KUCHLER TYPE DESCRIPTION
Kuchler Type: Cypress savanna


PHYSIOGRAPHY : 
Big Cypress Swamp is a large, basin-like area, with low limestone
outcrops, numerous sloughs, shallow ponds, and prairies on sand or marl
(unconsolidated calcitic clay).  It forms a discrete hydrological unit
[6,11].  Big Cypress Swamp drains south and west through sloughs,
strands, and culverts under the Tamiami Trail.  During periods of low
water levels, water is impounded in numerous ponds [6].  Elevation
ranges from 12 to 40 feet (3.6-12 m) above mean sea level in the
northern part of Big Cypress to sea level where it grades into mangrove
(Rhizophora mangle, Avicennia germinans, or Laguncularia racemosa)
swamps [6].

The formation of cypress domes, strands, and dwarf cypress savannas is
driven primarily by hydrology.  Cypress domes develop in depressions
within large watersheds.  The characteristic circular shape is probably
created by the slow dissolution of the underlying limestone over years
of acid water percolation [19].  The water level in cypress domes
normally fluctuates dramatically once or twice during the year [17].  In
Big Cypress Swamp and in the Everglades, cypress domes are underlain by
marl and limestone bedrock [8].

Cypress strands form where high water level and sufficient flow generate
a depression channel.  At low water there may be no discernible flow
[17].  Corkscrew Swamp, a cypress strand, is an elongate depression in
the mineral soil with very little relief (less than 4 inches/mile
[6cm/km]).  The ground surface in Corkscrew Swamp is more irregular in
the deeper parts of the strand due to mounds formed by stumps, logs,
litter, burned-out holes in peat, and root wells [9].

Dwarf cypress savannas are open stands of stunted cypresses (also called
hatrack cypress) with an understory of grasses.  They occur on sites
with a medium-length hydroperiod (6-9 months).  Rainfall is the most
important source of water for dwarf cypress savannas [6,17].


CLIMATE : 
The climate of southern Florida is moist and mild; it is frost-free
nearly all year.  Mean annual precipitation is around 60 inches (1,524
mm), 80 percent of which falls from May to October, creating distinct
wet and dry seasons [3].  Precipitation received in 1 year ranges from
30 to 100 inches (762-2,540 mm) [3].  Occasionally, drought in summer
(normally the wet season) can result in complete cypress defoliation
which normally does not occur until fall [17].


SOILS : 
In southern Florida, cypresses are found on a variety of soils including
organics, sands, marls, and rock lands [7], with pH usually in the range
of 6 to 8.  Cypress swamp soils are characterized by Coultas and Duever
[43].

Soils in Big Cypress Swamp are mostly derived from Tamiami limestone and
quartz sands.  The soils are usually pure sand, marl, or mixtures,
ranging from 2 to 24 inches (5-61 cm) deep on limestone bedrock.  Dwarf
cypress savanna occurs on thin marl, 3 to 6 inches (7.6-15 cm) deep [6]
Outcrops of dense, fine-grained limestone are scattered within the
cypress savanna ecosystem [6,23].


VEGETATION : 
There is no standard nomenclature for the vegetation associations of
southern Florida [42].  Cypress swamps occur in the oak-gum-cypress
Forest and Range Ecosystem.  Garrison and others [23] described the
alternating wetlands and drylands west of the Everglades as cypress
savanna.  Craighead [6] defined a number of physiographic provinces for
southern Florida.  His descriptions include cypress domes, strands, and
dwarf cypress and are similar to those of Davis [7].  Wade and others
[42] listed 10 vegetation associations for southern Florida and
included cypress as a single type.  Long and Lakela [32] described five
physiographic provinces for southern Florida, listing Big Cypress as a
single province.  The Florida Natural Areas Inventory [22] included
three natural community types that correspond to cypress swamps.

Baldcypress dominates alluvial floodplain forests, and pondcypress is
dominant in cypress domes [37].  It has been indicated by some authors,
however, that both species occur in cypress domes and strands [6,9,17,].
It is thought that distributional differences may be due differences in
tolerance to acidity [34], or because pondcypress is more drought
tolerant than baldcypress [1].  Many authors do not attempt to
discriminate between the two taxa, partly because of controversy over
their taxonomic status and partly because of the difficulty of
distinguishing them in the field.  Throughout this writeup, where
baldcypress and pondcypress have not been differentiated by the authors
or where the information is applicable to both taxa, the term cypress
will be used.

Plant associates in cypress swamps vary with depth, duration, and
frequency of flooding, soil type, geographic location, and stand density [17].

