State 1
Reference

This state represented the natural range of variability that dominated the dynamics of this ecological site prior to European influence. The primary disturbance mechanisms for this site in the reference condition included frequent fire and grazing by large herding ungulates. Timing of fires and grazing coupled with weather events dictated the dynamics that occurred within the natural range of variability. These factors likely caused the community to shift both spatially and temporally between two community phases.

Characteristics and indicators. (i.e. characteristics and indicators that can be used to distinguish this state from others). Because of changes in disturbances and other environmental factors (particularly the widespread occurrence of exotic species), the Reference State is considered to no longer exist.

Resilience management. (i.e. management strategies that will sustain a state and prevent a transition). If intact, the reference state should probably be managed with current disturbance regimes which has permitted the site to remain in reference condition as well as maintaining the quality and integrity of associated ecological sites. Maintenance of the reference state is contingent upon a monitoring protocol to guide management.

Community 1.1
Indiangrass-Big Bluestem-Switchgrass (Sorghastrum nutans-Andropogon gerardii-Panicum virgatum)

This community phase was historically the most dominant both temporally and spatially. It was dominated by tall and mid warm-season and mid cool-season grasses such as Indiangrass, big bluestem, switchgrass, porcupinegrass, and little bluestem. Other grass and grass-like species included prairie cordgrass, Canada wildrye, sideoats grama, slender wheatgrass, and sedges. A wide variety of native perennial forbs were present including Indianhemp, Norwegian cinquefoil, American licorice, Canada goldenrod, blackeyed Susan, and upright prairie coneflower. Common shrubs included leadplant, willow, white meadowsweet, and western snowberry. Annual production would have varied from about 3500-6000 pounds per acre with graminoids, forbs, and shrubs contributing 85%, 10%, and 5% respectively. Both warm-season grasses and cool-season grasses were well represented in the community, and as a result production would have been distributed throughout the growing season. This community represents the plant community phase upon which interpretations are primarily based and is described in the “Plant Community Composition and Group Annual Production” portion of this ecological site description.

Community 1.2
Forbs/Big Bluestem-Switchgrass-Sideoats Grama (Forbs/Andropogon gerardii-Panicum virgatum-Bouteloua curipendula)

Although still dominated by grasses this community phase would have been characterized by the conspicuous and diverse forb component. Showy forbs such as tall blazing star, sunflowers, mountain deathcamas, blackeyed Susan, goldenrods, and American licorice would have dominated the visual appearance of the site. Dominant grasses would have included switchgrass, prairie cordgrass, big bluestem, and sideoats grama. Annual production of graminoids would have been somewhat reduced and forb production increased in comparison to Community Phase 1.1.

Pathway 1.1A
Community 1.1 to 1.2

Community Pathway 1.1 to 1.2 occurred during periods of below average precipitation and increased disturbance. This resulted in a marked increase in forbs and a reduction in the more grazing sensitive species such as Indiangrass. Sideoats grama has also noticeably increased.

Pathway 1.2A
Community 1.2 to 1.1

Community Phase Pathway 1.2 to 1.1 occurred with the return to average precipitation and disturbance regime leading to a marked decrease in forbs and a corresponding increase in Indiangrass and other grazing sensitive plants.

State 2
Native/Invaded State

This state is similar to State 1: Reference State but has now been colonized by the exotic cool-season grasses, commonly Kentucky bluegrass, smooth brome, redtop, and/or quackgrass which are now present in small amounts. Although the state is still dominated by native grasses, an increase in these exotic cool-season grasses can be expected. These exotic cool-season grasses can be quite invasive on the site and are particularly well adapted to heavy grazing. They also often form monotypic stands. As these exotic cool-season grasses increase, both forage quantity and quality become increasingly restricted to late spring and early summer due to the monotypic nature of the stand even though annual production may increase. Native forbs generally decrease in production, abundance, diversity, and richness compared to that of State 1: Reference State. These exotic cool-season grasses have been particularly and consistently invasive under extended periods of no use and no fire. To slow or limit the invasion of these exotic grasses, it is imperative that managerial options (e.g. prescribed grazing, prescribed burning) be carefully constructed and evaluated with respect to that objective. If management does not include measures to control or reduce these exotic cool-season grasses, the transition to State 4: Invaded State should be expected. Annual production of this state can be quite variable, in large part due to the amount of exotic cool-season grasses. However, annual production may range from 3500-6000 pounds per acre.

