Ecological dynamics

State 1 Reference State
The reference state represents the plant communities and ecological dynamics of the wet saline meadow site. This state includes the biotic communities that become established on the ecological site if all successional sequences are completed under the natural disturbance regime. The reference state is generally dominated by saltgrass and mountain rush(Arctic or Baltic rush). The reference state is self sustaining and resistant to change due to high resistance to natural disturbances and high resilience following natural disturbances. When natural disturbances occur, the rate of recovery is variable due to disturbance intensity. Once invasive plants establish, return to the reference state may not be possible.

Reference State: Saltgrass/arctic rush state with natural fluctuations that form either a mixed grass meadow or a saltgrass dominated meadow depending on the sites natural disturbance history.

Indicators: A community dominated by saltgrass and arctic rush.

Feedbacks: Improper livestock grazing of perennial grasses and/or other disturbances that may allow for the establishment of invasive species.

At-risk Community Phase: This state is at risk when palatable native plants are stressed and nutrients become available for invasive plants to establish.

Trigger: The establishment of invasive plant species.

Community 1.1 Saltgrass meadow with other Grasses & Grass-likes.
This community is characterized by an open grassland aspect with saltgrass, arctic rush, and foxtail barley dominating the herbaceous layer. Other commonly occurring grasses and grass-likes include native Kentucky bluegrass, alkali bluegrass (Sandberg bluegrass), spikerush, and tufted hairgrass. Other perennial grasses, shrubs, and forbs are also present. A stable water table is present at 35 inches or less, providing season long moisture for plant growth.

State 2
Current Potential Community
The current potential state is similar to the reference state, however invasive grasses and/ or forbs are now present in all community phases. This state still has the visual aspect of a saltgrass meadow. Foxtail barley, arctic rush and alkali bluegrass are other primary perennial grass or grass like species present. Fivehorn bassia, povertyweed and other less palatable species now make up a large portion of the herbaceous layer.

Primary disturbance mechanisms include native herbivore and domestic livestock grazing. Timing of these disturbances dictates the ecological dynamics that occur. The current potential state is still self sustaining; but is losing resistance to change due to lower resilience following disturbances. When disturbances occur, the rate of recovery is variable depending on severity.

Current Potential State: Saltgrass meadow state with various other native and non-native grasses and forbs present.

Indicators: A community dominated by saltgrass and arctic rush where other native perennial grasses and forbs are also present. Invasive grasses and/or forbs are present.

Feedbacks: Frequent disturbances that may allow annual invasive species such as fivehook bassia to dominate.

At-risk Community Phase: As increased disturbance frequency allows for the increase and/or dominance of annual grasses and forbs, this community is at greater risk.

Trigger: Reoccurring disturbance that results in a dominance of annual grasses and/or forbs in the herbaceous layer.

Community 2.1 Saltgrass meadow with Invasive Species.
This community is characterized by an open grassland aspect with saltgrass, arctic rush, and foxtail still dominating the herbaceous layer. Other commonly occurring grasses and grass-likes include native Kentucky bluegrass, alkali bluegrass, spikerush, and tufted hairgrass. Non-native species including fivehorn bassia, poverty weed,and/or salt cedar are also present. A stable water table is present at 20 inches or less, providing season long moisture for plant growth. Species composition by air-dry weight is approximately 85 percent perennial grasses, 10 percent forbs, and 5 percent shrubs. Bare ground is variable (20-50%) depending on the amount of biological crust (0 to 10), and plant cover.

Community 2.2 Deteriated Saltgrass meadow with Invasive Species.
This community is characterized by an open grassland aspect with saltgrass, arctic rush, and foxtail still dominating the herbaceous layer. Palatable grasses and grass-likes including native Kentucky bluegrass, alkali bluegrass, spikerush, and tufted hairgrass are much reduced. Non-native species including fivehorn bassia, poverty weed,and/or salt cedar are also present and may dominate the site. Water table may be unstable and when deeper than 30 inches may allow annuals to out compete perennials.

Pathway 2.1A
Community 2.1 to 2.2
This pathway occurs when events favor a decrease in palatable perennial grasses and grass-likes and an increase in less palatable species such as saltgrass and arctic rush. Non-native annuals including mustards and fivehorn smotherweed may eventually dominate the community. Events may include, improper livestock grazing, and a declining water table that may favor annuals and decrease desirable perennials.

Pathway 2.2A Community 2.2 to 2.1
This pathway occurs when events favor a increase in palatable perennial grasses and grass-likes and a decrease in less palatable species such as saltgrass and arctic rush. Non-native annuals including mustards and fivehorn smotherweed may eventually be reduced in the community. Events may include, carefully managed livestock grazing over long periods, and a stable water table that is within 20 inches of the soil surface. These conditions generally favor desirable perennials and decrease annual weeds.

State 3 Disturbed State.
This state occurs when the site is burned or chemically treated to reduce saltgrass and other unwanted herbaceous species. The resulting plant communities can be highly variable ranging from the recovery of desired native species to the dominance of of invasive weeds such as salt cedar, fivehorn bassia, poverty weed and various mustard species.

Invasive Forb State: Burned or chemically treated community phases influenced by livestock grazing practices and fluctuating water tables.

Indicators: Perennial, annual, invasive grasses, grass-likes and forbs present in various amounts.

Feedbacks: Livestock grazing practices and fluctuating water tables that maintain or degrade or desirable species and increase non-native, weedy species present in the community.

Trigger: The further establishment of salt cedar, fivehorned bassia and/or other weedy species decrease perennial production and increase bare ground.

Community 3.1 Altered Community.
This community phase occurs when the site is chemically treated and/or furned to remove unwanted species. Results can be highly variable ranging from a mixture of native, non-native and invasive species being present. Non-palatable species such as arctic rush, salt cedar, fivehorn bassia & poverty weed may dominate. Kentucky bluegrass may occasionally be present. Water table may be unstable and when deeper than 30 inches may allow annuals to out compete perennials.

Transition T1A State 1 to 2
This transition is from the native perennial grass and grass-like community in the reference state to a state that contains non-native, invasive species. Events typically include the establishment of invasive grasses and forbs, and an increase in saltgrass,arctic rush and other less palatable species. Factors that drive such events may include any combination of improper livestock grazing, a fluctuating water table, and the presence of a seed source for invasive species. Invasive species such as fivehorn bassia however have been known to invade intact perennial plant communities with little to no disturbance. Once invasive species are found in the plant community a threshold has been crossed.

Transition T2A State 2 to 3
This transition is from the current potential state to an altered state created by chemical treatment or fire. Results can vary widely from little site production to a healthy mixed perennial grass and grass-like community.Non-native, invasive species may also dominate the site. Factors that drive such events include, improper livestock grazing of palatable perennial grasses, fluctuating water tables and the availability of invasive weeds.