Natural Resources
Conservation Service
Ecological site FX052X03X032
Loamy (Lo)
Dry Shrubland
Last updated: 5/07/2025
Accessed: 08/16/2026
-
Search
Major Land Resource Area or ecological site by name and/or ID.
PreviousSectionsNextGeneral 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.
Click to explore map
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.
MLRA notes
Major Land Resource Area (MLRA): 052X–Brown Glaciated Plains
The Brown Glaciated Plains, MLRA 52, is an expansive, agriculturally and ecologically significant area. It consists of approximately 14.5 million acres and stretches across 350 miles from east to west, encompassing portions of 15 counties in north-central Montana. This region represents the southwestern limit of the Laurentide Ice Sheet and is considered to be the driest and westernmost area within the vast network of glacially derived prairie pothole landforms of the northern Great Plains. Elevation ranges from 2,000 feet (610 meters) to 4,600 feet (1,400 meters).
Soils are primarily Mollisols, but Entisols, Inceptisols, Alfisols, and Vertisols are also common. Till from continental glaciation is the predominant parent material, but alluvium and bedrock are also common. Till deposits are typically less than 50 feet thick, and in some areas glacially deformed bedrock occurs at or near the soil surface (Soller, 2001). Underlying sedimentary bedrock largely consisting of Cretaceous shale, sandstone, and mudstone (Vuke et al., 2007) is commonly exposed on hillslopes, particularly along drainageways. Significant alluvial deposits occur along glacial outwash channels and major drainages, including portions of the Missouri, Teton, Marias, Milk, and Frenchman Rivers. Large glacial lakes, particularly in the western half of the MLRA, deposited clayey and silty lacustrine sediments (Fullerton et al., 2013).
Much of the western portion of this MLRA was glaciated towards the end of the Wisconsin age, with the maximum glacial extent occurring approximately 20,000 years ago (Fullerton et al., 2004). The result is a geologically young landscape that is predominantly a level till plain interspersed with lake plains and dominated by soils in the Mollisol and Vertisol orders. These soils are very productive and generally are well suited to dryland farming. Much of this area is aridic-ustic. Crop-fallow dryland wheat farming is the predominant land use. Areas of rangeland typically are on steep hillslopes along drainages.
The rangeland, much of which is native mixedgrass prairie, increases in abundance in the eastern half of the MLRA. The Wisconsin-age till in the north-central part of this area typically formed large disintegration moraines with steep slopes and numerous poorly drained potholes. A large portion of Wisconsin-age till occurring on the type of the level terrain that would typically be optimal for farming has large amounts of less-suitable sodium-affected Natrustalfs. Significant portions of Blaine, Phillips, and Valley Counties were glaciated approximately 150,000 years ago during the Illinoisan age. Due to erosion and dissection of the landscape, many of these areas have steeper slopes and more exposed bedrock than areas glaciated during the Wisconsin age (Fullerton and Colton, 1986).
While much of the rangeland in the aridic-ustic portion of MLRA 52 is classified as belonging to the “dry grassland” climatic zone, sites in portions of southern MLRA 52 may belong to the “dry shrubland” climatic zone. The dry shrubland zone represents the northernmost extent of the big sagebrush (Artemisia tridentata) steppe on the Great Plains. Because similar soils occur in both southern and northern portions of the MLRA, it is currently hypothesized that climate is the primary driving factor affecting big sagebrush distribution in this area. However, the precise factors are not yet fully understood.
Sizeable tracts of largely unbroken rangeland in the eastern half of the MLRA and adjacent southern Saskatchewan are home to the Northern Montana population of greater sage-grouse (Centrocercus urophasianus), and large portions of this area are considered to be a Priority Area for Conservation (PAC) by the U.S. Fish and Wildlife Service (U.S. Fish and Wildlife Service, 2013). This population is unique among sage grouse populations in the fact that many individuals overwinter in the big sagebrush steppe (dry shrubland) in the southern portion of the MLRA and then migrate to the northern portion of the MLRA, which lacks big sagebrush (dry grassland), to live the rest of the year (Smith, 2013).
Areas of the till plain near the Bearpaw and Highwood Mountains as well as the Sweetgrass Hills and Rocky Mountain foothills are at higher elevations, receive higher amounts of precipitation, and have a typic-ustic moisture regime. These areas have significantly more rangeland production than the drier aridic-ustic portions of the MLRA and have enough moisture to produce crops annually rather than just bi-annually, as in the drier areas. Ecological sites in this higher precipitation area are classified as the moist grassland climatic zone.Classification relationships
NRCS Soil Geography Hierarchy
• Land Resource Region: Northern Great Plains
• Major Land Resource Area (MLRA): 052 Brown Glaciated Plains
• Climate Zone: Dry Shrubland
National Hierarchical Framework of Ecological Units (Cleland et al., 1997; Nesser et al., 1997; McNab et al., 2007)
• Domain: Dry
• Division: Temperate Steppe
• Province: Great Plains-Palouse Dry Steppe Province 331
• Section: Northwestern Glaciated Plains 331D
• Subsection: Montana Glaciated Plains 331Dh
• Landtype Association/Landtype Phase: N/A
National Vegetation Classification Standard (Federal Geographic Data Committee, 2008)
• Class: Xeromorphic Woodland, Scrub and Herb Vegetation Class (3)
• Subclass: Cool Semi-Desert Scrub and Grassland Subclass (3.B)
• Formation: Cool Semi-Desert Scrub and Grassland Formation (3.B.1)
• Division: Cool Semi-Desert Scrub and Grassland Division (3.B.1.Ne)
• Macrogroup: Artemisia tridentata - Artemisia tripartita ssp. tripartita - Purshia tridentata Steppe and Shrubland Macrogroup (3.B.1.Ne.3)
• Group: Artemisia tridentata - Artemisia tripartita - Purshia tridentata Big Sagebrush Steppe and Shrubland Group (3.B.1.Ne.3.b)
• Alliance: Artemisia tridentata ssp. wyomingensis Mesic Steppe and Shrubland Alliance
• Association: Artemisia tridentata ssp. wyomingensis / Pascopyrum smithii Shrub Grassland
EPA Ecoregions
• Level 1: Great Plains (9)
• Level 2: West-Central Semi-Arid Prairies (9.3)
• Level 3: Northwestern Glaciated Plains (42)
• Level 4: North-Central Brown Glaciated Plains (42o) and Glaciated Northern Grasslands (42j)Ecological site concept
This provisional ecological site occurs in the Dry Shrubland climatic zone of MLRA 52. Figure 1 illustrates the distribution of this ecological site based on current data. This map is approximate, is not intended to be definitive, and may be subject to change. Onsite evaluations are necessary, particularly in boundary or intergrade areas where ecological sites from multiple climate zones may overlap. Loamy Dry Shrubland is an extensive ecological site occurring on most landscapes in MLRA 52. It occurs on till plains, hillslopes, outwash fans, alluvial fans, and high stream terraces where slopes are less than 15 percent. This site is typically on linear or concave backslopes, footslopes, shoulders, or summits.
This site is characterized by moderately deep to very deep (greater than 20 inches to bedrock) medium textured soils. Surface textures are of the fine-loamy or fine-silty textural family (less than 35 percent clay) and soils frequently have a mollic epipedon. Calcium carbonate equivalent is less than five percent in the upper five inches. Characteristic vegetation is Wyoming big sagebrush (Artemisia tridentata ssp. wyomingensis), western wheatgrass (Pascopyrum smithii), and needle and thread (Hesperostipa comata).Associated sites
FX052X03X062 Swale (Se) Dry Shrubland
This site is generally found downslope from the Loamy Dry Shrubland ecological site in swales and drainageways. It receives additional moisture from surface water run in. Soils are greater than 20 inches deep and mollic or pachic with higher available water holding capacity.
FX052X03X040 Loamy-Steep (Lostp) Dry Shrubland
This site occurs on moderate to steeply sloping hillslopes adjacent to or downslope from the Loamy Dry Shrubland ecological site. It is generally in backslope positions with slopes of 15 percent or greater.
FX052X03X006 Claypan (Cp) Dry Shrubland
This site occupies similar landscapes to the Loamy Dry Shrubland ecological site. In the natric soils complex, the Claypan Dry Shrubland ecological site is found in mid-level micro-topography; whereas, the Loamy Dry Shrubland ecological site occupies higher positions.
FX052X03X030 Limy (Ly) Dry Shrubland
This site occurs adjacent to the Loamy Dry Shrubland ecological site on similar landforms. It is generally on shoulders or crests with a convex slope; whereas, the Loamy Dry Shrubland ecological site is on summits or footslopes with linear or concave slope shapes.