Cypress domes and strands have few associates in the center; most of
those present are shade-tolerant species of epiphytic bromeliads,
orchids, ferns, and nettles, many of which do not occur in the United
States outside of Florida [6,17,42], or aquatic macrophytes such as tall
flag (Thalia geniculata) and arrowhead (Sagittaria spp.) [7,42].  Ground
cover is sparse in the center [42].  On the perimeter of cypress domes
and strands, associates include buttonbush (Cephalanthus occidentalis),
redbay (Persea borbonia), sweetbay (Magnolia virginiana), magnolia
(Magnolia spp.), cocoplum (Chrysobalanus icaco), dahoon (Ilex cassine),
myrsine (Myrsine florida), southern bayberry (Myrica cerifera), Coastal
Plain willow (Salix caroliniana), and Florida poisontree (Metopium
toxiferum) [6].  Slash pine (Pinus elliottii) is occasionally present in
cypress domes, particularly in northern Florida [17,19,20].  Water
tupelo (Nyssa sylvatica var. biflora) is also present in northern
cypress domes [10,20].  Red maple (Acer rubrum), pond apple (Annona
glabra), strangler fig (Ficus aureus), water ash (Fraxinus caroliniana),
swamp bay (Persea palustris), and paurotis palm (Paurotis wrightii) are
frequent in cypress domes and strands [6,7,17,44].  Spanish moss
(Tillandsia usneoides) is common in more northerly cypress domes.  Other
species of Tillandsia are more common in central and southern Florida.
Resurrection fern (Polypodium polypodioides) is another common epiphyte
[5].

In open stands grading to dwarf cypress savanna, sawgrass (Cladium
jamaicense) may be an important component on the higher layers of peat.
Occasionally palmettos (Sabal palmetto or Serenoa spp.) are present, and
greenbriars (Smilax spp.) are conspicuous.  Herbs present in cypress
domes and strands include sweet rush (Cyperus haspan), maidencane
(Panicum hemitomon), beakrushes (Rhynchospora spp.), spikerushes
(Eleocharis spp.), arrowweeds (Pluchea spp.), eupatorium (Eupatorium
spp.), fingergrasses (Chloris spp.), swamp fern (Blechnum serrulatum),
small yellow bladderwort (Utricularia juncea), and leather ferns
(Achrostichum spp.) [6,7,31,42].  Algal mats often cover the soil
surface in the wet season [42].


WILDLIFE : 
Cypress swamps play a unique role in animal ecology.  They do do not
have a distinct fauna, sharing many species with adjacent plant
comunities.  Most species and individuals spend only part of their lives
in the swamp [17,23,28].

Benthic invertebrates form the base of the food chain.  A high diversity
of invertebrates has been recorded for cypress domes and dwarf cypress
savannas.  In cypress domes, immature chironomids (Diptera) dominate the
benthic fauna [21].  Wild turkeys (Meleagris gallopavo) and other
predators feed on crayfish in cypress swamps [17]

In summer, reptiles and amphibians dominate cypress swamp vertebrate
communities; in winter the vertebrate fauna is dominated by birds.  High
temperatures allow herpetiles to remain active through the winter [28].
Jetter and Harris [45] trapped 23 species of reptiles and amphibians in
three cypress domes from 1974 to 1976.  The most numerous group was
ranid frogs, particularly southern leopard frog (Rana utricularia).
Other common species included cricket frogs (Acris spp.), oak toad (Bufo
quercicus), green treefrog (Hyla cinerea), and cottonmouths (Agkistrodon
spp.).  Undisturbed cypress domes in Bradford County, Florida, contained
(in addition to southern leopard frog) little grass frog (Pseudacris
ocularis), central newt (Notophthalmus viridescens louisianensis), pine
woods treefrog (Hyla femoralis), striped mud turtle (Kinosternon
baurii), and slender dwarf siren (Pseudobranchus striatus spheniscus).
Amphibian species outnumbered reptiles [28].

