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Ecological site R058AY717MT

Shallow 10-14

Last updated: 8/29/2024
Accessed: 11/23/2024

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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.

MLRA notes

Major Land Resource Area (MLRA): 058A–Northern Rolling High Plains, Northern Part

MLRA 058A, Northern Rolling High Plains (Northern Part), is an expansive and agriculturally and ecologically significant area encompassing 26 counties in southeast Montana (99 percent) and northeast Wyoming (1 percent). It stretches approximately 290 miles from east to west and 220 miles from north to south and comprises approximately 42,350 square miles (26,875,928 acres). The area is within the Missouri Plateau, Unglaciated, Section of the Great Plains Province of the Interior Plains. It is an area of old plateaus and terraces that have been eroded. Slopes generally are gently rolling to steep, and wide belts of steeply sloping badlands border a few of the larger river valleys. In some areas flat-topped, steep-sided buttes rise sharply above the general level of the plains. Elevations generally range from 1,950 to 3,280 feet, increasing from east to west and from north to south.

Tertiary continental shale, siltstone, and sandstone of the Fort Union Formation underlie the eastern one-third to one-half of this area. Marine and continental sediments of the Cretaceous Montana Group underlie the rest of the MLRA, generally at the higher elevations. There are also younger Cretaceous sediments of the Livingston Group occurring between the higher elevation Montana Group sediments and the lower elevation Tertiary sediments. The dominant soil orders in MLRA 058A are Entisols and Inceptisols. The soils in the area dominantly have a frigid soil temperature regime, an ustic soil moisture regime, and mixed or smectitic mineralogy. They range from shallow to very deep and are generally well drained and clayey or loamy.

The area primarily supports native prairie vegetation characterized by a variety of cool-season and warm-season graminoids, forbs, and shrubs. In the western portion of the area, cool-season grasses such as western wheatgrass and bluebunch wheatgrass are dominant but, in the eastern portion of the area, warm-season grasses such as little bluestem and sideoats grama become dominant. Wyoming big sagebrush, silver sagebrush, and fringed sagewort are common shrub species throughout the area. Forested areas occur in rough hilly areas and river breaks, particularly in areas with higher precipitation. Common tree species are ponderosa pine and Rocky Mountain juniper with scattered pockets of Douglas fir.

More than 75 percent of this MLRA is native rangeland utilized for livestock production and more than 50 percent of the MLRA consists of privately-owned ranches. Approximately 15 percent of the MLRA is used as cropland. Other land uses including forestland, urban development, water, and other uses combine for less than 10 percent of the total land use.

Classification relationships

NRCS Soil Geography Hierarchy
• Land Resource Region: Western Great Plains
• Major Land Resource Area (MLRA): 058A Northern Rolling High Plains, Northern Part

National Hierarchical Framework of Ecological Units (Cleland et al., 1997; McNab et al., 2007)
• Domain: Dry
• Division: Temperate Steppe
• Province: Great Plains-Palouse Dry Steppe Province (331)
• Section: North Central Highlands (331K) and Powder River Basin (331G)

National Vegetation Classification Standard (Federal Geographic Data Committee, 2008)
• Class: Mesomorphic Shrub and Herb Vegetation Class (2)
• Subclass: Temperate and Boreal Grassland and Shrubland Subclass (2.B)
• Formation: Temperate Grassland and Shrubland Formation (2.B.2)
• Division: Central North American Grassland and Shrubland Division (2.B.2.Nb)
• Macrogroup: Hesperostipa comata - Pascopyrum smithii - Festuca hallii Grassland Macrogroup (2.B.2.Nb.2)
• Group: Pascopyrum smithii - Hesperostipa comata - Schizachyrium scoparium Mixedgrass Prairie Group (2.B.2.Nb.2.c)

EPA Ecoregions
• Level 1: Great Plains (9)
• Level 2: West-Central Semi-Arid Prairies (9.3)
• Level 3: Northwestern Great Plains (9.3.3)
• Level 4: Montana Central Grasslands (43n), River Breaks (43c), and Pine Scoria Hills (43p)

Ecological site concept

This ecological site occurs primarily on hills, ridges, and escarpments at elevations ranging from 1,900 to 3,500 feet and on slopes ranging from 0 to 60 percent. Aspect can be significant, particularly on steep to very steep slopes. Aspect may result in slight variations in plant community composition and production. The soils of this ecological site are generally 10 to 20 inches deep to bedrock or soft beds of decomposed sandstone or siltstone. Plant root penetration is limited and rarely exceeds 20 inches. Soil textures on this ecological site are generally loam, silt loams, sandy loams, fine sandy loams, and very fine sandy loams.