FX052X03X165 Thin Claypan (Tcp) Dry Shrubland
This site occupies similar landscapes to the Loamy Dry Shrubland ecological site. In the natric soils complex, the Thin Claypan Shrubland ecological site is found in on lower micro-topography than Claypan and Loamy Dry Shrubland ecological sites.
Similar sites
FX052X03X030 Limy (Ly) Dry Shrubland
This site differs from Loamy Dry Shrubland ecological site in that soils contain more than 5 percent calcium carbonate in the upper 5 inches (as evidenced by strong or violent effervescence).
FX052X01X032 Loamy (Lo) Dry Grassland
This site differs from Loamy Dry Shrubland ecological site in that it has slightly cooler annual temperatures and supports silver sagebrush rather than big sagebrush.
FX052X03X040 Loamy-Steep (Lostp) Dry Shrubland
This site differs from Loamy Dry Shrubland ecological site in that slopes are 15 percent or greater.
FX052X03X062 Swale (Se) Dry Shrubland
This site differs from Loamy Dry Shrubland ecological site in that it receives additional moisture from surface water run in. Plant community is far more productive and is typically dominated by green needlegrass.
FX052X03X006 Claypan (Cp) Dry Shrubland
This site differs from Loamy Dry Shrubland ecological site in that soils contain an abrupt root-restrictive clay layer within 10 inches of the soil surface. Deep rooted bunchgrass are generally 10 percent cover or less.
Figure 1. Figure 4.Similar and associated sites diagrams
Figure 2.
Table 3. Dominant plant species
Tree Not specified
Shrub (1) Artemisia tridentata ssp. wyomingensis
Herbaceous (1) Pascopyrum smithii
(2) Hesperostipa comataLegacy ID
R052XY712MT
Physiographic features
Loamy Dry Shrubland is an extensive ecological site occurring primarily in the southern portions of MLRA 52. It largely occurs on moraines (ground, recessional or end) but can also occur on other landforms such as outwash fans or terraces. This site is typically found on linear and concave slope positions where slopes are less than 15 percent.
Figure 2. Figure 1. General distribution of the Loamy Dry Shrubland ecological site by map unit extent.
Table 4. Representative physiographic features
Landforms (1) Till plain > Moraine
(2) Till plain > Hillside
(3) Till plain > Fan
Elevation 2000 – 3870 ft Slope 0 – 14 % Aspect Aspect is not a significant factor Climatic features
The Brown Glaciated Plains is a semi-arid region with a temperate continental climate that is characterized by frigid winters and warm to hot summers (Cooper et al., 2001). The average frost-free period for this ecological site is 120 days. The majority of precipitation occurs as steady, soaking, frontal system rains in late spring to early summer. Summer rainfall comes mainly from convection thunderstorms that typically deliver scattered amounts of rain in intense bursts. These storms may be accompanied by damaging winds and large-diameter hail and result in flash flooding along low-order streams. Severe drought occurs on average in two out of every 10 years. Annual precipitation ranges from 10 to 14 inches, and 70 to 80 percent of this occurs during the growing season (Cooper et al., 2001). Extreme climatic variations, especially droughts, have the greatest influence on species cover and production (Coupland, 1958, 1961; Biondini et al., 1998).
During the winter months, the western half of MLRA 52 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 the reaction of plants to a “false spring” (Oard, 1993).Table 5 Representative climatic features
Frost-free period (characteristic range) 120-140 days Freeze-free period (characteristic range) 140-160 days Precipitation total (characteristic range) 10-10 in Frost-free period (average) 130 days Freeze-free period (average) 150 days Precipitation total (average) 10 in BarLineFigure 3. Monthly precipitation range
BarLineFigure 4. Monthly minimum temperature range
BarLineFigure 5. Monthly maximum temperature range
BarLineFigure 6. Monthly average minimum and maximum temperature
Figure 7. Annual precipitation pattern
Figure 8 Annual average temperature pattern
Climate stations used
-
(1) LOMA 1 WNW [USC00245153], Loma, MT
-
(2) CONTENT 3 SSE [USC00241984], Zortman, MT
-
(3) MALTA 7 E [USC00245338], Malta, MT
-
(4) MALTA 35 S [USC00245340], Zortman, MT
-
(5) FT PECK PWR PLT [USC00243176], Fort Peck, MT
-
(6) FT BENTON [USC00243113], Fort Benton, MT
">Influencing water features
This is a semi-arid upland ecological site and the water budget is normally contained within the soil pedon. During intense precipitation events, precipitation rates frequently exceed infiltration rates and this site delivers moisture to downslope sites via surface runoff. Moisture loss through evapotranspiration exceeds precipitation for the majority of the growing season. Soil moisture levels are greatest in May and June but rarely reach field capacity in the upper 40 inches. Soil moisture is the primary limiting factor for plant production on this ecological site.
Soil features
Soils that best represent the central concept of this ecological site are the benchmark soil series Joplin, Phillips, and Scobey. These three series cover more than 3 million acres of MLRA 52 combined. Scobey and Joplin are in the Argiustolls Great Group and have a relatively dark mollic epipedon and an underlying argillic horizon where clay has accumulated through weathering. Phillips is in the Haplustalfs Great Group and also has an argillic horizon but does not contain enough organic matter in the surface horizons to have a mollic epipedon. Joplin is a fine-loamy soil and has mixed mineralogy; whereas, Phillips and Scobey soils are in the fine family and have smectitic mineralogy. The typical parent material for these series is glacial till, although some soils in this concept are derived from alluvium. The soil moisture regime for these and all soils in this ecological site concept is ustic bordering on aridic which means that the soils are moist in some or all parts for either 180 cumulative days or 90 consecutive days during the growing season but are dry in some or all parts for over 90 cumulative days. These soils have a frigid soil temperature regime (Soil Survey Staff, 2014).
Surface textures found in this site are typically loam or clay loam and contain 18 to 35 percent clay. Underlying horizons typically, but not always, have an argillic horizon that contains between 18 to 45 percent clay depending on the soil series. Organic matter in the surface horizon typically ranges from one to three percent and moist colors vary from brown (10YR 4/3) to very dark grayish brown (10YR 3/2). Depth to secondary carbonates is usually between five and 20 inches below the soil surface. The calcium carbonate equivalent in the surface five inches is less than five percent. In the surface upper 20 inches, electrical conductivity is less than four and the sodium absorption ratio is less than 13. Soil pH classes are moderately acid to slightly alkaline in the surface horizon and neutral to strongly alkaline in the subsurface horizons. The soil depth class for this site can be moderately deep (between 20 and 40 inches to bedrock) in places where bedrock is present but is typically very deep (greater than 60 inches to bedrock). The content of coarse fragments is less than 35 percent in the upper 20 inches of soil and is most frequently less than 15 percent.
Figure 9. Typical Soil Profiles
Table 6. Representative soil features
Parent material (1) Till
(2) Alluvium
Surface texture (1) Loam
(2) Clay loam
Family particle size (1) Fine-loamy
(2) Fine
Drainage class Well drained Soil depth 60 – 72 in Available water capacity
(0-40in)6.5 – 7 in Calcium carbonate equivalent
(0-5in)0 – 4 % Electrical conductivity
(0-20in)0 – 3 mmhos/cm Sodium adsorption ratio
(0-20in)0 – 12 Soil reaction (1:1 water)
(0-40in)6.1 – 8.4 Subsurface fragment volume <=3"
(0-20in)0 – 14 % Subsurface fragment volume >3"
(0-20in)0 – 14 % Table 7. Representative soil features (actual values)
Drainage class Well drained Soil depth 20 – 72 in Available water capacity
(0-40in)6.5 – 7 in Calcium carbonate equivalent
(0-5in)0 – 4 % Electrical conductivity
(0-20in)0 – 3 mmhos/cm Sodium adsorption ratio
(0-20in)0 – 12 Soil reaction (1:1 water)
(0-40in)5.6 – 9 Subsurface fragment volume <=3"
(0-20in)0 – 34 % Subsurface fragment volume >3"
(0-20in)0 – 34 % Ecological dynamics
The information in this ecological site description, including the state-and-transition model (STM), was developed based on historical data, current field data, professional experience, and a review of the scientific literature. As a result, all possible scenarios or plant species may not be included. Key indicator plant species, disturbances, and ecological processes are described to inform land management decisions.
