Physiographic features

This site occurs on gently undulating to somewhat rolling and broken foothills. Slopes range from 8 to 35 percent, but are generally less than 20 percent. This site occurs on all aspects. Elevations range from 4800 to 7000 feet (1400 to 2150 meters).

Table 2. Representative physiographic features

Climatic features

MLRA 13, the Eastern Idaho Plateaus, is part of the Northwestern Wheat and Range Region. Its elevation ranges from 4209 to 9331 feet above sea level, with an average elevation of 5787 feet. The average annual precipitation is 16.41 inches, with a range of 13.56 to 18.75 inches, based on ten long term climate stations located throughout the MLRA. A spike in precipitation amount often occurs in late spring, usually in May.
Temperatures vary widely in the MLRA throughout the year. A maximum temperature of 103° Fahrenheit occurred at the McCammon climate station (# 105716; elevation 4770 feet), while a minimum of -41° was recorded at the Kilgore station (#104908). At all stations temperatures throughout the year are usually below the national average. Kilgore also recorded the greatest annual snowfall amount of 217 inches. The average temperature is 41.4 degrees F. with an average high of 55.3 degrees and an average low of 27.5 degrees.
The frost-free period ranges from 64 to 90 days, while the freeze-free period can be 98 to 123 days.

Table 3. Representative climatic features

Influencing water features

This site is not influenced by adjacent wetlands, streams, or run on.

Soil features

Soils are stony, dark colored, medium textured, moderately deep to deep silt loams, silty clay loams and clay loams, moderately high in organic matter with medium to high permeability. These soils have low available water holding capacity (AWC). Coarse fragments significantly affect vegetation. Erosion hazard ranges from slight to moderate, depending upon slope and ground cover.

Soil Series Correlated to this Ecological Site

None

Table 4. Representative soil features

Animal community

Wildlife Interpretations.
Animal Community – Wildlife Interpretations

This rangeland ecological site provides diverse habitat for many native wildlife species. The plant community exhibits a diverse mixture of forbs throughout the growing season offering excellent habitat for invertebrates. Mule deer, elk, and occasional pronghorn antelope may utilize the site at different times of the year. The rangeland provides seasonal habitat for resident and migratory animals including western toad, shrews, bats, ground squirrels, mice, coyote, red fox, badger, Ferruginous hawk, and prairie falcon. Area sensitive bird species include Brewer’s sparrow, sage thrasher, sage sparrow, and sage-grouse. Water features are sparse provided by seasonal runoff, artificial water catchments, and springs.

State 1 Phase 1.1 – Mountain Big Sagebrush/ Idaho Fescue/ Bluebunch Wheatgrass/ Antelope Bitterbrush Reference Plant Community (RPC): This plant community provides a diversity of grasses, forbs, and shrubs used by native insect communities that assist in pollination. An extensive array of forbs is represented throughout the growing season leading to a diverse insect community. Many avian and mammal species utilize this habitat based on the availability of invertebrate prey species. The reptile and amphibian community is represented by common sagebrush lizard, western rattlesnake, Great Basin spadefoot toad, western toad, and northern leopard frog. Amphibians are associated with springs and isolated water bodies adjacent to this plant community. Development of spring sites that collect all available water would exclude amphibian use on these sites. Native shrub-steppe obligate avian species utilizing the habitat include the Brewer’s sparrow, sage sparrow, sage grouse, and sage thrasher. Sage-grouse habitat (leks, nesting, brood-rearing, and winter) is provided by this plant community. The plant community provides seasonal (spring, summer, and fall) forage and cover for large mammals including mule deer and elk. Antelope bitterbrush, bluebunch wheatgrass, and Idaho fescue are important forage species for these animals. Some areas (south facing slopes) may provide winter food for mule deer and elk. A diverse small mammal population including golden-mantled ground squirrels, jackrabbits, deer mice, and Great Basin pocket mice may utilize this plant community. The deer mouse is beneficial to this site as it is the principal vector for planting bitterbrush seed.