Associated sites

R058AY722MT	Very Shallow 10-14 This site occurs on nearly level to steeply sloping uplands that are adjacent to or upslope from the Shallow ecological site. It occurs on upper backslope, crest, or summit positions and is often associated with rock outcrops.
R058AY710MT	Loamy Steep 10-14 This site occurs on moderate to steeply sloping hillslopes adjacent to or downslope from the Shallow ecological site. It occurs in backslope positions where slopes are 15 percent or greater and depth to bedrock is 20 inches or more.
R058AY716MT	Sandy Steep 10-14 This site occurs on moderate to steeply sloping hillslopes adjacent to or downslope from the Shallow ecological site. It occurs in backslope positions where slopes are 15 percent or greater and depth to bedrock is 20 inches or more.

R058AY722MT

Very Shallow 10-14

This site occurs on nearly level to steeply sloping uplands that are adjacent to or upslope from the Shallow ecological site. It occurs on upper backslope, crest, or summit positions and is often associated with rock outcrops.

R058AY710MT

Loamy Steep 10-14

This site occurs on moderate to steeply sloping hillslopes adjacent to or downslope from the Shallow ecological site. It occurs in backslope positions where slopes are 15 percent or greater and depth to bedrock is 20 inches or more.

R058AY716MT

Sandy Steep 10-14

Similar sites

R058AY710MT	Loamy Steep 10-14 This site differs from the Shallow ecological site in that that the depth to bedrock is 20 inches or more whereas the Shallow ecological site is between 10 and 20 inches to bedrock.
R058AY722MT	Very Shallow 10-14 This site differs from the Shallow ecological site in that that the depth to bedrock is less than 10 inches whereas the Shallow ecological site is between 10 and 20 inches to bedrock.
R058AY718MT	Shallow Clay 10-14 This site differs from the Shallow ecological site in that its soils have finer textures. Soil textures are typically clay, clay loam, silty clay, and silty clay loam

R058AY710MT

Loamy Steep 10-14

This site differs from the Shallow ecological site in that that the depth to bedrock is 20 inches or more whereas the Shallow ecological site is between 10 and 20 inches to bedrock.

R058AY722MT

Very Shallow 10-14

This site differs from the Shallow ecological site in that that the depth to bedrock is less than 10 inches whereas the Shallow ecological site is between 10 and 20 inches to bedrock.

R058AY718MT

Shallow Clay 10-14

This site differs from the Shallow ecological site in that its soils have finer textures. Soil textures are typically clay, clay loam, silty clay, and silty clay loam

Table 1. Dominant plant species

Tree	Not specified
Shrub	(1) Artemisia tridentata ssp. wyomingensis (2) Rhus trilobata
Herbaceous	(1) Pseudoroegneria spicata (2) Schizachyrium scoparium

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Physiographic features

This ecological site occurs on hills, ridges, and escarpments. Slopes typically range from 0 to 60 percent. This site occurs on all aspects. Aspect can be a significant factor.

Table 2. Representative physiographic features

Landforms	(1) Hill (2) Ridge (3) Escarpment
Runoff class	Low to medium
Flooding frequency	None
Ponding frequency	None
Elevation	1,900 – 3,500 ft
Slope	60%
Aspect	W, NW, N, NE, E, SE, S, SW

Climatic features

MLRA 058A is a semi-arid region and is considered to have a continental climate characterized by cold winters, hot summers, low humidity, light rainfall, and much sunshine. The climate is the result of the MLRA’s location in the geographic center of North America. Temperatures can be extreme. The average annual temperature is 41 to 49 degrees Fahrenheit. Summer daytime temperatures are typically quite warm, generally averaging in the lower to mid 80 degree range for July and August. Summertime temperatures will typically reach 100 degrees or more at some point during the summer and can reach 90 degrees during any month between May and September. Conversely, winter temperatures can be cold, averaging in the lower teens or less for December and January. There will typically be several days of below zero temperatures each winter. It is not uncommon for temperatures to reach 30 to 40 degrees below zero, or even colder, most any winter.

