Natural Resources
Conservation Service
Ecological site R058AE006MT
Sandy-Steep (SyStp) RRU 58A-E 10-14" p.z.
Accessed: 11/13/2024
General information
Provisional. A provisional ecological site description has undergone quality control and quality assurance review. It contains a working state and transition model and enough information to identify the ecological site.
Figure 1. Mapped extent
Areas shown in blue indicate the maximum mapped extent of this ecological site. Other ecological sites likely occur within the highlighted areas. It is also possible for this ecological site to occur outside of highlighted areas if detailed soil survey has not been completed or recently updated.
Associated sites
R058AE003MT |
Sandy (Sy) RRU 58A-E 10-14" p.z. |
---|---|
R058AE019MT |
Shallow (Sw) RRU 58A-E 10-14" p.z. |
Similar sites
R058AE003MT |
Sandy (Sy) RRU 58A-E 10-14" p.z. The Sandy site is mainly on slopes less than 15%. |
---|---|
R058AE019MT |
Shallow (Sw) RRU 58A-E 10-14" p.z. The Shallow site is mainly 20 inches or less to hard rock or other root limiting material. |
R058AE018MT |
Sands (Sa) RRU 58A-E 10-14" p.z. The Sands site differs mainly by being on slopes less than 15%. |
Table 1. Dominant plant species
Tree |
Not specified |
---|---|
Shrub |
Not specified |
Herbaceous |
Not specified |
Physiographic features
This ecological site occurs on moderately steep to steep hills and side slopes. Slopes are mainly between 15% and 45%. This site occurs on all exposures and aspect can be significant. Slight variations in plant community composition and production can result from aspect. Runoff and potential for water erosion can be significant.
Table 2. Representative physiographic features
Landforms |
(1)
Hill
(2) Plain (3) Ridge |
---|---|
Flooding frequency | None |
Ponding frequency | None |
Elevation | 1,900 – 3,500 ft |
Slope | 15 – 45% |
Water table depth | 60 in |
Climatic features
MLRAs 58A and 60B are considered to have a continental climate characterized by cold winters, hot summers, low humidity, light rainfall, and much sunshine. Extremes in temperature are typical. The climate is the result of this MLRA’s location in the geographic center of North America. 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. Seasonal precipitation is often limiting for plant growth. Annual fluctuations in species composition and total production are typical depending on the amount and timing of rainfall.
Temperatures can be very extreme in this part of Montana. Summer daytime temperatures are typically quite warm, generally averaging in the mid to upper 80º’s F for July and August. Summertime temperatures will typically reach in the 100º’s F at some point during the summer, and can reach 90º F any month between May and September. Conversely, winter temperatures can be cold, averaging in the mid teens to mid 20º’s F for December and January. There will typically be several days of below zero temperatures each winter. It is not uncommon for temperatures to reach 30–40º F below zero, or even colder, most any winter.
Spring can be windy throughout these MLRA’s, with winds averaging over 10 mph about 15 percent of the time. Speeds of 50 mph or stronger can occasionally occur as a weather system crosses this part of Montana.
MLRAs 58AE and 60BE have been divided into two distinct precipitation zones for the purpose of developing ecological site descriptions: 10–14” Mean Annual Precipitation (MAP) and 15–19” MAP.
10–14 inch zone:
The majority of the rangeland in these areas falls within the 11 to 13 inch range. During an average year, 70 to 75 percent of the annual precipitation falls between April and September, which are the primary growing season months.
Snowfall is not heavy in the area, averaging 28 total inches in the 10-14 inch MAP (Yellowstone Valley). Heavy snowfall occurs infrequently, usually late in the winter or early spring. Snow cover is typically 1 to 3 inches.
The frost free (32º F.) season averages about 105 to 145 days each year in the uplands, to nearly 170 days along the Yellowstone River Valley.
For local climate station information, refer to http://www.wcc.nrcs.usda.gov/cgibin/state.pl?state=mt.