The Loamy Dry Shrubland provisional ecological site in MLRA 52 consists of five states: The Reference state, the Shortgrass state, the Invaded state, the Cropland state, and the Post Cropland state. Plant communities associated with the Loamy Dry Shrubland ecological site evolved under the combined influences of climate, grazing, and fire. Extreme climatic variability results in frequent droughts, which can have the greatest influence on the relative contribution of species cover and production (Coupland, 1958, 1961; Biondini et al., 1998). Due to the dominance of cool-season graminoids, annual production is highly dependent upon mid- to late-spring precipitation (Heitschmidt and Vermeire, 2005; Anderson, 2006).
Native grazers also shaped these plant communities. American bison (Bison bison) were the dominant historic grazer, but pronghorn (Antilocapra americana), elk (Cervus canadensis), and deer (Odocoileus spp.) were also common. Small mammals such as prairie dogs (Cynomys spp.) and ground squirrels (Urocitellus spp.) also influenced this plant community (Salo et al., 2004). Grasshoppers and periodic outbreaks of Rocky Mountain locusts (Melanoplus spretus) also played an important role in the ecology of these communities (Lockwood, 2004).
Fire is a critical dynamic on the Loamy Dry Shrubland ecological site. The historic ecosystem experienced periodic lightning-caused fires. Historically, Native Americans also set periodic fires. The majority of lightning-caused fires occurred in July and August; whereas, Native Americans typically set fires during spring and fall to correspond with the movement of bison (Higgins, 1986). It is difficult to precisely determine the fire return interval in the Dry Shrubland climate zone, but estimates range from six to 25 years (Bragg, 1995) to 10 to 70 years (Howard, 1999). Generally, the herbaceous vegetation is resilient to fire and the primary effects of fire are reduction of litter and short-term fluctuations in production (Vermeire et al., 2011, 2014). However, studies have shown that very short fire return intervals (less than five years) can have a negative effect, shifting species composition toward warm-season, short-statured grasses (Shay et al., 2001; Smith and McDermid, 2014). Conversely, fire has a significant effect on Wyoming big sagebrush cover. Wyoming big sagebrush is a non-sprouting shrub and is most often killed by fire (Howard, 1999). Often, it may take 30 years or more for a stand to recover following fire (Watts and Wambolt, 1996; Wambolt et. al., 2001). Fire return intervals shorter than 30 years will likely result in a reduction in Wyoming big sagebrush cover over the long term. Long-term fire suppression in the 20th century removed periodic fire from the ecosystem altogether. Very little is known about how this has affected the Dry Shrubland ecosystem. Some studies suggest an increase in Wyoming big sagebrush cover, presumably due to fire suppression (Bloom-Cornelius, 2011). Increased decadence in Wyoming big sagebrush may also occur (Howard, 1999), but these results are inconclusive.
Lack of periodic fires can also increase litter accumulation and, in some cases, provide ideal conditions for seed germination and seedling establishment of non-native annual brome species, such as field or Japanese brome (Bromus arvensis) (Whisenant, 1990). These species have become naturalized in relatively undisturbed grasslands (Ogle et al., 2003; Harmoney, 2007) and can be present in any state within the scope of this ecological site. They typically do not have a significant ecological impact; however, their presence can reduce the production of cool-season perennial grasses in some cases (Haferkamp et al., 1997). Their abundance varies depending on precipitation and germination conditions. The fire-recovery cycle is a critical element in managing the Dry Shrubland ecosystem. Further study is needed in this area to determine a balanced and sustainable fire cycle.
Improper grazing of this site can result in a reduction in the cover of the cool-season midgrasses and eventually a decrease in other cool-season graminoids and an increase in blue grama (Smoliak et al., 1972; Smoliak, 1974). Improper grazing practices include any practices that do not allow sufficient opportunity for plants to physiologically recover from a grazing event or multiple grazing events within a given year and/or that do not provide adequate cover to prevent soil erosion over time. These practices may include, but are not limited to overstocking, continuous grazing, and/or inadequate seasonal rotation moves over multiple years. Periods of extended drought can reduce mid-statured, cool-season grasses and shift the species composition of this community to one dominated by blue grama (Coupland, 1958, 1961). Further degradation of the site due to improper grazing can result in a community dominated by shortgrasses such as blue grama and Sandberg bluegrass. Cover of mid-statured grasses and sedges is severely reduced or absent. Cover of prairie sagewort can increase.
Much of the highly productive Loamy Dry Shrubland ecological site has been converted to annual cropland. The most common crops are cereal grain crops, such as winter wheat, spring wheat, and barley. When taken out of production, the site is either allowed to revert to perennial grassland or is seeded with introduced species. Seeding of introduced grasses, particularly crested wheatgrass (Agropyron cristatum), was a common practice on eroded and abandoned agricultural areas after the droughts of the 1930s (Rogler and Lorenz, 1983). Crested wheatgrass is a highly drought-tolerant and competitive cool-season, perennial bunchgrass (Lesica and DeLuca, 1996). Crested wheatgrass can invade relatively undisturbed grasslands, reducing cover and production of native cool-season midgrasses (Heidinga and Wilson, 2002; Henderson and Naeth, 2005). Russian wildrye (Psathyrostachys juncea), though less widespread, was introduced in the 1950s to provide forage for livestock (Dormaar et al., 1995). Although Russian wildrye is typically planted in monocultures, this species is not considered invasive. Under ideal conditions, it may be able to spread into adjacent degraded plant communities (Ogle et al., 2012), but such conditions are unlikely in MLRA 52. Sites left to undergo natural plant succession after cultivation can, over several decades, support native vegetation similar to the Reference state (Christian and Wilson, 1999), although it may take over 75 years for soil organic matter to return to its pre-disturbed state (Dormaar and Willms, 1990). However, those sites seeded with non-native species, particularly crested wheatgrass, may persist with this cover type indefinitely (Christian and Wilson, 1999).
The state-and-transition model (STM) diagram (Figure 2) suggests possible pathways that plant communities on this site may follow as a result of a given set of ecological processes and management. The site may also support states not displayed in the STM diagram. Landowners and land managers should seek guidance from local professionals before prescribing a particular management or treatment scenario. Plant community responses vary across this MLRA due to variability in weather, soils, and aspects. The reference community may not necessarily be the management goal. The lists of plant species and species composition values are provisional and are not intended to cover the full range of conditions, species, and responses for the site. Species composition by dry weight is provided when available and is considered provisional based on the sources identified in the narratives associated with each community phase.State and transition model
Custom diagramStandard diagramMore interactive model formats are also available. View Interactive Models
Click on state and transition labels to scroll to the respective textEcosystem states
T1A - prolonged drought, improper grazing, or a combination of these factors T1B - introduction of non-native invasive species (crested wheatgrass, noxious weeds, etc.) T1C - conversion to cropland R2A - range seeding, grazing land mechanical treatment, timely moisture, proper grazing management (management intensive and costly) T2A - introduction of weedy species; combined with drought and/or improper grazing management T2B - conversion to cropland T3A - conversion to cropland T4A - cessation of annual cropping T5A - conversion to cropland State 1 submodel, plant communities
1.1A - fire 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 (greater than 30 years post fire) 1.3A - normal or above average precipitation, proper grazing management (less than 30 years post fire) State 2 submodel, plant communities
2.1A - fire 2.2A - approximately 30 years post-fire regrowth State 3 submodel, plant communities
State 4 submodel, plant communities
State 5 submodel, plant communities
State 1
ReferenceThe Reference state contains three communities characterized by mid-statured, cool-season grasses and Wyoming big sagebrush, a perennial, evergreen, non-sprouting shrub. This state evolved under the combined influences of climate, grazing, and fire with climatic variation having the greatest influence on cover and production. In general, this state was resilient to grazing and fire, although these factors could influence species composition in localized areas. Lesser spikemoss, also known as dense clubmoss (Selaginella densa), is frequently present and may constitute significant ground cover. Its dynamics are not well understood (Romo, 2011), however, and its abundance varies greatly from site to site without a discernable reason.
