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Wildlife, Animals, and Plants
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Introductory
SPECIES: Cladium jamaicense | Sawgrass
ABBREVIATION :
CLAJAM
SYNONYMS :
Mariscus jamaicensis (Crantz) Britt.
SCS PLANT CODE :
CLJA
COMMON NAMES :
sawgrass
Jamaica sawgrass
TAXONOMY :
The currently accepted scientific name of sawgrass is Cladium jamaicense
Crantz. [10,21]. There are no recognized varieties or subspecies.
LIFE FORM :
Graminoid
FEDERAL LEGAL STATUS :
No special status
OTHER STATUS :
NO-ENTRY
COMPILED BY AND DATE :
Ronald Uchytil, April 1992
LAST REVISED BY AND DATE :
NO-ENTRY
AUTHORSHIP AND CITATION :
Uchytil, Ronald J. 1992. Cladium jamaicense. In: Remainder of Citation
DISTRIBUTION AND OCCURRENCE
SPECIES: Cladium jamaicense | Sawgrass
GENERAL DISTRIBUTION :
Sawgrass is most extensive in southern Florida, but it occurs in all the
southeastern Coast States and Gulf States. Its range extends from
coastal Virginia to Florida and west to southeastern Texas. It is also
native to the West Indies. An outlying population grows in Guadalupe
Mountains National Park, Texas [10,29]. Sawgrass is also native to
Hawaii [31].
ECOSYSTEMS :
FRES16 Oak - gum - cypress
FRES41 Wet grasslands
STATES :
AL FL GA HI LA MS NC SC TX VA
ADMINISTRATIVE UNITS :
BICY BITH CAHA CALO CUIS EVER
GUMO GUIS JELA
BLM PHYSIOGRAPHIC REGIONS :
13 Rocky Mountain Piedmont
KUCHLER PLANT ASSOCIATIONS :
K073 Northern cordgrass prairie
K078 Southern cordgrass prairie
K080 Marl - everglades
K091 Cypress savanna
K092 Everglades
SAF COVER TYPES :
101 Baldcypress
106 Mangrove
SRM (RANGELAND) COVER TYPES :
NO-ENTRY
HABITAT TYPES AND PLANT COMMUNITIES :
Kushlan [14] speculated that sawgrass-dominated communities once covered
nearly 2 million acres (800,000 ha) of the Everglades. Although
sawgrass stands have declined due to reduced water flows and increased
salinity, they still dominate approximately 65 to 70 percent of the
remaining Everglades. Sawgrass marshes have been classified into two
general catagories: (1) dense stands occurring in shallow water
underlain by deep organic soils and (2) sparse stands occurring in deep
water on shallow peat or marl [14]. Dense stands appear monospecific
but often include other tall emergents. Sparse stands often include
considerable amounts of spikerush (Eleocharis spp.), arrowhead
(Sagittaria latifolia, S. lancifolia), and maidencane (Panicum
hemitomon).
Published classifications describing sawgrass community types (cts)
include:
Area Classification Authority
FL: Everglades general veg. cts Loveless 1959
se LA marshland veg. cts Penfound & Hathaway 1938
Loveless [15] found that the sawgrass-arrowhead-maidencane community
type was the most extensive in the Everglades and covered vast areas of
marsh. Common associates in sawgrass-dominated freshwater marshes in
southeastern Louisiana include cattail (Typha angustifolia, T.
latifilia) and giant bulrush (Scirpus californicus) [29].
VALUE AND USE
SPECIES: Cladium jamaicense | Sawgrass
WOOD PRODUCTS VALUE :
NO-ENTRY
IMPORTANCE TO LIVESTOCK AND WILDLIFE :
Sawgrass leaves are practically worthless as forage and are generally
avoided by livestock, wild ungulates, and small mammals [9,24]. The
starchy underground organs are consumed occasionally by muskrat [25],
and frequently by nutria [20].
The seeds are eaten by ducks and shorebirds but generally in small to
moderate quantities [4,19,28]. After a few years without burning,
sawgrass stands become very dense and accumulate much standing dead
material. This dense cover prevents waterfowl from foraging for the
seeds. Burning opens the stands, making foraging for seeds much easier
[23,27].
PALATABILITY :
Sawgrass's palatability to livestock is low [9,24].
