Natural Resources
Conservation Service
Ecological site R058AC042MT
Sandy (Sy) RRU 58A-C 11-14" p.z.
Last updated: 6/14/2023
Accessed: 04/19/2024
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
| R058AC040MT |
Silty (Si) RRU 58A-C 11-14" p.z. |
|---|
Similar sites
| R058AC040MT |
Silty (Si) RRU 58A-C 11-14" p.z. The Silty site occupies similar landscape positions, differing mainly by texture. |
|---|
Table 1. Dominant plant species
| Tree |
Not specified |
|---|---|
| Shrub |
Not specified |
| Herbaceous |
(1) Pseudoroegneria spicata |
Physiographic features
Table 2. Representative physiographic features
| Landforms |
(1)
Alluvial fan
(2) Terrace (3) Plain |
|---|---|
| Flooding frequency | None |
| Ponding frequency | None |
| Elevation | 2,250 – 4,500 ft |
| Slope | 15% |
| Ponding depth |
Not specified |
| Water table depth | 60 in |
| Aspect | Aspect is not a significant factor |
Climatic features
Major Land Resource Area (MLRA) 58AC in Montana is 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 this MLRA, 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.
The majority of the rangeland in MLRA 58AC is within the 11 to 14 inch Mean Annual Precipitation (MAP) 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 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) | 135 days |
|---|---|
| Freeze-free period (average) | 155 days |
| Precipitation total (average) | 14 in |
Influencing water features
Soil features
These soils are coarse to fine sandy loams more than 20 inches deep. They are well drained, permeability is mostly moderate to moderately rapid, and effective rooting depth is greater than 20 inches. Available water holding capacity to 40 inches is mainly over 4 inches.
Table 4. Representative soil features
| Surface texture |
(1) Coarse sandy loam (2) Fine sandy loam |
|---|---|
| Family particle size |
(1) Loamy |
| Drainage class | Well drained to somewhat excessively drained |
| Permeability class | Moderate to moderately rapid |
| Soil depth | 20 – 72 in |
| Surface fragment cover <=3" | 5% |
| Available water capacity (0-40in) |
4 – 9 in |
Ecological dynamics
The following are descriptions of several plant communities that may occupy this site:
State and transition model
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Ecosystem states
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 Grass/ Forbs/ Shrubs (HCPC)
Community 1.1
Plant Community 1: Tall and Medium Grass/ Forbs/ Shrubs (HCPC)
Figure 2. 58AC Plant Community 1
The physical aspect of this site in Historic Climax is that of a level to undulating grassland dominated by warm and cool-season grasses, with forbs and shrubs occurring in small percentages. Approximately 80 – 90% of the annual production is from grasses and sedges, 1 – 10% from forbs, and 1 – 5% is from shrubs and half-shrubs. Canopy cover of shrubs is 0 – 5%. Dominant species include bluebunch wheatgrass, prairie sandreed, Indian ricegrass, needleandthread, and plains muhly, and short grasses and sedges (sand dropseed, threadleaf sedge). There are abundant forbs (prairie clovers, dotted gayfeather) which occur in smaller percentages. Shrubs and half-shrubs occur occasionally. This plant community is well adapted to the Northern Great Plains climatic conditions. The diversity in plant species and presence of tall, deep-rooted perennial grasses allows for drought tolerance. Plants on this site have strong, healthy root systems that allow production to increase significantly with favorable moisture conditions. 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. This plant community provides for soil stability and a functioning hydrologic cycle.