Characteristics and indicators. The presence of trace amounts of exotic cool-season grasses indicates a transition from State 1 to State 2. The presence of exotic biennial or perennial leguminous forbs (i.e. sweet clover, black medic) may not, on their own, indicate a transition from State 1 to State 2 but may facilitate that transition.

Resilience management. To slow or limit the invasion of these exotic grasses, it is imperative that managerial options (e.g. prescribed grazing, prescribed burning) be carefully constructed and evaluated with respect to that objective. Grazing management should be applied that enhances the competitive advantage of native grass and forb species. This may include: (1) grazing when exotic cool-season grasses are actively growing and native cool-season grasses are dormant; (2) applying proper deferment periods allowing native grasses to recover and maintain or improve vigor; (3) adjusting overall grazing intensity to reduce excessive plant litter (above that needed for rangeland health indicator #14 – see Rangeland Health Reference Worksheet); (4) incorporating early heavy spring utilization which focuses grazing pressure on exotic cool-season grasses and reduces plant litter provided that livestock are moved when grazing selection shifts from exotic cool-season grasses to native grasses. Prescribed burning should be applied in a manner that maintains or enhances the competitive advantage of native grass and forb species. Prescribed burns should be applied as needed to adequately reduce/remove excessive plant litter and maintain the competitive advantage for native species. Timing of prescribed burns (spring vs. summer vs. fall) should be adjusted to account for differences in annual growing conditions and applied during windows of opportunity to best shift the competitive advantage to the native species.

Community 2.1
Indiangrass-Big Bluestem-Switchgrass (Sorghastrum nutans-Andropogon gerardii-Panicum virgatum)

This Community Phase is similar to Community Phase 1.1 but has been colonized by exotic cool-season grasses, often Kentucky bluegrass, smooth brome, redtop, and/or quackgrass. However, these exotics are present in smaller amounts with the community still dominated by native grasses. Annual production is similar to that of the reference plant community (3500-6000 pounds per acre).

Community 2.2
Big Bluestem-Indiangrass/Exotic Grasses (Andropogon gerardii-Sorghastrum nutans/Exotic Grasses)

The removal of disturbances has allowed the plant community to shift to one visually dominated by tall warm-season species with Kentucky bluegrass or perhaps other exotic cool-season grasses invading this plant community. Tall warm-season grasses have decreased in vigor and density but are still visually dominate. This plant community is short-lived and is at risk, approaching the threshold which could readily transition to State 4: Invaded State. If management is significantly altered, this community phase can still revert back to Plant Community Phase 2.1. A combination of prescribed grazing and prescribed burning may be the most effective method to move this community phase towards a community resembling State 1: Reference State. Kentucky bluegrass constitutes 20 to 30 percent of the annual production with tall and mid statured warm-season native grasses such as Indiangrass, switchgrass, little bluestem, and sideoats grama constituting at least 40 percent of the annual production. Native forbs such as Maximilian sunflower, goldenrods, white heath aster, common yarrow, Cuman ragweed, and white sagebrush are present along with introduced forbs such as sweet clover and black medic. Shrubs include western snowberry and prairie rose. Annual production is similar to that of the reference plant community (3500-6000 pounds per acre).

