Ecological dynamics
Historic vegetation on this site was dominated by tall (7 ft) cool-season grasses, which are adapted to occasional high water tables. Other significant vegetation includes a variety of forbs and shrubs.
The dominant aspect of this site was grasses. The composition and production will vary naturally due to location (north to south of the MLRA), fluctuating precipitation, and fire return interval.
Due to the abundant forage, thermal cover, and often close proximity to water sources, this site has a high probability of receiving grazing pressures from domestic and wildlife grazers as well as having received historical grazing pressure.
Great basin wildrye is sensitive to spring grazing and clipping and frequent herbage removal during the growing season (Perry and Chapman 1976). Thus, under repetitive harvesting, Great basin wildrye can be “grazed out” of the system. As ecological condition deteriorates due to improper grazing, cool-season grasses Great basin wildrye and Nevada bluegrass decrease in frequency and production. The ungrazed plants or grazing tolerant plants such as Basin big sagebrush, rabbitbrush and other will increase in frequency and production. This increase combined with the declining perennial grasses can lead to a site dominated by sagebrush and rabbitbrush with little to no understory. The area without an understory of perennial grasses and forbs has little value as a functioning ecosystem.
As a result of the grass dominated system, this site had lots of root mass and vegetation production which creates and maintains an organic layer and a mollic epipedon. If the perennial grasses are removed from the system, it is typical to see a decrease in organic matter and accelerated erosion.
Great Basin wildrye is also susceptible to black grass bugs. Black grass bugs populations will invade a site, and can destroy most of the living grasses.
The fire regime for this site is similar to the surrounding sagebrush lands. The intensity of a fire determines the vegetation succession and structure. Low intensity or ground fires typically result in the removal of litter and decadent grasses while maintaining the nominal shrub cover, while higher intensity fires will remove the shrub species. After normal to high intensity fires, basin big sagebrush decreases while rubber rabbitbrush increases. If the fire regime is suppressed, this site may be invaded by junipers.
Because of the position on the landscape, this site is typically one of the first to be invaded. Junipers will start to creep down into the sagebrush communities by using this site as a corridor. The fire transition stages are relatively short-lived and tend to be mosaic in nature.
If thistles, houndstongue or other strongly invasive species, invade the site concurrent to the area being stressed by disturbances or drought, they are likely to invade and dominate this site.
When more information is available, this section will include a discussion of seral stages; fire influence and effects; effects of prolonged wet or dry periods; resistance to change; the influence of such things as grazing, rodent concentrations, insects, diseases, introduced species, and soil erosion or deposition; other stable vegetative states associated with this site as a result of extreme disturbance.
Community 1.1
Basin big sagebrush / Rubber rabbitbrush
Great basin wildrye / Western wheatgrass
Longleaf Hawksbeard / Arrowleaf Balsamroot
This community is dominated by Great basin wildrye. Basin big sagebrush is the major shrub. Other significant herbaceous species in the plant community include western wheatgrass, Nevada bluegrass, longleaf hawksbeard and arrowleaf balsamroot. Rubber rabbitbrush and black greasewood are other important shrubs. Percent composition by air-dry weight is 70 percent grass, 10 percent forbs, and 20 percent shrubs. Natural fire frequency is estimated to be 40 to 50 years.
Community 1.2
Great basin wildrye / Western wheatgrass
Yellow rabbitbrush / Greasewood
Basin big sagebrush decreases in the community; rubber rabbitbrush also decreases, but to a lesser degree. Yellow rabbitbrush, black greasewood and, at times, horsebrush species resprout and increase in the community; much of the excess fine fuel accumulation is removed. Basin wildrye and other cool-season bunchgrasses recover following fire and flourish, western wheatgrass increases. Fire tolerant shrubs may persist as dominants in the shrub community for 30 years or longer.
Community 1.3
Basin big sagebrush / Rubber rabbitbrush /Greasewood / perennial grasses
Basin big sagebrush, rubber rabbitbrush and black greasewood increase in percent composition. Shrubs show signs of decadence due to age. Great basin wildrye and other cool-season bunchgrasses begin losing vigor due to increased shrub competition and increase in old vegetation. Percent composition by air-dry weight is 40 percent grass, 10 percent forbs, and 50 percent shrubs.
Pathway 1.1b
Community 1.1 to 1.2
Disturbance: Recent fire occurrence (1 to 30 years).
Pathway 1.1a
Community 1.1 to 1.3
Extended period of time without a major disturbance such as fire; insect infestation (i.e. black grass bugs); or prolonged drought. Fire frequency extends well beyond the 40 to 50 year average for the site.
