Natural Resources
Conservation Service
Ecological site R012XY002ID
Gravelly Loam 12-16 PZ ARAR8/PSSP6-FEID
Last updated: 9/21/2020
Accessed: 11/21/2024
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.
MLRA notes
Major Land Resource Area (MLRA): 012X–Lost River Valleys and Mountains
Land Resource Region: B (Northwestern Wheat and Range)
MLRA: 12 (Lost River Valleys and Mountains)
EPA EcoRegion: Level III (Middle Rockies)
LRU notes
012X-Lost River Valleys and Mountains
Precipitation or Climate Zone: 12-16” P.Z.
https://soils.usda.gov/survey/geography/mlra/index.html
Classification relationships
Artemisia arbuscula / Agropyron spicatum HT in “Hironaka, M., M.A. Fosberg, A. H. Winward. 1983. Sagebrush-Grass Habitat Types of Southern Idaho. University of Idaho. Moscow, Idaho. Bulletin Number 35”.
Ecological site concept
Site does not receive additional water.
Soils are:
not saline or saline-sodic.
Shallow to very deep. If very deep is >55% (by volume) gravels and cobbles, skeletal within 20” of soil surface. Otherwise is shallow to bedrock.
strongly or violently effervescent throughout the soil profile.
textures usually range from loam to silt loam in surface mineral 4”.
Slope is < 30%.
Clay content is = <35% in surface mineral 4”.
Site does not have an argillic horizon with > 35% clay.
Table 1. Dominant plant species
| Tree |
Not specified |
|---|---|
| Shrub |
(1) Artemisia arbuscula |
| Herbaceous |
(1) Pseudoroegneria spicata |
Physiographic features
This site occurs on alluvial and colluvial fans, terraces, gentle foothills, ridges and mountain slopes. Slopes range from 5 to 30 percent on all aspects. Elevations range from 6200 to 8500 feet (1900 to 2600 meters).
Table 2. Representative physiographic features
| Landforms |
(1)
Alluvial fan
(2) Terrace (3) Ridge |
|---|---|
| Elevation | 6,200 – 8,500 ft |
| Slope | 5 – 30% |
Climatic features
MLRA 12 is dominated by dramatic changes in elevation which, in turn, influence local weather patterns. The intermontane valleys have elevations as low as 3800 feet, while the adjacent mountains may reach more than 12,600 feet. The average annual precipitation for the entire MLRA, based on 10 long term climate stations located throughout the MLRA, is approximately 9.38 inches. However, the dry valleys may have averages as low as 6 inches, while the upper peaks may have averages that exceed 46 inches per year.
Temperatures vary considerably over the year. The average annual temperature is 42.25 degrees F. The average low is 27.4 degrees while the average high temperature is 57 degrees.
In the summer the sun shines 78% of the time, but drops to 40% in the winter. The prevailing wind is location-dependent, and generally flows parallel to the orientation of the dominant valleys. In the summer localized afternoon upslope winds and evening downslope winds are common. The average windspeed is greatest in the spring and early summer.
The frost free period ranges from 102 to 107 days while the freeze free period ranges from 134 to 139 days across the MLRA.
Table 3. Representative climatic features
| Frost-free period (average) | 107 days |
|---|---|
| Freeze-free period (average) | 139 days |
| Precipitation total (average) | 11 in |
Figure 1. Monthly precipitation range
Figure 2. Monthly average minimum and maximum temperature
Influencing water features
This site is not influenced by adjacent wetlands, streams or run on.
Soil features
The soils of this site are predominately gravelly loams. Gravel exceeds 40 percent by volume in the B horizon. They can be shallow to very deep to bedrock. Mountainboy is shallow to a duripan. If very deep, gravels exceed 60 percent by volume in the soil profile below 12 inches in depth, thus inserting a shallow depth soil influence on the plant community. Parent material consists of colluvium and alluvium from sedimentary and metamorphic rocks, heavily influenced by limestone. Occasionally they are moderately alkaline. The soils are well drained and have slow to moderately rapid permeability. Available water capacity is very low to moderate. The moisture supplying capacity of the soils is limited by the depth to the gravel layer or bedrock. Water erosion can be high when the plant cover is reduced and slope increases. These soils are characterized by an aridic soil moisture regime or an aridic bordering on xeric. The soil temperature regime is either frigid or cryic.
