Physiographic features

This site occurs on basalt plains, fans and footslopes. Slopes are usually less than 30 percent and occur on all aspects. Elevation ranges from 4800-6500 feet (1400-2000 meters).

Table 2. Representative physiographic features

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

Influencing water features

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

Soil features

The soils on this site have loam surface textures and clay or silty clay subsoils. Coarse fragments are generally present in the soil profile. The soils are very deep and have moderately slow to no permeability. The clayey subsoil prevents water and root penetration below 14-18 inches. Water intake is slow. The soils are well drained. The available water holding capacity is low to moderate. Runoff is very high. Water erosion can be high when plant cover is reduced. The soils have a xeric soil moisture regime. The soil temperature regime is cryic.

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, elk, and pronghorn antelope. The site can provide winter habitat for mule deer and antelope. 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, medusahead, and bulbous bluegrass) 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/ Idaho Fescue/ Bluebunch Wheatgrass/ Nevada Bluegrass/ Thurber’s Needlegrass/ Bottlebrush Squirreltail 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 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 resident or migratory include mountain bluebird, lazuli bunting, vesper sparrow, grasshopper sparrow, and lesser goldfinch. Brood-rearing, winter cover, and winter food habitat for sage grouse is provided by this diverse plant community. The plant community provides spring, fall, and winter forage needs for large mammals including mule deer and pronghorn. Mule deer and pronghorn have a preference for alkali sagebrush and antelope bitterbrush. A diverse small mammal population may include Idaho pocket gopher, golden-mantled ground squirrels, marmots, and chipmunks.


State 1 Phase 1.2- Alkali Sagebrush/ Idaho Fescue/ Bluebunch Wheatgrass/ Antelope Bitterbrush Plant Community: This phase has developed due to fire frequency being much longer than normal. An increase in canopy cover of sagebrush and bitterbrush contributes to a decline in herbaceous understory. Insect diversity and populations would be similar to State 1 Phase 1.1. The reptile community will be similar to the State 1 Phase 1.1 community represented by leopard lizard, short horned lizard, sagebrush lizard, and western skink. Sagebrush will provide brood-rearing habitat, winter cover, and winter food for sage-grouse. The plant community supports seasonal forage habitat for mule deer and pronghorn. As bitterbrush encroaches, the site will provide limited thermal and young of year for large mammals. An increase in bitterbrush may increase the quality of winter habitat 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/ Kentucky Bluegrass Plant Community: This phase has developed due to improper grazing management and lack of fire. An increase in canopy cover of 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 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 habitat for mule deer and pronghorn. As juniper encroaches, the site will provide additional thermal and young of year cover for large mammals. 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/ Rabbitbrushes 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 State 1 Phase 1.1 would still support select pollinators. Encroachment of rabbitbrush would add fall pollinator habitat to the site over time. As rabbitbrush matures it would help replace the loss of sagebrush cover. 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 if 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). Winter habitat for pronghorn and mule deer would be reduced or eliminated with the loss of sagebrush and bitterbrush. Small mammal diversity and populations would be reduced due to loss of cover and increase in 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 and numbers of insects. The reptile community will be similar to the 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 sagebrush increases, habitat for Brewer’s sparrow, sage thrasher, and sage sparrow may increase. Quality of brood-rearing habitat for sage-grouse would decline with the loss of vigor and amount of forbs and deep-rooted perennial bunch grasses. Winter cover and winter food for sage-grouse would still be provided. The plant community provides important winter habitat for mule deer and antelope. A small mammal population may include Idaho pocket gopher, golden-mantled ground squirrels, and chipmunks.

State 2 Phase 2.1 - Alkali Sagebrush/ Sandberg Bluegrass/ Annuals Plant Community: This phase has developed due to improper grazing management and a lack of fire. An increase in canopy cover of sagebrush and noxious weeds contributes to a sparse native 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 but the quality of habitat has been severely reduced. As sagebrush increases, habitat cover for Brewer’s sparrow, sage thrasher, and sage sparrow may increase. Quality of brood-rearing habitat for sage-grouse would decline with the loss of vigor and amount of forbs and deep-rooted perennial bunch grasses. Winter cover and winter food for sage-grouse would still be provided. The plant community provides winter habitat for mule deer and pronghorn. A 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 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 any of 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. Mule deer and pronghorn 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. Winter habitat for mule deer and pronghorn would not be available. Small mammal populations and diversity would be reduced due to poor quality cover and food, and an increase in success of hunting by predators.

State 3 – Utah Juniper/ Sandberg Bluegrass/ Annuals: 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. 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 spring and fall. Winter habitat for mule deer may increase in value. As juniper encroaches, the site will provide additional thermal and young of year cover for large mammals.

State 4 – Range Seeding Plant Community: The proposed seeding mixture (native or non-native) would determine the animal species that would utilize the area. A diverse seed mixture of grasses and forbs would provide similar habitat conditions as in the herbaceous plant community described in State 1 Phase 1.4. A diverse seed mixture of grasses, forbs, and shrubs would provide similar habitat conditions as described in State 1 Phase 1.1 or 1.2. A monoculture of non-native grass species would not support diverse populations of insects, reptiles, birds, or mammals. Grassland animal species including western meadowlark, horned lark, savannah sparrow, deer mouse, kangaroo rat, mule deer, and pronghorn would utilize this site for nesting and/or seasonal foraging. Birds of prey including hawks and falcons may range throughout these areas looking for prey species.


Grazing Interpretations
This site is suited for grazing by domestic livestock in late spring to early summer after the soils have dried out and firmed up enough to prevent trampling damage.

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. When ground cover is at or near potential, the erosion hazard is moderate.

Recreational uses

The site offers minimal recreation or aesthetic values.

Wood products

None.

Other products

None.

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

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, 12/11/2019