NUTRITIONAL VALUE :
NO-ENTRY
COVER VALUE :
Sawgrass provides good hiding cover for ducks, muskrat, racoon, mink,
and otter [17]. In Louisiana, dense sawgrass stands support high
densities of mink because they provide excellent cover, elevation above
the water, and prey [2]. In the Everglades, round-tailed muskrats use
sawgrass stands for nesting only when the stands are bordered by other
communities which contain preferred foods [25].
VALUE FOR REHABILITATION OF DISTURBED SITES :
NO-ENTRY
OTHER USES AND VALUES :
NO-ENTRY
MANAGEMENT CONSIDERATIONS :
Sawgrass is susceptible to changes in salinity and hydroperiod [see
Successional Status].
BOTANICAL AND ECOLOGICAL CHARACTERISTICS
SPECIES: Cladium jamaicense | Sawgrass
GENERAL BOTANICAL CHARACTERISTICS :
Sawgrass is a coarse, rhizomatous, perennial sedge. The flat
0.5-inch-wide (1.2 cm) leaves have saw-toothed margins, and are seldom
less than 3 feet (1 m) long, and typically 6 to 10 feet (2-3 m) long
[8]. Sawgrass often grows in dense, nearly monospecific stands which
result from an extensive network of rhizomes. Apical meristems arise
from the top of the rhizomes. In the Everglades, Yates [28] found that
rhizomes were generally within the top 4 inches (10 cm) in marl soil,
and within the top 6 to 8 inches (15-20 cm) of peat soil. On
permanently flooded sites sawgrass forms tussocks and the roots and
rhizomes grow above the sediment surface [28].
RAUNKIAER LIFE FORM :
Cryptophyte
REGENERATION PROCESSES :
Sawgrass's predominant mode of reproduction is vegetative through an
extensive rhizome system [1].
Sexual reproduction via seedling establishment is generally
insignificant [1,24]. Although seeds are produced each year in most
stands, seedling establishment and survival are rare. Seed production
varies greatly from year to year, and from one location to another.
Occasionally large numbers of seeds are produced, but viability is
usually low. Germination of southern Florida seed averaged about 20
percent [1]. In southern Florida, seedfall begins in early August,
which coincides with the wet season. The floating seeds are primarily
water-dispersed. Some seeds are also dispersed by waterfowl after
passing through the digestive tract unharmed [28]. Naturally
germinating seedlings have been observed in the fall following summer
seed dispersal. They are usually found in open areas with wet but
unflooded soils. Seedling survival is poor because the seedlings are
intolerant of fluctuating water levels and are killed by either dry-down
or flooding [1].
SITE CHARACTERISTICS :
Sawgrass primarily grows in shallow, freshwater marshes, although it
occasionally grows in and may even dominate some brackish water areas
[27,29]. It grows best on seasonally flooded sites in which the period
of inundation is 6 to 9 months, or longer [14,15,27]. Optimum water
depth is about 1 foot (0.28 m) [1]. Sawgrass grows best on deep organic
soils. In fact, the vast sawgrass marshes of the Everglades grow on
peat and muck deposits up to 13 feet (4 m) deep [24]. Sawgrass also
grows on marl soil and even in small solution holes in rocky areas, but
with decreased vigor [8]. Sawgrass has extremely low nutrient
requirements. It dominates the Everglade's organic peats which are
deficient in minor elements and have low quantities of available
phosphorus and potash [14,24].
SUCCESSIONAL STATUS :
Sawgrass stands are relatively stable on sites shallowly flooded for
most of the year. However, when flooding depth or hydroperiod is
altered, sawgrass is replaced by other communities. When water levels
increase, sawgrass is often replaced by cattails, pickerelweed
(Pontederia lanceolata), fire flag (Thalia geniculata), maidencane,
spikerush, white water lily (Nymphaea odorata), neverwet (Orontium
aquaticum), and yellow lotus (Nelumbo lutea) [1,14]. When water levels
are reduced or hydroperiods shortened, drier site species replace
sawgrass. These include wax myrtle (Myrica cerifera), saltbush
(Baccharis spp.), buttonwood (Concarpus erecta), red mangrove
(Rhizophora mangle), plume grass (Erianthus giganteus), muhly grass
(Muhlenbergia spp.), marsh fleabane (Pluchea spp.), fennels (Eupatorium
spp.), hemp vine (Mikania spp.), pigweed (Acnida cuspidata), bluestems
(Andropogon spp.), and giant bristlegrass (Setaria magna) [5,15,27].
