Saline Subirrigated (SS) Absaroka Upper Foothills

Description

The Saline Subirrigated ecological site is a wet site that hosts a mixture of sedges and grasses, as well as a minor component of shrubs. The communities that represent the reference communities are native driven. Disturbances and the natural hydrologic processes involved in these generally riparian communities will affect which community is occurring along a landscape gradient. In communities not tied to a riparian system, the same shift in species will occur with the shift in the water table over time.

Characteristics and indicators

Alkali sacaton, Nuttall's alkaligrass, alkali bluegrass, and inland saltgrass are dominant with Nebraska sedge, beaked sedge, and baltic rush. Common shrubs in this community is greasewood, wild rose, shrubby cinquefoil, and on occasion willows. As a community is in drier stages or degrades, foxtail barley, little barley and ryegrass are common.

Resilience management

The wet nature of this community creates a fragile community that is easily altered with management pressures. The community is also resilient because of the wet nature and the significant freeze and thaw cycles common to this higher elevation soil. The salt-laden characteristic of these soils limits resiliency slightly, but the community does have the potential to recover after disturbance.

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Description

Increased activity on the landscapes provides more opportunity for disturbances as well as an increase of non-native species seed source. Disturbances to the soil surface and exiting canopy cover provides opportunity for non-native species to establish.

The most prevelant invader on saline sites is foxtail barley, redtop bentgrass, and occasionaly Kentucky bluegrass on these subirrigated sites. There are instances where these communities cross on the landscape, and they are at-risk of further transformation. The occurrence of these communities can be a process of time or of disturbance.

Historic studies have documented the presence of non-native species such as Kentucky bluegrass and dandelions prior to the early 1950's. Another concern is the threat of large scale weed invasions. Currently, most of the mountain has retained only small or isolated patches of invasive weeds. Areas of leafy spurge, toadflax (yellow or dalmation) and thistles have been identified. Although early detection/rapid response techniques are applied for land management, limited resources make it difficult to track all current and new infestation sites. Overall, the weed infestation level is not seen as a critical concern, but the threat is growing and being monitored closely.

Characteristics and indicators

Non-native or tame species and invasive species are less of a concern on the salt-laden soils. There are, however, species that are salt-tolerant that will establish on the Saline Subirrigated ecological site, reducing or pushing native species out. The threshold that is crossed to indicate an invaded site is 5 percent composition by cover or by weight.

The dominant non-native/invader species are Kentucky bluegrass, redtop bentgrass, thistles, toadflax (Dalmatian, yellow), and swanson's pea. As new species are found, this list will be adapted to include these species.

Resilience management

Non-native and invasive species are resistant to change and resilient following disturbances.
This makes a stable community that is difficult to change without significant inputs. The salt-laden soils limit the type of treatment, access, and species adapted to help recovery of the Invaded Community.

Kentucky bluegrass, smooth brome, and other non-native species have a high resiliency once they have established in a community. The management of the native species is difficult, and is dependent on what specific species composition exists in the individual community. The removal or treatment of encroaching woody species is best tackled when they occur at a low intensity, before they may be seen as a concern.

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 from haylands or have been left to recover and may be in varying stages of succession. 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, 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.

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