Dominant plant species
-
Wyoming big sagebrush (Artemisia tridentata ssp. wyomingensis), shrub
-
western wheatgrass (Pascopyrum smithii), grass
-
needle and thread (Hesperostipa comata), grass
Community 1.1
Western Wheatgrass, Needle and Thread, and Wyoming Big SagebrushThis plant community is dominated by western wheatgrass (Pascopyrum smithii) and Wyoming big sagebrush. Cool-season, mid-statured bunchgrasses such as needle and thread (Hesperostipa comata) are commonly associated species. The cool-season, perennial bunchgrass green needlegrass, typically more abundant on sites with finer-textured soils, occurs where microsite conditions protect from wind and enhanced soil moisture (Coupland 1950, 1961; Cooper et al., 2001). The mat-forming, warm-season, perennial grass blue grama (Bouteloua gracilis) is also a common component of this site, although it typically occurs at approximately five percent cover. Several other grasses and sedges are present at low cover including prairie Junegrass (Koeleria macrantha), Sandberg bluegrass (Poa secunda), threadleaf sedge (Carex filifolia), needleleaf sedge (Carex duriuscula), and plains reedgrass (Calamagrostis montanensis). The cover of forbs typically ranges from five to 15 percent. Common forbs are scarlet globemallow (Sphaeralcea coccinea) and spiny phlox (Phlox hoodii). Dense clubmoss cover varies substantially, with some sites having 70 to 80 percent cover and other sites having little or no cover. The principal shrub on this site is Wyoming big sagebrush with a canopy cover of eight to 25 percent. The subshrubs prairie sagewort (Artemisia frigida) and winterfat (Krascheninnikovia lanata) commonly occur at low cover. The approximate species composition of this plant community is shown in the accompanying tables. All cover and production data are based on current data and are subject to revision.
Average Shrub Height:
Low: Seven inches
Representative Value: 17 inches
High: 26 inchesDominant plant species
-
Wyoming big sagebrush (Artemisia tridentata ssp. wyomingensis), shrub
-
western wheatgrass (Pascopyrum smithii), grass
-
needle and thread (Hesperostipa comata), grass
Figure 10. Annual production by plant type (representative values) or group (midpoint values)
Table 8. Annual production by plant type
Plant type Low
(lb/acre)Representative value
(lb/acre)High
(lb/acre)Grass/Grasslike 300 545 850 Shrub/Vine 110 200 325 Forb 40 80 125 Total 450 825 1300 Table 9. Ground cover
Tree foliar cover 0% Shrub/vine/liana foliar cover 10-30% Grass/grasslike foliar cover 40-70% Forb foliar cover 10-20% Non-vascular plants 0% Biological crusts 0% Litter 40-70% Surface fragments >0.25" and <=3" 0-10% Surface fragments >3" 0% Bedrock 0% Water 0% Bare ground 0-10% Table 10. Soil surface cover
Tree basal cover 0% Shrub/vine/liana basal cover 0-10% Grass/grasslike basal cover 0-10% Forb basal cover 60-80% Non-vascular plants 0% Biological crusts 0-10% Litter 0% Surface fragments >0.25" and <=3" 0-10% Surface fragments >3" 0% Bedrock 0% Water 0% Bare ground 10-40% Table 11. Canopy structure (% cover)
Height Above Ground (ft) Tree Shrub/Vine Grass/
GrasslikeForb <0.5 – 1-5% 5-10% 5-15% >0.5 <= 1 – 4-10% 25-50% 0-5% >1 <= 2 – 4-13% 5-15% – >2 <= 4.5 – 0-2% – – >4.5 <= 13 – – – – >13 <= 40 – – – – >40 <= 80 – – – – >80 <= 120 – – – – >120 – – – – Community 1.2
Western Wheatgrass and Needle and ThreadThe Western Wheatgrass and Needle and Thread plant community (1.2) occurs when the plant community is burned either by wildfire or prescribed fire and may persist for as long as 30 years after burning. It is characterized by a rhizomatous wheatgrass and mid-statured bunchgrass plant community. Both western wheatgrass and thickspike wheatgrass can occur on this site. The northern portion of MLRA 52 appears to include the area of transition in dominance between thickspike wheatgrass and western wheatgrass (Heidel et al., 2000; Cooper et al., 2001). Western wheatgrass tends to be predominant in the Loamy Dry Shrubland ecological site due to its greater tolerance of higher temperatures and droughty conditions (Coupland, 1961; Cooper et al., 2001). Needle and thread is the primary mid-statured bunchgrass, although green needlegrass occurs on sites with more favorable moisture conditions. Blue grama is common, but cover is typically 5 percent or less. Other species that occur in this phase include prairie Junegrass, Sandberg bluegrass, and sedges. Wyoming big sagebrush will be eliminated or nearly so immediately following fire. Recovery of Wyoming big sagebrush depends on many factors including climate, proximity to a seed source, and fire intensity. Typically, there is little or no regeneration for 5 to 10 years post-fire, then cover begins to increase gradually until an equilibrium level is reached (Watts and Wambolt, 1996). Generally, recovery is prolonged, sometimes taking as long as 30 years (Wambolt et al., 2001).
Dominant plant species
-
western wheatgrass (Pascopyrum smithii), grass
-
needle and thread (Hesperostipa comata), grass
Community 1.3
Western Wheatgrass and Blue GramaThe Western Wheatgrass and Blue Grama community (1.3) occurs when site condition declines due to drought or improper grazing management. Multiple fires in close succession can also transition the site to this community. This community is characterized by an increase in the warm-season, mat-forming blue grama. The cover of blue grama in this community equals or nearly equals mid-statured grasses, which decrease in this community. If present on the site, the cool-season, bunchgrass green needlegrass will become rare or disappear from the site. Prairie Junegrass, Sandberg bluegrass and the subshrub, prairie sagewort, also increase. Cover of Wyoming big sagebrush will vary depending on the length of time since the last burn.
Dominant plant species
-
Wyoming big sagebrush (Artemisia tridentata ssp. wyomingensis), shrub
-
western wheatgrass (Pascopyrum smithii), grass
-
blue grama (Bouteloua gracilis), grass
Pathway 1.1A
Community 1.1 to 1.2Fire will transition the Western Wheatgrass, Needle and Thread, and Wyoming Big Sagebrush community (1.1) to the Western Wheatgrass and Needle and Thread community (1.2). Wyoming big sagebrush is killed and perennial grasses will dominate the site.
Context dependence.Fire may be more likely following wet years that increase herbaceous production.
Pathway 1.1B
Community 1.1 to 1.3Drought, improper grazing management, or a combination of these factors can shift the Western Wheatgrass, Needle and Thread, and Wyoming Big Sagebrush community (1.1) to the Western Wheatgrass and Blue Grama (1.3) community. These factors favor an increase in blue grama and a decrease in cool-season mid-statured grasses (Coupland, 1961; Shay et al., 2001). Wyoming big sagebrush cover will be similar to the Wheatgrass, Needle and Thread, and Wyoming Big Sagebrush community (1.1).
Context dependence.Timing of precipitation may affect species composition of perennial grasses.
Pathway 1.2A
Community 1.2 to 1.1Thirty years or more of natural vegetative regrowth will transition the Western Wheatgrass and Needle and Thread community (1.2) to the Western Wheatgrass, Needle and Thread, and Wyoming Big Sagebrush community (1.1). Thirty years or more without fire permits Wyoming big sagebrush to recolonize the site.
Context dependence.High intensity fire and/or less proximity to a seed source may increase sagebrush recovery time.
Pathway 1.2B
Community 1.2 to 1.3Drought, improper grazing management, multiple fires in close succession, or a combination of these factors can shift the Western Wheatgrass and Needle and Thread community (1.2) to the Western Wheatgrass and Blue Grama 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). Wyoming big sagebrush cover will be similar to the Western Wheatgrass and Needle and Thread community (1.2).
Context dependence.Timing of precipitation may affect species composition of perennial grasses.
Pathway 1.3B
Community 1.3 to 1.130 years or more post-fire; normal or above-average precipitation and proper grazing management transitions the Western Wheatgrass and Blue Grama community (1.3) to the Western Wheatgrass, Needle and Thread, and Wyoming Big Sagebrush community (1.1).
Context dependence.Timing of precipitation may affect species composition of perennial grasses.
Pathway 1.3A
Community 1.3 to 1.2Less than 30 years post-fire; normal or above-average precipitation and proper grazing management transitions the Western Wheatgrass and Blue Grama community (1.3) to the Western Wheatgrass and Needle and Thread community (1.2).
Context dependence.Timing of precipitation may affect species composition of perennial grasses.
State 2
ShortgrassThe Shortgrass state consists of two communities. The dynamics of this state are driven by long-term drought, improper grazing management, or a combination of these factors. Blue grama increases with long-term improper grazing at the expense of cool-season mid-statured grasses (Coupland, 1961; Biondini and Manske, 1996; Derner and Whitman, 2009). Once established, blue grama-dominated communities can alter soil properties, creating conditions that resist the establishment of other grass species (Dormaar and Willms, 1990; Dormaar et al., 1994). Reductions in stocking rates can reduce blue grama cover and increase the cover of cool-season mid-statured grasses, although this recovery may take decades (Dormaar and Willms, 1990, Dormaar et al., 1994). Dense clubmoss may or may not be present in this state. Its density is highly variable and the dynamics of this species are not well understood. Cover of Wyoming big sagebrush varies depending on fire frequency, with dynamics similar to the Reference state.
