« Bottomland Forest Ecosystems
Stillwater Swamps
Groundwater seepage and rainfall dominate the water budget of stillwater swamps. Most have saturated soils and may have standing water for more than half the year.
Plant species richness is lower in acidic stillwater swamps than in river swamps. A single species may dominate large areas of swamps with long hydroperiods, but vegetation along the edges of stillwater swamps is often more dense and diverse than in the deeper centers.
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Cypress Swamps
Cypress swamps are the most common and widespread of Florida's stillwater swamps. These swamps occur where depressions expose the shallow water table.
Introduction
In North Florida, they are scattered throughout a matrix of flatwoods and pine plantations. The impermeable clay layers which underlie this landscape are found beneath these swamps as well. In South Florida, they occupy depressions in the mineral soil underlain by marl and limestone bedrock.
Cypress swamps appear to be even-aged stands, but it is not clear if this is due to natural conditions or previous harvesting practices. Regeneration does not occur every year because of variations in seed production and water level. Seeds are not produced every year by every tree and they will not germinate under standing water. Also, regeneration seems to be best in nearly full sunlight, so new seedlings may establish only once in several years.
Most cypress swamps in the Southeast were harvested during the late 1800s and early 1900s. The wood was used for a variety of purposes, some of which took advantage of the rot-resistant properties of the heartwood in very old (>100 yrs.) trees. Most of the cypress trees we see in swamps today were established after those harvests.
The water level of most cypress swamps fluctuates dramatically once or twice a year, exposing the peat floor for weeks to months at a time. This is when these ecosystems can be exposed to fire.
When water is present, litter decomposition rates are slow, and organic acids accumulate in the water column. This is the reason why the standing water in these swamps appears reddish-brown. This organic material decreases the amount of light available to phytoplankton, which in turn reduces productivity and oxygen production. Also, there is very little wind at the water surface because it is blocked by the swamp trees. This eliminates another source of oxygenation.
Cypress strands are common throughout Florida and form where there is sufficient water and flow to cut a depression channel. However, this flow is seldom observed. Some swamps become strands for several weeks when connected during unusually high rainfall. The term cypress head is believed to refer to the cypress swamp at the head of a cypress strand.
Vegetation
The diversity of plants is relatively low in cypress swamps, but increases in strands and swamp edges. These swamps will burn during droughts, which is thought to reduce the number of species and the relative importance of broadleaved plants, thereby maintaining the dominance of cypress trees. When protected from fire, cypress swamps may eventually develop into mixed hardwood swamps or bay swamps. Cypress swamps are characterized by:
Trees:
- pond cypress(Taxodium ascendens)
- bald cypress (Taxodium distichum)
- blackgum (Nyssa sylvatica)
- coastal plain willow (Salix caroliniana)
- red maple (Acer rubrum)
Shrubs:
- fetterbush(Lyonia lucida) - a common shrub
- buttonbush (Cephalanthus occidentalis)
- wax myrtle (Myrica cerifera)
For more information on these and other trees and shrubs, visit our Trees of Florida page.
Herbaceous Plants and Vines:
- cinnamon fern (Osmunda cinnamomea)
- fall-flowering ixia (Nemastylis floridana)
- laurel greenbriar (Smilax laurifolia)
- pickerel weed (Pontederia cordata)
- royal fern (Osmunda regalis)
- Spanish moss (Tillandsia usneoides)
- stiff-leafed wild pine (Tillandsia utriculata)
- sphagnum moss (Sphagnum spp.)
