Anoka Ecosystems:
Floodplain Forest
Floodplain forests are deciduous forests which exist in seasonally wet areas, most commonly on the active floodplains along major rivers and streams. The canopy and diversity can vary based on the amount of disturbance the site typically faces, especially soil and debris deposition along with erosion, which can consistently inhibit plant growth. Based on these variables, species composition may be dominated by a single species, or composed of a variety.
In the 1800s, prior to settlement, floodplain forests covered approximately 1% of the landscape. In fact, these ecosystems were so prevalent that humans as well as plants and animals have used them for migration corridors for quite some time. However, in the past century and a half, human activities, such as land clearing, wetland filling and dredging, have drastically reduced the acreage of this ecosystem. Still, floodplain forests have not been cleared as completely as other forest systems in the state, which has provided much needed refuge for wildlife losing other habitat.
The most dominant tree species are silver maple, cottonwood, and black willow, although boxelder, green ash, America elm and slippery elm can contribute to the canopy as well. The understory, if vegetated at all, is dominated by herbaceous plants which have adapted to flooding, erosion and depositional patterns. These plants include annuals such as wood nettle, clearweed, beggar-ticks, and smartweed, as well as perennials such as rice cut-grass, goldenglow, Ontario aster, and Virgina wild-rye. In addition to these herbaceous species, woody vines, such as wild grape, and Virginia creeper are also extremely common in this ecosystem.
Sources:
"Minnesota Land Cover Classification System: User Manual." Version 5.3 Minnesota Department of Natural Resources, Central Region, 2004.
"Minnesota's Native Vegetation: A Key to Natural Communities" Version 1.5 Minnesota Department of Natural Resources, Natural Heritage Program, 1993.
Wovcha, D, Delaney, B, Nordquist, G. Minnesota's St. Croix River Valley and Anoka Sandplain: A Guide to Native Habitats Minneapolis: University of Minnesota, 1995.