Table 3. Representative climatic features
Frost-free period (average) | 145 days |
---|---|
Freeze-free period (average) | 170 days |
Precipitation total (average) | 14 in |
Influencing water features
None
Soil features
These soils are sands, loamy sands, or sandy loams on moderately steep, steep, or hilly landscapes. They are over 20 inches deep to any root limiting feature.
Table 4. Representative soil features
Surface texture |
(1) Sandy loam (2) Loamy sand (3) Sand |
---|---|
Family particle size |
(1) Sandy |
Drainage class | Well drained to somewhat excessively drained |
Permeability class | Moderate to moderately rapid |
Soil depth | 20 – 60 in |
Available water capacity (0-40in) |
5 – 8 in |
Calcium carbonate equivalent (0-40in) |
10% |
Electrical conductivity (0-40in) |
2 mmhos/cm |
Sodium adsorption ratio (0-40in) |
4 |
Soil reaction (1:1 water) (0-40in) |
7.4 – 8.4 |
Ecological dynamics
This site developed under Northern Great Plains climatic conditions, which included the natural influence of large herbivores and occasional fire. The plant community upon which interpretations are primarily based is the Historic Climax Plant Community (HCPC). This plant community is described as a reference to understand the original potential of this site, and is not always considered to be the management goal for every acre of rangeland. The following descriptions should enable the landowner or manager to better understand which plant communities occupy their land, and assist with setting goals for vegetation management. It can also be useful to understand the environmental and economic values of each plant community.
This site is considered moderately resilient to disturbance as it has only moderate soil limitations (slope) for plant growth. Changes may occur to the Historic Climax Plant Community due to management actions and/or climatic conditions. Under continued adverse impacts, a moderate to extreme decline in vegetative vigor and composition will occur. Under favorable vegetative management treatments, this site can more readily return to the Historic Climax Plant Community (HCPC).
Continual adverse impacts to the site over a period of years results in a departure from the HCPC, with a decrease of the taller, more palatable species such as prairie sandreed, little bluestem, and bluebunch wheatgrass. These plants will be replaced by needleandthread, sand dropseed, threadleaf sedge, prairie junegrass, non-palatable forbs, and shrubs such as yucca.
Plants that are not a part of the climax community that are most likely to invade are cheatgrass, Japanese brome, annual and biennial forbs, and broom snakeweed.
State and transition model
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View Interactive Models
Click on state and transition labels to scroll to the respective text
State 1 submodel, plant communities
State 2 submodel, plant communities
State 3 submodel, plant communities
State 4 submodel, plant communities
State 1
Plant Community 1: Tall and Medium Grasses/ Forbs/ Shrubs
Community 1.1
Plant Community 1: Tall and Medium Grasses/ Forbs/ Shrubs
This is the interpretive plant community and is considered to be the Historic Climax Plant Community (HCPC) for this site. This plant community is a mixture of cool and warm season grasses, including prairie sandreed, little bluestem, bluebunch wheatgrass, and needleandthread. There are also several short grasses and sedges, forbs and shrubs in small percentages, including sand dropseed, prairie junegrass, threadleaf sedge, winterfat, prairie rose, and skunkbush sumac. This plant community is well adapted to the Northern Great Plains climatic conditions. The diversity in plant species and the presence of tall, deep-rooted perennial grasses allows for high drought tolerance. Individual species can vary greatly in production depending on growing conditions (timing and amount of precipitation and temperature). Plants on this site have strong, healthy root systems that allow production to increase significantly with favorable precipitation. Abundant plant litter is available for soil building and moisture retention. Plant litter is properly distributed with very little movement off-site and natural plant mortality is very low. Run-off from adjacent sites and moderate or high available water capacity provides a favorable soil-water-plant relationship. This plant community provides for soil stability and a functioning hydrologic cycle.
