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Swamps
Description
A swamp is any wetland dominated by woody plants. There are many different
kinds of swamps, ranging from the forested Red Maple, (Acer rubrum), swamps of the
Northeast,
to the extensive bottomland hardwood forests found along the sluggish rivers of the Southeast.
Swamps are characterized by saturated soils during the growing season, and standing
water during certain times of the year. The highly organic soils of swamps
form a thick, black, nutrient-rich environment for the growth of water-tolerant
trees such as Cypress (Taxodium spp.), Atlantic White Cedar
(Chamaecyparis thyoides), and Tupelo (Nyssa aquatica). Some swamps are dominated
by shrubs,
such as Buttonbush or Smooth Alder. Plants, birds, fish, and invertebrates
such as freshwater shrimp, crayfish, and clams require the habitats provided
by swamps. Many rare species, such as the endangered American Crocodile
depend on these ecosystems as well. Swamps may be divided into two major classes,
depending on the type of vegetation present:
shrub swamps, and
forested swamps.
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Skunk Cabbage (Symplocarpus foetidus) sprouts very early in the spring, melting the surrounding snow. The insects that pollinate it are attracted by its odor, which resembles decaying flesh.
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Prothonotary Warblers (Protonotaria citrea) are found in southern swamplands.
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Functions &Values
Swamps serve vital roles in flood protection and nutrient removal. Floodplain
forests are especially high in productivity and species diversity because
of the rich deposits of alluvial soil from floods. Many upland creatures
depend on the abundance of food found in the lowland swamps, and valuable timber can
be sustainably harvested to provide building materials for people. |
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Status
Due to the nutrient-rich soils present in swamps, many of these fertile
woodlands have been drained and cleared for agriculture and other development.
Over 70 percent of the Nation's floodplain forested swamps have been lost.
Historically, swamps have been portrayed as frightening no-man's-lands.
This perception led to the vast devastation of immense tracts of swampland
over the past 200 years, such as the destruction of more than half of the legendary Great
Dismal Swamp of southeastern Virginia.
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A well-inundated southeastern swamp.
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Swamps frequently support highly diverse vegetation because of the many layers of vegetation present: shrubs, saplings, and herbacous plants. |
Forested swamps are found throughout the United States. They
are often inundated with floodwater from nearby rivers and streams. Sometimes,
they are covered by many feet of very slowly moving or standing water. In very dry years
they may represent the only shallow water for miles and their presence
is critical to the survival of wetland-dependent species like Wood Ducks (Aix sponsa),
River Otters (Lutra canadensis), and Cottonmouth Snakes (Agkistrodon piscivorus).
Some of the common species of trees found in these wetlands are Red Maple and Pin Oak
(Quercus palustris) in the Northern United States, Overcup Oak (Quercus lyrata)
and Cypress in the South, and Willows (Salix spp.) and Western Hemlock
(Tsuga sp.) in the Northwest.
Bottomland hardwood swamp
is a name commonly given to forested swamps in the south central United States.
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Shrub swamps, are similar to forested swamps, except that shrubby
vegetation such as Buttonbush, Willow, Dogwood (Cornus sp.)
, and Swamp Rose (Rosa palustris) predominates. In fact,
forested and shrub swamps are often found adjacent to one another.
The soil is often water logged for much of the year, and covered at times by as
much as a few feet of water because this type of swamp is found along slow moving streams
and in floodplains. Mangrove swamps
are a type of shrub swamp dominated by mangroves that covers vast expanses of
southern Florida.
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Button bush (Cephalanthus occidentalis) is found only in shrub swamps.
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