Physiographic features

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 are well drained and moderately deep to very deep to bedrock. They occur on limestone hillslopes and mountain slopes and are formed in slope alluvium and residuum. Textures are dominantly gravelly loam, very gravelly loam, gravelly silt loam, and extremely gravelly loam. Available water holding capacity (AWC) is very low to low. Water erosion can be very high when the plant cover is reduced and slope increases. These soils are characterized by a xeric or an aridic bordering on xeric soil moisture regime. The soils are either a mesic or frigid soil temperature regime.

Soil Series Correlated to this Ecological Site


Crossley
Lonjon
Pinegap
Pyrat

Table 4. Representative soil features

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 and pronghorn antelope. The site can provide winter habitat for these large mammals. The rangeland provides important seasonal habitat for resident and migratory animals including western toad, sagebrush lizard, western rattlesnake, 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 tumblemustard) 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 – Black Sagebrush/ Bluebunch Wheatgrass 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 common 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. Birds that may be resident or migratory include mountain bluebird, lazuli bunting, vesper sparrow, grasshopper sparrow, and lesser goldfinch. Nesting cover, brood-rearing habitat, winter cover, and winter food for sage-grouse are provided by this plant community. Black sagebrush is desirable browse for mule deer and pronghorn. The plant community provides spring, fall, and winter food for mule deer and pronghorn. A diverse small mammal population may include golden-mantled ground squirrels and chipmunks.

State 1 Phase 1.2 - Black Sagebrush/ Sandberg Bluegrass/ Utah Juniper 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 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 reptile populations. As juniper increases, habitat for Brewer’s sparrow, sage thrasher, and sage sparrow may increase. Black sagebrush provides brood-rearing habitat, winter cover, and winter food for sage-grouse, but as juniper encroaches the quality of this habitat is severely reduced or eliminated. As juniper encroaches the site will provide additional thermal and young of year cover for mule deer. A small mammal population including golden-mantled ground squirrels, chipmunks, and yellow-bellied marmots 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 the one in State 1 Phase 1.1 would still support select pollinators. Encroachment of rabbitbrush and horsebrush would add fall pollinator habitat to the site. Until rabbitbrush is established diversity and populations of reptiles would be limited. The dominance of herbaceous vegetation with no sagebrush canopy cover would eliminate use of this area for nesting, winter cover, and winter feeding 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 bird species (horned lark and western meadowlark). Winter habitat for large mammals would be reduced or eliminated with the loss of black sagebrush. Small mammal diversity and populations would be reduced due to a loss of cover and subsequent increase in success of hunting by predators.

State 1 Phase 1.4- Black Sagebrush/ Sandberg Bluegrass Plant Community: This phase has developed due to improper grazing management and no fire. The animal community would be similar to that in State 1 Phase 1.1. The reduced vigor and canopy cover of forbs would lower the quality of habitat for pollinators. The reptile community includes sagebrush lizard and western rattlesnake. The reduced diversity of insects and understory cover may reduce the quality of food and cover for reptile populations. The site would provide winter cover and winter food for sage-grouse. The quality of brood-rearing habitat and nesting cover for sage-grouse would be reduced as the herbaceous understory is depleted. Mule deer and pronghorn may utilize this site for winter habitat. A small mammal population including golden-mantled ground squirrels, chipmunks, and yellow-bellied marmots may utilize this site.



State 2 - Annuals/ Sandberg Bluegrass 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, forage, and an increase in the success of hunting by predators.

State 3 – Utah Juniper/ Sandberg Bluegrass/ Annuals Plant Community: This state has developed due to improper grazing management and no 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. Reptilian species present would be similar to the species identified in State 1 Phase 1.1. This plant community does not support the habitat requirements for sage-grouse. Resident and migratory birds using this site 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 forage habitat for mule deer in the spring and fall. Winter cover and food is provided for mule deer. As juniper encroaches the site will provide additional thermal cover for large mammals.

Grazing Interpretations.

This site is best adapted for livestock grazing in the late spring, early summer, and fall. Natural water supply is limited or absent; however, water is generally 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

The soils in this site are in hydrologic group D. They have high runoff potential.

Recreational uses

This site is open space on steep terrain with low growing vegetation and generally offers little recreational activities.

Wood products

None.

Other products

None.

Other information

Field Offices

American Falls
Blackfoot
Burley
Driggs
Idaho Falls
Malad
Pocatello
Rexburg
Soda Springs
St. Anthony

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

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.
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