Figure 2. Annual production by plant type (representative values) or group (midpoint values)
Table 5. Annual production by plant type
Plant type | Low (lb/acre) |
Representative value (lb/acre) |
High (lb/acre) |
---|---|---|---|
Grass/Grasslike | 712 | 900 | 1350 |
Forb | 142 | 180 | 270 |
Shrub/Vine | 95 | 120 | 180 |
Total | 949 | 1200 | 1800 |
Table 6. Ground cover
Tree foliar cover | 0% |
---|---|
Shrub/vine/liana foliar cover | 1-5% |
Grass/grasslike foliar cover | 55-70% |
Forb foliar cover | 5-10% |
Non-vascular plants | 0% |
Biological crusts | 0-1% |
Litter | 0% |
Surface fragments >0.25" and <=3" | 0% |
Surface fragments >3" | 0% |
Bedrock | 0% |
Water | 0% |
Bare ground | 0% |
Table 7. Soil surface cover
Tree basal cover | 0% |
---|---|
Shrub/vine/liana basal cover | 1-2% |
Grass/grasslike basal cover | 3-7% |
Forb basal cover | 1-2% |
Non-vascular plants | 0% |
Biological crusts | 0-1% |
Litter | 15-25% |
Surface fragments >0.25" and <=3" | 0-4% |
Surface fragments >3" | 0% |
Bedrock | 0% |
Water | 0% |
Bare ground | 60-80% |
Table 8. Canopy structure (% cover)
Height Above Ground (ft) | Tree | Shrub/Vine | Grass/ Grasslike |
Forb |
---|---|---|---|---|
<0.5 | – | – | – | – |
>0.5 <= 1 | – | – | – | – |
>1 <= 2 | – | 1-5% | 55-70% | 5-10% |
>2 <= 4.5 | – | – | – | – |
>4.5 <= 13 | – | – | – | – |
>13 <= 40 | – | – | – | – |
>40 <= 80 | – | – | – | – |
>80 <= 120 | – | – | – | – |
>120 | – | – | – | – |
State 2
Plant Community 2: Medium and Short Grasses/ Medium Shrubs
Community 2.1
Plant Community 2: Medium and Short Grasses/ Medium Shrubs
Slight variations can result in a community similar to the HCPC/PPC but with higher proportions of medium and short grasses, such as needleandthread, sand dropseed, and threadleaf sedge. There may also be some increase in the proportion of forbs and shrubs, including yucca. Grass biomass production and litter become reduced on the site as the taller grasses disappear, increasing evapotranspiration and reducing moisture retention. Additional open space in the community can result in undesirable invader species. This plant community provides for moderate soil stability.
State 3
Plant Community 3: Short Grasses/ Medium Shrubs/ Half-shrubs
Community 3.1
Plant Community 3: Short Grasses/ Medium Shrubs/ Half-shrubs
With continued heavy disturbance on Community 2, the plant community tends to become dominated by medium and short grasses. The taller grasses and palatable forbs are reduced to a minor component of the plant community. They are replaced by threadleaf sedge, prairie junegrass, sand dropseed, and needleandthread. The more desirable forbs are replaced by species such as hairy goldenaster, and green sagewort. Fringed sagewort, and yucca become a more significant component of the plant community. This plant community is less productive than Plant Community 1 or 2. The lack of litter and short plant heights result in higher soil temperatures, poor water infiltration rates, and high evapotranspiration. This community has lost many of the attributes of a healthy rangeland, including good infiltration, minimal erosion and runoff, nutrient cycling and energy flow. This community will respond positively to improved grazing management, but significant economic inputs and time would be required to move this plant community toward a higher successional stage and a more productive plant community.