Threatened or Endangered Plants
Herbaceous Plants and Vines:
- bird's nest spleenwort (Asplenium serratum)
- climbing dayflower (Commelina gigas)
- fuzzy-wuzzy air plant (Tillandsia pruinosa)
- giant water dropwort (Oxypolis greenmanii)
- hidden orchid (Maxillaria crassfolia)
- nodding catopsis (Catopsis nutans)
- grass-of-parnassus (Parnassia grandiflora)
Fauna
Mammals:
- white-tailed deer (Odecoileus virginianus)
- mink (Mustela vison)
- raccoon (Procyon lotor)
- otter (Lutra canadensis)
Birds:
- anhinga (Anhinga anhinga)
- barred owl (Strix varia)
- limpkin (Aramus guarauna)
- pileated woodpecker (Dryocopus pileatus)
- purple gallinule (Gallinula chloropus)
- prothonotary warbler (Protonotaria citrea)
- wood duck (Aix sponsa)
- wood stork (Mycteria americana)
- egrets
- herons
Amphibians:
- frogs
- salamanders
Reptiles:
- alligator (Alligator mississippiensis)
- turtles
- water snakes
Threatened or Endangered Wildlife
Mammals:
- Florida black bear (Ursus americanus floridanus)
Birds:
- ivory-billed woodpecker (Campephilus principalis)
- bald eagle (Halliaeetus leucocephalus)
- wood stork (Mycteria americana)
Additional Resources
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Bay Swamps
Bay swamps occur throughout Florida as relatively small communities. This community can be found on hillsides, in depressions in pine flatwoods, in ravines, or as strips along edges of creeks.
The soil layers beneath bay swamps appear to be similar to those beneath cypress swamps. Bay swamps occupy peat-filled depressions, but tend to have more shallow standing water and deeper peat than cypress ponds.
These swamps are characterized by dense, low vegetation and are believed to be fed by groundwater draining from higher land. Unlike cypress swamps, they are drained by small blackwater streams. This may be a result of restricted downward flow and slow evapotranspiration.
Vegetation
The vegetation of bay swamps is dominated by evergreen shrubs and trees. Bay swamps are either dominated by sweet bay, loblolly bay, or mixtures of sweet bay, loblolly bay, and red bay. Scattered slash pine and pond pine and an occasional cypress are also found in this community. Bay swamps are characterized by the following species. Note that occurrence of these plants will varies greatly from swamp to swamp:
Trees:
- swamp bay(Persea palustris)
- red bay (Persea borbonia)
- sweet bay(Magnolia virginiana)
- loblolly bay(Gordonia lasianthus)
- pond cypress(Taxodium ascendens)
- Atlantic white cedar (Chamaecyparis thyoides)
- blackgum (Nyssa sylvatica)
- pond pine (Pinus serotina)
- slash pine (Pinus elliottii var. elliottii)
Shrubs:
- black titi (Cliftonia monophylla)
- dog-hobble (Leucothoe spp.)
- fetterbush (Lyonia lucida)
- giant gallberry (Ilex coriacea)
- myrtle-leaved holly (Ilex myrtifolia)
- summersweet clethra (Clethra alnifolia)
- swamp titi (Cyrilla racemiflora)
For more information on these and other trees and shrubs, visit our Trees of Florida page.
Herbaceous Plants and Vines:
- greenbriars (Smilax spp.)
- Sphagnum moss (Sphagnum spp.)
Threatened or Endangered Plants
Shrubs:
- Chapman's rhododendron (Rhododendron chapmanii)
Herbs:
- Harper's beauty (Harperocallis flava)
Fauna
Bay swamps support a wide variety of wildlife. Most mammals use bay swamps for cover. Common wildlife include:
Mammals:
- Florida black bear (Ursus americanus floridanus)
- mink (Mustela vison)
- white-tailed deer (Odecoileus virginianus)
- raccoon (Procyon lotor)
- otter (Lutra canadensis)
Birds:
- egrets
- herons
Amphibians:
- frogs
- salamanders
Reptiles:
- snakes
Threatened or Endangered Wildlife
Mammals:
- Everglades mink (Mustela vison evergladensis)
- Florida black bear (Ursus americanus floridanus)
- Florida panther (Felis concolor coryi)
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Swamp Hardwoods
Vegetation
Swamp hardwoods are characterized by a high percentage of deciduous hardwoods. Many swamp hardwood communities may have originally been dominated by cypress, but when the large cypress was cut, hardwoods became dominant. Tree species commonly found in swamp hardwoods include:
Trees:
- black gum(Nyssa sylvatica var. biflora)
- water tupelo(Nyssa aquatica)
- red maple (Acer rubrum)
Shrubs:
- buttonbush (Cephalanthus occidentalis)
- dahoon holly (Ilex cassine)
For more information on these and other trees and shrubs, visit our Trees of Florida page.