Table 4. Representative soil features
| Surface texture |
(1) Gravelly loam (2) Very gravelly silt loam (3) Stony |
|---|---|
| Drainage class | Well drained to somewhat excessively drained |
| Permeability class | Slow to moderately rapid |
| Soil depth | 10 – 60 in |
| Surface fragment cover <=3" | 10 – 40% |
| Surface fragment cover >3" | 14% |
| Available water capacity (0-40in) |
0.8 – 6.4 in |
| Calcium carbonate equivalent (0-40in) |
60% |
| Electrical conductivity (0-40in) |
2 mmhos/cm |
| Soil reaction (1:1 water) (0-40in) |
6.1 – 8.4 |
| Subsurface fragment volume <=3" (Depth not specified) |
20 – 60% |
| Subsurface fragment volume >3" (Depth not specified) |
10% |
Ecological dynamics
The dominant visual aspect of this site is low sagebrush with bluebunch wheatgrass and Idaho fescue in the understory. Composition by weight is approximately 50 to 60 percent grasses, 10 to 15 percent forbs and 25 to 35 percent shrubs.
In the last few thousand years, this site has evolved in an arid climate characterized by dry summers and cold, wet winters. Herbivory has historically occurred on this site at low levels of utilization. Herbivores include mule deer, bighorn sheep, Rocky Mountain elk, pronghorn antelope, lagomorphs and small rodents. Fire has historically occurred on the site at intervals of 60-80 years.
The Historic Climax Plant Community (HCPC), the Reference State (State 1), moves through many phases depending on the natural and man-made forces that impact the community over time. State 1, described later, indicates some of these phases. The Reference Plant Community Phase is Phase A. This plant community is dominated by bluebunch wheatgrass and Idaho fescue in the understory and low sagebrush in the overstory. Subdominant species include Sandberg bluegrass, prairie junegrass and Hoods phlox. There is a variety of other grasses, forbs and shrubs that can occur in minor amounts. The plant species composition of Phase A is listed later under “Reference Plant Community Phase Plant Species Composition”.
Total annual production is 400 pounds per acre (448 kilograms per hectare) in a normal year. Production in a favorable year is 725 pounds per acre (812 kilograms per hectare). Production in an unfavorable year is 275 pounds per acre (308 kilograms per hectare). Structurally, cool season deep rooted perennial bunchgrasses are dominant followed by low to medium shrubs being more dominant than perennial forbs while shallow rooted bunchgrasses are subdominant.
Function
This site is suited for livestock grazing in the spring, fall and early winter. There are few limitations to grazing. Natural water supplies may be insufficient or absent. The site provides fair to good habitat for various upland wildlife. The site can be valuable winter habitat for mule deer, Rocky Mountain elk and pronghorn antelope. This site is easily degraded by improper grazing management due to low production and flat slopes. The site offers minimal recreational value except limited hunting opportunities. A mixed stand of shrubs and perennial grasses is necessary to reach the potential of the site.
Impacts on the Plant Community.
Influence of fire:
In the absence of normal fire frequency, low sagebrush can gradually increase on the site. Grasses and forbs decrease as shrubs increase. With the continued absence of fire, low sagebrush can displace most of the primary understory species. Utah juniper can invade the site if a seed source is in the vicinity. See “Influence of Juniper Invasion” below.
When fire frequency is greater than historic levels, low sagebrush is reduced significantly. Rabbitbrush can increase slightly. With continued short fire frequency, low sagebrush can be completely eliminated along with many of the desirable understory species such as bluebunch wheatgrass and Idaho fescue. These species may be replaced by Sandberg bluegrass along with a variety of annual and perennial forbs including noxious and invasive weeds. Fine fuels will increase the fire frequency.
Influence of improper grazing management:
Season-long grazing can be very detrimental to this site. Excessive utilization is also detrimental. This type of management leads to reduced vigor of the bunchgrasses. With reduced vigor, recruitment of these species declines. As these species decline, the plant community becomes susceptible to increase in low sagebrush and noxious and invasive weeds. Utah juniper can invade the site if a seed source is in the vicinity. Continued improper grazing management influences fire frequency by reducing fine fuels that carry fires. As annuals increase and becomes co-dominant with Sandberg bluegrass, fires become frequent.