Pathway 1.2a
Community 1.2 to 1.1
40 to 50 years or more without a fire occurrence (normal fire frequency).
Pathway 1.3a
Community 1.3 to 1.2
Disturbance: Recent fire occurrence (1 to 30 years).
State 2
Current Potential State
Plant communities in this state can include native, acclimatized, naturalized and invasive non-native species. This state is irreversibly changed from the Reference State because these non-native species will now remain a permanent part of the community.
Community 2.1
Basin big sagebrush / Rubber rabbitbrush
Great basin wildrye / Western wheatgrass
Longleaf Hawksbeard / Arrowleaf Balsamroot
Non-native species
This community is dominated by Great basin wildrye. Basin big sagebrush is the major shrub. Other significant herbaceous species in the plant community include western wheatgrass, Nevada bluegrass, longleaf hawksbeard and arrowleaf balsamroot. Rubber rabbitbrush and black greasewood are other important shrubs. This community is dominated by native species, but may include acclimatized, naturalized and invasive non-native species. Percent composition by air-dry weight is 70 percent grass, 10 percent forbs, and 20 percent shrubs.
Community 2.2
Great basin wildrye / Western wheatgrass
Yellow rabbitbrush / Greasewood
Non-native species
Basin big sagebrush decreases in the community; rubber rabbitbrush also decreases, but to a lesser degree. Yellow rabbitbrush, black greasewood and, at times, horsebrush species resprout and increase in the community; much of the excess fine fuel accumulation is removed. Basin wildrye and other cool-season bunchgrasses recover following fire and flourish, western wheatgrass increases. Fire tolerant shrubs may persist as dominants in the shrub community for 30 years or longer. This community is dominated by native species, but may include acclimatized, naturalized and invasive non-native species.
Community 2.3
Basin big sagebrush / Rubber rabbitbrush /Greasewood / perennial grasses
Non-native species
Pathway 2.1b
Community 2.1 to 2.2
Recent fire occurrence (1 to 30 years).
Pathway 2.1a
Community 2.1 to 2.3
Extended period of time without a major disturbance such as fire; insect infestation (i.e. black grass bugs); or prolonged drought. Fire frequency extends well beyond the 40 to 50 year average for the site.
Pathway 2.2a
Community 2.2 to 2.1
40 to 50 years or more without a fire occurrence (normal fire frequency).
Pathway 2.3a
Community 2.3 to 2.2
Recent fire occurrence (1 to 30 years).
State 3
Utah Juniper, Brush with Annual Weeds State
Community 3.1
Basin big sagebrush and Utah juniper
Invasive annuals / Native perennials
Where Utah juniper has invaded, basin big sagebrush, rubber rabbitbrush and black greasewood may decrease, otherwise they dominate the community; yellow rabbitbrush often increases. Remaining perennial herbaceous vegetation is mostly found only in protected locations under shrubs. Invasive, non-native grasses and weeds, including cheatgrass, annual mustards, redstem storksbill, etc. dominate the understory.
Community 3.2
Basin big sagebrush and Utah juniper
Invasive annuals
Where Utah juniper has invaded, basin big sagebrush, rubber rabbitbrush, and black greasewood decrease, otherwise they may dominate the community; yellow rabbitbrush often increases. Remaining perennial herbaceous vegetation is rare and is found only in protected locations under shrubs. Invasive, non-native grasses and weeds, including cheat grass, annual mustards, redstem storksbill, etc., dominate the understory.
Pathway 3.1a
Community 3.1 to 3.2
Disturbance: Long-term improper grazing (including, season long, overstocking, wrong season, etc.) and drought reduce perennial grasses. Fine fuels are reduced lessening the potential for fire to occur. Fire frequency is greater than 100 years.
Pathway 3.2a
Community 3.2 to 3.1
Site is properly grazed over an extended period of time. Native perennial vegetation slowly recovers; annual weeds dominate the understory. Fire frequency remains well beyond normal for the site.
Fire frequency is greater than 100 years.
State 4
Sprouting Shrub with Annual Weeds State
Community 4.1
Rabbitbrushes / Greasewood
Invasive annuals / Native perennials
Yellow rabbitbrush, black greasewood and smooth horsebrush resprout and dominate the shrub layer. Rubber rabbitbrush can be plentiful if conditions are right.
Fire tolerant shrubs may persist as dominants with fire periods of 10 to 30 years.
Broom snakeweed may be an episodic dominant species when conditions are favorable. Native bunchgrasses are significantly reduced; invasive annuals including cheatgrass, annual mustards, redstem storksbill, etc. dominate the understory.
