Sandy Upland Savannas

Description

The Sandy Upland Savannas ecological site reference state is a dry to dry-mesic savanna that exhibits a diversity of native grasses and forbs along with scattered oaks. Plant community structure and composition within the Reference State are variable and dependent upon the impacts of drought, grazing, and fire events. Depending upon disturbance regimes, woody species will vary in density and structure. Areas with frequent fire will trend toward a shrubby prairie. Longer fire return intervals will result in a mixed oak savanna. A long-term absence of fire will transition the site toward a dry woodland. Characteristic vegetation in the reference savanna state includes bur oak, northern pin oak, American hazelnut, leadplant, little bluestem, and porcupinegrass. High-quality, untilled areas of the Sandy Upland 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. In this state, dynamic soil properties such as bulk density, structure, organic carbon content, and saturated hydraulic conductivity are altered by agricultural practices. 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.

Some areas in this ecological site are not appropriate for intensive crop production due to slope. Where the gradient exceeds 20 percent row crop production is not feasible due to limitations on farm machinery.

A few areas within this ecological site have been tilled but seeded back to grass. Under conservation programs such as the NRCS Conservation Reserve Program (CRP), previously tilled areas have been converted to warm-season grasslands. 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 these areas are not as diverse as the reference state, they still provide 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), the presence of invasive plant species, and a reduction in the diversity of native understory and shrub species. Oaks still generally dominant but are joined by a mix of hardwood species. Non-native plants, such as Kentucky bluegrass and common buckthorn, are often dominant the understory. As the tree and shrub density increases, the ground layer plant diversity decreases and transitions to more shade-tolerant species.

Submodel