Good grazing management that addresses frequency, duration and intensity of grazing can also keep fine fuels from developing, thus reducing fire frequency. This can lead to gradual increases in low sagebrush and Utah juniper if a seed source is in the vicinity. A planned grazing system can be developed to intentionally accumulate fine fuels in anticipation of a prescribed fire.
Weather influences:
Above normal precipitation in April, May and June can dramatically increase total annual production of the plant community. These weather patterns can also increase viable seed production of desirable species to provide for recruitment. Likewise, below normal precipitation during these spring months can significantly reduce total annual production and be detrimental to good seed production. Overall plant composition is normally not effected when perennials have good vigor.
Below normal temperatures in the spring can have an adverse impact on total production regardless of the precipitation. A hard, early freeze can kill some plants occasionally.
Prolonged drought adversely affects this plant community in several ways. Vigor, recruitment and production are usually reduced. Mortality can occur. Prolonged drought can lead to reductions in fire frequency.
Influence of Insects and disease:
Outbreaks can affect health of vegetation. Mormon cricket and grasshopper outbreaks occur periodically. Outbreaks seldom cause plant mortality since defoliation of the plant occurs only once during the year of the outbreak.
Influence of noxious and invasive weeds:
Many of these species add to the fine-fuel component and lead to increased fire frequency. Perennial and annual weeds compete with desirable plants for moisture and nutrients. The result is reduced production and change in composition of the understory.
Influence of wildlife:
Big game use this site in the spring, fall and in moderate winters. Their numbers are seldom high enough to adversely affect the plant community.
Watershed:
Decreased infiltration and increased runoff occur with an increase in low sagebrush. Desired understory species can be reduced. This composition change can affect nutrient and water cycles. Increased runoff also causes sheet and rill erosion. Abnormally short fire frequency also gives the same results, but to a lesser degree. The long -term effect is a transition to a different state.
Influence of juniper invasion:
The following discussion deals with Utah juniper.
In plant communities that are invaded by juniper, the species has a competitive advantage for the following reasons:
Juniper is very drought tolerant.
It has the ability to extract soil moisture from a wide range of soil depths.
Juniper has high evapo-transpiration rates.
The species intercepts rain and snow before it reaches the soil surface.
It has the ability to grow as long as there is soil moisture and the temperature is above freezing.
Juniper has a relatively rapid growth rate and is long-lived. It can readily over-top shade intolerant species which leads to mortality.
Nutrient cycling is reduced.
As the canopy closes, juniper gains control of energy capture.
As juniper extracts water, other plants are unable to acquire sufficient water and nutrients to sustain growth and reproduction, thus reducing cover and biomass in the interspaces. After the canopy closes, there is sufficient soil moisture available for shallow-rooted, shade tolerant species to persist directly under the tree.
The following hydrological impacts occur on sites invaded by juniper:
Infiltration in the interspaces is reduced.
Run-off increases resulting in increased sheet and rill erosion with elevated sediment loads.
Soil temperatures increase in the interspaces which results in accelerated drying of the soil surface.
Increased bare ground in the interspaces.
Soil moisture storage is reduced.
As bare ground and interconnectiveness of bare ground increases, flow rates are accelerated (reduction of flow sinuosity) and run-off out of the area increases.
Degradation of these systems can result in the formation of a feedback cycle in which greater juniper cover and density results in greater plant and soil disturbance between the canopies.
In summary, a closed juniper community takes control of the following ecological processes: hydrology, energy capture and nutrient cycling. The changes are primarily driven by the hydrological processes. The development of a closed juniper canopy always results in a transition across the threshold to a different state. Generally, when juniper canopy cover nears 20%, the plant community is approaching the threshold.
Plant Community and Sequence:
Transition pathways between common vegetation states and phases:
State 1.
Phase A to B. Develops in the absence of fire. Improper grazing management could also be
present. There is a juniper seed source near the site.
Phase A to C. Usually results from wildfire or brush management.
Phase A to D. Results from improper grazing management and no fire.