During an average year, 70 to 75 percent of the annual precipitation falls between April and September, which are the primary growing season months. Most of the rainfall occurs as frontal storms early in the growing season during the months of May and June. Some high-intensity, convective thunderstorms occur in July and August, and some rainfall occurs in autumn. Later summer precipitation is greater in the eastern portion of the MLRA, which effects plant community composition. Winter precipitation occurs as snow although snowfall is not heavy, averaging about 39 inches annually, and snow cover is typically 1 to 3 inches. Heavy snowfall occurs infrequently, usually late in the winter or early spring. The average annual precipitation ranges from 8 to 22 inches but is typically 11 to 17 inches throughout most of the area. This site occurs on the lower range of 10 to 14 inches precipitation. Precipitation fluctuates widely from year to year and severe drought occurs 2 out of 10 years on average.

There are few natural barriers on the northern Great Plains and the winds move freely across the plains and account for rapid changes in temperature. Spring can be windy throughout the MLRA, with winds averaging over 10 mph about 15 percent of the time. Speeds of 50 mph or stronger can occasionally occur. During the winter months, the western half of the MLRA commonly experiences Chinook winds, which are strong west to southwest surface winds accompanied by abrupt increases in temperature. The Chinook winds are strongest on the western boundary of the MLRA near the Rocky Mountain foothills and decrease eastward. In addition to producing damaging winds, prolonged Chinook episodes can result in drought or vegetation kills due to a reaction of plants to a “false spring” (Oard, 1993).

For local climate station information, refer to https://wrcc.dri.edu/summary/Climsmemt.html.

Table 3. Representative climatic features

Frost-free period (characteristic range)	85-150 days
Freeze-free period (characteristic range)	115-170 days
Precipitation total (characteristic range)	10-14 in
Frost-free period (average)	125 days
Freeze-free period (average)	145 days
Precipitation total (average)	13 in

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Figure 1. Monthly precipitation range

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Figure 2. Monthly average minimum and maximum temperature

Figure 3. Annual precipitation pattern

Figure 4. Annual average temperature pattern

Climate stations used

(1) RAPELJE [USC00246862], Rapelje, MT
(2) HYSHAM 25 SSE [USC00244364], Bighorn, MT
(3) BRANDENBERG [USC00241084], Rosebud, MT
(4) TERRY 21 NNW [USC00248169], Terry, MT
(5) BLOOMFIELD 5 NNE [USC00240923], Bloomfield, MT
(6) GLENDIVE [USC00243581], Glendive, MT
(7) POWDERVILLE 8 NNE [USC00246691], Volborg, MT
(8) JORDAN 23 ENE [USC00244530], Jordan, MT
(9) FT PECK PWR PLT [USC00243176], Fort Peck, MT
(10) CIRCLE [USC00241758], Circle, MT
(11) BROCKWAY 3 WSW [USC00241169], Brockway, MT
(12) MILES CITY F WILEY FLD [USW00024037], Miles City, MT
(13) MIZPAH 4 NNW [USC00245754], Ismay, MT
(14) SAND CREEK [USC00247342], Roy, MT
(15) ROCK SPRINGS [USC00247136], Angela, MT
(16) COHAGEN [USC00241875], Cohagen, MT

Influencing water features

This is upland ecological site and is not influenced by a water table or run in from adjacent sites. Due to the semi-arid climate in which it occurs, the water budget is normally contained within the soil pedon. Soil moisture is recharged by spring rains, but it but rarely exceeds field capacity in the upper 40 inches before being depleted by evapotranspiration. Steep slopes combined with bedrock at relatively shallow depths result in very high runoff potential. During intense precipitation events, the site delivers moisture to downslope sites via surface runoff. Moisture loss through evapotranspiration exceeds precipitation for the majority of the growing season and soil moisture is the primary limiting factor for plant production on this ecological site.

Wetland description

Not Applicable

Soil features

Soils for this ecological site are typically shallow (10 to 20 inches) to paralithic bedrock, well drained, and derived from sandstone and siltstone residuum. Surface horizon textures are typically silt loam, loam, sandy clay loam, or very fine sandy loam and contain less than 32 percent clay. The underlying horizons typically contain less than 35 percent clay and have silt loam, loam, or sandy clay loam textures. The soil temperature regime is primarily frigid, with smaller areas of mesic temperature regime present. The soil moisture regime is aridic ustic. Figure 5 shows a typical soil profile for this ecological site.

