Clayey Overflow (CyO) Absaroka Upper Foothills
Scenario model
Current ecosystem state
Select a state
Management practices/drivers
Select a transition or restoration pathway
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Transition T1-2
Frequent or high intensity herbivory (continuous season-long grazing) and prolonged drought removes native grasses and lack of fire allows sagebrush to become dominant in the community.
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Transition T1-3
Drought stress, fire, mechanical disturbance including grazing impacts and recreation provide opportunity for introduced and invasive species to establish.
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Restoration pathway R2-1
Treatment to thin the canopy followed by prescribed grazing and time allow herbaceous species to increase in the sagebrush canopy.
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Transition T2-3
Prolong Drought stress, long-term continuous season-long grazing, fire, brush control, or other ground disturbances allow the community to be invaded.
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Restoration pathway R3-4
Integrated pest management plan and intense weed control with seeding of desired species is required to reclaim this community.
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Transition T4-3
Post-treatment disturbances or failure to change management, shifts the community to an invaded state.
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No transition or restoration pathway between the selected states has been described
Target ecosystem state
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Description
This state evolved with moderate grazing pressure from wildlife (large ungulates such as elk and deer). As areas were settled sheep were the prominent domestic grazers on these landscapes, but have since shifted to mainly cattle with only a few bands of sheep still utilizing these summer pastures. Fire had a role in this system. Although not frequent, these fires helped to manage the health and cover of the woody vegetation in these communities.
Characteristics and indicators
A dominance of native perennial tall and mid-stature cool-season grasses, both bunchgrasses and rhizomatous, is a key indicator of this state, with a healthy cover of mountain big sagebrush, silver sagebrush and rubber rabbitbrush. Snowberry is common as well with a mixture of forbs. Basin wildrye is the key species for the Reference Community. Once basin wildrye begins to decline and mountain big sagebrush becomes the dominant component in this community the state is beginning to transition.
Resilience management
This state is relatively resilient, with species adapted to the fluctuating climatic conditions of the upper foothills. Once the herbaceous understory is compromised and the woody cover begins to increase, the resistance to change is lowered and the State is at-risk.
Submodel
Description
Continuous grazing pressure and lack of fire in this system allows the shrub cover to dominate the community while the herbaceous understory is reduced. Herbivory pressure is a combination of wildlife use as well as the historical season-long use by sheep and cattle. Increased predation pressures, shifts in climate, and increased human activity are a few of the reasons that have been listed for the cause of increased elk herds and deer use on the upper foothills zone for longer periods of time, or more frequent use. This increased use with continued frequent and severe use by cattle have compromised this system.
Characteristics and indicators
The dominant cover in this State is mountain big sagebrush with limited herbaceous understory. The forb component has shifted to lower stature forbs and has increased in composition, while the grass and grass-like cover has declined in stature, percent cover, and composition. The major grass cover is Idaho fescue, bluegrasses, and rhizomatous wheatgrasses.
Resilience management
The increased bare ground and reduced vigor of the herbaceous component of this State, puts the community at high risk of transitioning to a further degraded state. The increased woody cover elevates the risk of and changes the behavior of fire in the system.
Submodel
State 3
Invaded
Description
Any disturbance provides an opportunity for aggressive species, such as many of our introduced invaders, to establish in a community. Catastrophic events or natural climatic events (drought, wildfire, etc) can be a source of this invasion.
Characteristics and indicators
The major indication of entering this State is the abundant or significant presence of an introduced species, whether invasive or just an invader. To meet the terms of abundant or significant, the presence has to account for greater than or equal to ten percent cover of the community. Species considered in this category are Kentucky bluegrass, timothy, redtop bent, or smooth brome for non-native invaders; or cheatgrass for invasive species. Thistle and common dandelion are other species of concern on this ecological site.
Resilience management
These aggressive and persistent species will exclude many of the native species and are extremely difficult to reduce or remove from the community once established. These species are able to tolerate repeated defoliation and drastic climatic swings without losing their foothold in the community, creating a resistant and resilient community.
Submodel
Description
Although to a much smaller extent than in lower elevations, there are areas that have been accessed for irrigation convenience ditches or were part of a homestead. These areas have remnants of introduced species for haylands or have been left to recover and may be in at varying stages of succession. Or there are areas that are heavily impacted by recreational vehicles, parking, trails, roadways, or other land disturbances that have reduced or removed most native perennial vegetation and left a highly disturbed land.
The Disturbed State could be drafted as a stand-alone box within the state and transition model diagram. No matter what state a site originally is ranked in, once the site is mechanically disturbed, or suffers a catastrophic or significant natural disaster that alters the soil properties (erosional, depositional, or chemical), the site potential is altered. The most prominent shift for this site tends to be a shift in the natural hydrology that is key to this site. This can include both the loss of or enhancement to the additional moisture to the site (seepage from irrigation ditches).