Phase B to C. Results from wildfire or brush management.
Phase B to A. Occurs with prescribed grazing and brush management or prescribed burning.
Phase C to A. Results from prescribed grazing and no fire.
Phase D to A. Occurs with proper grazing management.
State 1 to 2. Develops through improper grazing management and frequent fire.
State 1 to 3. Develops with no fire and improper grazing management from a juniper invaded phase of State 1.
State 2 to unknown site. Excessive soil loss and changes in the hydrologic cycle caused by improper grazing management and no fire or frequent fire cause this state to retrogress to a new site with reduced potential.
State 3 to unknown site. Continued lack of fire and improper grazing management cause this state to retrogress to a new site with reduced potential due to significant soil loss and changes in hydrology.
Practice Limitations:
This site is generally not suitable for seeding due to the gravels and low production. Brush management is not normally useful or desirable on ths site. There are few limitations for implementing vegetation management or facilitating practices on this site.
State and transition model
More interactive model formats are also available.
View Interactive Models
More interactive model formats are also available.
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 5 submodel, plant communities
State 6 submodel, plant communities
State 7 submodel, plant communities
State 1
State 1. Phase A, Reference Plant Community Phase
Community 1.1
State 1. Phase A, Reference Plant Community Phase
This plant community is dominated by bluebunch wheatgrass and Idaho fescue in the understory and low sagebrush in the overstory. Sub-dominant species include Sandberg bluegrass, prairie junegrass and Hoods phlox. There is a variety of other grasses, forbs and shrubs that can occur in minor amounts. The natural fire frequency is about 60 to 80 years.
State 2
State 1, Phase B
Community 2.1
State 1, Phase B
This plant community is dominated by low sagebrush with Sandberg bluegrass in the understory. Bluebunch wheatgrass and other deep- rooted perennial bunchgrasses are present but in reduced amounts and in low vigor. Utah juniper has invaded the site in the form of seedlings and saplings. A Utah juniper seed source is in the vicinity. Some annuals may have invaded the site. This phase has developed due to improper grazing management and no fire.
State 3
State 1. Phase C
Community 3.1
State 1. Phase C
This plant community is dominated by bluebunch wheatgrass and Sandberg bluegrass. Idaho fescue may have died due to fire. Bottlebrush squirreltail and Sandberg bluegrass have increased. Rabbitbrush and a variety of forbs can be present. Some annuals may have invaded the site. This phase has developed due to fire.
State 4
State 1. Phase D
Community 4.1
State 1. Phase D
This plant community is dominated by low sagebrush with Sandberg bluegrass in the understory. Remnants of bluebunch wheatgrass and other bunchgrasses are present but in reduced vigor. No Utah juniper seed source is in the vicinity. Some annuals may have invaded the site. This phase has developed due to improper grazing management and no fire.
State 5
State 2
Community 5.1
State 2
This plant community is dominated by Sandberg bluegrass, annual grasses and forbs. Some perennial forbs are present. The community has developed due to continued improper grazing management and fire. Some soil loss has occurred. It is not economical to return this site to State 1 with accelerating practices.
State 6
State 3
Community 6.1
State 3
This plant community is dominated by Utah juniper. Remnants of bluebunch wheatgrass and low sagebrush can be found in the understory. Shallow–rooted grasses, such as Sandberg bluegrass and annuals, can be found in the interspaces. Few shrubs are present. Generally, shrub cover is below 10-15%, bare ground is above 25-30% and juniper cover is greater than 20%. The site is near or has crossed the threshold to this state. It is economically impractical to return this plant community to State 1 with accelerating practices. This state has developed in the absence of fire. Improper grazing management can contribute to this state.
State 7
Unknown Site
Community 7.1
Unknown Site
This plant community has gone over the threshold to a new site. Site potential has been reduced. Significant soil loss has occurred. Infiltration has been reduced and run-off has become more rapid. This community has developed due to continued improper grazing management and/ or fire.