Dominant plant species
-
Wyoming big sagebrush (Artemisia tridentata ssp. wyomingensis), shrub
-
blue grama (Bouteloua gracilis), grass
-
Sandberg bluegrass (Poa secunda), grass
Community 2.1
Blue Grama and Wyoming Big SagebrushThe Blue Grama and Wyoming Big Sagebrush community (2.1) occurs when site conditions decline due to long-term drought or improper grazing, and a fire has not occurred on the site for at least 30 years. In this phase, mid-statured grasses have been largely eliminated and replaced by short-statured species, such as blue grama, prairie Junegrass, and Sandberg bluegrass. Blue grama resists grazing due to its low stature and extensive root system. Prairie sagewort may also increase in this community. When clubmoss is absent, there can be a high amount of bare ground, which exposes the soil to wind and water erosion. Cover of Wyoming big sagebrush is five to 15 percent.
Dominant plant species
-
Wyoming big sagebrush (Artemisia tridentata ssp. wyomingensis), shrub
-
blue grama (Bouteloua gracilis), grass
Community 2.2
Blue Grama and Sandberg BluegrassThe Blue Grama and Sandberg Bluegrass community (2.2) occurs when site conditions decline due to long-term drought or improper grazing, and a fire has occurred on the site less than 30 years prior. In this community, mid-statured grasses have been largely eliminated and replaced by short-statured species, such as blue grama, prairie Junegrass, and Sandberg bluegrass. Blue grama resists grazing due to its low stature and extensive root system. Prairie sagewort may also increase in this community. When clubmoss is absent, there can be a high amount of bare ground, which exposes the soil to wind and water erosion. Wyoming big sagebrush is rare.
Dominant plant species
-
blue grama (Bouteloua gracilis), grass
-
Sandberg bluegrass (Poa secunda), grass
Pathway 2.1A
Community 2.1 to 2.2Fire will transition the Blue Grama and Wyoming Big Sagebrush plant community (2.1) to the Blue Grama and Sandberg Bluegrass plant community (2.2). Wyoming big sagebrush is killed, and perennial grasses will dominate the site.
Context dependence.Fire may be more likely following wet years that increase herbaceous production.
Pathway 2.2A
Community 2.2 to 2.1It is likely that 30 years or more of natural vegetative regrowth could transition the Blue Grama and Sandberg Bluegrass plant community (2.2) to the Blue Grama and Wyoming Big Sagebrush plant community (2.1).
Context dependence.High intensity fire and/or less proximity to a seed source may increase sagebrush recovery time.
State 3
InvadedThe Invaded state occurs when invasive plant species invade adjacent native grassland communities. Crested wheatgrass is a common concern, especially when native plant communities are adjacent to seeded pastures. An estimated 20 million acres of crested wheatgrass have been planted in the western U.S. (Holechek, 1981). Crested wheatgrass produces abundant seeds that can dominate the seed bank of invaded grasslands (Henderson and Naeth, 2005), although crested wheatgrass cover decreases with increasing distance from seeded areas (Heidinga and Wilson, 2002). The early growth of crested wheatgrass allows this species to take advantage of early-season soil moisture, which may result in competitive exclusion of native cool-season rhizomatous wheatgrasses and bunchgrasses, such as needle and thread and prairie Junegrass (Christian and Wilson, 1999; Heidinga and Wilson, 2002; Henderson and Naeth, 2005). Reduced soil quality (Dormaar et al., 1995), reduced plant species diversity, and simplified structural complexity (Henderson and Naeth, 2005) result in a state that is substantially departed from the Reference state.
Other invasive species that could be a concern are annual bromes and noxious weeds. Annual bromes are generally not a significant concern in MLRA 52, however, in the Loamy Dry Shrubland, there could be instances where they do significantly affect the site. More information is needed to assess this condition. Noxious weeds such as leafy spurge are uncommon on this site, but they may also invade and displace native species. Although very aggressive, these species can sometimes be suppressed through intensive management (herbicide application, biological control, or intensive grazing management). Control efforts are unlikely to eliminate noxious weeds, but their density can be sufficiently suppressed so that species composition, structural complexity, and soil quality are similar to that of the Reference state. However, cessation of control methods will most likely result in recolonization of the site by the noxious species.Dominant plant species
-
crested wheatgrass (Agropyron cristatum), grass
-
field brome (Bromus arvensis), grass
-
blue grama (Bouteloua gracilis), grass
Community 3.1
Blue Grama and Crested WheatgrassEncroachment by crested wheatgrass and other invasives common. Rangeland health attributes departed substantially from Reference state.
Dominant plant species
-
blue grama (Bouteloua gracilis), grass
-
crested wheatgrass (Agropyron cristatum), grass
State 4
CroplandThe Cropland state occurs when land is put into cultivation. Major crops in MLRA 52 include winter wheat, spring wheat, and barley.
Community 4.1
CroplandAnnual, cool-season cereal grains such as spring wheat, winter wheat, and barley are the most common crops.
State 5
Post CroplandThe Post Cropland state occurs when cultivated cropland is abandoned and allowed to either re-vegetate naturally or is seeded back to perennial species for grazing or wildlife use. This state can transition back to the Cropland state if the site is put back into cultivation.
Community 5.1
Abandoned CroplandIn the absence of active management, the site can re-vegetate naturally and, over time, potentially return to a perennial grassland community with needle and thread and blue grama. Shortly after cropland is abandoned, annual and biennial forbs and annual brome grasses invade the site (Samuel and Hart, 1994). The site is highly susceptible to erosion due to the absence of perennial species. Eventually, these pioneering annual species are replaced by perennial forbs and perennial shortgrasses, such as Sandberg bluegrass and blue grama. Depending on the historical management of the site, perennial bunchgrasses such as needle and thread may also return; however, species composition will depend upon the seed bank. Cover and production of cool-season rhizomatous wheatgrasses is low, even after several decades (Dormaar and Smoliak, 1985; Dormaar et al., 1994; Christian and Wilson, 1999). Invasion of the site by exotic species, such as crested wheatgrass, and annual bromes will depend upon the site’s proximity to a seed source.
Fifty or more years after cultivation, these sites may have species composition similar to phases in the Reference state. However, soil quality is consistently lower than conditions before cultivation (Dormaar and Smoliak, 1985; Christian and Wilson, 1999) and a shift to the Reference state is unlikely within a reasonable timeframe.Community 5.2
Perennial GrassThe Perennial Grass community occurs when the site is seeded to perennial forage species. When seeded to introduced species, particularly perennial grasses such as crested wheatgrass, this plant community can persist for several decades. Monocultures of crested wheatgrass can persist for at least 60 years (Krzic et al., 2000; Henderson and Naeth, 2005). A mixture of native species may also be seeded to provide species composition and structural complexity similar to that of the contemporary Reference state. However, soil quality conditions have been substantially altered and will not return to pre-cultivation conditions within a reasonable timeframe (Dormaar et al., 1994).
Transition T1A
State 1 to 2Prolonged drought, improper grazing practices, 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 contribute little to production. Shortgrasses such as blue grama, Sandberg bluegrass, and prairie Junegrass dominate the plant community.
Context dependence.Drought may accelerate or exacerbate change. Soils are particularly susceptible to erosion when dry.
Transition T1B
State 1 to 3The Reference state transitions to the Invaded state when aggressive perennial grasses or noxious weeds invade the Shortgrass state. Crested wheatgrass, in particular, is a concern when native plant communities are adjacent to seeded pastures. Exotic plant species dominate the site in terms of cover and production. Site resilience has been substantially reduced. In addition, other rangeland health attributes, such as the reproductive capacity of native grasses (Henderson and Naeth, 2005) and soil quality (Smoliak and Dormaar, 1985; Dormaar et al., 1995), have been substantially altered from the Reference state.
Context dependence.Close proximity to a seed source increases likelihood of encroachment by invasive species.
Transition T1C
State 1 to 4Tillage or application of herbicide followed by seeding of cultivated crops, such as winter wheat, spring wheat, and barley, transitions the Reference state to the Cropland state.
Context dependence.Drought may accelerate or exacerbate change. Cropped soils are particularly susceptible to erosion during drought.
