Physiographic features

This site occurs on steeply sloping upper mountainsides, backslopes, and convex shoulders generally on east and north aspects. Slopes generally range from 30-45 percent. Elevations range from 6200-6700 feet (1850-2050 meters).

This site occurs on steeply sloping upper mountainsides, ridges and hillslopes on east and north aspects. Slopes generally range from 30 to 60 percent. Elevations range from 6200-6800 feet (1850 to 2080 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

The soils on this site are well drained and have a permeability rating of moderate. These shallow to moderately deep soils are formed from residuum and alluvium from limestone and sandstone. Textures are dominantly gravelly loam, gravelly silty clay loam, very gravelly loam, and very gravelly silt loam. Reactions range from moderately alkaline to strongly alkaline. The available water holding capacity (AWC) ranges from very low to low, while runoff is high. These soils are characterized by a xeric soil moisture regime and a frigid soil temperature regime.


Soil Series Correlated to this Ecological Site


Lonjon
Mumford

Table 4. Representative soil features

Animal community

Wildlife Interpretations.

Animal Community – Wildlife Interpretations

This rangeland ecological site provides habitat for a variety of native wildlife species. Large herbivore use of the reference plant community is dominated by mule deer and pronghorn antelope. The rangeland 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, Russian thistle) 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 – Alkali Sagebrush/ Bluebunch Wheatgrass/ Indian Ricegrass/ Nevada Bluegrass/ Thickspike Wheatgrass/ Hood’s Phlox Plant Community (RPC): 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 sagebrush lizard, western rattlesnake, northern leopard frog, 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. Resident or migratory birds using the site include mountain bluebird, lazuli bunting, vesper sparrow, grasshopper sparrow, and lesser goldfinch. Brood-rearing habitat, nesting cover, winter cover, and winter food for sage grouse are provided by this plant community. The plant community provides spring, summer, and fall forage habitat for mule deer and pronghorn. Mule deer and pronghorn have a preference for alkali sagebrush. A diverse small mammal population may include Idaho pocket gopher, golden-mantled ground squirrels, marmots, and chipmunks.

State 1 Phase 1.2- Alkali Sagebrush/ Bluebunch Wheatgrass/ Indian Ricegrass/ Thickspike Wheatgrass/ Antelope Bitterbrush Plant Community: This phase has developed due to fire return intervals being much longer than normal. An increase in canopy cover of sagebrush and antelope bitterbrush contributes to a decline in the herbaceous understory. Invertebrates’ diversity and populations would be similar to those in State 1 Phase 1.1. The reptile community will be similar to the State 1 Phase 1.1 community represented by sagebrush lizard and western rattlesnake. Sagebrush will provide brood-rearing habitat, winter cover, and winter food for sage-grouse. Quality of nesting habitat for sage-grouse may decline with the reduction of herbaceous understory. The plant community provides seasonal (spring summer and fall) forage habitat for mule deer and pronghorn. Antelope bitterbrush is a preferred browse for mule deer and pronghorn. A diverse small mammal population may include Idaho pocket gopher, golden-mantled ground squirrels, marmots, and chipmunks.

State 1 Phase 1.3 – Utah Juniper/ Alkali Sagebrush/ Sandberg Bluegrass Plant Community: This phase has developed due to improper grazing management and a lack of fire. An increase in canopy cover of juniper contributes to a sparse herbaceous understory. A reduced herbaceous understory results in a lower diversity of insects. The reptile community will be similar to the State 1 Phase 1.1 community, represented by common sagebrush lizard and western rattlesnake. The reduced diversity of insects and understory cover may reduce the quality of food and cover for reptiles. As juniper increases, habitat cover for Brewer’s sparrow, sage thrasher, and sage sparrow may increase. Remaining alkali sagebrush provides brood-rearing habitat for sage-grouse but as juniper encroaches, the quality of this habitat is severely reduced or eliminated. The plant community supports limited seasonal (spring, fall, and winter) habitat for mule deer and pronghorn. As juniper encroaches the site will provide additional thermal and young of year cover for large mammals. Juniper will increase winter habitat value for mule deer. A small mammal population including golden-mantled ground squirrels, chipmunks, deer mice, and yellow-bellied marmots may utilize this site.