State 4
Plant Community 4: Short Grasses/ Half-shrubs/ Annuals
Community 4.1
Plant Community 4: Short Grasses/ Half-shrubs/ Annuals
Continued deterioration can result in a community having smaller proportions of plants that occur in community 2 or 3. Species such as threadleaf sedge, sand dropseed, and needleandthread are still present, but are being replaced by green sagewort and hairy goldenaster. Annual grasses such as Japanese and cheatgrass brome, cactus, and broom snakeweed also become prominent components. This plant community is significantly less productive than the HCPC and has lost many of the attributes of a healthy rangeland. The loss of deep perennial root systems reduces total available moisture for plant growth. Reduction of plant litter will result in higher surface soil temperatures and increased evaporation losses. Annual species are often aggressive and competitive with seedlings of perennial plants.
Additional community tables
Table 9. Community 1.1 plant community composition
Group | Common name | Symbol | Scientific name | Annual production (lb/acre) | Foliar cover (%) | |
---|---|---|---|---|---|---|
Grass/Grasslike
|
||||||
1 | Native grasses and sedges | 700–1170 | ||||
bluebunch wheatgrass | PSSP6 | Pseudoroegneria spicata | 142–900 | – | ||
little bluestem | SCSCS | Schizachyrium scoparium var. scoparium | 190–540 | – | ||
prairie sandreed | CALO | Calamovilfa longifolia | 190–540 | – | ||
needle and thread | HECOC8 | Hesperostipa comata ssp. comata | 48–270 | – | ||
big bluestem | ANGE | Andropogon gerardii | 0–270 | – | ||
western wheatgrass | PASM | Pascopyrum smithii | 48–180 | – | ||
Indian ricegrass | ACHY | Achnatherum hymenoides | 0–90 | – | ||
threadleaf sedge | CAFI | Carex filifolia | 10–90 | – | ||
sun sedge | CAINH2 | Carex inops ssp. heliophila | 10–90 | – | ||
plains muhly | MUCU3 | Muhlenbergia cuspidata | 10–90 | – | ||
2 | Native grasses and sedges | 10–180 | ||||
Grass, perennial | 2GP | Grass, perennial | 10–90 | – | ||
blue grama | BOGR2 | Bouteloua gracilis | 10–90 | – | ||
needleleaf sedge | CADU6 | Carex duriuscula | 10–90 | – | ||
prairie Junegrass | KOMA | Koeleria macrantha | 10–90 | – | ||
green needlegrass | NAVI4 | Nassella viridula | 10–90 | – | ||
Sandberg bluegrass | POSE | Poa secunda | 10–90 | – | ||
sand dropseed | SPCR | Sporobolus cryptandrus | 10–90 | – | ||
3 | Native grasses | 1–2 | ||||
Fendler threeawn | ARPUL | Aristida purpurea var. longiseta | 1–2 | – | ||
Forb
|
||||||
4 | Native forbs | 142–270 | ||||
Forb, perennial | 2FP | Forb, perennial | 10–90 | – | ||
onion | ALLIU | Allium | 10–90 | – | ||
tarragon | ARDR4 | Artemisia dracunculus | 10–90 | – | ||
aster | ASTER | Aster | 10–90 | – | ||
white prairie clover | DACA7 | Dalea candida | 10–90 | – | ||
purple prairie clover | DAPU5 | Dalea purpurea | 10–90 | – | ||
blacksamson echinacea | ECAN2 | Echinacea angustifolia | 10–90 | – | ||
sanddune wallflower | ERCAC | Erysimum capitatum var. capitatum | 10–90 | – | ||
hairy false goldenaster | HEVI4 | Heterotheca villosa | 10–90 | – | ||
dotted blazing star | LIPU | Liatris punctata | 10–90 | – | ||
western stoneseed | LIRU4 | Lithospermum ruderale | 10–90 | – | ||
white milkwort | POAL4 | Polygala alba | 10–90 | – | ||
scurfpea | PSORA2 | Psoralidium | 10–90 | – | ||
upright prairie coneflower | RACO3 | Ratibida columnifera | 10–90 | – | ||
Missouri goldenrod | SOMI2 | Solidago missouriensis | 10–90 | – | ||
longbract spiderwort | TRBR | Tradescantia bracteata | 10–90 | – | ||
5 | Native forbs (toxic properties) | 1–2 | ||||
white locoweed | OXSE | Oxytropis sericea | 1–2 | – | ||
deathcamas | ZIGAD | Zigadenus | 1–2 | – | ||
Shrub/Vine
|
||||||
6 | Native shrubs and half-shrubs | 95–180 | ||||
Shrub, broadleaf | 2SB | Shrub, broadleaf | 10–40 | – | ||