Community 2.3
Forbs/Exotic Grasses/Switchgrass (Forbs/Exotic Grasses/Panicum virgatum)

This community phase results from heavy season-long grazing of Community Phase 2.1 or 2.2. This results in a marked increase in forbs and exotic cool-season grasses with a corresponding decline in the tall warm-season grasses (i.e. Indiangrass, big bluestem). The more abundant forbs often include white sagebrush, white heath aster, Cuman ragweed, Canada goldenrod, and pussytoes. This community phase is often dispersed throughout a pasture in an overgrazed/undergrazed pattern, typically referred to as patch grazing. Some overgrazed areas will exhibit the impacts of heavy use, while the ungrazed areas will have a build-up of litter and increased plant decadence. This is a typical pattern found in properly stocked pastures grazed season-long. As a result, Kentucky bluegrass tends to increase more in the undergrazed areas while the more grazing tolerant short statured species such as blue grama, and sedges increase in the heavily grazed areas. This Community Phase is approaching the threshold leading to a transition to State 4: Invaded State. As a result, it is an “at risk” community. If management does not include measures to control or reduce these exotic cool-season grasses, the transition to State 4: Invaded State should be expected.

Pathway 2.1A
Community 2.1 to 2.2

Community Phase Pathway 2.1 to 2.2 occurs during periods of no use and no fire which results in an increase in exotic cool-season grasses and corresponding decline in Indiangrass and other warm-season grasses.

Pathway 2.1B
Community 2.1 to 2.3

Community Phase Pathway 2.1 to 2.3 results from heavy season-long grazing without adequate recovery periods which results in a marked increase in forbs and exotic cool-season grass with a corresponding decrease in the less grazing tolerant grasses (i.e. Indiangrass and big bluestem).

Pathway 2.2A
Community 2.2 to 2.1

Community Phase Pathway 2.2 to 2.1 can occur with the implementation of prescribed grazing and prescribed burning. This results in a marked increase in Indiangrass and other warm-season grasses along with a corresponding decrease in the exotic cool-season grasses.

Pathway 2.2B
Community 2.2 to 2.3

Community Phase Pathway 2.2 to 2.3 results from heavy season-long grazing without adequate recovery periods which results in a marked increase in forbs and exotic cool-season grass with a corresponding decrease in the less grazing tolerant grasses (i.e. Indiangrass and big bluestem).

Pathway 2.3A
Community 2.3 to 2.1

Community Phase Pathway 2.3 to 2.1 can occur with the implementation of prescribed grazing and prescribed burning resulting in a marked increase in Indiangrass, big bluestem, and switchgrass with a corresponding decrease in exotic cool-season grasses and forbs. The prescribed burning is particularly important in restoring the production and vigor of Indiangrass.

Pathway 2.3B
Community 2.3 to 2.2

Community Phase Pathway 2.3 to 2.2 can occur with the implementation of prescribed grazing. This results in an increase in big bluestem and Indiangrass and a corresponding decrease in the exotic cool-season grasses. This pathway is similar to that of Community Phase Pathway 2.3A; however, it involves prescribed grazing but not prescribed burning. The lack of prescribed burning leads to (among other things) markedly reduced vigor and production of Indiangrass compared to Community Phase Pathway 2.3A.

State 3
Wooded State

This state historically existed as small patches of shrubs scattered across the site, particularly during high precipitation periods. A marked increase in non-use management and active fire suppression since European influence has also been a factor enabling this state to expand and become more widespread. Common shrubs often include willows, white meadowsweet, and western snowberry. Russian olive can also increase under this scenario.

Community 3.1
Shrubs/Exotic Grasses/Forbs

Visually, this community phase is characterized by a dominance of shrubs such as willow, white meadowsweet, western snowberry, and an understory of exotic cool-season sod forming grass, commonly Kentucky bluegrass. Common associated forbs include Cuman ragweed, goldenrods, and white sagebrush. Native grasses may be still present but below that which would allow for recovery. Annual production is comparatively low due to the lack of tall and mid statured warm-season grasses; peak production has shifted to spring and early summer. Use by domestic livestock is greatly reduced due to the increase in shrubs.

