Saline Lowland

Description

The Grassland State is supported by empirical data, historical data, local expertise, and photographs. This state is defined by two native plant communities that are a result of periodic fire, drought and grazing. These events are part of the natural disturbance regime and climatic process. The plant communities within the Grassland State may not represent every possibility, but they probably are the most prevalent and repeatable plant communities. The plant composition table shown below has been developed from the best available knowledge at the time of this revision. As more data is collected, some of these plant communities may be revised or removed, and new ones may be added. None of these plant communities should necessarily be thought of as “Desired Plant Communities”. According to the USDA NRCS National Range and Pasture Handbook, Desired Plant Communities will be determined by the decision-makers and will meet minimum quality criteria established by the NRCS. The main purpose for including any description of a plant community here is to capture the current knowledge and experience at the time of this revision.

Submodel

Description

The Grassland State ecosystem has been driven beyond the limits of ecological resilience and has crossed a threshold into the Sod State. The designation of the Sod State denotes changes in plant community composition and soil property changes such as aggregate stability, and/or bulk density. This change in soil dynamic properties and species composition affect hydrologic function, biotic integrity, and soil site stability.

This alternative state should be treated as a hypothesis that will be tested through long-term observation of ecosystem behavior, and repeated application of conservation and restoration practices. This state should be re-evaluated and refined on a continuous basis.

Submodel

Description

The Grassland State ecosystem has been driven beyond the limits of ecological resilience and has crossed a threshold into the Tillage State. The designation of the Tillage State denotes changes in soil structure and plant community composition. This change in soil properties and plant species affects soil site stability, biotic integrity, and hydrologic function.

The Tillage State consist of abandoned cropland that has been naturally revegetated (go-back) or has been planted/seeded to grassland. Many reseeded plant communities were planted with a local seeding mix or were planted to a monoculture of sideoats grama. Go-back communities are difficult to define due to the variability of plant communities that exist. Many of these communities are represented by the genus Aristida (three-awns).

This is an alternative state because the ecological functions, i.e. dynamic soil properties, and plant communities are not fully restored to that of the Reference State. Tillage can destroy soil aggregation. Soil aggregates are an example of dynamic soil property change. Aggregate stability is critical for infiltration, root growth, and resistance to water and wind erosion (Brady and Weil, 2008).

This alternative state should be treated as a hypothesis that will be tested through long-term observation of ecosystem behavior, and repeated application of conservation and restoration practices. This state should be re-evaluated and refined continually.

Submodel