silver sagebrush | ARCA13 | Artemisia cana | 10–40 | – | ||
prairie sagewort | ARFR4 | Artemisia frigida | 10–40 | – | ||
Wyoming big sagebrush | ARTRW8 | Artemisia tridentata ssp. wyomingensis | 10–40 | – | ||
winterfat | KRLA2 | Krascheninnikovia lanata | 10–40 | – | ||
skunkbush sumac | RHTR | Rhus trilobata | 10–40 | – | ||
prairie rose | ROAR3 | Rosa arkansana | 10–40 | – | ||
soapweed yucca | YUGL | Yucca glauca | 10–40 | – | ||
7 | Native shrubs and half-shrubs | 1–2 | ||||
broom snakeweed | GUSA2 | Gutierrezia sarothrae | 1–2 | – | ||
brittle pricklypear | OPFR | Opuntia fragilis | 1–2 | – | ||
plains pricklypear | OPPO | Opuntia polyacantha | 1–2 | – |
Interpretations
Animal community
Livestock Grazing Interpretations:
Managed livestock grazing is suitable on this site as it has the potential to produce a moderate amount of high quality forage. Forage production is somewhat limited by steep slopes and the potential for runoff, reducing the effectiveness of the precipitation received for plant growth. The steeper slopes may also limit livestock travel and result in poor grazing distribution, especially in areas away from water. Management objectives should include maintenance or improvement of the plant community. Shorter grazing periods and adequate re-growth after grazing are recommended for plant maintenance and recovery. Heavy stocking and season long use of this site can be detrimental and will
alter the plant community composition and production over time.
Whenever Plant Community 2 (medium and short grasses) occurs, grazing management strategies need to be implemented to avoid further deterioration. This community is still stable, productive, and healthy provided it receives proper management. This community will respond fairly quickly to improved grazing management including increased growing season rest of key forage plants. Grazing management alone can usually move this community back to one more similar to potential if a good seed source of the taller grasses still exists.
Plant Communities 3 and 4 have substantially reduced forage production, and a high percentage of aggressive, non-palatable species. Once these plant communities become established, it will be much more difficult to restore the site to a community that resembles the potential with grazing management alone. Additional growing season rest is often necessary for re-establishment of the desired species and to restore the stability and health of the site. Brush management and seeding may be necessary to restore desirable native perennial species.
The potential for seeding or using mechanical treatment to improve site health is limited due to steep slopes.
Wildlife Interpretations:
The following is a description of habitat values for the different plant communities that may occupy the site:
Plant Community 1: Tall Grasses/Forbs/Shrubs (HCPC):
The predominance of grasses and diversity of forbs, shrubs and half-shrubs in this community favors grazers and mixed feeders such as bison, pronghorn and elk. Large animal nutrition levels are relatively high year-long with the diversity of grasses, forbs and shrubs. South-facing exposures may provide winter habitat for mule deer. The complex plant structural diversity provides habitat for a wide array of small mammals (both seed-eaters, i.e., pocket mouse, and herbivores, i.e. prairie vole) and neotropical migratory birds. Diverse prey populations are available for raptors such as ferruginous hawks and prairie falcons. The mix of grass stature and life forms, along with scattered shrubs and a variety of forbs, provides habitat for many bird species including the sharp-tailed grouse, loggerhead shrike, vesper and lark sparrow, and western meadowlark.