Additional community tables
Interpretations
Animal community
Wildlife Interpretations
Animal Community – Wildlife Interpretations
This rangeland ecological site provides habitat for select native wildlife species that can tolerate cold sites, high in elevation, with a sparse plant community. Large herbivore use of the reference plant community is dominated by mule deer, elk, and pronghorn antelope. The site can provide critical winter habitat for these large mammals. The site provides important seasonal habitat for resident and migratory animals including western toad, sagebrush lizard, shrews, bats, jackrabbits, ground squirrels, mice, coyote, red fox, badger, sage-grouse, Ferruginous hawk, prairie falcon, horned lark, and western meadowlark. Sage-grouse and Idaho pocket gopher are area sensitive species that may be present on this site. In isolated areas encroachment of noxious and invasive plant species (cheatgrass and medusahead) can replace native plant species which provide critical feed, brood-rearing, and nesting cover for a variety of native wildlife. Water is limited, being provided only by seasonal runoff, artificial water catchments, and spring sites.
State 1 Phase 1.1 – Low Sagebrush/ Bluebunch Wheatgrass/ Idaho Fescue Plant Community (HCPC): This plant community provides a diversity of grasses, forbs, and shrubs used by native insect communities that assist in pollination. The reptile and amphibian community is represented by leopard lizard, short horned lizard, sagebrush lizard, western skink, and western toad. Amphibians are associated with springs and isolated water bodies adjacent to this plant community. Spring developments that capture all available water would preclude the use of these sites by amphibians. Birds that may be residents or migratory include mountain bluebird, lazuli bunting, vesper sparrow, grasshopper sparrow, lesser goldfinch, and burrowing owl where deep soils exist. Brood-rearing, winter cover, and winter food for sage grouse are provided by this diverse plant community. Low sagebrush is a preferred winter food for sage-grouse. The plant community provides spring, fall, and winter forage needs for large mammals including mule deer, elk, and antelope. Mule deer have a high preference for low sagebrush. A diverse small mammal population may include golden-mantled ground squirrels, chipmunks, and pikas when adjacent to talus slopes at high elevations.
State 1 Phase 1.2- Low Sagebrush/ Sandberg Bluegrass Plant Community: This plant community is the result of improper grazing management and no fire. An increase in canopy cover of sagebrush and juniper contributes to a sparse herbaceous understory. A reduced herbaceous understory results in lower diversity and numbers of insects. The reptile community will be similar to State 1 Phase 1.1 community represented by leopard lizard, short horned lizard, sagebrush lizard, and western skink. The reduced diversity of insects and understory cover may reduce the quality of food and cover for reptile populations. As juniper increases, habitat cover for Brewer’s sparrow, sage thrasher, and sage sparrow may increase. Remaining low sagebrush provides brood-rearing, winter cover, and winter food for sage-grouse but as juniper encroaches the quality of this habitat is severely reduced or eliminated. The plant community supports limited seasonal habitat for mule deer, elk, and antelope. As juniper encroaches the site will provide additional thermal cover for large mammals. A small mammal population including golden-mantled ground squirrels, chipmunks, yellow-bellied marmots, and pikas may utilize this site.
State 1 Phase 1.3 – Bluebunch Wheatgrass/ Sandberg Bluegrass/ Plant Community: This phase has developed due to fire. The plant community, dominated by herbaceous vegetation with little or no sagebrush provides less vertical structure for animals. Insect diversity would be reduced with the loss of sagebrush but a native forb plant community similar to State 1 Phase 1.1 would still support select pollinators. Encroachment of rabbitbrush would add fall pollinator habitat to the site. Until rabbitbrush is established diversity and populations of reptiles would be limited or excluded. The dominance of herbaceous vegetation with no sagebrush canopy cover would eliminate use of this area for nesting, winter cover, and winter food for sage-grouse. This plant community provides limited brood-rearing habitat for sage-grouse if the site is adjacent to sagebrush cover. The dominant herbaceous vegetation improves habitat for grassland avian species (horned lark and western meadowlark). Winter habitat for large mammals would be reduced or eliminated with the loss of low sagebrush. Small mammal diversity and populations would be reduced due to loss of cover and increase in hunting success by predators.