Restoration pathway R2A
State 2 to 1Blue grama can resist displacement by other species (Dormaar and Willms, 1990; Laycock, 1991; Dormaar et al., 1994; Lacey et al., 1995). A reduction in livestock grazing pressure alone may not be sufficient to reduce the cover of blue grama in the Shortgrass state (Dormaar and Willms, 1990) and mechanical treatments may be necessary (Hart et al., 1985). Therefore, returning the Shortgrass state to the Reference state can require considerable cost, energy, and time.
Context dependence.Drought may inhibit recovery despite management inputs. Reseedings are more likely to fail during drought.
Transition T2A
State 2 to 3The Shortgrass state transitions to the Invaded state when aggressive perennial 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.
Context dependence.Close proximity to a seed source increases likelihood of encroachment by invasive species.
Transition T2B
State 2 to 4Tillage or application of herbicide followed by seeding of cultivated crops, such as winter wheat, spring wheat, and barley, transitions the Shortgrass state to the Cropland state.
Context dependence.Drought may accelerate or exacerbate change. Cropped soils are particularly susceptible to erosion during drought.
Transition T3A
State 3 to 4The Invaded state will transition to the Cropland state when the site is placed under cultivation.
Context dependence.Drought may accelerate or exacerbate change. Cropped soils are particularly susceptible to erosion during drought.
Transition T4A
State 4 to 5The transition from the Cropland state to the Post Cropland state occurs with the cessation of cultivation. The site may also be seeded to perennial forage species, such as crested wheatgrass and alfalfa, or a mix of native species.
Context dependence.Drought may inhibit recovery despite management inputs. Reseedings are more likely to fail during drought.
Transition T5A
State 5 to 4Tillage or application of herbicide followed by seeding of cultivated crops, such as winter wheat, spring wheat, and barley, transitions the Post Cropland state to the Cropland state.
Context dependence.Drought may accelerate or exacerbate change. Cropped soils are particularly susceptible to erosion during drought.
Additional community tables
Table 12. Community 1.1 plant community composition
Group Common name Symbol Scientific name Annual production () Foliar cover (%) Grass/Grasslike1 Rhizomatous Wheatgrasses 135–390 western wheatgrass PASM Pascopyrum smithii 0–390 0–25 thickspike wheatgrass ELLA3 Elymus lanceolatus 0–390 0–25 2 Mid-Statured Bunchgrasses 90–260 needle and thread HECO26 Hesperostipa comata 90–260 10–15 green needlegrass NAVI4 Nassella viridula 0–65 0–5 3 Shortgrasses 45–130 blue grama BOGR2 Bouteloua gracilis 25–105 2–5 Sandberg bluegrass POSE Poa secunda 5–65 2–5 prairie Junegrass KOMA Koeleria macrantha 5–65 1–5 4 Other native grasses/grasslikes 25–65 Grass, native 2GN Grass, native 0–70 0–10 Forb5 Native Forbs 45–130 Forb, native 2FN Forb, native 0–70 0–10 American vetch VIAM Vicia americana 0–20 0–5 scarlet globemallow SPCO Sphaeralcea coccinea 0–20 0–5 spiny phlox PHHO Phlox hoodii 0–20 0–5 Shrub/Vine6 Shrubs 90–260 Wyoming big sagebrush ARTRW8 Artemisia tridentata ssp. wyomingensis 90–260 8–25 Shrub, other 2S Shrub, other 0–65 0–5 7 Subshrubs 20–65 prairie sagewort ARFR4 Artemisia frigida 0–65 0–5 winterfat KRLA2 Krascheninnikovia lanata 0–65 0–5 Subshrub (<.5m) 2SUBS Subshrub (<.5m) 0–65 0–5 Table 13. Community 1.2 plant community composition
Group Common name Symbol Scientific name Annual production () Foliar cover (%) Table 14. Community 1.3 plant community composition
Group Common name Symbol Scientific name Annual production () Foliar cover (%) Table 15. Community 2.1 plant community composition
Group Common name Symbol Scientific name Annual production () Foliar cover (%) Table 16. Community 2.2 plant community composition
Group Common name Symbol Scientific name Annual production () Foliar cover (%) Table 17. Community 3.1 plant community composition
Group Common name Symbol Scientific name Annual production () Foliar cover (%) Table 18. Community 4.1 plant community composition
Group Common name Symbol Scientific name Annual production () Foliar cover (%) Table 19. Community 5.1 plant community composition
Group Common name Symbol Scientific name Annual production () Foliar cover (%) Table 20. Community 5.2 plant community composition
Group Common name Symbol Scientific name Annual production () Foliar cover (%) Interpretations
Supporting information
Inventory data references
A minimum of 20 low or medium observations are required to meet verification level status. This ESD is citing NRI and 417 data to meet these minimums. Individual observations are listed in EDIT and are viewable behind the login. A corresponding tracking sheet is available in the MLRA office that links the list to the actual observations used in analysis. A total of 21 plots ranging from low to high intensity were used as a basis for this ecological site.
Other references
Adams, B.W., et al. 2013. Rangeland plant communities for the dry mixedgrass natural subregion of Alberta. Second approximation. Rangeland Management Branch, Policy Division, Alberta Environment and Sustainable Resource Development, Lethbridge, Pub. No. T/040.
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.
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.
Clarke, S.E, E.W. Tisdale, and N.A. Skoglund. 1947. The effects of climate and grazing practices on short-grass prairie vegetation in southern Alberta and southwestern Saskatchewan. Canadian Department of Agriculture Technical Bulletin No. 46.
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.
Cooper, S.V., C. Jean, and P. Hendricks. 2001. Biological survey of a prairie landscape in Montana’s glaciated plains. Report to the Bureau of Land Management. Montana Natural Heritage Program, Helena.
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.
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.
Derner, J.D., W.K. Lauenroth, P. Stapp, and D.J. Augustine. 2009. Livestock as ecosystem engineers for grassland bird habitat in the western Great Plains of North America. Rangeland Ecology and Management 62:111-118.
Dix, R.L. 1960. The effects of burning on the mulch structure and species composition of grasslands in western North Dakota. Ecology 41:49-56.
Dormaar, J.F., and S. Smoliak. 1985. Recovery of vegetative cover and soil organic matter during revegetation of abandoned farmland in a semiarid climate. Journal of Range Management 38:487-491.
Dormaar, J.F., and W.D. Willms. 1990. Effect of grazing and cultivation on some chemical properties of soils in the mixed prairie. Journal of Range Management 43:456-460.
Dormaar, J.F., B.W. Adams, and W.D. Willms. 1994. Effect of grazing and abandoned cultivation on a Stipa-Bouteloua community. Journal of Range Management 47:28-32.
Dormaar, J.F., M.A. Naeth, W.D. Willms, and D.S. Chanasyk. 1995. Effect of native prairie, crested wheatgrass (Agropyron cristatum) and Russian wildrye (Elymus junceus) on soil chemical properties. Journal of Range Management 48:258-263.
Fansler, V.A., and J.M. Mangold. 2010. Restoring native plants to crested wheatgrass stands. Restoration Ecology 19:16-23.
Federal Geographic Data Committee. 2008. The National Vegetation Classification Standard, Version 2. FGDC Vegetation Subcommittee. FGDC-STD-005-2008 (Version 2). pp. 126.
Fullerton, D.S., and R.B. Colton. 1986. Stratigraphy and correlation of the glacial deposits on the Montana Plains. U.S. Geological Survey.
Fullerton, D.S., R.B. Colton, C.A. Bush, and A.W. Straub. 2004. Map showing spatial and temporal relations of mountain and continental glaciations on the northern plains, primarily in northern Montana and northwestern North Dakota. U.S. Geologic Survey pamphlet accompanying Scientific Investigations Map 2843.
Fullerton, D.S., R.B. Colton, and C.A. Bush. 2013. Quaternary geologic map of the Shelby 1° x 2° quadrangle, Montana: U.S. Geological Survey Open-File Report 2012–1170, scale 1:250,000.
Haferkamp, M.R., R.K. Heitschmidt, and M.G. Karl. 1997. Influence of Japanese brome on western wheatgrass yield. Journal of Range Management 50:44-50.
Harmoney, K.R. 2007. Grazing and burning Japanese brome (Bromus japonicus) on mixed grass rangelands. Rangeland Ecology and Management 60:479-486.
Hart, M., S.S. Waller, S.R. Lowry, and R.N. Gates. 1985. Disking and seeding effects on sod bound mixed prairie. Journal of Range Management 38:121-125.