Mechanical disturbances and reclamation practices using non-native species could qualify some stages of this state to be considered as a land use shift. The result is the shift in potential and response in management so that it is no longer similar to the reference community. The potential shifts are highly variable, so a dynamic state was captured to highlight the altered communities that exist on the landscape.
Characteristics and indicators
The soil disturbance and mechanical or physical removal of the vegetative canopy is the key characteristic of the Disturbed State. The initial indicators are the primary successional species that establish following a disturbance including Russian thistle, kochia, six weeks fescue, and sunflowers. These initial colonizers will then be followed by any seeded species, or other species from within the locations seed bank.
Resilience management
The Disturbed State is highly variable and in a state of flux as the successional processes occur. Continued disturbance of these communities is a potential threat; and the communities are at high risk of transitioning to the Invaded State.
Submodel
Mechanism
Many of these higher elevation communities are used for season or year-long grazing by cattle, sheep, or other livestock. Elk, deer, moose, and other wildlife also utilize these areas intensively throughout the year (specifically spring and fall). This frequent or high intensity herbivory weakens the ability for native grasses to persist in the community, and will begin to decline over time. Prolonged drought or unusually early warm temperatures over time dry the soils out impacting the grasses even harder. Lack of fire in this system allows sagebrush to become the majority of the composition in the community. Fire does not occur frequently, but has a shorter return interval than the lower elevation sagebrush communities.
Constraints to recovery
Rest or time for the native herbaceous species to recover as well as the necessary nursery source for these species are the major limitations to recovery for this community.
Mechanism
Seed sources are abundant for many non-native and invasive species. Drought stress, wildfire or prescribed burning and associated activities, and brush control provide opportunity and many times the seed source for invasion. Ground and soil disturbances by human activities are a primary source for seeds. However, wildlife are a major transporter of many seeds. These impacts by grazing large herbivores and the vehicular impacts including recreation create the niche for establishment while providing the seed source for an array of non-native and invasive species to invade.
Constraints to recovery
Once most introduced or invasive species establish, it is extremely difficult to control or remove these species from the system. Many times the cost effectiveness of wide scale treatment hinders the ability for many landowners from trying.
Mechanism
Treatment to thin the sagebrush canopy improves the sun exposure and moisture available to the herbaceous native vegetation. Complete removal of the sagebrush canopy may slow the recovery time and provides opportunity for negative shifts in the community, but it can be an effective means to recovery. Following canopy treatment, prescribed grazing to prevent damage to the grasses as they are re-establishing and to prevent damage to the shrub canopy, is required. The tools used to thin the canopy will vary depending on the exact composition of grasses remaining and the potential threats to the location.
Relevant conservation practices
| Practice | External resources |
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Brush Management |
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Prescribed Burning |
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Critical Area Planting |
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Prescribed Grazing |
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Heavy Use Area Protection |
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Recreation Area Improvement |
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Integrated Pest Management (IPM) |
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Upland Wildlife Habitat Management |
Mechanism
Seed sources are abundant for cheatgrass, knapweed, and other invasive species. Drought stress, wildfire or prescribed burning, brush control, or ground/soil disturbance including impacts by grazing large herbivores or recreation create a niche for undesirable weeds to invade.
Constraints to recovery
The common invasive and introduced species are difficult to control or maintain, and the ability to eradicate these species from the system has not been successful. This challenge to removing these species is the constraint to recovery for these communities.
Mechanism
A long-term Integrated pest management plan that includes both pre- and post-treatment intense weed control is necessary to overcome a severe weed infestation. The treatment for this community is a seeding treatment following extensive seedbed preparation. Selecting herbaceous species that are adapted to the location and using either improved varieties, native seed, or in some cases an introduced species suited for the management use intended may be the only way to overcome some invasive species. A grazing management plant to incorporate rest into the system and rotation of use is needed to further allow recovery.
Relevant conservation practices
| Practice | External resources |
|---|---|
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Brush Management |
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Prescribed Burning |
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Critical Area Planting |
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Grazing Land Mechanical Treatment |
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Range Planting |
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Heavy Use Area Protection |
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Recreation Area Improvement |
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Integrated Pest Management (IPM) |
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Restoration and Management of Rare and Declining Habitats |
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Upland Wildlife Habitat Management |
Mechanism
Following reclamation or restoration practices, the community is sensative to further disturbance or to climatic influences. Seeding failure or weed control failures promote rapid transitions back to the Invaded State. Further land disturbances or failure to change management of the lands are other means for this transition to occur. Wildfire, prescribed burning, drought, or frequent and severe grazing by large herbivores are a source disturbance.
Constraints to recovery
The inability to control climatic factors, the challenge of controlling invasive species, and the aversion to changing management practices and financial limitations are the major constraints to recovery for this community.
Model keys
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The Ecosystem Dynamics Interpretive Tool is an information system framework developed by the USDA-ARS Jornada Experimental Range, USDA Natural Resources Conservation Service, and New Mexico State University.