State 2 - Cheatgrass / Sandberg Bluegrass / Annuals Plant Community:
This plant community is the result of continued improper grazing management and fire. The reduced forb and shrub components in the plant community would support a very limited population of pollinators. Most reptilian species identified in State 1 Phase 1.1 are not supported with food, water, or cover. This plant community does not support the habitat requirements for sage-grouse. Diversity of grassland avian species is reduced due to poor cover and available food. Birds of prey including hawks and falcons may range throughout these areas looking for prey species. Hunting success by raptors may increase. Large mammals may utilize the herbaceous vegetation in the early part of the year when the invasive annuals (cheatgrass) are more palatable. At other times of the year large mammals would not regularly utilize these areas due to poor food and cover conditions. Small mammal populations and diversity would be reduced due to poor quality cover, food, and increase in hunting success by predators.
State 3 – Utah Juniper/ Annuals/ Sandberg Bluegrass: This site has developed due to improper grazing management and no fire. The loss of native forbs and understory vegetation will reduce insect diversity on the site. The lack of flowering plants will reduce pollinators like butterflies and moths. Most reptilian species identified in State 1 Phase 1.1 are not supported with food, water, or cover. This plant community does not support the habitat requirements for sage-grouse. Birds using this site as resident or migratory habitat include Juniper titmouse, western bluebird, and Virginia’s warbler. The Juniper titmouse relies heavily on juniper seeds for winter food. Hunting success by raptors may decrease due to a heavy overstory of juniper. The plant community supports limited seasonal habitat for mule deer, elk, and antelope in spring and fall. As juniper encroaches the site will provide additional thermal cover for large mammals.
Grazing Interpretations
This site is best suited for livestock grazing in the spring, fall and early winter. Natural water supplies are short or absent. Heavy fall or winter sheep use may reduce the vigor of low sagebrush.
Estimated initial stocking rate will be determined with the landowner or decision-maker. They will be based on the inventory which includes species, composition, similarity index, production, past use history, season of use and seasonal preference. Calculations used to determine estimated initial stocking rate will be based on forage preference ratings.
Hydrological functions
The soils in this group are in hydrologic groups B and D. They have moderately low to high runoff potential.
Recreational uses
Pronghorn antelope and sagegrouse hunting are the major recreation uses of this site. There is limited opportunities for off-road vehicles, hiking, horseback riding and photography.
Wood products
None.
Other products
None.
Supporting information
Inventory data references
Information presented here has been derived from NRCS clipping and other inventory data. Also, field knowledge of range-trained personnel was used.
Those involved in developing this site description include:
Dave Franzen, co-owner, Intermountain Rangeland Consultants, LLC
Jacy Gibbs, co-owner, Intermountain Rangeland Consultants, LLC
Jim Cornwell, Range Management Specialist, IASCD, Idaho
Kristen May, Resource Soil Scientist, NRCS, Idaho
Lee Brooks, Range Management Specialist, IASCD, Idaho
Brendan Brazee, State Range Management Specialist, NRCS, Idaho
Other references
Hironaka, M., M.A. Fosberg, A. H. Winward. 1983. Sagebrush-Grass Habitat Types of Southern Idaho. University of Idaho. Moscow, Idaho. Bulletin Number 35.
Petersen, S.L., 2004. A Landscape-Scale Assessment of Plant Communities, Hydrologic Processes, and State-and-Transition Theory in a Western Juniper Dominated Ecosystem. PhD Dissertation. Oregon State University, Corvallis, Oregon.
USDA Forest Service, Rocky Mountain Research Station. 2004. Restoring Western Ranges and Wildlands. General Technical Report RMRS-GTR-136-vols. 1-3.
USDA, NRCS.2001. The PLANTS Database, Version 3.1 (http://plants.usda.gov.). National Plant Data Center, Baton Rouge, LA 70874-4490 USA
USDA, Forest Service, Fire Effects Information Database. 2004. www.fs.fed.us/database/feis
Approval
Kendra Moseley, 9/21/2020
Rangeland health reference sheet
Interpreting Indicators of Rangeland Health is a qualitative assessment protocol used to determine ecosystem condition based on benchmark characteristics described in the Reference Sheet. A suite of 17 (or more) indicators are typically considered in an assessment. The ecological site(s) representative of an assessment location must be known prior to applying the protocol and must be verified based on soils and climate. Current plant community cannot be used to identify the ecological site.