Figure 5. Typical Soil Profile

Table 4. Representative soil features

Parent material	(1) Residuum – sandstone and siltstone
Surface texture	(1) Silt loam (2) Loam (3) Sandy clay loam (4) Very fine sandy loam
Drainage class	Well drained
Permeability class	Moderate
Soil depth	10 – 20 in
Surface fragment cover <=3"	35%
Surface fragment cover >3"	15%
Available water capacity (0-20in)	2 – 4 in
Electrical conductivity (0-20in)	2 mmhos/cm
Sodium adsorption ratio (0-20in)	Not specified
Subsurface fragment volume <=3" (0-20in)	35%
Subsurface fragment volume >3" (0-20in)	5%

Ecological dynamics

Interpretations are primarily based on the Reference state, which is used as a reference in order to understand the original potential of the site. This ecological site developed under the combined influences of climatic conditions, periodic fire activity, grazing by large herbivores, and impacts from small mammals and insects. Changes may occur to the Reference state due to management actions such as improper grazing management, climatic conditions such as drought, and natural events such as multiple fires in close succession. The Reference state is dominated by a diversity of medium height, cool-season and warm-season grasses, which are tightly intermixed and well distributed over the site. Various forbs, half-shrubs, and shrubs are common on this site. The Reference state is not necessarily the management goal, as other vegetative states may be considered desired plant communities as long as critical resource concerns are met.

In addition to the Reference state, other plant communities can occur on this site and are usually the result of historic management practices. Long term overgrazing on this ecological site results in a decrease of mid-grasses and more palatable forbs and in an increase of shortgrasses, sedges, and less palatable forbs. Half-shrubs and shrubs increase in the absence of prescribed fire and wildfire. More frequent fire intervals decreases the shrub component resulting in a site dominated by herbaceous species. There are various transitional stages which may occur on this ecological site.

State and transition model

More interactive model formats are also available. View Interactive Models
Click on state and transition labels to scroll to the respective text

Ecosystem states

1. Reference

2. Shortgrass

3. Invaded

T1A	-	Prolonged drought, improper grazing, or a combination of these factors
T1B	-	Introduction of non-native invasive species (annual bromes, crested wheatgrass, noxious weeds, etc.)
R2A	-	Proper grazing management in combination with rangeland seeding, grazing land mechanical treatment, and timely moisture (management intensive and costly)
T2A	-	Introduction of non-native invasive species (annual bromes, crested wheatgrass, noxious weeds, etc.)

State 1 submodel, plant communities

1.1. Wyoming Big Sagebrush, Skunkbush Sumac, Bluebunch Wheatgrass, and Little Bluestem

1.2. Bluebunch Wheatgrass and Little Bluestem

1.3. Wyoming Big Sagebrush, Skunkbush Sumac, Western Wheatgrass, and Blue Grama

1.4. Western Wheatgrass and Blue Grama

1.1A	-	Prescribed fire and wildfire, mechanical and chemical treatments, and biological processes
1.1B	-	Drought, improper grazing management
1.2A	-	Approximately 30 years post-fire regrowth
1.2B	-	Drought, improper grazing management, multiple fires in close succession
1.3B	-	Normal or above average precipitation, proper grazing management
1.3A	-	Prescribed fire and wildfire, mechanical and chemical treatments, and biological processes
1.4B	-	Normal or above average precipitation, proper grazing management
1.4A	-	Approximately 30 years post-fire regrowth

State 2 submodel, plant communities

2.1. Wyoming Big Sagebrush, Blue Grama, and Threadleaf Sedge

2.2. Blue Grama and Threadleaf Sedge

2.1A	-	Prescribed fire and wildfire, mechanical and chemical treatments, and biological processes
2.2A	-	Approximately 30 years post-fire regrowth

State 3 submodel, plant communities

3.1. Cheatgrass and Field Brome

State 1
Reference

The Reference state for this ecological site consists of four communities and evolved under the combined influences of climatic conditions, periodic fire activity, grazing by large herbivores, and impacts from small mammals and insects. The Reference state is the plant community in which interpretations are primarily based and is used as a reference in order to understand the original potential of the site.

