Calcareous Loess Upland Woodland

Description

The reference plant community is categorized as an open oak woodland. The two community phases within the reference state are dependent on a fire frequency of every two to fifteen years. Shorter fire intervals maintain dominance by tallgrass prairie species in the understory, while less frequent intervals allow more shade-tolerant species to increase in importance. Drought, ice storm, periodic insect defoliation, and native grazing disturbances have less impact in the reference phases, but do contribute to overall species composition, diversity, cover, and productivity.

Submodel

Description

Fire suppression can transition the reference oak woodland community into a closed-canopy fire-suppressed forest state. This state is evidenced by a closed-canopy that is overstocked and overgrown with a sparse herbaceous understory. Invasive and exotic species, particularly Eastern redcedar (Juniperus virginiana L.) and sericea lespedeza, have invaded these sites and decreased the understory diversity (Nelson 2010).

Submodel

Description

The cool-season pasture state occurs when the reference state has been anthropogenically-altered for livestock production. Early settlers harvested the trees for timber and fuel and seeded such non-native cool-season species as smooth brome (Bromus inermis Leyss.) and Kentucky bluegrass (Poa pratensis L.), converting the woodland to pasture (Smith 1998; IDNR 2013). Over time, as lands were continually grazed by large herds of cattle, the non-native species were able to spread and expand across the site, reducing the native species diversity.

Submodel

Description

The Midwest is well-known for its highly-productive agricultural soils, and as a result, much of the MLRA has been converted to cropland, including portions of this ecological site. The continuous use of tillage, row-crop planting, and chemicals (i.e., herbicides, fertilizers, etc.) have effectively eliminated the reference community and many of its natural ecological functions in favor of crop production. Corn (Zea mays L.) and soybeans (Glycine max (L.) Merr.) are the dominant crops for the site. These areas are likely to remain in crop production for the foreseeable future.

Submodel

Description

The combination of natural and anthropogenic disturbances occurring today has resulted in a number of forest health issues, and restoration back to the historic reference condition may not always be feasible. Woodlands and forests are being stressed by non-native diseases and pests, habitat fragmentation, permanent changes in soil hydrology, and overabundant deer populations on top of naturally-occurring disturbances (severe weather and native pests) (Flickinger 2010). However, these habitats provide multiple ecosystem services including carbon sequestration; clean air and water; soil conservation; biodiversity support; wildlife habitat; timber, fiber, and fuel products; as well as a variety of cultural activities (e.g., hiking, camping, hunting) (Millennium Ecosystem Assessment 2005; Flickinger 2010). Therefore, conservation of forests and woodlands should still be pursued. Woodland reconstructions are an important tool for repairing natural ecological functioning and providing habitat protection for numerous species of Calcareous Loess Upland Woodlands. Therefore ecological restoration should aim to aid the recovery of degraded, damaged, or destroyed ecosystems. A successful restoration will have the ability to structurally and functionally sustain itself, demonstrate resilience to the ranges of stress and disturbance, and create and maintain positive biotic and abiotic interactions (SER 2002). The reconstructed woodland state is the result of a long-term commitment involving a multi-step, adaptive management process.

Submodel