Heidel, B., S.V. Cooper, and C. Jean. 2000. Plant species of special concern and plant associations of Sheridan County, Montana. Report to U.S. Fish and Wildlife Service. Montana Natural Heritage Program, Helena, Montana.
Heidinga, L., and S.D. Wilson. 2002. The impact of an invading alien grass (Agropyron cristatum) on species turnover in native prairie. Diversity and Distributions 8:249-258.
Heitschmidt, R.K., and L.T. Vermeire. 2005. An ecological and economic risk avoidance drought management decision support system. In: J.A. Milne (ed.) Pastoral Systems in Marginal Environments, XXth International Grasslands Congress, July 2005, p. 178.
Henderson, D.C., and M.A. Naeth. 2005. Multi-scale impacts of crested wheatgrass invasion in mixed-grass prairie. Biological Invasions 7:639-650.
Herrick, J.E., J.W. Van Zee, K.M. Havstad, L.M. Burkett, and W.G. Whitford. 2009. Monitoring manual for grassland, shrubland and savanna ecosystems. U.S. Department of Agriculture, Agricultural Research Service, Jornada Experimental Range, Las Cruces, NM.
Higgins, K.F. 1986. Interpretation and compendium of historical fire accounts in the Northern Great Plains. U.S. Fish and Wildlife Service Resource Publication 161.
Holechek, J.L. 1981. Crested wheatgrass. Rangelands 3:151-153.
Howard, J. L. 1999. Artemisia tridentata subsp. wyomingensis. In: Fire Effects Information System, U.S. Department of Agriculture, Forest Service http://www.fs.fed.us/database/feis/plants/shrub/arttriw/all.html accessed (8/11/2016).
Krzic, M., K. Broersma, D.J. Thompson, and A.A. Bomke. 2000. Soil properties and species diversity of grazed crested wheatgrass and native rangelands. Journal of Range Management 53:353-358.
Lacey, J., R. Carlstrom, and K. Williams. 1995. Chiseling rangeland in Montana. Rangelands 17:164-166.
Lauenroth, W.K., O.E. Sala, D.P. Coffin, and T.B. Kirchner. 1994. The importance of soil water in recruitment of Bouteloua gracilis in the shortgrass steppe. Ecological Applications 4:741-749.
Laycock, W.A. 1988. History of grassland plowing and grass planting on the Great Plains. In: J.E. Mitchell (ed.) Impacts of the Conservation Reserve Program in the Great Plains—Symposium Proceedings, September 16-18, 1987. USDA Forest Service, Rocky Mountain Forest and Range Experiment Station, General Technical Report RM-158.
Laycock, W.A. 1991. Stable states and thresholds of range condition on North American rangelands. Journal of Range Management 44:427-433.
Lesica, P., and T.H. DeLuca. 1996. Long-term harmful effects of crested wheatgrass on Great Plains grassland ecosystems. Journal of Soil and Water Conservation 51:408-409.
Lockwood, J.A. 2004. Locust: The devastating rise and mysterious disappearance of the insect that shaped the American frontier. Basic Books, New York, NY.
Looman, J., and D.H. Heinrichs. 1973. Stability of crested wheatgrass pastures under long-term pasture use. Canadian Journal of Plant Science 53:501-506.
McNab, W.H., et al. 2007. Description of ecological subregions: Sections of the conterminous United States [CD-ROM]. USDA Forest Service, General Technical Report WO-76B.
Miller, J.J., and J.A. Brierley. 2011. Solonetzic soils of Canada: Genesis, distribution, and classification. Canadian Journal of Soil Science 91:889-902.
Montana State College. 1949. Similar vegetative rangeland types in Montana. Montana State College, Agricultural Experiment Station.
Nesser, J.A., G.L. Ford, C.L. Maynard, and D.S. Page-Dumroese. 1997. Ecological units of the Northern Region: Subsections. USDA Forest Service, Intermountain Research Station, General Technical Report INT-GTR-369.
Oard, M.J. 1993. A method of predicting chinook winds east of the Montana Rockies. Weather and Forecasting 8:166-180.
Ogle, D., et al. 2012. Plant guide for Russian wildrye (Psathyrostachys junceus). USDA Natural Resources Conservation Service, Aberdeen Plant Materials Center.
Ogle, S.M., W.A. Reiners, and K.G. Gerow. 2003. Impacts of exotic annual brome grasses (Bromus spp.) on ecosystem properties of the northern mixed grass prairie. American Midland Naturalist 149:46-58.
Roath, L.R. 1988. Implications of land conversions and management for the future. In: J.E. Mitchell (ed.) Impacts of the Conservation Reserve Program in the Great Plains—Symposium Proceedings, September 16-18, 1987. USDA Forest Service, Rocky Mountain Forest and Range Experiment Station, General Technical Report RM-158.
Rogler, G.A., and R.J. Lorenz. 1983. Crested wheatgrass: Early history in the United States. Journal of Range Management 36:91-93.
Romo, J.T. 2011. Clubmoss, precipitation, and microsite effects on emergence of graminoid and forb seedlings in the semiarid northern mixed prairie of North America. Journal of Arid Environments 75:98-105.
Rowe, J.S. 1969. Lightning fires in Saskatchewan grassland. Canadian Field Naturalist 83:317-327.
Salo, E.D., et al. 2004. Grazing intensity effects on vegetation, livestock and non-game birds in North Dakota mixed-grass prairie. Proceedings of the 19th North American Prairie Conference, Madison, Wisconsin.
Samuel, M.J., and R.H. Hart. 1994. Sixty-one years of secondary succession on rangelands of the Wyoming High Plains. Journal of Range Management 47:184-191.
Shay, J., D. Kunec, and B. Dyck. 2001. Short-term effects of fire frequency on vegetation composition and biomass in mixed prairie in south-western Manitoba. Plant Ecology 155:157-167.
Smith, B., and G.J. McDermid. 2014. Examination of fire-related succession within the dry mixed-grass subregion of Alberta with the use of MODIS and Landsat. Rangeland Ecology and Management 67:307-317.
Smith, R.E. 2013. Conserving Montana’s sagebrush highway: Long distance migration in sage-grouse. M.S. thesis, University of Montana, Missoula.
Smoliak, S. 1974. Range vegetation and sheep production at three stocking rates on Stipa-Bouteloua prairie. Journal of Range Management 27:23-26.
Smoliak, S., and J.F. Dormaar. 1985. Productivity of Russian wildrye and crested wheatgrass and their effect on prairie soils. Journal of Range Management 38:403-405.
Smoliak, S., J.F. Dormaar, and A. Johnston. 1972. Long-term grazing effects on Stipa-Bouteloua prairie soils. Journal of Range Management 25:246-250.
Soil Survey Staff. 2014. Keys to soil taxonomy, 12th edition. USDA Natural Resources Conservation Service.
Soller, D.R. 2001. Map showing the thickness and character of Quaternary sediments in the glaciated United States east of the Rocky Mountains. U.S. Geological Survey Miscellaneous Investigations Series I-1970-E, scale 1:3,500,000.
Stephens, S.E., J.J. Rotella, M.S. Lindberg, M.L. Taper, and J.K. Ringelman. 2005. Duck nest survival in the Missouri Coteau of North Dakota: Landscape effects at multiple spatial scales. Ecological Applications 15:2137-2149.
Umbanhowar, Jr., C.E. 2004. Interactions of climate and fire at two sites in the Northern Great Plains. Palaeogeography, Palaeoclimatology, and Palaeoecology 208:141-152.
USDA-NRCS. Glossary of Landform and Geologic Terms. In: National soil survey handbook, title 430-VI. Part 629.02c http://www.nrcs.usda.gov/wps/portal/nrcs/detail/soils/ref/?cid=nrcs142p2_054242 accessed (4/13/2016).
U.S. Fish and Wildlife Service. 2013. Greater sage-grouse (Centrocercus urophasianus)
conservation objectives: Final report.
Van Dyne, G.M., and W.G. Vogel. 1967. Relation of Selaginella densa to site, grazing, and climate. Ecology 48:438-444.
Vaness, B.M., and S.D. Wilson. 2007. Impact and management of crested wheatgrass (Agropyron cristatum) in the northern Great Plains. Canadian Journal of Plant Science 87:1023-1028.
Vermeire, L.T., J.L. Crowder, and D.B. Wester 2011. Plant community and soil environment response to summer fire in the northern Great Plains. Rangeland Ecology and Management 64:37-46.
Vermeire, L.T., J.L. Crowder, and D.B. Wester 2014. Semiarid rangeland is resilient to summer fire and postfire grazing utilization. Rangeland Ecology and Management 67:52-60.