Plant Community 2: Medium and Short Grasses/ Medium Shrubs:
The partial loss of tall, palatable grasses, forbs and shrubs makes this community somewhat less attractive for the variety of wildlife species using the HCPC. A decrease in litter and residual plant cover reduces habitat value for ground-nesting birds and herbivorous small mammals like voles. However, an increase in the proportion of forbs and shrubs still provides food and cover for a variety of breeding birds such as vesper and lark sparrows, loggerhead shrikes and upland sandpipers. Small mammal species composition may shift toward higher proportions of seed-eaters, like deer mice, as litter cover is reduced.
Plant Community 3: Short Grasses/ Medium Shrubs and Half-shrubs:
Wildlife food and cover value is considerably reduced at this successional stage following loss of many desirable plant species and structural habitat diversity. Big game animal cover and browse is largely missing. Breeding bird habitat suffers from a lack of litter and residual plant material as well as structural diversity in all plant canopy layers. Small mammal populations are dominated by the adaptable, seed-eating deer mouse.
Plant Community 4: Short Grasses/ Half-shrubs/ Annuals:
This community has very low habitat value
for most wildlife species because of the lack of plant structural diversity and ground cover.
Hydrological functions
The soils associated with this ecological site are generally in Hydrologic Soil Group B. The infiltration rates for these soils will normally be moderate, to moderately rapid. The runoff potential for this site is low high depending on slope and ground cover/health. Runoff curve numbers generally range
from 65 to 83.
Good hydrologic conditions exist on rangelands if plant cover (grass, litter, and brush canopy) is greater than 70%. Fair conditions exist when cover is between 30 and 70%, and poor conditions exist when cover is less than 30%. Sites in high similarity to HCPC (Plant Communities 1 and 2) generally have enough plant cover and litter to optimize infiltration, minimize runoff and erosion, and have a good hydrologic condition. The deep root systems of the potential vegetation help maintain or increase infiltration rates and reduce runoff.
Sites in low similarity (Plant Communities 3 and 4) are generally considered to be in poor hydrologic condition as the majority of plant cover is from shallow-rooted species such as threadleaf sedge and annual grasses.
Erosion is minor for sites in high similarity. Rills and gullies should not be present. Water flow patterns, if present, will be barely observable. Plant pedestals are essentially non-existent. Plant litter remains in place and is not moved by erosion. Soil surfaces should not be compacted or crusted. Plant cover and litter helps retain soil moisture for use by the plants. Maintaining a healthy stand of perennial vegetation will optimize the amount of precipitation that is received. (Reference: Engineering Field Manual, Chapter 2 and Montana Supplement 4).
Recreational uses
This site provides recreational opportunities for big game and upland bird hunting, and hiking. The forbs have flowers that appeal to photographers. This site provides valuable open space and visual aesthetics.
Other information
The following is an example of how to calculate the recommended stocking rate. This example does not use production estimates from this specific ecological site. You will need to adjust the annual production values and run the calculations using total annual production values from the ecological sites encountered on each individual ranch/pasture. Before making specific recommendations, an on-site evaluation must be made.
Example of total annual production amounts by type of year:
Favorable years = 2200 lbs/acre
Normal years = 1480 lbs/acre
Unfavorable years = 1200 lbs/acre
It is recommended that on slopes of 30% or less, stocking rate should be derived from the total annual production pounds minus 500 pounds for residual dry matter and 25% harvest efficiency. On slopes over 30%, stocking rate is derived from total annual production pounds minus 800 pounds for residual dry matter and 25% harvest efficiency. Refer to the NRCS National Range and Pasture Handbook for a list of Animal Unit Equivalents.
Sample Calculations using Favorable Year production amounts:
< 30% slopes: AUM/AC = [(2200-500)(0.25)]/915 lbs/month for one AU = 0.46 AUM/AC
AC/AUM = (1.0 AU)/(0.46AUM/AC) = 2.2 AC/AUM
> 30% slopes: AUM/AC = [(2200-800)(0.25)]/915 lbs/month for one AU = 0.38 AUM/AC
AC/AUM = (1.0 AU)/(0.38 AUM/AC) = 2.6 AC/AUM
NOTE: 915 lbs/month for one Animal Unit is used as the baseline for maintenance requirements. This equates to 30 lbs/day of air-dry forage (1200 lb cow at 2.5% of body weight).