State 4
Invaded

This state is the result of invasion and dominance by introduced species. This state is characterized by the dominance of primarily Kentucky bluegrass but may also include quackgrass, redtop, and other non-native forbs such as leafy spurge and Canada thistle. Other forbs present are western ragweed and goldenrods. Once this state is well established, even drastic events such as high intensity fires driven by high fuel loads of litter and thatch will not result in more than a very short term reduction of Kentucky bluegrass.

Community 4.1
Exotic Grasses/Exotic Forbs/Goldenrod

This community phase is typically dominated by exotic grasses, commonly Kentucky bluegrass, smooth brome, quackgrass, and/or redtop with lesser amounts of sedges. Some native and exotic forbs can increase in production and cover as well. The dominant grass is typically Kentucky bluegrass along with common forbs including white sagebrush, goldenrod, aster, Cuman ragweed, common yarrow, and a variety of introduced forbs such as black medic. Native warm-season species are no longer present. The longer this community phase exists, the more resistant to change it becomes. Natural or management disturbances that reduce the cover of Kentucky bluegrass or the other exotic cool-season grasses are very short-lived. Due to the preponderance of Kentucky bluegrass or other exotic cool-season grasses, production is largely limited to the early growing season.

State 5
Go-Back State

This state is highly variable depending on the level and duration of disturbance. In this MLRA, the most probable origin of this state is plant succession following cropland abandonment. This plant community will initially include a variety of annual forbs and grasses, some of which may be noxious weeds and need control. Over time, the exotic cool-season grasses Kentucky bluegrass, smooth brome, redtop, and/or quackgrass will likely predominate.

Community 5.1
Annual/Pioneer Perennial /Exotics

This community phase is highly variable depending on the level and duration of disturbance related to the T6A transitional pathway. In this MLRA, the most probable origin of this phase is secondary succession following cropland abandonment. This plant community will initially include a variety of annual forbs and grasses, including noxious weeds (e.g. Canada thistle, leafy spurge) which may need control. Over time, the exotic cool-season grasses Kentucky bluegrass, smooth brome, redtop, and/or quackgrass will likely predominate.

State 6
Cropland State

Cropland State results from planting and production of annual crops. This plant community is most commonly associated with cropped fields. Soil conditions can be quite variable on the site, in part due to variations in the management/cropping history (e.g. development of tillage induced compaction, erosion, fertility, herbicide/pesticide carryover). Thus, soil conditions should be assessed when considering restoration techniques..

Transition T1A
State 1 to 2

This is the transition from the State 1: Reference State to the State 2: Native/Invaded State due to the introduction and establishment of exotic cool-season grasses, typically Kentucky bluegrass, smooth brome, redtop, and/or quackgrass. This transition was probably inevitable and corresponded to a decline in native warm-season and cool-season grasses. This transition may have been exacerbated by chronic season-long or heavy late season grazing. Complete rest from grazing and suppression of fire could also have hastened the transition. The threshold between states was crossed when Kentucky bluegrass, smooth bromegrass, redtop, quackgrass, or other exotic species became established on the site.

Constraints to recovery. (i.e. variables or processes that preclude recovery of the former state). Current knowledge and technology will not facilitate a successful restoration to Reference State.

Transition T2A
State 2 to 3

This transition from the State 2: Native/Invaded to State 3: Wooded State generally occurs during extended periods of no use or very light grazing and no fire which results in a marked increase in shrubs such as willows, western snowberry, and white meadowsweet. It has become more frequent following European settlement when the historic fire regime was markedly reduced.

Constraints to recovery. Variations in growing conditions (e.g. cool, wet spring) will influence effects of various management activities on exotic cool-season grass populations.

