« Bottomland Forest Ecosystems
River Swamps
River swamps have a shorter hydroperiod than stillwater swamps and a perceptible flow rate for at least a part of each year.
These wetlands constitute about one-third of Florida's swampland and are found primarily in north Florida. Reduced topography and abrupt changes in soil type in Florida river swamps may "blur" individual vegetation zones. This ecological diversity likely makes river swamps the most diverse of Florida swamps.
River swamps may occupy the floodplains of:
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Whitewater Floodplain Forests
Whitewater (alluvial) rivers carry clays and suspended organic matter in their waters. The forest communities within the floodplains of whitewater rivers are designated as bottomland hardwoods by the USDA Soil Conservation Service. The forests of the Appalachicola River floodplain and a few other floodplains of Florida's rivers are typical of this community, which is a critical component of the southeastern landscape.
Importance: the Flow-through System
The unique traits of these forests set them apart from other forests and make them very important to the southeastern U.S. Bottomland hardwoods are part of a larger landscape system that starts at the river's headwaters and ends in a bay, or estuary, at the ocean.
As the water flows through the flat land of the coastal plain it seasonally overflows the normal channels and spreads out to form a shallow layer throughout the bottomland forest. As it overflows and recedes, silt, nutrients, organisms and impurities flow back and forth between the river and forest. The landscape is shaped by the constant flux of water by way of new channels, deserted channels, deposited sediments and the build-up of levees and deltas.
These forests act as "safety valves", detaining flood waters when the rivers overflow the main channel. A diverse network of trees, shrubs and vines holds the soil in place and protect it from being eroded by the moving water. Without these forests to detain the floodwaters both the soil and the large pulse of water could have adverse effects on downstream bays, which are adapted to periodic and gradual increases in fresh water and silt. Too much at once can kill many of the plants and animals in the estuary, harming important fishing industries.
Nature's Water Treatment System
Bottomland forests forests improve water quality by filtering and flushing nutrients, processing organic wastes, and reducing sediment before it reaches open water.
Vegetation
The vegetation of bottomland hardwoods is extremely diverse. Shrubs, vines, grasses, and herbaceous plants grow vigorously where sunlight reaches the forest floor. As the forest matures, and competition for light, nutrients, and space increases, this community begins to take on an open, park-like appearance. Plants found in bottomland hardwoods include:
Trees:
- American elm (Ulmus americana)
- American hornbeam (musclewood, ironwood) (Carpinus caroliniana)
- black willow (Salix nigra)
- sugarberry (Celtis laevigata)
- hackberry (Celtis occidentalis)
- green ash (Fraxinus pennsylvanica)
- overcup oak (Quercus lyrata)
- swamp chestnut oak (Q. michauxii)
- Shumard oak (Q. shumardii)
- water oak (Q. nigra)
- willow oak (Q. phellos)
- river birch (Betula nigra)
- sweetgum (Liquidambar styraciflua)
- American sycamore (Platanus occidentalis)
- water hickory (Carya aquatica)
For more information on these and other trees and shrubs, see our Trees of Florida page.
Herbaceous Vines:
- crossvine (Bignonia capreolata)
- greenbriars (Smilax spp.)
- peppervine (Ampelopsis arborea)
- poison ivy (Toxicodendrom radicans)
- trumpet creeper (Campsis radicans)
- wild grape (Vitus spp.)
Threatened or Endangered Plants
Trees:- Florida torreya (Torreya taxifolia)
- Florida yew (Taxus floridana)
- Pagoda dogwood (Cornus alternafolia)
Shrubs:
- needle palm (Rhapidophyllum hystrix)
- orange azalea (Rhododendron austrinum)
Forest Types
5 forest types have been distinguished in the Apalachicola River floodplain forest based on topography, hydrology, and species diversity:
TYPE A
Type A whitewater floodplain forests occur on levees and ridges where soils are only occasionally saturated by flooding. These forests are characterized by the following tree species:
- sweet gum (Liquidambar styraciflua)
- sugarberry (Celtis laevigata)
- water oak (Quercus nigra)
TYPE B
Type B whitewater floodplain forests occur on high flats and low ridges where flooding is more frequent. These forests are characterized by these species:
- water hickory (Carya aquatica)
- green ash (Fraxinus pennsylvanica)
- overcup oak (Quercus lyrata)
- swamp laurel oak (Q. laurifolia)
TYPE C
Type C whitewater floodplain forests occur in low areas where ridges or hammocks provide some drainage. These forests are characterized by these tree species:
- water tupelo (Nyssa aquatica)
- Ogeechee-lime (Nyssa ogeche)
- bald cypress (Taxodium distichum)
TYPE D
Type D whitewater floodplain forests occur on low, flat, poorly drained areas where soils are clay and saturation is nearly continuous. These forests are characterized by:
- water tupelo (Nyssa aquatica)
- swamp tupelo (Nyssa sylvatica var. biflora)
TYPE E
Type E whitewater floodplain forests occur in the lowest areas along the river's length. These forests are characterized by:
- water tupelo (Nyssa aquatica)
- bald cypress (Taxodium disticum)
Fauna
The diverse array of trees, shrubs and vines in bottomland hardwood forests provide a complex habitat that supports a large variety of wildlife. Common species include:
Mammals:
- bobcat (Lynx rufus)
- white-tailed deer (Odecoileus virginianus)
- flying squirrel (Glaucomys volans)
- gray fox (Urocyon cinereoargenteus)
- gray squirrel (Sciurus carolinensis)
- mink (Mustela vison)
- oppossum (Didelphis virginiana)
- otter (Lutra canadensis)
- raccoon (Procyon lotor)
- swamp rabbit (Sylvilagus aquaticus)
Birds:
- turkey (Meleagris gallopavo)
- hawks
- owls
- songbirds
- woodpeckers
Reptiles:
- alligator (Alligator mississippiensis)
- canebrake (Crotalus horridus)
- diamondback rattlesnake (Crotalus adamanteus)
- water moccasin (Agkistrodon piscivorus)
Threatened or Endangered Wildlife
Mammals:
- Florida black bear (Ursus americanus floridanus)
- Florida panther (Felis concolor coryi)
- gray bat (Myotis grisescens)
- Indiana bat (Myotis sodalis)
Birds:
- Bachman's warbler (Vermivora bachmanii)
- ivory-billed woodpecker (Campephilus principalis)
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Blackwater Floodplain Forests
Blackwater rivers carry dissolved organic matter in their waters. The sandy soils underlying flatwoods in watersheds of blackwater rivers contribute few nutrients to runoff that supplies blackwater rivers.
Floodplains on blackwater rivers may be underlain by impermeable soil layers extending into them from the surrounding landscape, therefore, horizontal groundwater flow may contribute as much water as surface runoff to the river and the standing water in the floodplain.
Flooding is closely related to local rain events, and water levels rise and fall somewhat rapidly.
Vegetation
Blackwater floodplain forests are often not as diverse as whitewater floodplain forests. The zones occupied by different forest types are very narrow or absent, with the exception of gum (Nyssa)/cypress (Taxodium) communities which may be quite extensive. One species such as bald cypress (Taxodium distichum) or American elm (Ulmus americana) may dominate in
Fauna
All types of swamps provide food, cover, nesting sites, and hibernating places for a variety of animals. However, most animals spend only a part of their lives in swamps, moving to uplands or other water bodies as water levels rise and fall. Animals common to blackwater floodplain forests include:
Mammals:
- otters (Lutra canadensis)
- golden mouse (Ochrotomys nuttalli)
- southeastern shrew (Sorex longirostris)
- cotton mouse (Peromyscus gossypinus)
- beaver (Castor canadensis) (in north Florida in floodplains of small streams)
- raccoons (Procyon lotor)
Birds:
- yellow-rumped warbler (Dendroica coronata)
- pine warbler (Dendroica pinus)
- limpkin (Aranus guarauna)
- white ibis (Eudocimes albus)
- glossy ibis (Plegadis falcinellus)
- wood duck (Aix sponsa)
- turkey (Meleagris gallopavo)
- Mississippi kites (Ictinia mississippiensis)
- swallow-tailed kites (Elanoides forficatus)
- Swainson's warbler (Limnothlypis swainsonii)
- prothonotary warbler (Protonotaria citrea)
Amphibians
- marbled salamander (Ambystoma opacum)
- four-toed salamander (Hemidactylium scutatum)
- dwarf siren (Pseudobranhus striatus)
- bird-voiced tree frog (Hyla avivoca)
Reptiles:
- alligator (alligator mississippiensis)
- burrowing sirens (Siren spp.)
- amphiumas (Amphiuma means)
- mud snake (Farancia abacura)
- rainbow snake (Farancia erytrogramma)
Threatened or Endangered Wildlife
Mammals:
- Florida black bear (Ursus americanus floridanus)
- Florida panther (Felis concolor coryi)
- mangrove fox squirrel (Sciurus niger)
- mink (Mustela vison)
Birds:
- bald eagle (Haliaeetus leucaocephalus)
- osprey (Pandion haliaetus)
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Spring Run Swamps
Flooding is usually less dramatic in river swamps along spring runs and hydroperiods may be short.
Since spring runs are fed from the limestone aquifer, the chemical characteristics of spring run waters differ from those of the silt-laden whitewater rivers and the dark, acidic blackwater rivers. However, many spring runs discharge directly into larger rivers. During the wet season, water backing up into spring runs may obscure the subtle differences between the river swamps introduced above and spring run swamps.