Dominant plant species

Wyoming big sagebrush (Artemisia tridentata ssp. wyomingensis), shrub
skunkbush sumac (Rhus trilobata), shrub
bluebunch wheatgrass (Pseudoroegneria spicata), grass
little bluestem (Schizachyrium scoparium), grass
western wheatgrass (Pascopyrum smithii), grass
blue grama (Bouteloua gracilis), grass

Community 1.1
Wyoming Big Sagebrush, Skunkbush Sumac, Bluebunch Wheatgrass, and Little Bluestem

This plant community is characterized by a mixed-grass and shrub community with grass species such as bluebunch wheatgrass, needle and thread, western wheatgrass, little bluestem, prairie sandreed, sideoats grama, and plains muhly and shrubs species such as Wyoming big sagebrush, skunkbush sumac, yucca, prairie rose, Rocky Mountain juniper, creeping juniper, rabbitbrush, and prairie sagewort. Shortgrasses and sedges such as blue grama and threadleaf sedge are present at low cover. Forbs such as white prairie clover, purple prairie clover, black samson, hairy false goldenaster, evening primrose, spiny phlox, common yarrow, dotted blazing star, milkvetch, scurfpea, and buckwheat occur at approximately 10 percent canopy cover. Shrubs and half-shrubs occurs at approximately 5 to 10 percent canopy cover.

Community 1.2
Bluebunch Wheatgrass and Little Bluestem

This plant community is characterized by mixed-grass community including species such as bluebunch wheatgrass, needle and thread, western wheatgrass, little bluestem, prairie sandreed, sideoats grama, and plains muhly. Shortgrasses and sedges such as blue grama and threadleaf sedge are present at low cover. Forbs such as white prairie clover, purple prairie clover, black samson, hairy false goldenaster, evening primrose, spiny phlox, common yarrow, dotted blazing star, milkvetch, scurfpea, and buckwheat occur at approximately 10 percent canopy cover. Shrubs and half-shrubs are absent to rare. This community occurs following shrub mortality due to wildfire, prescribed fire, mechanical and chemical treatments, or biological processes and may persist for 30 years or more thereafter (Watts and Wambolt, 1996; Wambolt et. al., 2001).

Community 1.3
Wyoming Big Sagebrush, Skunkbush Sumac, Western Wheatgrass, and Blue Grama

Community 1.4
Western Wheatgrass and Blue Grama

This plant community is characterized by shortgrasses, sedges, and mid-statured grasses including blue grama, threadleaf sedge, bluebunch wheatgrass, needle and thread, western wheatgrass, little bluestem, prairie sandreed, sideoats grama, and plains muhly. Shortgrass species are increasing and mid-statured grasses are decreasing. Grazing sensitive bunchgrasses such as bluebunch wheatgrass are rare. Unpalatable, fire-tolerant shrubs and half-shrubs such as skunkbush sumac and rabbitbrush are increasing and unpalatable, fire-sensitive shrubs and half-shrubs such as yucca, prairie rose, Rocky Mountain juniper, creeping juniper, and prairie sagewort are decreasing. This plant community occurs when site conditions decline due to long-term drought or improper grazing management, and shrub mortality due to wildfire, prescribed fire, mechanical and chemical treatments, or biological processes has occurred on the site less than 30 years prior.

Pathway 1.1A
Community 1.1 to 1.2

Community 1.1 will transition to community 1.2 through prescribed fire and wildfire, mechanical and chemical treatments, and biological processes. Shrub cover is greatly reduced and perennial grasses will dominate the site.

Pathway 1.1B
Community 1.1 to 1.3

Drought, improper grazing management such as continuous season-long or year-long grazing, or a combination of these factors can shift community 1.1 to community 1.3. These factors favor an increase in blue grama and a decrease in cool-season mid-statured grasses (Coupland, 1961; Shay et al., 2001). Shrub cover will be similar to community 1.1.

Pathway 1.2A
Community 1.2 to 1.1

Approximately 30 years or more of natural vegetative regrowth will shift community 1.2 to community 1.1. Approximately 30 years or more without major mortality permits shrubs such as Wyoming big sagebrush to recolonize the site.

Pathway 1.2B
Community 1.2 to 1.4

Drought, improper grazing practices such as continuous season-long or year-long grazing, multiple fires in close succession, or a combination of these factors can shift community 1.2 to community 1.3. These factors favor an increase in blue grama and a decrease in cool-season mid-statured grasses (Coupland, 1961; Shay et al., 2001). Shrub cover will be similar to community 1.2.