Transition T2B
State 2 to 4

This transition from the State 2: Native/Invaded State to State 4: Invaded State generally occurs with heavy season-long grazing but may also occur under other management. Exotic cool-season grasses such as quackgrass, Kentucky bluegrass, redtop, and/or smooth brome become the dominant graminoids. Studies indicate that a threshold may exist in this transition when Kentucky bluegrass exceeds 30% of the plant community and native grasses represent less than 40% of the plant community composition. Similar thresholds may exist for smooth brome and quackgrass. Once the threshold is crossed, a change in grazing management alone cannot cause a reduction in the exotic cool-season grasses.

Constraints to recovery. Variations in growing conditions (e.g. cool, wet spring) will influence effects of various management activities on exotic cool-season grass populations.

Restoration pathway R3A
State 3 to 2

This from State 3: Wooded State to State 2: Native/Invaded State can be accomplished with brush control, perhaps followed by a range planting. Initial use of herbicides and/or mechanical brush control to reduce the shrubs will permit adequate fine fuel loads to enable the application of prescribed burning to further control sprouting shrubs species. However, depending upon level of remnant native grasses and forbs, a range planting may also be necessary to complete the restoration. A combination of mechanical brush management, chemical treatment, and prescribed burning is necessary to remove the woody vegetation and, if necessary, to prepare the seedbed for a successful range planting. Once this is accomplished, it may be possible using selected plant materials and agronomic practices to approach something very near the functioning of State 2: Native/Invaded State. Application of chemical herbicides and the use of mechanical seeding methods using adapted varieties of the dominant native grasses are possible and can be successful. The application of several prescribed burns may be needed at relatively short intervals in the early phases of this restoration process, in part because many of the shrubs (e.g. western snowberry) sprout profusely following one burn. After establishment of the native plant species, management objectives must include the maintenance of those species, the associated reference state functions, and continued treatment of exotic grasses. Due to the resprouting nature of woody species within MLRA 56, repeated treatments will be necessary for a transition from this state. Following the removal of woody species, other restoration practices such as range planting, prescribed burning, and prescribed grazing may be necessary to complete the restoration. The prescribed grazing should include adequate recovery periods following each grazing event and stocking levels which match the available resources. If properly implemented, this will help suppress any exotic cool-season grasses on the site.

Context dependence. Prescribed burning should be applied in a manner that enhances the competitive advantage of native grass and forb species over the exotic species. Prescribed burns should be applied at a frequency which mimics the natural disturbance regime or more frequently as is ecologically (e.g. available fuel load) and economically feasible. Burn prescriptions may need adjustment to: (1) account for change in fuel type (herbaceous vs. shrub vs. tree), fine fuel amount and orientation; (2) fire intensity and duration by adjusting ignition pattern (e.g. backing fires vs head fires); (3) account for plant phenological stages to maximize stress on woody and exotic species while favoring native species (both cool- and warm-season grasses). The method of brush management will be site specific but generally the goal would be to apply pesticide, mechanical control, or biological control, either singularly or in combination, in a manner that shifts the competitive advantage from the targeted species to the native grasses and forbs. The control method(s) should be as specific to the targeted species as possible to minimize impacts to non-target species. A successful range planting will include proper seedbed preparation, weed control (both prior to and after the planting), selection of adapted native species representing functional/structural groups inherent to the State 1, and proper seeding technique. Management (e.g. prescribed grazing, prescribed burning) during and after establishment must be applied in a manner that maintains the competitive advantage for the seeded native species. Adding non-native species can impact the above and below ground biota. Some evidence suggests the addition of exotic legumes to the seeding mixture may favor exotic cool-season grass expansion/invasion.

Transition T3A
State 3 to 4

This is the transition from State 3: Wooded State to State 4: Invaded State resulting from brush control (e.g. mechanical and/or chemical, repeated prescribed burns).

Constraints to recovery. Labor and financial cost of removal/control of woody species either through repeated prescribed burns, mechanical and/or chemical treatment.

Context dependence. Societal norms have accepted woody invasion as positive for wildlife habitat, carbon sequestration, aesthetics, etc. Livestock managers may not understand the loss of production due to woody invasion and loss of native grass species. Wildlife managers may need to manage woody habitat for exotic wildlife species such as ring-necked pheasants instead of sharp-tailed grouse or other grassland nesting birds which are intolerant to woody species invasion.

