Loamy Floodplain Forest

Description

The reference plant community is categorized as a closed canopy oak-cottonwood forest. The two community phases within the reference state are dependent on seasonal flood events. Long-term sediment accumulation can elevate the forest floor resulting in less flooding and a more stable plant community with an increasing number of upland species inhabiting the site. A catastrophic flood event removes younger, flood-intolerant species, resetting the site to an earlier stage of succession. Windthrow, beaver predation, and periodic insect and disease outbreak have less impact in the reference phases, but do contribute to overall species composition, diversity, cover, and productivity.

Submodel

Description

Agricultural drainage, stream channelization, and levee construction in hydrologically-connected waters has drastically changed the natural hydrologic cycle of Loamy Floodplain Forests. These alterations have resulted in higher than normal flood events. Excessive siltation from upland soil erosion and streambank erosion is deposited across this site and has caused the historic tree canopy to be killed off. This has resulted in a type conversion from the species-rich oak-cottonwood forest to a simplified cottonwood-dominated state, similar to the Sandy/Loamy Floodplain Forest ecological site (Nelson 2010; Steinauer and Rolfsmeier 2010). In addition, exotic species are able to inhabit and continuously spread, reducing native diversity and ecosystem stability (Rodgers et al. 2008; Nelson 2010; Steinauer and Rolfsmeier 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 Kentucky bluegrass (Poa pratensis L.), converting the woodland to pasture (Smith 1998). 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 ecosystem health issues, and restoration back to the historic reference condition is likely not possible. Many natural forest communities are being stressed by non-native diseases and pests, habitat fragmentation, permanent changes in hydrologic regimes, and overabundant deer populations on top of naturally-occurring disturbances (severe weather and native pests) (Flickinger 2010; Nelson 2010). However, these habitats provide multiple ecosystem services including carbon sequestration; clean air and water; soil conservation; biodiversity support; wildlife habitat; as well as a variety of cultural activities (e.g., hiking, hunting) (Millennium Ecosystem Assessment 2005; Flickinger 2010). Therefore, conservation of bottomland forests should still be pursued. Habitat reconstructions are an important tool for repairing natural ecological functioning and providing habitat protection for numerous species of Loamy Floodplain Forests. 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 forest state is the result of a long-term commitment involving a multi-step, adaptive management process.

Submodel