State 1 Phase 1.2- Mountain Big Sagebrush/ Utah Juniper/ Idaho Fescue/ Bluebunch Wheatgrass/ Bottlebrush Squirreltail Plant Community: This phase has developed due to fire return interval being much longer than normal and/or improper grazing management. 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 the State 1 Phase 1.1 community. The reduced diversity of insects and understory cover may reduce quality of food and cover for reptile populations. As juniper increases, habitat for Brewer’s sparrow, sage thrasher, and sage sparrow may increase. Remaining sagebrush provides brood-rearing, winter cover, and winter food habitat for sage-grouse but as juniper encroaches the quality of this habitat is severely reduced or eliminated. The plant community provides limited spring and fall forage for mule deer and elk due to the loss of understory vegetation. Juniper can provide winter habitat (cover and food) for mule deer. As juniper increases, the site will provide additional thermal cover for large mammals. A diverse small mammal population including golden-mantled ground squirrels, jackrabbits, deer mice, and Great Basin pocket mice may utilize this plant community.

State 1 Phase 1.3 – Bluebunch Wheatgrass/ Sandberg Bluegrass/ Bottlebrush Squirreltail/ Thickspike Wheatgrass Plant Community: This plant community is a result of recent wildfire, prescribed burning, or brush management. The plant community, dominated by herbaceous vegetation with little to no sagebrush or antelope bitterbrush would provide less vertical structure for animals. Patches of root sprouting shrubs (rabbitbrush, horsebrush, and mt. snowberry) may be present to provide limited vertical structure for wildlife. Insect diversity would be reduced but a native forb plant community similar to that in State 1 Phase 1.1 would still support select pollinators. Habitat for reptiles including common sagebrush lizard and western rattlesnake would be limited or excluded due to the loss of sagebrush. Amphibian habitat would be tied to permanent spring sites in the area. Development of spring sites that collect all available water would exclude the use of amphibians on these sites. The dominance of herbaceous vegetation with little sagebrush or antelope bitterbrush canopy cover would limit use of these areas as nesting habitat by Brewer’s sparrow, sage sparrow, sage grouse, and sage thrasher. Sharp-tailed grouse may find this site suitable habitat. The dominant herbaceous vegetation improves habitat for grassland avian species (horned lark, savannah sparrow, vesper sparrow, and western meadowlark). Mule deer and elk use would be seasonal but the site would offer little thermal or young of year cover due to the loss of shrub cover. The open terrain may offer more suitable habitat for pronghorn. The populations of small mammals would be dominated by open grassland species. Large blocks of this plant community would fragment the reference plant community and reduce the quality of the habitat for shrub-steppe obligate animal species.


State 1 Phase 1.4 – Mountain Big Sagebrush/ Sandberg Bluegrass/ Bottlebrush Squirreltail/ Thickspike Wheatgrass/ Antelope Bitterbrush Plant Community: This plant community is the result of improper grazing management and no fire. An increase in canopy cover of sagebrush contributes to a sparse herbaceous understory. Grasses, forbs, and shrubs are used by native insects that assist in pollination but the reduced herbaceous understory results in lower diversity of insects. The reptile and amphibian community is represented by common sagebrush lizard, western rattlesnake, Great Basin spadefoot toad, western toad, and northern leopard frog. The reduced diversity of insects may reduce reptile diversity and populations. Reduced herbaceous understory is a key factor in limiting the use of this plant community by avian species. Shrub-steppe obligate avian species include Brewer’s sparrow, sage sparrow, sage thrasher, and sage-grouse. Quality of habitat (brood-rearing and nesting cover) for sage-grouse is reduced due to a less diverse herbaceous plant community. Winter habitat (cover and food) for sage-grouse is provided. The reduced vigor of understory vegetation provides a shorter forage season for mule deer and elk. Young of year cover would be provided for deer. Small mammal diversity and populations would be similar to those in State 1 Phase 1.1.