Pathway 1.3B
Community 1.3 to 1.1

Approximately 30 years or more following mortality; normal or above-average precipitation and proper grazing management shifts community 1.3 to community 1.1.

Pathway 1.3A
Community 1.3 to 1.4

Community 1.3 will transition to community 1.4 through prescribed fire and wildfire, mechanical and chemical treatments, and biological processes. Shrub cover is greatly reduced and perennial grasses will dominate the site.

Pathway 1.4B
Community 1.4 to 1.2

Less than approximately 30 years following mortality; normal or above-average precipitation and proper grazing management shifts community 1.4 to community 1.2.

Pathway 1.4A
Community 1.4 to 1.3

Approximately 30 years or more of natural vegetative regrowth will shift community 1.4 to community 1.3. Approximately 30 years or more without fire or similar mortality permits shrubs such as Wyoming big sagebrush to recolonize the site.

State 2
Shortgrass

The dynamics of the Shortgrass state are driven by long-term drought, improper grazing management such as continuous season-long or year-long grazing, or a combination of these factors. The Shortgrass state for this ecological site consists of two communities.

Dominant plant species

Wyoming big sagebrush (Artemisia tridentata ssp. wyomingensis), shrub
blue grama (Bouteloua gracilis), grass
threadleaf sedge (Carex filifolia), grass

Community 2.1
Wyoming Big Sagebrush, Blue Grama, and Threadleaf Sedge

This plant community is characterized by a dominance of shortgrass species and sedges such as blue grama and threadleaf sedge. Mid-statured grasses such as bluebunch wheatgrass, needle and thread, western wheatgrass, little bluestem, prairie sandreed, sideoats grama, and plains muhly are rare or absent. Unpalatable half-shrubs such as prairie sagewort are common and shrubs and half-shrubs such as skunkbush sumac, yucca, prairie rose, Rocky Mountain juniper, creeping juniper, rabbitbrush, and prairie sagewort occur at moderate canopy cover. This community phase results in a reduction of soil surface litter, soil organic matter, and infiltration and an increase of soil surface runoff. This plant community is capable of tolerating season-long, heavy grazing and therefore is highly resistant to change.

Community 2.2
Blue Grama and Threadleaf Sedge

This plant community is characterized by a complete dominance of short-statured grasses and sedges such as blue grama and threadleaf sedge. Mid-statured grasses such as bluebunch wheatgrass, needle and thread, western wheatgrass, little bluestem, prairie sandreed, sideoats grama, and plains muhly are rare or absent. Unpalatable half-shrubs such as prairie sagewort are common species. This plant community occurs when site conditions decline due to long-term drought or improper grazing management such as continuous season-long or year-long grazing, and shrub mortality due to wildfire, prescribed fire, mechanical and chemical treatments, or biological processes has occurred on the site less than 30 years prior.

Pathway 2.1A
Community 2.1 to 2.2

Community 2.1 will transition to community 2.2 through prescribed fire and wildfire, mechanical and chemical treatments, and biological processes. Shrub cover is greatly reduced and perennial grasses will dominate the site.

Pathway 2.2A
Community 2.2 to 2.1

It is estimated that approximately 30 years or more of natural vegetative regrowth could transition community 2.2 to community 2.1. It is possible that this transition could occur over time, however, the processes are not fully understood at this time. Therefore, this pathway is considered hypothetical until further investigation can be completed.

State 3
Invaded

The Invaded state occurs when invasive plant species invade native plant communities and displace the native species. The Invaded state consists of one community.

Dominant plant species

cheatgrass (Bromus tectorum), grass
field brome (Bromus arvensis), grass

Community 3.1
Cheatgrass and Field Brome

Observations suggest that native species diversity declines significantly when invasive or noxious species exceed approximately 30 percent of the plant community. Non-native, perennial, drought tolerant grasses such as crested wheatgrass, non-native, annual, invasive species such as cheatgrass and field brome, and noxious weed species can eventually dominate the seedbank of this site and displace native species. Reduced plant species diversity, simplified structural complexity, and altered ecological processes result in a state that is substantially departed from the Reference state. The dominance of annual, invasive grasses such as cheatgrass and field brome increases the fire cycle frequency.