| Author(s)/participant(s) | |
|---|---|
| Contact for lead author |
USDA/Natural Resources Conservation Service Brendan Brazee, State Range Conservationist 9173 W. Barnes Drive, Suite C Boise, ID 83709 (208) 378-5722 |
| Date | 01/18/2008 |
| Approved by | Kendra Moseley |
| Approval date | |
| Composition (Indicators 10 and 12) based on | Annual Production |
Indicators
-
Number and extent of rills:
Rills are rare on this site. They are most likely to occur immediately following a wildfire and on slopes greater than 15 percent. Surface gravels reduce rill formation. -
Presence of water flow patterns:
Water-flow patterns are rare on this site. They are most likely to occur with high intensity convection storms and when slopes are greater than 15 percent. When they do occur, they are short, disrupted by cool season perennial grasses and tall shrubs and are not extensive. -
Number and height of erosional pedestals or terracettes:
Erosional pedestals or terracettes are rare on this site. They are most likely to occur with high intensity convection storms and when slopes are greater than 15 percent. When they do occur, they are short, disrupted by cool season perennial grasses and tall shrubs and are not extensive. -
Bare ground from Ecological Site Description or other studies (rock, litter, lichen, moss, plant canopy are not bare ground):
Bare ground ranges from 20-40 percent but data is needed to verify. -
Number of gullies and erosion associated with gullies:
Gullies do not occur on this site. -
Extent of wind scoured, blowouts and/or depositional areas:
Blowouts and depositional areas are rare. -
Amount of litter movement (describe size and distance expected to travel):
Fine litter in the interspaces may move up to 2-3 feet or further following a significant run-off event and on slopes greater than 15 percent. Coarse litter generally does not move. -
Soil surface (top few mm) resistance to erosion (stability values are averages - most sites will show a range of values):
Values should range from 3 to 5 but need to be tested. -
Soil surface structure and SOM content (include type of structure and A-horizon color and thickness):
The A or A1 horizon is typically 2 to 8 inches thick. Structure ranges from weak or moderate very fine, fine or medium granular, to weak or moderate very fine, fine subangular blocky. Soil organic matter (SOM) ranges from 1 to 6 percent.
-
Effect of community phase composition (relative proportion of different functional groups) and spatial distribution on infiltration and runoff:
Bunchgrasses, especially deep-rooted, slow run-off and increase infiltration. Shrubs catch snow in the interspaces. Terracettes provide a favorable micro-site for vegetation establishment, which further increases infiltration. Surface gravels help slow surface water movement and increase infiltration. -
Presence and thickness of compaction layer (usually none; describe soil profile features which may be mistaken for compaction on this site):
Compaction layer is not present. -
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 deep-rooted perennial bunchgrasses >>Sub-dominant:
Tall shrubs> perennial forbs> shallow rooted grassesOther:
Additional:
-
Amount of plant mortality and decadence (include which functional groups are expected to show mortality or decadence):
Low sagebrush will become decadent in the absence of fire and ungulate grazing. Grass and forb mortality will occur as tall shrubs increase. -
Average percent litter cover (%) and depth ( in):
Annual litter cover in the interspaces will be 5-10 percent to a depth of <0.1. Under the mature shrubs, litter is greater than 0.5 inches. Fine litter can accumulate on the terracettes. -
Expected annual annual-production (this is TOTAL above-ground annual-production, not just forage annual-production):
Annual production is 400 lbs. per acre in a year with normal precipitation and temperatures. Perennial grasses produce 50-60 percent of the total, forbs 10-15 percent and shrubs 25-35 percent. -
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:
Invasive species include cheatgrass, rush skeletonweed, scotch thistle, spotted and diffuse knapweed, Russian thistle, mustard. clasping pepperweed, beggar ticks, tansymustard, Jim Hill tumblemustard, yellow salsify, burr buttercup, medusahead, halogeton. -
Perennial plant reproductive capability:
All functional groups have the potential to reproduce in normal years.
Print Options
Sections
Font
Other
The Ecosystem Dynamics Interpretive Tool is an information system framework developed by the USDA-ARS Jornada Experimental Range, USDA Natural Resources Conservation Service, and New Mexico State University.
Click on box and path labels to scroll to the respective text.