Bird densities are higher in cypress swamps in winter than during
breeding season, largely due to the presence of wintering birds that
breed elsewhere.  Birds using cypress swamps include wild turkey, ibis
(Plegadis spp.), double-crested cormorant (Phalacrocorax auritus),
herons (Ardea herodias, Butorides striatus, Egretta caerulea, Nycticorax
nyticorax, and Nyctorax violaceus), snowy egret (Egretta thula), great
egret (Casmerodius albius), anhinga (Anhinga anhinga), and belted
kingfisher (Ceryle alcyon) [23].  The limpkin (Aramus guarauna) is a
characteristic occupant of cypress swamps due to the availability of
snails.  Canopy-feeding passerines are common, but there are usually
only a few mid-story species such as red-bellied woodpecker (Melanerpes
carolinus), red-headed woodpecker (M.  erythrocephalus), pileated
woodpecker (Drycopus pileatus), tufted titmouse (Parus bicolor), and
great crested flycatcher (Myiarchus crinitus).  The wood duck (Aix
sponsa) is common in the larger cypress domes that contain sufficiently
large trees [28].  Swainson's warbler (Limnothlypis swainsonii) and
prothonotary warbler (Protonotaria citrea) are also typical members of
the cypress swamp avian community.  Endangered bird species occurring in
cypress swamps include Bachman's warbler (Vermivora bachmanii) and
southern bald eagle (Halieetus leucocephalus leucocephalus).
Mississippi kite (Ictinia mississippiensis) and American swallow-tailed
kite (Elanoides forficatus) breed only in swamps, including cypress
swamps [17].  The globally endangered (extinct in the United States)
ivory-billed woodpecker (Campephilus principalis) once inhabited cypress
swamps [23,28].

Most mammals occurring in cypress swamps occupy ecotones.  Mammals
include white-tailed deer (Odocoileus virginiana), gray fox (Urocyon
cinereoargenteus), fox squirrel (Sciurus niger), raccoon (Procyon
lotor), Virginia opossum (Didelphis marsupialis), striped skunk
(Mephitis mephitis), eastern cottontail (Silvilagus floridana), and
swamp rabbit (S. aquaticus) [23,28].  River otter (Lutra canadensis) and
bobcat (Lynx rufus) are common residents of large cypress domes [28].
There are many rodents and shrews [23] including southeastern shrew
(Sorex longirostris), short-tailed shrew (Blarina brevicauda), cotton
mouse (Peromyscus gossypirus), hispid cotton rat (Sigmodon hispidus),
and golden mouse (Ochrotomys nutalli).  The latter nests in trees to
avoid floodwaters [17,28].  Away from the center of cypress domes small
mammals include marsh rabbit (Silvilagus palustris) and wood rats
(Neotoma spp.) in addition to species mentioned previously.  Arboreal
mammals include southern flying squirrel (Glaucomys volans), eastern
gray squirrel (Sciurus carolinensis), and several species of bats [28].
Rare and endangered species, and species whose ranges formerly included
cypress swamps, include mangrove fox squirrel (Sciurus niger avicenna),
elk (Cervus canadensis), black bear (Ursus americanus), Florida panther
(Felis concolor), mink (Mustela vison), and gray wolf (Canis lupus)
[17,23,28].


ECOLOGICAL RELATIONSHIPS : 
Successional Processes:  Cypresses are dependent on regular water level
fluctuation for successful germination and establishment [17].  Cypress
stands become established on open sites during periods of drought
[27,42,44].  Conditions that exist following crown-killing fires that do
not consume the surface peat layer are conducive to cypress
establishment [27].  In the absence of fire, cypresses are succeeded by
hardwoods. Cypresses are not the most rapidly growing trees in swamps;
hardwoods, particularly water ash and red maple, produce more wood
(basal area) relative to their biomass than cypresses [9].

Cypress dome establishment within sawgrass marshes (i.e., the
Everglades) can proceed on batteries of peat:  peat masses that float
loose from the substrate and provide a relatively dry site suitable for
colonization.  Peat batteries may be initially colonized by buttonbush,
hurrahbush (Lyonia lucida), or dahoon.  These shrubs stabilize the mass
and increase the rate of peat formation, favoring subsequent invasion by
bays (Persea spp.) and cypresses.  The resulting community is similar to
that found in cypress domes in closed depressions.  These communities
are usually referred to as tree islands or cypress islands and usually
succeed to hardwoods in a short period of time [5].

Community Structure:  Distinct seasonal communities dominate cypress
swamps.  The wet season flora dominants include species adapted to
growing under flooded conditions; a different group of species grows
during periods when there is no standing water [9].

Dwarf cypress savannas do not usually have standing water in late
winter, but are wet the remainder of the year [6].  Duever and others
[11] reported a hydroperiod for dwarf cypress savanna of 120 days, with
a maximum water depth of 6 to 8 inches (15-20 cm).  On a dwarf cypress
savanna study site in Big Cypress Swamp, the water table was above
ground level for approximately 4 months between July and November.
Maximum depth of surface water was 4 inches (10 cm).  In March of the
dry season, maximum depth to the water table was 40 inches (103 cm) [3].

In dwarf cypress savannas, cypress seedlings become established in wet
years but grow very slowly [6].  Trees are usually less than 12 feet
(3.4 m) tall and have disproportionately large buttressed trunks.  Many
of these small trees are over 100 years old; trees the same size in
nearby cypress domes may be only 25 years old.  Trees are often 50 to 65
feet (15-20 m) apart [6].

