Strands and Barrier Islands
D. Bruce Means, Ph.D. Professor
purpose of this course is to learn about the diversity of upland and wetland
habitats in the coastal strands and barrier islands of the Gulf and Atlantic
coasts of Florida and southeastern Georgia. Coastal strands are important
uplands along the continental margins of the coasts of the world, affected
in their plant and animal composition by wind, waves, and saltwater. Dry
scrub habitats are formed along coastlines of the continent because of
the actions of the three physical agents, producing very different biotic
associations when compared to those on similar soils just a few hundreds
of meters inland. Barrier islands, peninsulas, and spits are unique coastal
environments created by wave and wind action, and affected by saltwater
and intense sunlight. Islands are unique ecological and evolutionary laboratories
containing plants and animals that are especially adapted for the harsh
physical conditions on islands. Also, each barrier island is different,
biotically, because of historical accidents of colonization and extinction.
Fresh water, when it exists on barrier islands and peninsulas, teems with
animal life and wetlands plants. Among the habitats we will explore are
beaches, beach ridges, aeolian dunes, interdune swales, coastal scrub,
slash pine maritime forest, sand pine forest, harwood maritime hammocks,
and barrier island freshwater marshes, lakes, and ponds.
In this course, we will explore the differences
among the Gulf coastal islands close to Tallahassee (St. Vincent, Crooked
Island East and Shell Island) and two barrier spits (St. Joe Peninsula,
Alligator Peninsula). We will explore the lower Apalachicola River floodplain
and delta to understand the geological source of coastal sand bodies,
then compare a Georgia or Florida coastal barrier island (Cumberland,
Little St. Simons, or Amelia) on an overnight field trip for the course
finale. The geological and physical processes that build-up and tear-down
coastal strands and barrier islands will be thoroughly discussed in the
classroom and in the field, with an examination of the effects upon humans--and
the effects of human activities upon our coastlines.
Field Trip Itinerary:
Lower Apalachicola River. We go upriver from the town of Apalachicola
into the floodplain swamps along the Brotherís River near Fort Gadsden.
We walk the floodplain examining levees, tupelo-cypress swamp, mixed hardwood
forest, point-bar plant succession, dredge-dumping sites, an old tram
road through the swamp, and other riverine ecology. Field stops at archeological
site upriver, mixed hardwood forest. Examine Apalachicola River riverine
processes, high and low water hydrological regimes, low-water channel
migration, oxbow lake. Discuss nutrient inputs to the Apalachicola Bay
and visit sites where litter and organic muck are building up. Time permitting,
examine the ecology of Alligator Peninsula on John H. Phipps Preserve.
Look at human effects on coastal peninsula habitats, including man-made
groundwater pond, control burning, and newly accreted peninsular tip.
Crooked Island East is compared with Shell Island, Tyndall Air Force Base.
Examine Crooked Island East ecology in morning: drive peninsula to tip,
walk beach, foredune field, backdunes, interdune flats, coastal grassland,
coastal strand, Alligator Lakes, Hurricane Lakes, slash pine flatwoods,
tip of peninsula accretion. Learn basic beach and dune ecology--wave-
and wind-created sand deposits. Discuss St. Andrew Bay beach mouse evolution
and ecology. Shell Island in afternoon. Walk from bay side through habitats
to Gulf beach: cattail marsh, fresh water potholes, coastal grassland,
coastal strand, slash pine flatwoods, back dunes and interdune flats,
foredune field, beach. Discuss Choctawhatchee Bay beach mouse ecology,
and compare what we have seen between the two different islands.
St. Vincent Island. Spend all day on the island, transported by USFWS
people mover, by special arrangement. The island is a series of parallel
beach ridges and interdune flat sets. There are about 12 different beach
ridge sets, and about 180 separate beach ridges, averaging approximately
30 years per beach ridge. The beach ridges are usually close together,
are not extremely high (20 feet above the flats), and are not very dune
decorated. The highest dunes on the island are interior dunes that rise
only to about 30 feet. The vegetation of the beach ridges varies from
xeric mixed species scrub oak sandhills to exclusively liveoak-dominated
sandhills, to liveoaks that have magnolias in them. Apparently liveoak
is kept off the interdune flats by saturated and inundated soils during
summer rains. Slash pine flourishes in the interdune flats and may be
kept out of the beach ridges when young by shading from the liveoaks.
We will visit a small stand of dwarf cyrilla in the center of the Island,
but generally titis are wanting on the island and are replaced by buttonbush
and, of all things, persimmon, in the low, wet sites in which one normally
expects to see titi. About 200 Sambur Deer, Cervus unicolor, live
on the island. This exotic deer with strong 3-pointed antlers weighs up
to 650 lbs. We will visit "Tahiti Beach" on the east end, and another
midden area on the northwest end of the island. These are 5-10 feet high
oyster shell middens created by aboriginal man during the life of St.
Vincent Id. (5,000-6,000 B. P.), and are up to 100-200 feet wide along
the coastal margin. Note how much mollusk shell material was piled up
by aboriginal human hands, favoring the establishment of cabbage palm,
which has no doubt become the dominant tree on these sites since the middens
were created. The midden on the northwest side of the island is a mixture
of hardwoods (pignut hickory, southern magnolia, laurel oak, and wax myrtle
and red cedar), all of large diameter.