Transition T1A
State 1 to 2

Prolonged drought, improper grazing management such as continuous season-long or year-long grazing, or a combination of these factors weaken the resilience of the Reference state and drive its transition to the Shortgrass state. The Reference state transitions to the Shortgrass state when mid-statured graminoids become rare and shortgrass species and sedges such as blue grama and threadleaf sedge dominate the plant community.

Transition T1B
State 1 to 3

The Reference state transitions to the Invaded state when non-native grasses or noxious weeds invade the plant community. Exotic plant species dominate the site in terms of cover and production and site resilience has been substantially reduced. In addition, other rangeland health attributes, such as reproductive capacity of native grasses and soil quality, have been substantially altered from the Reference state.

Restoration pathway R2A
State 2 to 1

Blue grama can resist displacement by other species. A reduction in livestock grazing pressure alone may not be sufficient to reduce the cover of blue grama in the Shortgrass state and mechanical treatments may be necessary. Therefore, returning the Shortgrass state to the Reference state can require considerable cost, energy, and time.

Conservation practices

Prescribed Grazing

Transition T2A
State 2 to 3

The Shortgrass state transitions to the Invaded state when non-native grasses, noxious weeds, and other invasive plants invade the Shortgrass state. Exotic plant species dominate the site in terms of cover and production. Site resilience has been substantially reduced.

Additional community tables

Supporting information

Inventory data references

Specific field data was not obtained for this provisional ecological site description. Existing field data were used in conjunction with a review of the scientific literature and professional experience to approximate the plant communities, states, and transitions. All community phases are considered provisional based on the sources identified in this ecological site description.

Other references

Anderson, R.C. 2006. Evolution and origin of the central grassland of North America: Climate, fire, and mammalian grazers. Journal of the Torrey Botanical Society 133:626-647.

Baskin, J.M., and C.C. Baskin. 1981. Ecology of germination and flowering in the weedy winter annual grass Bromus japonicus. Journal of Range Management 34:369-372.

Biondini, M.E., and L. Manske. 1996. Grazing frequency and ecosystem processes in a northern mixed prairie, USA. Ecological Applications 6:239-256.

Biondini, M.E., B.D. Patton, and P.E. Nyren. 1998. Grazing intensity and ecosystem processes in a northern mixed-grass prairie, USA. Ecological Applications 8:469-479.

Bloom-Cornelius, I.V. 2011. Vegetation response to fire and domestic and native ungulate herbivory in a Wyoming big sagebrush ecosystem. M.S. thesis, Oklahoma State University. Stillwater, OK.

Bragg, T.B. 1995. The physical environment of the Great Plains grasslands. In: A. Joern and K.H. Keeler (eds.) The Changing Prairie, Oxford University Press, Oxford, pp. 49–81.

Christian, J.M., and S.D. Wilson. 1999. Long-term ecosystem impacts of an introduced grass in the Northern Great Plains. Ecology 80:2397-2407.

Cleland, D.T., et al. 1997. National hierarchical framework of ecological units. In: M.S. Boyce and A. Haney (eds.) Ecosystem Management Applications for Sustainable Forest and Wildlife Resources, Yale University Press, New Haven, CT.

Coupland, R.T. 1950. Ecology of the mixed prairie of Canada. Ecological Monographs 20:271-315.

Coupland, R.T. 1958. The effects of fluctuations in weather upon the grasslands of the Great Plains. Botanical Review 24:273-317.

Coupland, R.T. 1961. A reconsideration of grassland classification in the Northern Great Plains of North America. Journal of Ecology 49:135-167.

Coupland, R.T., and R.E. Johnson. 1965. Rooting characteristics of native grassland species in Saskatchewan. Journal of Ecology 53:475-507.

DeLuca, T.H., and P. Lesica. 1996. Long-term harmful effects of crested wheatgrass on Great Plains grassland ecosystems. Journal of Soil and Water Conservation 51:408-409.

Derner, J.D., and R.H. Hart. 2007. Grazing-induced modifications to peak standing crop in northern mixed-grass prairie. Rangeland Ecology and Management 60:270-276.

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Contributors

Jeff Fenton
Scott Brady
Maryjo Kimble
Brian Kloster

Approval

Kirt Walstad, 8/29/2024

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	09/01/2024
Approved by	Kirt Walstad
Approval date
Composition (Indicators 10 and 12) based on	Annual Production