In areas of the Everglades receiving nutrient rich inflows such as along
canal system inflow gates, sawgrass stands are being invaded by
Dominican cattail (T. domingensis) [6].
Primarily a freshwater species, sawgrass has been replaced by saltmarsh
species in the southern Everglades as brackish water moves farther
inland due to reduced freshwater inflows and the slowly rising sea level
[27].
SEASONAL DEVELOPMENT :
In Florida, sawgrass vegetative growth is not winter dormant. In fact,
it is one of the most cold-tolerant of Florida's marsh species [24].
Leaf growth continues year-round but does slow somewhat during the dry
season [11]. Flowering stalks are first visible in March or April.
They grow rapidly and are in full flower by June or July. Seeds mature
by August, and thereafter begin dropping [1,28]. After flowering, the
culm and its associated leaves and rhizome die. Death and decay are
rapid [1].
FIRE ECOLOGY
SPECIES: Cladium jamaicense | Sawgrass
FIRE ECOLOGY OR ADAPTATIONS :
Plant adaptations to fire: For much of the year, sawgrass rhizomes are
buried in soil under water where they cannot be harmed by the heat of a
fire. Even when marsh soils are exposed during low water level periods,
the meristems are insulated by surrounding, tightly overlapping leaves.
Furthermore, these attached leaves often act as wicks when soils are
moist, keeping the base of the culm moist [14,27]. When aboveground
foliage is consumed by fire, sawgrass quickly initiates new top-growth
(often within a day) from these surviving rhizomes.
Yates [28] observed sawgrass seeds germinating on recently burned sites.
However, seedling establishment is an insignificant mode of postfire
recovery for sawgrass.
Fire ecology: Sawgrass evolved under a regime of frequent fire, and
requires fire to maintain dominance. Without fire, litter builds up and
surpasses live biomass in just 3 to 5 years [27]. After many years
without burning, plant vigor declines. Estimates of natural fire
frequencies range from 3 to 25 years [27]. Kushlan [14] felt that
sawgrass marsh is best adapted to burning about once every 10 years;
however, sawgrass responds well to prescribed buring intervals of 3 to 5
years [27], and has also shown no detrimental effects from burning 2
successive years [8].
Fire plays an important role in the competitive relationship between
sawgrass and maidencane. In many marshes sawgrass competitively
excludes maidencane. However, maidencane quickly invades when sawgrass
stands are destroyed by severe, peat-consuming fires. Sawgrass
reestablishment is slow because maidencane inhibits sawgrass seedling
establishment. Sawgrass may eventually reclaim these areas, but only
slowly, through rhizome expansion [16].
POSTFIRE REGENERATION STRATEGY :
Rhizomatous herb, rhizome in soil
FIRE EFFECTS
SPECIES: Cladium jamaicense | Sawgrass
IMMEDIATE FIRE EFFECT ON PLANT :
In general, fires carry well in both drained and flooded sawgrass
stands, consuming most of the aboveground or abovewater biomass. On
flooded sites, plants are burned down to a uniform height, usually
several inches above the water surface [8,27].
The effects of fire on sawgrass mortality vary with water depth and soil
moisture. On flooded sites, and on sites with exposed but saturated
soils, no underground regenerative structures are harmed. As soils
begin to dry, however, some meristems are killed by the heat of fire.
When soils become dry because of drought or marshland drainage by man,
fires can burn deep into peat layers, consuming all of the rhizomes and
roots, thus killing entire stands [8,27].
Sawgrass typically sprouts and grows rapidly after fire, but is killed
if water levels rise rapidly, keeping the new growth completely
submerged [14].
DISCUSSION AND QUALIFICATION OF FIRE EFFECT :
In the Everglades, peat-destroying fires have been recorded in the
1920's, 1937, 1945, 1946, 1947, 1951, 1952, 1962, and 1965 [12]. In
some areas, the peat burned to bedrock or marl soil [5]. These fires
destroyed "tremendous expanses" of sawgrass communities, which were
replaced by maidencane or shallow-water aquatic communities. The
increased frequency of these severe fires, which would normally only
occur under extended drought conditions, is a result of man's
alterations of the Everglade's hydrology (lowering of the water table).