State 1 Phase 1.4 - Bluebunch Wheatgrass/ Sandberg Bluegrass Plant Community: This plant community is the result of 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 that in State 1 Phase 1.1 would still support select pollinators. Encroachment of rabbitbrush would add fall pollinator habitat in the future. Until rabbitbrush is established, diversity and populations of native reptiles would be limited or excluded. The dominance of herbaceous vegetation with no sagebrush canopy cover would eliminate use of this area for winter cover and winter food for sage-grouse. This plant community provides limited brood-rearing habitat for sage-grouse when site is adjacent to sagebrush cover. The dominant herbaceous vegetation improves habitat for grassland avian species (horned lark, western meadowlark, vesper sparrow, and grasshopper sparrow). Spring and fall forage for mule deer and pronghorn would be provided by this plant community. Small mammal diversity and populations would be reduced due to a loss of cover and an increase in the success of hunting by predators.

State 1 Phase 1.5 - Alkali Sagebrush/ Sandberg Bluegrass Plant Community: This phase has developed due to improper grazing management and a lack of fire. An increase in canopy cover of sagebrush contributes to a sparse herbaceous understory. A reduced herbaceous understory results in lower diversity of insects. The reptile community will be similar to the State 1 Phase 1.2 community represented by sagebrush lizard and western rattlesnake. The reduced diversity of insects and understory cover may reduce the quality of food and cover for reptile populations. As sagebrush increases, habitat for Brewer’s sparrow and sage thrasher may increase. Quality of brood-rearing habitat and nesting cover for sage-grouse would decline with the loss native forbs and deep-rooted perennial bunchgrasses. Winter cover and winter food for sage-grouse would still be provided. Spring and fall forage for mule deer and pronghorn would be provided by this plant community although the quality of forage would decline with the reduction of perennial deep rooted grasses. The small mammal population may include Idaho pocket gopher, golden-mantled ground squirrels, and chipmunks.

State 2 Phase 2.1 - Alkali Sagebrush/ Sandberg Bluegrass/ Annuals/ Cheatgrass Plant Community: This phase has developed due to improper grazing management and a lack of fire. An increase in canopy cover of sagebrush and invasive plants contributes to a sparse native herbaceous understory. A reduced herbaceous understory results in lower diversity of insects. The reptile community will be similar to that in State 1 Phase 1.5 but the quality of habitat has been severely reduced due to poor understory vegetation. As sagebrush increases, habitat for Brewer’s sparrow and sage thrasher may increase. Quality of brood-rearing habitat for sage-grouse would decline with the loss forbs and deep-rooted perennial bunchgrasses. Winter cover and winter food for sage-grouse would still be provided. Quality of forage habitat for mule deer and pronghorn in the spring and fall is reduced. The small mammal population would include Idaho pocket gopher, golden-mantled ground squirrels, and chipmunks.

State 2 Phase 2.2 - Sandberg Bluegrass/ Annuals/ Forbs/ Green Rabbitbrush/ Mountain Snowberry Plant Community: This plant community is the result of continued improper grazing management and fire. Pollinator habitat may be similar to that in State 1 Phase 1.2. Reptile species would be similar to those in State 2 Phase 1.1 with vertical structure provided by rabbitbrush and snowberry. This plant community does not support the habitat requirements for sage-grouse. Birds of prey including hawks and falcons may range throughout these areas looking for prey species. Mule deer and pronghorn may utilize the herbaceous vegetation in the early part of the year when the invasive annuals (cheatgrass) are more palatable. Mountain snowberry is desirable browse the entire year for mule deer and pronghorn. Small mammal populations and diversity would be similar to those in State 1 Phase 1.2.

State 3 – Utah Juniper/ Sandberg Bluegrass/ Annuals: This state 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 reduces the quality of pollinator habitat for butterflies and moths. The quality of habitat for reptiles is severely reduced resulting in a less diverse population. 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 provides limited seasonal habitat for mule deer in the spring and fall. Winter habitat for mule deer may increase in value as juniper becomes established. As juniper encroaches, the site will provide additional thermal and young of year cover for large mammals.


Grazing Interpretations.

This site is suited for grazing by domestic livestock in the summer and fall. Natural water supply is short or absent, however water may be available on adjacent sites.
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

Soils on this site are in hydrologic group D. The site has high run-off potential.

Due to the relatively steep slopes and gravelly surface soils, this site is not easily degraded by improper grazing management.

Recreational uses

This site provides open space on steep mountain side slopes with a varied floristic component.

Wood products

None.

Other products

None.

Other information

Field Offices

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

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
Kristen May, Resource Soil Scientist, NRCS, Idaho
Lee Brooks, Range Management Specialist, IASCD

Type locality

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.
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.

Approval

Kendra Moseley, 9/23/2020