Community 4.2
Rabbitbrushes / Greasewood
Invasive annuals
Yellow rabbitbrush, black greasewood and smooth horsebrush dominate the overstory community. Rubber rabbitbrush can be plentiful if conditions are right.
Fire tolerant shrubs may persist as dominants in this community with fire periods of 10 to 30 years. Broom snakeweed may be an episodic dominant species when conditions are favorable. Only remnant native bunchgrasses remain; invasive annuals including cheatgrass, annual mustards, redstem storksbill, etc. dominate the understory.
Pathway 4.1a
Community 4.1 to 4.2
Disturbance: Long-term, improper grazing (including, season long, overstocking, wrong season, etc.) and drought reduce perennial grasses. Highly combustible fine fuels from invasive annuals dominate the community resulting in a shortened fire frequency. Fire frequency is typically 10 to 30 years.
Pathway 4.2a
Community 4.2 to 4.1
Site is properly grazed for an extended period of time. Perennial vegetation very slowly recovers. Fire frequency is typically 10 to 30 years.
State 5
Seeded Rangeland State
Community 5.1
Basin big sagebrush and Utah juniper
Invasive annuals / Non-Native perennials
Rangeland seeding that may be composed of introduced, native or combination grass and forb species. Unwanted trees and shrubs are reduced but may occupy a portion of the site because of natural regeneration. Invasive annual grasses and weedy forb species, primarily cheatgrass and various annual mustards, may be present in the seeding. Seeding, when healthy, is resistant to fire.
Community 5.2
Basin big sagebrush and Utah juniper
Invasive annuals
This state is present after either a failed seeding or an improperly grazed one. Site may be herbaceous or may be returning to trees and shrubs.
Pathway 5.1a
Community 5.1 to 5.2
Disturbance: Long-term improper grazing (including, season long, overstocking, wrong season, etc.) and drought reduce perennial grasses. Fine fuels are reduced lessening the potential for fire to occur. Fire frequency is greater than 100 years.
Pathway 5.2a
Community 5.2 to 5.1
Site is properly grazed over an extended period of time. Native perennial vegetation slowly recovers; annual weeds dominate the understory. Fire frequency remains well beyond normal for the site. Fire frequency is greater than 100 years.
State 6
Cropland State
This state occurs when the Upland Loam ecological site is altered and permanently replaced with agricultural crops such as Alfalfa and Grain. This State is identified here to recognize that a very large portion of this ecological site has been converted to a cropland land use.
Transition T1a
State 1 to 2
Improper grazing (i.e. season long, overstocking, wrong season, etc.) and drought remove fine fuels from the site lessening the potential for fire to occur. This allows both sprouting and non-sprouting shrubs such as basin big sagebrush, rubber rabbitbrush and black greasewood to increase in the community. Shrubs may become decadent due to age. Great basin wildrye and other native bunchgrasses lose vigor and decrease in the community due to shrub competition and grazing pressure; Western wheatgrass may increase. Utah juniper seedlings and saplings may begin to invade the community if a seed source is available.
The threshold is crossed when there is an introduction of non native species, primarily cheatgrass and various annual mustards, that become established on the site.
Prior to crossing the threshold, if this site is properly grazed over an extended period of time native perennial vegetation may recover. Fire frequency can return to within the normal range for the site. These events could set the site back into the normal range of variability.
Transition T2a
State 2 to 3
Long-term improper grazing (including, season-long, overstocking, wrong season, etc.); and prolonged drought; lengthened fire return interval resulting in a dense non-sprouting tree and shrub overstory, reduction of native perennial understory vegetation and increasing invading annuals. Utah junipers may increase to occupy a significant portion of the overstory, if a seed source is present. Basin big sagebrush dominates the shrub layer and may be decadent due to age. Rubber rabbitbrush and greasewood may also be present. Great basin wildrye and other native bunchgrasses are significantly reduced due to increased shrub competition and heavy grazing pressure; western wheatgrass may increase. The threshold is crossed when invasive annuals including cheatgrass, annual mustards, redstem storksbill, etc. dominate the understory. The occurrence of fire extends well beyond the normal period for the site.
Transition T2b
State 2 to 4
Disturbance: Sustained, long-term improper grazing (including, season long, overstocking, wrong season, etc.) and prolonged drought; shortened fire frequency allows site to be dominated by sprouting shrubs including yellow rabbitbrush, black greasewood and smooth horsebrush; a significant reduction of perennial bunchgrass species is common. There is an invasion of annual grasses and weedy forb species primarily cheatgrass and various annual mustards.
Restoration pathway R3a
State 3 to 5
Disturbance: Mechanical chaining of Utah juniper where present, or mechanical or chemical treatment of unwanted brush species; with seeding of introduced, native or combination rangeland species.
