhat with slope.
Number and height of erosional pedestals or terracettes:
None to Slight. Perennial vegetation shows little evidence of erosional pedestalling (2 to 3% of individual plants). Plant roots are covered and litter remains in place around plant crowns. Terracettes should be absent or, if present, stable. A slight increase in both pedestal and terracette development may occur with increasing slope.
Bare ground from Ecological Site Description or other studies (rock, litter, lichen, moss, plant canopy are
not bare ground):
10-15% bare ground. Soil surface is typically covered by <5% coarse fragments. Bare ground spaces should not be greater than 2 to 3 feet in diameter and should not be connected.
Number of gullies and erosion associated with gullies:
None to rare. Rare gullies may be present in landscape settings where they transport runoff from areas of greater water flow such as exposed bedrock. These gullies will be limited to slopes exceeding 20% slope and adjacent to sites where this runoff accumulation occurs. Any gullies present should show little sign of accelerated erosion and should be stabilized with perennial vegetation.
Extent of wind scoured, blowouts and/or depositional areas:
None. No evidence of wind generated soil movement is expected.
Amount of litter movement (describe size and distance expected to travel):
Most litter resides in place with some redistribution caused by water movement. Minor litter removal may occur in flow channels with deposition occurring within 1 to 2 feet at points of obstruction. The majority of litter accumulates at the base of plants. Some grass leaves and small twigs (grass stems) may accumulate in soil depressions adjacent to plants. Woody stems are not likely to move. However, some litter movement is expected (up to 6 feet) with increases in slopes >10% and/or increased runoff resulting from heavy thunderstorms.
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 4 or 5 under the plant canopies, and a rating of 3 to 4 in the interspaces. The average rating should be a 4. Soil surface texture is typically a loam.
Soil surface structure and SOM content (include type of structure and A-horizon color and thickness):
(Econ) Soil surface 0-2 inches. Texture is a loam; color is dark brown (7.5YR 4/4); structure is moderate fine platy parting to moderate fine granular. Ochric epipedon ranges to 5 inches. 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:
The heavy loam surface texture and clay within the soil profile provide a runoff surface that will normally reduce infiltration in all but gentle storms and slow snowmelt. Perennial vegetation produces sufficient cover and spatial arrangement to intercept most raindrops and reduce raindrop splash erosion. Litter on soil surface and biological soil crusts, where present, also protects soil from splash erosion and encourages a higher rate of infiltration. Good plant spatial distribution should slow runoff, allowing additional time for infiltration. Bare spaces are expected to be small and irregular in shape and are usually not connected. Vegetative structure is usually adequate to capture snow and ensure that snowmelt occurs in a controlled manner, allowing maximum time for infiltration, and reducing runoff and erosion in all but the most extreme storm events. When perennial grasses and shrubs decrease due to natural events including drought, insect damage, etc., which reduce ground cover and increasing bare ground, runoff is expected to increase and any associated infiltration reduced.
Presence and thickness of compaction layer (usually none; describe soil profile features which may be
mistaken for compaction on this site):
None. This site has a well developed argillic horizon beginning at 5 inches that should not be mistaken for a compaction laver.
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):
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:
Natural disturbance regimes include fire, drought, and insects. Assumed fire cycle of 50 to 60+ years. Functional/structural groups may appropriately contain non-native species if their ecological function is the same as the native species in the reference state. Following a disturbance such as fire, drought, rodents or insects that remove woody vegetation, forbs and perennial grasses (herbaceous species) may dominate the community for a period of time. If a disturbance has not occurred for an extended period of time, woody species may continue to increase. These conditions would reflect a functional community phase within the reference state.
Amount of plant mortality and decadence (include which functional groups are expected to show mortality or
decadence):
All age classes of perennial grasses should be present under average to above average growing conditions with age class expression likely subdued during periods of extended drought. Slight decadence in the principle shrubs could occur near the end of the fire cycle or during periods of extended drought, or insect infestations. In general, a mix of age classes should be expected with some dead and decadent plants present.
Average percent litter cover (%) and depth ( in):
Litter cover will be heavier under plants. Most litter will be herbaceous and depths of 1/2 to 3/4 inch would be considered normal. Perennial vegetation should be well distributed on the site.
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 850 - 950#/acre on an average year, but could range from 650 to 1200#/acre during periods of prolonged drought or above average precipitation.
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:
All perennial plants should have the ability to reproduce in all years, except in extreme drought years. Green rabbitbrush sprouts vigorously following fire. There are no restrictions on either seed or vegetative reproduction. Some seedling recruitment of major species is present during average and above average growing years.
The Ecosystem Dynamics Interpretive Tool is an information system framework developed by the USDA-ARS Jornada Experimental Range, USDA Natural Resources Conservation Service, and New Mexico State University.
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