Loamy Wet Savannas

Description

The Loamy Wet Savannas reference state is a savanna community on poorly drained, loamy soils, that exhibits a diversity of native grasses, forbs, and scattered hardwoods. Plant community structure and composition within the reference state are variable and dependent upon the impacts of drought, grazing, fire events, and human disturbances. Fire was historically present on these sites but to a much lesser degree than the prairie ecological sites. This reduced occurrence of fire resulted in a plant community that included woody shrubs and scattered trees. A secondary trigger for maintenance or conversion of this ecological site is grazing. Intensive grazing can reduce the extent of highly palatable species thereby allowing the growth of less desirable plants to increase.

Depending upon fire frequency, periods of drought, and/or grazing intensity, a mosaic of plant community composition may be present on this site. Characteristic vegetation in the reference savanna state includes scattered aspen, basswood, and maple in a native grassland of big bluestem and prairie cordgrass. Other native prairie grasses and forbs will be present in reference plant community. High-quality, untilled areas of the Loamy Wet Savannas ecological site are uncommon in MLRA 103 as most sites have been transitioned to agricultural production.

Submodel

Description

Soil tillage is the primary mechanism to transition a site to the Tillage State. Hydrological modifications, such as ditching and tiling, are often present. Most areas in this state will remain in use for crop production in the foreseeable future.

Tillage alters the dynamic soil properties such as bulk density, structure, organic carbon content, and saturated hydraulic conductivity. Certain practices can mitigate the impacts of traditional agricultural practices on soil health. Conservation tillage minimizes soil disturbance and can improve soil structure and overall soil health. Corn or soybean plantings and a cover crop rotation can build soil structure, improve infiltration rates, reduce runoff and erosion, and protect water quality.

A few areas within this ecological site have been seeded back to grass. Some previously tilled areas have been converted to warm-season grasslands through NRCS conservation programs. Native forbs are commonly included in seed mixes to benefit wildlife and pollinators. Cool-season grasses are also feasible . Species selection will depend on the landowner’s objectives and site specifics. Although cool-season grasslands are not as biologically diverse as warm-season grasslands, they still offer various soil health and wildlife benefits.

Submodel

Description

This state is characterized by a disturbed and degraded woodland condition. Characteristics include the dominance of trees (no longer a true savanna community) and the presence of invasive plant species. Mixed hardwoods are present and include aspen. Invasive, non-native species such as Kentucky bluegrass and common buckthorn, are in the understory. As the tree and shrub density increases, the ground layer plant diversity transitions to more shade-tolerant species.

Submodel