PLANT RESPONSE TO FIRE :
Leaf growth: If rhizomes and meristems are undamaged, regrowth is rapid
following fires occurring at any time of the year. Plants may sprout
the day after burning, and within 2 weeks, leaves are commonly 8 to 16
inches (20-40 cm) tall [8]. Within 6 months plants have typically grown
3 to 6 feet (1-2 m) tall, and within 1 to 2 years approach preburn
heights [8,12,23,25,28].
Cover and weight: Most of the cover in unburned sawgrass stands is from
accumulated litter [8]. Thus, even 1 year after burning, cover remains
low because the cover is entirely from live leaves. In the Everglades,
sawgrass regained about 50 percent of its preburn cover and 70 percent
of its standing crop (aboveground dry weight) within 1 year of burning
[8]. If fire damages the meristems, regrowth is much slower. A
wildfire burned sawgrass stands in the Everglades in May 1971, an
extreme drought year. Eighteen months after burning, the standing crop
of burned stands was only 38 percent of that of unburned stands [24].
Density: In the Everglades, sawgrass density was neither increased
nor decreased following burning when standing water was present [8].
Flowering: Fire does not seem to stimulate flowering in sawgrass.
Flower stalks are usually produced the second year following burning
[5], but have been observed in April following January and February
prescribed burns [12].
DISCUSSION AND QUALIFICATION OF PLANT RESPONSE :
Growth rates following burning vary with soil moisture and season of
burning. The most rapid growth occurs following winter or spring
burning on sites that are flooded or have saturated soils. Tilmant [25]
observed sawgrass growing up to 2.5 feet (0.75 m) 2 weeks after an early
March burn that took place when water was at the ground surface level.
In the Everglades, plants regained 73 to 98 percent of their preburn
height within 7 to 12 months after burning [8] :
date burned
--------------------------------------------------
Oct. 31, 1971 Dec. 9, 1971 March 8 or 16, 1972
avg. preburn height 107 inches 133 inches 93 inches
avg. postburn height 90 inches 97 inches 92 inches
in Oct. 1972
preburn height
regained by Oct. 1972 85% 73% 98%
The sites burned in March, 1972, had burned 1 year earlier, and thus
preburn leaf height was lower than normal. Nevertheless, the rate of
growth following this spring burn was greater than the fall burn growth
rates.
FIRE MANAGEMENT CONSIDERATIONS :
Sawgrass leaves have a high surface area-to-volume ratio, and, after a
few years without burning, stands accumulate much of this dead fuel
which promotes fire spread. In general, dense stands are easy to ignite
and burn hot. They will burn within hours after a rain and when water
levels are a foot (0.28 m) or more deep [27]. The highest temperatures
during sawgrass fires occur at about 1.6 feet (0.5 m) above the water
surface where most litter accumulates. During sawgrass fires in the
Everglades, maximum temperatures at this height ranged from 576 to 750
degrees Fahrenheit (302-399 C) [8].
Fires will generally not carry in sparse sawgrass stands when water is
present or soils are saturated. In dense sawgrass stands in the
Everglades, when water was present, fire spread in a fingering or mosaic
pattern and stopped when it reached sparse sawgrass, open glade, or
dense hardwood stands [8]. Containment is not a problem when burning
sawgrass because most prescribed burning takes place when water is
present, and thus fire usually stops when it reaches an area of sparse
fuel more than a few feet (1 m) wide [27].
In sawgrass stands burns are prescribed mainly to reduce wildfire
hazard. To accomplish this, burning has to remove much of the
accumulated litter. Prescribed burning can be done safely anytime the
soil is wet, but is usually done when several inches of water is present
to allow the use of airboats [27]. Burning when water is present also
ensures sawgrass survival because the water layer protects the rhizomes.
Conversely, prescribed burns can be used to kill sawgrass if burning
takes place when the marsh floor is completely dry. Whenever possible,
headfires or spot fires should be used when burning sawgrass [27].
Pushed by the wind, these fires will cross areas of sparse fuels
backfires are unable to. Also, because headfires are fast-moving, they
are less likely to dry-out and ignite any elevated areas of organic
soil.
REFERENCES
SPECIES: Cladium jamaicense | Sawgrass
REFERENCES :
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Index
Related categories for Species: Cladium jamaicense
| Sawgrass
|
 |