Figure 3. 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 | 1300 | 1440 | 1650 |
| Forb | 80 | 160 | 170 |
| Shrub/Vine | 65 | 80 | 90 |
| Total | 1445 | 1680 | 1910 |
Table 6. Ground cover
| Tree foliar cover | 0% |
|---|---|
| Shrub/vine/liana foliar cover | 0-10% |
| Grass/grasslike foliar cover | 70-85% |
| Forb foliar cover | 1-5% |
| Non-vascular plants | 0% |
| Biological crusts | 0% |
| Litter | 0% |
| Surface fragments >0.25" and <=3" | 0% |
| Surface fragments >3" | 0% |
| Bedrock | 0% |
| Water | 0% |
| Bare ground | 0% |
Table 7. Soil surface cover
| Tree basal cover | 0% |
|---|---|
| Shrub/vine/liana basal cover | 1-4% |
| Grass/grasslike basal cover | 5-15% |
| Forb basal cover | 1-4% |
| Non-vascular plants | 0% |
| Biological crusts | 0-1% |
| Litter | 50-70% |
| Surface fragments >0.25" and <=3" | 0-5% |
| Surface fragments >3" | 0% |
| Bedrock | 0% |
| Water | 0% |
| Bare ground | 10-20% |
Table 8. Canopy structure (% cover)
| Height Above Ground (ft) | Tree | Shrub/Vine | Grass/ Grasslike |
Forb |
|---|---|---|---|---|
| <0.5 | – | – | – | – |
| >0.5 <= 1 | – | – | – | – |
| >1 <= 2 | – | – | – | – |
| >2 <= 4.5 | – | – | – | – |
| >4.5 <= 13 | – | – | – | 1-5% |
| >13 <= 40 | – | 0-10% | 70-85% | – |
| >40 <= 80 | – | – | – | – |
| >80 <= 120 | – | – | – | – |
| >120 | – | – | – | – |
State 2
Plant Community 2: Medium and Short Grasses and Sedges/ Half-shrubs
Community 2.1
Plant Community 2: Medium and Short Grasses and Sedges/ Half-shrubs
Figure 4. 58AC Sandy Plant Community 2
This community occurs due to minor climate shifts or slight variations in soils and/or topography or disturbance, including non-prescribed grazing. Dominant species include prairie sandreed and needleandthread. Western or thickspike wheatgrass, sand dropseed, threadleaf sedge and green and fringed sagewort tend to become a slightly larger part of the plant community. The more palatable grasses (bluebunch wheatgrass, Indian ricegrass, plains muhly) will still be present but in smaller amounts. Palatable and nutritious forbs will be replaced by less desirable and more aggressive species. Yucca may become more common. Grass biomass production and litter become reduced on Community 2 as the taller grasses become less prevalent, increasing evaporation and reducing moisture retention. Additional open space in the community can result in undesirable invader species. These plant communities provide for moderate soil stability
State 3
Plant Community 3: Short and Medium Grasses and Sedges/ Half-shrubs
Community 3.1
Plant Community 3: Short and Medium Grasses and Sedges/ Half-shrubs
Figure 5. 58AC Sandy Plant Community 3
This is a disturbance induced community, with dominant species including needleandthread, western or thickspike wheatgrass, threadleaf sedge, sand dropseed and blue grama. Forbs and green and fringed sagewort tend to make up a larger part of the plant community. There may still be remnant amounts of some of the late-seral species such as bluebunch wheatgrass or prairie sandreed present. Palatable forbs will be mostly absent. Yucca or other shrubs may increase.
State 4
Plant Community 4: Short Sedges and Grasses/ Half-Shrubs/ Cactus/ Annual Grasses
Community 4.1
Plant Community 4: Short Sedges and Grasses/ Half-Shrubs/ Cactus/ Annual Grasses
This community is the result of continual adverse disturbances. Dominants include threadleaf sedge, blue grama, and other short grasses. A remnant of the potential plant community may remain, especially needleandthread, but in much smaller proportions. Species that are un-palatable become more common, including Fendler’s threeawn, green and fringed sagewort, broom snakeweed, annual bromes, six-weeks fescue, and plains pricklypear. Plant Communities 3 and 4 are much less productive than Plant Communities 1 or 2, and have 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. This community can respond positively to improved grazing management but it will take additional inputs to move it towards a community similar in production and composition to that of Plant Community 1 or 2.