Cypress domes are small, roughly circular, forested wetlands that occur
in poorly drained depressions [5,7,17,42].  In cypress domes and
strands, decomposition rates are slow and peat accumulates [17].  In
some cypress domes the peat layer is up to 20 feet (6 m) deep; a record
depth of 96 feet (29 m) was reported for one cypress dome [7,11].  Most
of the cypress domes in southern Florida have a central pond, surrounded by
the tallest trees [6].

The cypress canopy may be up to 60 feet tall (18 m) around the central
pond with almost complete crown closure [42].  Further away from the
pond, the trees are shorter.  Some authors report that the shorter trees
are younger [7].  However, Craighead [6] stated that the trees in the
middle are not much older than the trees on the periphery; in some
cases, the trees on the shallow soil of the periphery are older.  This
occurs for two reasons:  the lower fertility of the soil on the
periphery and the lower likelihood of severe fire due to a smaller
quantity of fuel.  Trees are killed in the center during peat-consuming
fires.  The higher fertility in the center contributes to relatively
rapid growth rates for new trees established after the fire.  Further
discussion of fire and community structure is in FIRE EFFECTS ON
VEGETATION [6,9,42].  Cypress domes sometimes expand and grow together
to form meandering cypress strands [11].

Cypress strands are found along major drainageways, mostly oriented
north-south.  Cypress strands have a well developed layer of peat, up to
6 feet (2 m) deep [11].  Cypress strands have a hydroperiod of 8 months
or more [10], and are sometimes flooded year-round [42].  Normal wet
season water levels in Corkscrew Swamp may fluctuate from 1.6 to 5 feet
(0.5 to 1.5 m) deep and there is usually a measurable but slow flow
rate.  Water level may be relatively stable in a wet year (with dry
season rainfall) but may drop as much as 6.6 feet (2 m) in a drought
year [9].

The trees in the middle of cypress strands are larger than those in
domes and may be 100 to 115 feet (30-35 m) tall and 6 feet (1.8 m) in
diameter above the butt swell.  Strands intergrade with dwarf cypress
savanna on the edge.  Trees near the periphery of the strand are usually
smaller than trees in the center, probably for reasons similar to those
for similar structure in cypress domes.  The best correlation between
tree size and environmental factors was found to occur with peat depth;
larger trees tended to be found on deeper peat [9].  The relationship of
tree size and fire is discussed further in FIRE EFFECTS ON VEGETATION.

In Gordon Swamp (a small strand on the edge of Corkscrew Swamp
Sanctuary), cypresses near the center of the strand grew 50 percent
faster than trees near the edge for the first 50 years of growth.  Trees
over 150 years old had ring widths that were similar in all parts of the
strand.  It was hypothesized that young trees were better able to take
advantage of improved site quality in the center of the strand than
older trees [9].

In cypress domes and strands hardwood species contribute to the
formation of a thick layer of peat.  With the gradual reduction of
cypress in older stands due to lack of regeneration, hardwoods increase
in dominance, and the stand becomes a mixed swamp (a transitional
stand), and then a bay head (hardwood swamp stand dominated by bays
[Persea spp.])  [6].

Nutrient Status and Community Productivity:  Nutrient inflow to dwarf
cypress savanna is extremely low.  For example, total phosphorus inflow,
which is solely via rainfall, is approximately 0.1 g/sq m/year [1].
Nutrient concentrations in dwarf cypress savanna surface water were
reported:  Nitrate nitrogen ranged from 0.07-0.18 mg/L and total
phosphorus ranged from 0.005-0.013 mg/L [3].  An increase in nutrient
flow can occur when lower water levels allow more rapid decomposition
and nutrient mineralization [17].  Spanish moss extracts nutrients from
incident rainfall and may play an important role in nutrient cycling
[5].  There is not an appreciable contribution by nitrogen-fixation [17].

Gross primary productivity and net primary productivity are low in
cypress swamps, which are supplied with nutrients primarily by rainfall
and have little nutrient storing capacity.  Dwarf cypress savanna is
rated the lowest in productivity, and cypress domes and strands are
slightly higher.  Estimated gross primary productivity for southern
Florida cypress strands is approximately 6.74 g of carbon/sq m/day; and
for southern Florida dwarf cypress savanna gross primary productivity is
1.82 to 2.41 g of carbon/sq m/day.  Aboveground biomass productivity is
also low:  0.5 kg/sq m/year [17].  Mean basal area increment for dwarf
cypress savanna trees ranged from 7.2 to 12.7 sq cm/year [3].  Biomass,
productivity, and water relations were discussed for Fakahatchee Strand
[4].

Related categories for Kuchler Type: Cypress savanna