State 2 – Sandberg/ Annuals/ Cheatgrass Plant Community:
This state has developed due to continued improper grazing management and frequent fire. The plant community does not support a diverse insect community. The reduced forb and shrub components in the plant community would support a very limited population of pollinators. Habitat for sagebrush lizard, Great Basin spadefoot toad, and western toad would be limited due to the loss of sagebrush. This plant community does not provide quality habitat for sage thrasher, Brewer’s sparrow, sage-grouse, or sage sparrow. 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. Large mammals may utilize the herbaceous vegetation in the early part of the year when the vegetation is more palatable. The populations of small mammals would be dominated by open grassland species. Predator hunting success would increase due to reduced cover for small mammals. Large blocks of this plant community would fragment the reference plant community and reduce the quality of the habitat for shrub-steppe obligate animal species.

State 3 - Utah Juniper/ Sandberg Bluegrass/ Annuals/ Cheatgrass Plant Community: This state has developed due to improper grazing management and a lack of fire. The loss of native understory vegetation will reduce insect diversity on the site. The lack of flowering plants reduces use by pollinators like butterflies and moths. Habitat for sagebrush lizard, Great Basin spadefoot toad, and western toad would be limited due to the loss of sagebrush. 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. As juniper encroaches the site will provide additional thermal cover for large mammals. The plant community provides cover and forage value for mule deer.



Grazing Interpretations.

This site is best suited for livestock grazing in the spring, early summer and fall. Access is sometimes limited due to surface stones.

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 site are in hydrologic group B. They have moderately low runoff potential.

Recreational uses

This site has some value for hunting small game, big game, and upland game birds. There are some aesthetic values for viewing and photography of spring blooming flowers. The site has moderate to severe limitations for ATV use due to surface stones.

Wood products

Mature juniper that has invaded and increased on the site can be cut for posts, poles, firewood and lumber.

Other products

None

Other information

Field Offices

American Falls, ID
Blackfoot, ID
Burley, ID
Driggs, ID
Ft. Hall, ID
Idaho Falls, ID
Malad, ID
Pocatello, ID
Rexburg, ID
Soda Springs, ID
St. Anthony, ID

Revision Notes: “Previously Approved” Provisional
This Provisional ecological site concept has passed Quality
Control (QC) and Quality Assurance (QA) to ensure that the site
meets the 2014 NESH standards for a Provisional ecological site
description. This is an updated “Previously Approved” ESD that
represents a first-generation tier of documentation that, prior to the
release of the 2014 National Ecological Site Handbook (NESH),
met all requirements as an “Approved” ESD as laid out in the 1997
(rev.1, 2003) National Range and Pasture Handbook (NRPH). The
document fully described the Reference State and Community
Phase in the State-and-Transition model. All other alternative
states are at least described in narrative form. The “Previously
Approved” ESD has been field-tested for a minimum of five years
and is a proven functional document for conservation planning.
The “Previously Approved” ESD does not contain all tabular and
narrative entries as required in the current “Approved” level of
documentation, but it is expected that the “Previously Approved”
ESD will continue refinement toward an “Approved” status.

Site Development and Testing Plan:
Future work, as described in a Project Plan, is necessary to
validate the information in this Provisional Ecological Site
Description. This will include field activities to collect low-,
medium-, and high-intensity sampling, soil correlations, and
analysis of that data. Annual field reviews should be done by soil
scientists and vegetation specialists. The final field review, peer
review, quality control, and quality assurance reviews of the ESD
will be required to produce the final document.

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
Brendan Brazee, State Rangeland Management Specialist, NRCS, Idaho
Lee Brooks, Range Management Specialist, IASCD
Kristen May, Resource Soil Scientist, NRCS, Idaho

Type locality

Other references

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.

Hironaka, M., M.A. Fosberg, A. H. Winward. 1983. Sagebrush-Grass Habitat Types of Southern Idaho. University of Idaho. Moscow, Idaho. Bulletin Number 35.
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
USDI Bureau of Land Management, US Geological Survey; USDA Natural Resources Conservation Service, Agricultural Research Service; Interpreting Indicators of Rangeland Health. Technical Reference 1734-6; Version 4-2005.

Contributors

DF

Approval

Kendra Moseley, 9/23/2020