Loamy Floodplain Forest

Description

The reference plant community is categorized as a floodplain forest community, dominated by hydrophytic woody and herbaceous vegetation. The three community phases within the reference state are dependent on a periodic flood regime. The amount and duration of flooding alters species composition, cover, and extent. Windthrow, beaver activity, and periodic insect and disease outbreaks have more localized impacts on the reference phases, but do contribute to overall species composition, diversity, cover, and productivity.

Community Phase 1.1 Silver Maple – Eastern Cottonwood/Whitegrass – Canadian Woodnettle – Sites in this reference community phase are a closed canopy forest (up to 70 percent cover) dominated by silver maple and eastern cottonwood, with sub-dominants including green ash, American elm, common hackberry, and boxelder (Acer negundo L.). Trees are medium in size (9-21 inches DBH) and range in height from 16 to 80 feet tall (LANDFIRE 2009). Climbing vines, especially riverbank grape and common moonseed (Menispermum canadense L.), can be common. Whitegrass and Canadian woodnettle are the dominant herbaceous species, but other species that can be encountered include cutleaf coneflower (Rudbeckia laciniata L.), sweet woodreed (Cinna arundinacea L.), and Canadian clearweed (Pilea pumila (L.) A. Gray). This community phase occurs from approximately 35 to 155 years (MDNR 2005).

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Description

Agricultural tile 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 forest to a simplified silver maple-dominated state. In addition, exotic species have encroached and continuously spread, reducing native diversity and ecosystem stability (Eggers and Reed 2015).

Community Phase 2.1 Silver Maple/Reed Canarygrass – Whitegrass – This community phase represents a shift in plant community composition as a result of soil dehydration and excessive siltation. Silver maple is the dominant, sometimes only, tree species present. Willows may also occur on the site. The understory maintains some native species such as whitegrass, but conditions become suitable for the initial invasion of exotic species such as reed canarygrass (Phalaris arundinacea L.) and garlic mustard (Alliaria petiolata (M. Bieb.) Cavara & Grande) (MDNR 2005; Eggers and Reed 2015).

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Description

The forage state arises when the site is converted to a farming system that emphasizes domestic livestock production, known as grassland agriculture. Fire suppression, periodic cultural treatments (e.g., clipping, drainage, soil amendment applications, planting new species and/or cultivars, mechanical harvesting) and grazing by domesticated livestock transition and maintain this state (USDA-NRCS 2003). Early settlers seeded non-native species, as smooth brome (Bromus inermis Leyss.) and Kentucky bluegrass (Poa pratensis L.), to help extend the grazing season (Smith 1998). Over time, as lands were continuously harvested or grazed by herds of cattle, these species were able to spread and expand across the prairie ecosystem, reducing the native species diversity and ecological function.

Community Phase 3.1 Hayfield – Sites in this community phase consist of forage plants that are planted and mechanically harvested. Mechanical harvesting removes much of the aboveground biomass and nutrients that feed the soil microorganisms (Franzluebbers et al. 2000; USDA-NRCS 2003). As a result, soil biology is reduced leading to decreases in nutrient uptake by plants, soil organic matter, and soil aggregation. Frequent biomass removal can also reduce the site’s carbon sequestration capacity (Skinner 2008).

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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.) has 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.

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Description

The combination of natural and anthropogenic disturbances occurring today has resulted in numerous ecosystem health issues, and restoration back to the historic reference state may not be 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). 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 floodplain 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.

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