![](/images/logos/USDA-logo.png)
Natural Resources
Conservation Service
Ecological site F146XY011ME
Floodplain
Accessed: 08/17/2024
General information
Provisional. A provisional ecological site description has undergone quality control and quality assurance review. It contains a working state and transition model and enough information to identify the ecological site.
Ecological site concept
The floodplain ecological site includes floodplains, banks, terraces, sand and cobble bars, and all other land surfaces associated with major river and stream deposits. Flood frequency and intensity are the primary drivers of plant community distribution within this complex of soils and vegetation. Where seasonal flooding deposits or drought expose sands and cobbles along the river’s edge, herbs, sedges, and grasses predominate. Shrub communities, dominated by speckled alder, redosier dogwood, and willows appear to thrive in more stabilized areas receiving moderate to high amounts of disturbance, such as ice scour and moderate flooding. The most stabilized banks and floodplains are dominated by silver maple, with some of the medium and smaller streams dominated by balsam poplar forests. These forests flood regularly, but are not as intensely disturbed as the shrub communities on this site. Floodplain terraces, which flood rarely, are typically dominated by sugar maple, yellow birch, green ash, and basswood.
Soils are consistently deep, but otherwise extremely variable within this riverine system. Silt loams predominate, with occasional lenses of coarser sands, gravels, and cobbles deposited during high-energy flood events. Oxbows and backwater sloughs diversify the soils even further, resulting in a broad range of textures and drainage classes. Where soils are well or moderately well-drained, this site is considered prime farmland and is mostly under cultivation.
Not all of these soils and associated plant communities will be present in all areas where this site occurs, and further study is required to determine which communities consistently occur together, and under what circumstances.
The natural processes of scouring and deposition along waterways may be subdued in areas where dams regulate flow, or where banks are armored by man-made structures, thus reducing disturbance and favoring those communities adapted to more stable surfaces.
Table 1. Dominant plant species
Tree |
(1) Acer saccharinum |
---|---|
Shrub |
(1) Alnus incana |
Herbaceous |
(1) Calamagrostis canadensis |
Click on box and path labels to scroll to the respective text.