Restoration pathway R4A
State 4 to 2

This restoration pathway from State 4: Invaded State to State 2: Native/Invaded State may be accomplished with the implementation of long-term prescribed grazing and prescribed burning, assuming there is an adequate component of native grasses to respond to the treatments. Both prescribed grazing and prescribed burning are likely necessary to successfully initiate this restoration pathway, the success of which depends upon the presence of a remnant population of native grasses in Community Phase 4.1. That remnant population, however, may not be readily apparent without close inspection. The application of several prescribed burns may be needed at relatively short intervals in the early phases of this restoration process, in part because many of the shrubs (e.g. western snowberry) sprout profusely following one burn. Early season prescribed burns have been successful; however, fall burning may also be an effective technique. The prescribed grazing should include adequate recovery periods following each grazing event and stocking levels which match the available resources. If properly implemented, this will shift the competitive advantage from the exotic cool-season grasses to the native cool-season grasses.

Transition T4A
State 4 to 3

This is the transition from State 4: Invaded State to State 3: Wooded State during periods of no use and no fire which results in a marked increase in shrubs such as willow, western snowberry, and white meadowsweet.

Restoration pathway R5A
State 5 to 2

This Restoration Pathway from State 5: Go-Back State to the State 2: Native/Invaded State can be accomplished with a successful range planting. Following seeding, prescribed grazing, prescribed burning, haying, or use of herbicides will generally be necessary to achieve the desired result and control any noxious weeds. It may be possible using selected plant materials and agronomic practices to approach something very near the functioning of State 2: Native/Invaded State. Application of chemical herbicides and the use of mechanical seeding methods using adapted varieties of the dominant native grasses are possible and can be successful. After establishment of the native plant species, prescribed grazing should include adequate recovery periods following each grazing event and stocking levels which match the available resources; management objectives must include the maintenance of those species, the associated reference state functions, and continued treatment of exotic grasses.

Context dependence. Grazing management should be applied in a manner that enhances/maximizes the competitive advantage of native grass and forb species over the exotic species. This may include the use of prescribed grazing to reduce excessive plant litter accumulations above that needed for rangeland health indicator #14 (see Rangeland Health Reference Worksheet). Increasing livestock densities may facilitate the reduction in plant litter provided length and timing of grazing periods are adjusted to favor native species. Grazing prescriptions designed to address exotic grass invasion and favor native species may involve earlier, short, intense grazing periods with proper deferment to improve native species health and vigor. Fall (e.g. September, October) prescribed burning followed by an intensive, early spring graze period with adequate deferment for native grass recovery may shift the competitive advantage to the native species, facilitating the restoration to State 2: Native/Invaded. Prescribed burning should be applied in a manner that enhances the competitive advantage of native grass and forb species over the exotic species. Prescribed burns should be applied at a frequency which mimics the natural disturbance regime, or more frequently as is ecologically (e.g. available fuel load) and economically feasible. Burn prescriptions may need adjustment to: (1) account for change in fine fuel orientation (e.g. “flopped” Kentucky bluegrass); (2) fire intensity and duration by adjusting ignition pattern (e.g. backing fires vs head fires); (3) account for plant phenological stages to maximize stress on exotic species while favoring native species (both cool- and warm-season grasses).

Restoration pathway R5B
State 5 to 4

A failed range planting and/or secondary succession will lead to State 4: Invaded State.

Context dependence. Failed range plantings can result from many causes, both singularly and in combination, including: drought, poor seedbed preparation, improper seeding methods, seeded species not adapted to the site, insufficient weed control, herbicide carryover, poor seed quality (purity & germination), improper management.

Transition T6A
State 6 to 5

TheT6A transitional pathway, in this MLRA, is most probable secondary succession following cropland abandonment.