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 | 1156–1528 | ||||
| prairie sandreed | CALO | Calamovilfa longifolia | 217–1242 | – | ||
| bluebunch wheatgrass | PSSP6 | Pseudoroegneria spicata | 145–955 | – | ||
| needle and thread | HECOC8 | Hesperostipa comata ssp. comata | 145–382 | – | ||
| Indian ricegrass | ACHY | Achnatherum hymenoides | 72–286 | – | ||
| plains muhly | MUCU3 | Muhlenbergia cuspidata | 80–191 | – | ||
| western wheatgrass | PASM | Pascopyrum smithii | 72–191 | – | ||
| tufted wheatgrass | ELMA7 | Elymus macrourus | 72–191 | – | ||
| 2 | Native grasses | 1–191 | ||||
| Grass, perennial | 2GP | Grass, perennial | 1–96 | – | ||
| blue grama | BOGR2 | Bouteloua gracilis | 1–96 | – | ||
| threadleaf sedge | CAFI | Carex filifolia | 1–96 | – | ||
| prairie Junegrass | KOMA | Koeleria macrantha | 1–96 | – | ||
| Sandberg bluegrass | POSE | Poa secunda | 1–96 | – | ||
| sand dropseed | SPCR | Sporobolus cryptandrus | 1–96 | – | ||
| 3 | Native grasses | 1–3 | ||||
| Fendler's threeawn | ARPUF | Aristida purpurea var. fendleriana | 1–3 | – | ||
|
Forb
|
||||||
| 4 | Native forbs | 14–191 | ||||
| Forb, perennial | 2FP | Forb, perennial | 14–96 | – | ||
| common yarrow | ACMI2 | Achillea millefolium | 14–96 | – | ||
| rockcress | ARABI2 | Arabis | 14–96 | – | ||
| tarragon | ARDR4 | Artemisia dracunculus | 14–96 | – | ||
| milkvetch | ASTRA | Astragalus | 14–96 | – | ||
| bastard toadflax | COUM | Comandra umbellata | 14–96 | – | ||
| white prairie clover | DACA7 | Dalea candida | 14–96 | – | ||
| purple prairie clover | DAPU5 | Dalea purpurea | 14–96 | – | ||
| annual buckwheat | ERAN4 | Eriogonum annuum | 14–96 | – | ||
| buckwheat | ERIOG | Eriogonum | 14–96 | – | ||
| hairy false goldenaster | HEVI4 | Heterotheca villosa | 14–96 | – | ||
| Lewis flax | LILE3 | Linum lewisii | 14–96 | – | ||
| dotted blazing star | LIPU | Liatris punctata | 14–96 | – | ||
| desertparsley | LOMAT | Lomatium | 14–96 | – | ||
| beardtongue | PENST | Penstemon | 14–96 | – | ||
| spiny phlox | PHHO | Phlox hoodii | 14–96 | – | ||
| scurfpea | PSORA2 | Psoralidium | 14–96 | – | ||
| Missouri goldenrod | SOMI2 | Solidago missouriensis | 14–96 | – | ||
| manyflowered aster | SYERP2 | Symphyotrichum ericoides var. pansum | 14–96 | – | ||
| prairie thermopsis | THRH | Thermopsis rhombifolia | 14–96 | – | ||
| American vetch | VIAM | Vicia americana | 14–96 | – | ||
| 5 | Native forbs (toxic properties) | 1–3 | ||||
| twogrooved milkvetch | ASBI2 | Astragalus bisulcatus | 1–3 | – | ||
| larkspur | DELPH | Delphinium | 1–3 | – | ||
| locoweed | OXYTR | Oxytropis | 1–3 | – | ||
| deathcamas | ZIGAD | Zigadenus | 1–3 | – | ||
|
Shrub/Vine
|
||||||
| 6 | Native shrubs and half-shrubs | 1–96 | ||||
| Shrub, broadleaf | 2SB | Shrub, broadleaf | 1–96 | – | ||
| silver sagebrush | ARCA13 | Artemisia cana | 1–96 | – | ||
| prairie sagewort | ARFR4 | Artemisia frigida | 1–96 | – | ||
| rubber rabbitbrush | ERNAN5 | Ericameria nauseosa ssp. nauseosa var. nauseosa | 1–96 | – | ||
| creeping juniper | JUHO2 | Juniperus horizontalis | 1–96 | – | ||
| skunkbush sumac | RHTR | Rhus trilobata | 1–96 | – | ||
| prairie rose | ROAR3 | Rosa arkansana | 1–96 | – | ||
| soapweed yucca | YUGL | Yucca glauca | 1–96 | – | ||
| 7 | Native shrubs and half-shrubs | 1–3 | ||||
| broom snakeweed | GUSA2 | Gutierrezia sarothrae | 1–3 | – | ||
| plains pricklypear | OPPO | Opuntia polyacantha | 1–3 | – | ||
Interpretations
Animal community
Livestock Grazing Interpretations:
Managed livestock grazing is suitable on this site as it has the potential to produce an abundance of high quality forage. This is often a preferred site for grazing by livestock, and animals tend to congregate in these areas. In order to maintain the productivity of this site, grazing must be managed carefully on adjoining sites with less production to be sure livestock drift onto the Sandy site is not excessive. 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 and sedges) 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 towards the potential community.