Supporting information
Contributors
Bob Leinard
JVF, REL, RSN, MJR, SKW, SVF, POH
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) | T. DeCock; R Kilian |
---|---|
Contact for lead author | Tammy DeCock |
Date | 06/11/2014 |
Approved by | Jon Siddoway |
Approval date | |
Composition (Indicators 10 and 12) based on | Annual Production |
Indicators
-
Number and extent of rills:
None. -
Presence of water flow patterns:
None on slopes less than 25%. On slopes 25 – 40% water flow patterns may be 2-3 feet long and 4 inches wide. -
Number and height of erosional pedestals or terracettes:
Pedestals up to 0.5 inch high are common. On slopes greater than 25% Terracettes may be present but should be less than 0.25 inches high. -
Bare ground from Ecological Site Description or other studies (rock, litter, lichen, moss, plant canopy are not bare ground):
Bare ground is < 35%. Bare ground will occur as small areas less than 3 inches in diameter. -
Number of gullies and erosion associated with gullies:
Active gullies should not be present. Existing gullies should be “healed” with a good vegetative cover. -
Extent of wind scoured, blowouts and/or depositional areas:
Active blowouts should not be present although a few, small, scattered scour sites may be observed. Historic blowouts should be “healed” with a good vegetative cover. -
Amount of litter movement (describe size and distance expected to travel):
Plant litter remains in place and is not moved by erosional forces on slopes less than 25%. Herbaceous litter may move up to 4 inches on slopes > 25%. -
Soil surface (top few mm) resistance to erosion (stability values are averages - most sites will show a range of values):
Surface Soil Aggregate Stability under plant canopy should typically be 5 or greater. Surface Soil Aggregate Stability not under plant canopy should typically be 5 or slightly less. -
Soil surface structure and SOM content (include type of structure and A-horizon color and thickness):
Use soil survey series description. -
Effect of community phase composition (relative proportion of different functional groups) and spatial distribution on infiltration and runoff:
High grass canopy and basal cover and small gaps between plants should reduce raindrop impact and slow overland flow, providing increased time for infiltration to occur. A combination of shallow and deep rooted species has a positive effect on infiltration. -
Presence and thickness of compaction layer (usually none; describe soil profile features which may be mistaken for compaction on this site):
No compaction layer or soil surface crusting should be evident. -
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:
Warm season, tall-stature, rhizomatous grasses > Warm season, mid-stature, bunch grasses > Cool season, Mid-stature, bunch grassesSub-dominant:
forbs > Cool season, mid-stature, rhizomatous grasses = shrubs = Cool season, short-stature, bunch grasses and sedgesOther:
Minor components: Cool season, short-stature, rhizomatous grasses and sedgesAdditional:
(Blue grama should be grouped with warm season, short-stature, rhizomatous grasses due to its growth form) -
Amount of plant mortality and decadence (include which functional groups are expected to show mortality or decadence):
Very low. -
Average percent litter cover (%) and depth ( in):
Litter cover is in contact with soil surface. -
Expected annual annual-production (this is TOTAL above-ground annual-production, not just forage annual-production):
1500 to 1800 #/acre (13 to 14 inch precip. Zone) 950 to 1200 #/ac (10 to 12 inch precip. Zone). -
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:
Sulphur cinquefoil, common tansy, oxeye daisy, Leafy spurge, knapweeds, whitetop, Dalmatian toadflax, yellow toadflax, St. Johnswort, perennial pepperweed. Kentucky bluegrass and smooth brome can be invasive on the eastern boarder of Montana for these MLRAs. -
Perennial plant reproductive capability:
All species are capable of reproducing.
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