Vuke, S.M., K.W. Porter, J.D. Lonn, and D.A. Lopez. 2007. Geologic map of Montana - information booklet: Montana Bureau of Mines and Geology Geologic Map 62-D.
Wambolt, C.L., K.S. Walhof, and M.R. Frisina. 2001. Recovery of big sagebrush communities after burning in south-western Montana. Journal of Environmental Management 61:243-252
Watts, M.J. and C.L. Wambolt. 1996. Long-term recovery of Wyoming big sagebrush after four treatments. Journal of Environmental Management 46:95-102
Whisenant, S.G. 1990. Postfire population dynamics of Bromus japonicus. American Midland Naturalist 123:301-308.
Wilson, S.D., and J.M. Shay. 1990. Competition, fire, and nutrients in a mixed-grass prairie. Ecology 71:1959-1967.Contributors
Scott Brady
Stuart VeithApproval
Kirt Walstad, 5/07/2025
Acknowledgments
This provisional ecological site description could not have been completed without the contributions of Karen Newlon. She conducted an extensive literature review, which provided most of the background information for this project as well as many of the references. She also co-authored the Loamy and Thin Claypan Dry Grassland ecological sites previously prepared in MLRA 52. A number of USDA-NRCS and USDI-BLM staff supported this project. Staff contributions are as follows: Soil Concepts, Soils Information, and Field Descriptions Charlie French, USDA-NRCS Josh Sorlie, USDI-BLM NASIS Reports, Data Dumps, and Soil Sorts Bill Drummond, USDA-NRCS Pete Weikle, USDA-NRCS Peer Review and Beta Testing Kirt Walstad, USDA-NRCS Kyle Steele, formerly USDA-NRCS Kelsey Molloy, USDA-NRCS Rick Caquelin, USDA-NRCS Josh Sorlie, USDI-BLM BJ Rhodes, USDI-BLM Editing Ann Kinney, USDA-NRCS Jenny Sutherland, USDA-NRCS Quality Control Kirt Walstad, USDA-NRCS Quality Assurance Stacey Clark, USDA-NRCS
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) Scott Brady Contact for lead author 206 25th Ave. West Havre, MT 59501 Date 04/09/2025 Approved by Approval date Composition (Indicators 10 and 12) based on Foliar Cover Indicators
-
Number and extent of rills:
Rills are typically not present in the reference condition. -
Presence of water flow patterns:
Water flow patterns are rare in the reference condition. If present, they are most likely to occur on steeper slopes (10 to 15 percent) and are typically faint, disconnected, and very short in length. -
Number and height of erosional pedestals or terracettes:
Pedestals are typically not evident in the reference condition. If present, they are generally limited to steeper slopes (10 to 15 percent), are rare (approximately 1 percent of plants), and less than ½ inch in height. -
Bare ground from Ecological Site Description or other studies (rock, litter, lichen, moss, plant canopy are not bare ground):
Bare ground is typically low (less than 5 percent) in large part due to ground cover of dense clubmoss. It typically consists of small, randomly scattered patches, particularly where clubmoss is absent or disturbed. Note: Indicator should be evaluated in the context of current years climate and disturbance patterns. Events such as drought, hail, fire, etc. may increase bare ground. Bare ground is defined as exposed mineral soil without cover from vegetation, litter, surface fragments, or biotic crust (as measured by Line-Point-Intercept method). -
Number of gullies and erosion associated with gullies:
Active gullies are not present in the reference state. Any remnants of gullies on the site have stable vegetative cover and no active erosion is evident. -
Extent of wind scoured, blowouts and/or depositional areas:
Wind scoured or depositional areas are typically not evident in the reference condition. -
Amount of litter movement (describe size and distance expected to travel):
Litter movement is typically not evident in the reference condition. If present, fine litter movement is typically less than 1 foot and is dispersed, with little or no accumulation around obstructions. Large litter movement is not evident. -
Soil surface (top few mm) resistance to erosion (stability values are averages - most sites will show a range of values):
The average soil stability rating is 5 to 6 for both: under plant canopies and in plant interspaces. -
Soil surface structure and SOM content (include type of structure and A-horizon color and thickness):
The soil surface horizon averages 4 inches (10 cm) thick but may vary from 2 to 6 inches (5 to 15 cm) thick depending on slope, aspect, and climate. It typically has fine granular structure and moist color typically ranges from brown (10YR 4/3) to very dark grayish brown (10YR 3/2). -
Effect of community phase composition (relative proportion of different functional groups) and spatial distribution on infiltration and runoff:
Foliar cover of 70 to 90 percent reduces raindrop impact, slow overland flow, and increases time for infiltration. 10 to 15 percent of the cover is comprised of bunchgrasses with dense, extensive root systems which aids infiltration. 15 to 25 percent cover of rhizomatous wheatgrasses further reduces soil surface exposure to raindrop impact while 5 to 10 percent cover of shortgrasses fills in plant interspaces. -
Presence and thickness of compaction layer (usually none; describe soil profile features which may be mistaken for compaction on this site):
A compaction layer is not present in the reference condition. Soil structure is typically fine granular or prismatic and root restriction is not evident. Some soils will have an E horizon immediately below the surface horizon that has platy structure, but this is due to normal soil forming factors rather than compaction. -
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:
Typically, rhizomatous wheatgrasses are the dominant functional/structural group with foliar cover ranging from 15 to 25 percent.Sub-dominant:
Shrubs and mid-statured bunchgrasses are subdominant groups ranging from 8 to 25 percent and 10 to 15 percent foliar cover respectively. Forbs are a subdominant or minor component with 5 to 15 percent foliar cover.Other:
Shortgrasses and subshrubs are minor components ranging from 5 to 10 percent and 1 to 5 percent foliar cover respectively.Additional:
Functional and structural groups must be evaluated in the context of the current years climate. Climatic fluctuations such as amount and timing of precipitation, temperature, and stored soil moisture may affect composition and structure on the site. -
Amount of plant mortality and decadence (include which functional groups are expected to show mortality or decadence):
Mortality in herbaceous species is not evident, particularly in rhizomatous species. Species with bunch growth forms may have some mortality in centers but is typically 3 percent or less. Shrubs, subshrubs, or cactus species may show dead or dying plants, but mortality typically does not exceed 5 percent for any given species. -
Average percent litter cover (%) and depth ( in):
Total litter cover typically ranges from 40 to 60 percent. This includes all dead plant material, both on the soil surface and suspended in the canopy. Most litter is loosely distributed throughout the canopy and it is estimated that only 5 to 10 percent is in contact with the soil surface. It does not typically accumulate to a measurable depth on the soil surface. Note: Indicator should be evaluated in the context of current years climate and disturbance patterns. Above average precipitation may increase litter amounts whereas events such as drought, hail, fire, etc. may decrease litter amounts. -
Expected annual annual-production (this is TOTAL above-ground annual-production, not just forage annual-production):
Total annual production is strongly influenced by climatic factors such as amount and timing of precipitation, temperature, and stored soil moisture and must be evaluated within the context of the current climatic conditions. Estimated annual production expected on this site for below average, average, and above average years is as follows: Below Average (pounds per acre) Grasses: 300 to 490 Forbs: 40 to 75 Shrubs: 110 to 185 Total: 450 to 750 Average (pounds per acre) Grasses: 410 to 675 Forbs: 65 to 100 Shrubs: 150 to 250 Total: 625 to 1025 Above Average (pounds per acre) Grasses: 520 to 850 Forbs: 80 to 125 Shrubs: 200 to 325 Total: 800 to 1300 -
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:
Potential invasive plants on this site are: crested wheatgrass, leafy spurge, and annual bromes. Invasive species are typically absent or constitute less than 5 percent cover in the reference condition. However, abundance of annual species such as field brome (<a class="species-link" href="https://plants.usda.gov/core/profile?symbol=BRAR5" target="_blank" title="Open in plants.usda.gov"><i>Bromus arvensis</i></a>) may fluctuate depending on moisture and germination conditions resulting in short-term departures from reference. -
Perennial plant reproductive capability:
In the reference condition, all plants are vigorous enough for reproduction either by seed or tillers. For grasses and forbs: at least 50 percent of plants are capable of producing seedheads. For shrubs: 50 percent or more of plants are capable of producing flowering leaders. Note: Must be evaluated in the context of the current years climate. Climatic fluctuations such as amount and timing of precipitation, temperature, and stored soil moisture may effect flower or seed production depending on the particular species.
Print Options
Sections
Font
AAAAOther
PrintThe 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.
Accessibility statement