Herbaceous Plants and Vines:
- cinnamon fern (Osmunda cinnamomea)
- lizard's tail (Saururus cernuus)
- royal fern (Osmunda regalis)
- wild pine (Tillandsia fasiculata)
Threatened or Endangered Wildlife
Herbaceous Plants and Vines:
- dwarf spleenwort (Asplenium pumilum)
- hanging club moss (Lycopodium dichotomum)
- Harper's beauty (Harperocallis flava)
Fauna
Animals living in swamp hardwoods are adapted to wet conditions and withstand periodic flooding. Dense vegetation provides good cover and food resources. Common wildlife include:
Mammals:
- Florida black bear (Ursus americanus floridanus)
- bobcat (Lynx rufus)
- white-tailed deer (Odecoileus virginianus)
- mink (Mustela vison)
- otter (Lutra canadensis)
- raccoon (Procyon lotor)
Birds:
- barred owl (Strix varia)
- horned owl (Bubo virginianus)
- pileated woodpecker (Drycopus pileatus)
- turkey (Meleagris gallopavo)
- wood duck (Aix sponsa)
- hawks
- songbirds
Reptiles:
- alligator (Alligator mississippiensis)
- turtles
- snakes
Threatened or Endangered Wildlife
Mammals:
- Florida black bear (Ursus americanus floridanus)
- Florida panther (Felis concolor coryi)
Birds:
- Bachman's warbler (Vermivora bachmanii)
- ivory-billed woodpecker (Campephilus principalis)
- bald eagle (Haliaeetus leucocephalus)
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Fire in Stillwater Swamps
Fire is rarest in the driest swamps where rapid decomposition and occasional floods prevent organic matter accumulation.
No swamps appear to be entirely free from burning. Among groundwater swamps, bay swamps seldom burn.
The waxy cuticles of the understory vegetation in swamps, including many species of the Ericaceae (heath) family, are particularly flammable.
Cypress swamps may burn several times each century in north Florida. Pond cypress have been shown to survive fire more readily than hardwoods in these swamps.
The nature of fires in all parts of Florida have changed dramatically within the last century:
- Severe burning after logging or drainage may destroy both seeds and roots in the soil. This favors replacement by willows and, subsequently, succession to mixed hardwoods.
- In south Florida, Melaleuca quinquenervia rapidly invades cypress swamps that have been drained and burned.
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Silviculture in Stillwater Swamps
Virtually every swamp in the state was logged between the late 1800s and 1950. The second-growth cypress now being harvested is marketed as "yellow cypress". It has little heartwood and no exceptional rot-resistant properties.
Timber production is a major land use activity in Florida swamps, which make up more than 25% of commercial forest land. Stillwater swamps are somewhat less vulnerable to logging practices than river swamps because the hydroperiod of stillwater swamps is less likely to be affected. However, the long-term effects of continued harvesting on wildlife populations has not yet been determined.
Best Management Practices (BMPs)
The best management practices currently promoted in Florida emphasize protection of rivers and lakes by prohibiting logging within a buffer zone.
The 4 key ecological characteristics of different kinds of swamps can be identified and incorporated into management plans. Those characteristics are:
- Hydroperiod - length of time soils are saturated with water
- Fire Frequency
- Organic matter accumulation
- Water Quality - which impacts productivity
Low topography, high water table, and abundant animal populations indicate that wetlands are closely linked with uplands and aquatic ecosystems. These wetlands demand management as part of the landscape rather than as individual ecosystems.
For more information on silviculture and BMPs, visit our Silviculture and Best Management Practices page.