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. Seeding may be necessary to restore desirable native perennial species.
Wildlife Interpretations:
The Sandy ecological site occurs over large acreages on the Northern Great Plains except where it is fragmented by conversion to cropland, which is significant in many areas. Habitat fragmentation of this site has contributed to the decline of some “area sensitive” wildlife species, particularly such ground-nesting birds as the grasshopper sparrow. This site is home to a diverse native wildlife complex resulting from the varied habitat structure provided by a mixture of grasses, forbs, and shrubs. Historically, huge herds of migratory bison and pronghorn as well as large numbers of sharp-tailed grouse were probably the dominant “game” species in addition to a wide variety of ground-nesting songbirds, waterfowl and shorebirds, small mammals and mammalian predators. Grazing patterns, topographic diversity, extensive acreages, and interspersion with other ecological sites make this type very important to numerous wildlife species. Small mammal diversity and abundance is high which, in turn, supports a varied raptor population. Invasive plant species such as leafy spurge, Canada thistle and several knapweeds are contributing to a loss of biodiversity within this ecological site. Wildlife water requirements are provided by springs and seeps, intermittent and perennial streams, and in modern times, numerous artificial ponds and livestock pipelines. These areas are locally important for northern leopard frogs, tiger salamanders and a number to toad species, all of which feed on a variety of insects. Grazing, fire, drought cycles, and insect population fluctuations create a shifting mosaic of wildlife habitats across this site.
Plant Community 1: Tall and Medium Grasses/ Forbs/ Shrubs (HCPC):
The diversity of plant species and life forms provides feeding substrate for a variety of beneficial pollinating insects. Numerous warm and cool water fish species inhabit the intermittent and perennial streams associated with this community. Northern pike, lake chub, carp, a variety of suckers and walleye are examples. Common reptile and amphibian species include tiger salamanders in ponds and stock tanks, Woodhouse’s toad, western chorus frogs, short-horned lizards, bull snake and rattlesnake, and three species of garter snakes. The diversity of grass stature and life forms, along with scattered shrubs and a variety of forbs, provides habitat for many bird species including the upland sandpiper, sharp-tailed grouse, loggerhead shrike, grasshopper and savanna sparrow, chestnut-collared longspur, and western meadowlark. This community is especially favorable for ground-nesting birds because of the abundant residual plant material and litter available for nesting, escape, and thermal cover. Diverse prey populations are available for raptors such as ferruginous and Swainson’s hawks. The predominance of grasses plus a diversity of forbs, shrubs and half-shrubs in this community favors grazers and mixed feeders such as bison, pronghorn and elk. Complex plant structural diversity and litter cover provide habitat for a wide array of small mammals (both seed eaters, i.e. deer mice and herbivores, i.e. voles and jackrabbits) and neotropical migratory birds.
Plant Community 2: Medium and Short Grasses and Sedges/ Half-shrubs:
The partial loss of structural diversity makes this plant community somewhat less attractive to the variety of wildlife species using the HCPC. Insects still find a wide variety of plant species to utilize. A decrease in residual plant material and litter cover is usually associated with degradation of the HCPC, which makes this community less attractive for amphibians and ground-nesting birds. The reduction in Indian ricegrass decreases seed supplies for both birds and small mammals. Pronghorn make considerable use of this type because of forb and half-shrub availability in the generally open landscape.
Plant Community 3: Short and Medium Grasses and Sedges / Half-shrubs:
Insect diversity is reduced and grasshopper infestations may increase because of better breeding conditions on the warmer, drier soil surface. Likewise, generally drier conditions reduce habitat value for amphibians. Ground-nesting birds are adversely affected by the loss of residual cover and surface litter. Small mammal diversity is reduced with the loss of varied habitat structure. The seed-eating deer mouse may increase and herbivores, such as voles, decrease.
Plant Community 4: Short Sedges and Grasses/ Half-shrubs/ Cactus/ Annual Grasses:
Harmful insects, such as grasshoppers, can breed very successfully on the hot, dry soil surface. Habitat conditions for most wildlife species are very poor, reflecting the lack of structural diversity, residual cover and litter cover. Mountain plovers and horned larks may nest on the open soil surface.
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, depending on slope and ground cover/health. Runoff curve numbers generally range from 65 to 83.
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
Inventory data references
Supporting Data for Site Development:
NRCS Production & Composition Record for Native Grazing Lands (Range-417): 5
BLM Soil & Vegetation Inventory Method (SVIM) Data: 2
NRCS Range Condition Record (ECS-2): 25
NRCS Range/Soil Correlation Observations & Soil 232 notes: 25
Ecological Site Reference: NRCS 417 No.: Golden Valley County 520
Field Offices where this site occurs within the state:
Big Sandy
Big Timber
Billings
Chinook
Columbus
Crow Agency
Fort Belknap
Hardin
Harlowton
Joliet
Lewistown
Malta
Roundup
Stanford
White Sulphur Springs
Winnett
Other references
Site Documentation:
Authors:
Original: NRCS, 1983
Revised: Matthew J. Ricketts, Robert E. Leiland, Rhonda Sue Noggles, Peter O. Husby, 2003
Contributors
MJR, REL, RSN, POH
RSN
Approval
Kirt Walstad, 6/14/2023
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) | Loretta Metz |
|---|---|
| Contact for lead author | |
| Date | 04/10/2005 |
| Approved by | Kirt Walstad |
| Approval date | |
| Composition (Indicators 10 and 12) based on | Annual Production |
Indicators
-
Number and extent of rills:
Minor rills (less than 0.5 to 1.0 inches in depth; less than 2.5 feet long) may be present in the reference state when slopes are greater than 8%. Plant community 2 has more rills than Plant community 1. -
Presence of water flow patterns:
Water flow patterns are generally not evident in Plant community 1 in the reference state. Following heavy thunderstorms, or on slopes over 8%, short (less than 6.0 feet long) flow patterns may be apparent. -
Number and height of erosional pedestals or terracettes:
These should not be evident in the reference state. -
Bare ground from Ecological Site Description or other studies (rock, litter, lichen, moss, plant canopy are not bare ground):
Bare ground is less than 20% in the reference state. In HCPC, bare ground should not exceed 12%. -
Number of gullies and erosion associated with gullies:
Gully erosion is not evident in the reference state. -
Extent of wind scoured, blowouts and/or depositional areas:
These are uncommon, but may certainly occur in the reference state. Size and extent vary too greatly to describe an “average” situation. -
Amount of litter movement (describe size and distance expected to travel):
Litter movement varies by size and depth of litter. In the reference state, litter should be coarse, anywhere from 1.5 inches up to 4 inches in length, and will not move more than a couple of inches from where it originated. Winds may move less persistent litter farther than water will move it. -
Soil surface (top few mm) resistance to erosion (stability values are averages - most sites will show a range of values):
Stability values of 2-3 in plant interspaces. Stability values of 3-5 under plant canopies and at plant bases. -
Soil surface structure and SOM content (include type of structure and A-horizon color and thickness):
Granular structure, light brown to dark brown color, A-horizon is approximately 2-10 inches in depth. Organic matter in A-horizon approximately 1-4%. -
Effect of community phase composition (relative proportion of different functional groups) and spatial distribution on infiltration and runoff:
Deep-rooted native perennial grasses optimize infiltration and runoff. Grasses should be spaced approximately 2-4 feet apart in the reference state. -
Presence and thickness of compaction layer (usually none; describe soil profile features which may be mistaken for compaction on this site):
No compaction layer present in the reference state. -
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:
cool season, mid-height, native perennial bunchgrasses > warm season, mid- and short- height native perennial bunchgrasses >> native forbs > native shrubs.Sub-dominant:
Other:
Additional:
-
Amount of plant mortality and decadence (include which functional groups are expected to show mortality or decadence):
Plant mortality is very low; decadence is minimal except in prolonged periods of drought. -
Average percent litter cover (%) and depth ( in):
-
Expected annual annual-production (this is TOTAL above-ground annual-production, not just forage annual-production):
1445 – 1910 #/acre. -
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:
plains pricklypear, broom snakeweed, cheatgrass, Japanese brome, fringed sagewort, threadleaf sedge, blue grama, etc. -
Perennial plant reproductive capability:
This is not impaired in the reference state. Except in extended periods of drought, plants are able to reproduce sexually or vegetatively.
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