Trip #4. Field
trip to Cape San Blas, the largest cuspate foreland in western Florida,
and St. Joe Peninsula. The Cape and peninsula have a complex recent history.
Spend most of the day in St. Joseph Peninsula State Park examining beach
dynamics, aeolian dunes, foredune herbaceous communities, backdune scrub
communities, slash pine barrier island flatwoods, virgin sand pine stunted
forest, hurricane blowouts, bayside marshes, midden hardwood hammock,
and bayside beach wrack. Examine Atlantic ridley turtle nests. Compare
and contrast St. Joe Peninsula with Crooked Island East and Shell Island.
Trip #5 & 6 Two-day,
overnight field trip to coastal Georgia sea island. Day 1, drive to St.
Mary's, take boat to Cumberland Island. Examine ancient relict dune communities
on bay side of island in afternoon: magnolia-cedar-liveoak maritime forest,
interdune swamps and ponds. Overnight camp out. Day 2, examine broad saltmarsh
flats, wax myrtle and muhly grass sand ridges, back dune fields, foredunes,
beach of sand and shells. Examine coastal zonation: marsh elder, sea oxeye,
wax myrtle, muhlenbergia grass, bare sand. See alligators, wading birds,
shore birds, marsh rabbits, and more. Compare Atlantic and Gulf barrier
SUGGESTED REFERENCES FOR COASTAL STRANDS AND BARRIER
Bartram, William. 1791. Travels through North and
South Carolina, Georgia, East and West Florida. Available as a Dover reprint,
softbound, in bookstores.
Clewell, Andre F. 1985. Guide to the vascular plants
of the Florida Panhandle. Florida State Univ. Press. 605pp. [Order from
University Presses of Florida, 15 NW 15th St., Gainesville, Florida 32603.]
Doyle, Larry J., D. C. Sharma, A. C. Hine, O. H.
Pilkey, Jr., W. J. Neal, O. H. Pilkey, Sr., D. Martin, and D. F. Belknap.
1984. Living with the west Florida shore. Duke Univ. Press, Durham, N.C.
Duncan, Wilbur H. and Marion B. Duncan. 1987. The
Smithsonian guide to seaside plants of the Gulf and Atlantic coasts, from
Louisiana to Massachusetts, exclusive of lower peninsular Florida. Smithsonian
Institution Press, Washington, D. C.
Fernald, Edward A. 1981. Atlas of Florida. Florida
State Foundation, Tallahassee. [Sold at counter, Center for Professional
Field, M. E., and D. B. Duane. 1976. Post-Pleistocene
history of the United States inner continental shelf: significance to
the origin of barrier islands. Bulletin of the Geological Society of America
Grow, Gerald. 1981. Guide to camping in Florida
state parks. Longleaf Press. [Available in local bookstores, or from Gerald
Grow, 809 Teague Street, Tallahassee, FL 32303, 385-0383.]
Jahoda, Gloria. 1967. The other Florida. Charles
Scribnerís Sons, New York.
Johnson, Ann F. and Michael G. Barbour. 1990. Dunes
and maritime forests. Pages 429-480 in R. Myers and J. Ewel, eds. Ecosystems
of Florida. Univ. Florida Presses, Gainesville. 765 pages.
Kaufman, Wallace and Orrin H. Pilkey, Jr. 1983.
The beaches are moving. Duke Univ. Press, Durham, N.C. 336 pp.
Kurz, H. 1942. Florida dunes and scrub, vegetation
and geology. Florida Geological Survey, Geological Bulletin 23:161-207.
Laessle, A. M. 1942. The plant communities of the
Welaka area. University of Florida press, Biological Science Series IV(l):1-143.
Laessle, A. M. 1958. The origin and successional
relationships sandhill vegetation and sand pine scrub. Ecological Monographs
Lazell, James D., Jr. 1989. Wildlife of the Florida
Keys, a natural history. Island Press, Washington, D. C.
Means, D. Bruce. 1994. Florida Scrub. Florida Wildlife
Myers, Ronald L. 1990. Scrub and high pine. Pages
150-193 in R. Myers and J. Ewel, editors. Ecosystems of Florida.
Univ. Florida Presses, Gainesville. 765 p.
Pilkey, Orrin H., Jr., D. C. Sharma, H. R. Wanless,
L. J. Doyle, O. H. Pilkey, Sr., W. J. Neal, and B. L. Gruver. 1984. Living
with the east Florida shore. Duke Univ. Press, Durham, N.C. 259 pp.
Schwartz, M. L. 1971. Multiple causality of barrier
islands. Journal of Geology 79:91-94.
Wharton, Charles H. 1977. The natural environments
of Georgia. Georgia Department of Natural Resources. 227 pp.
Wolfe, Steven H., J. A. Reidenauer, and D. Bruce
Means. 1987. An ecological characterization of Panhandle Florida. U. S.
and Barrier Islands
Winds and waves sculpt sand into dunes and
flats, barrier islands and spits, along the coastlines of the world.
This course features pristine Gulf and Atlantic coastal strands, barrier
islands, and their unique habitats: sea-oat dominated foredunes, scrubby
backdunes, interdune grassland flats and swales, barrier island marshes,
lakes, and ponds, slash pine flatwoods, and maritime hardwoods. Each
island has its own unique mix of animals and plants, and all coastal
islands teem with birds and wildlife. Spend some glorious time this
summer on Shell Island, Crooked Island, St. Joe Peninsula, St. Vincent
Island, John H. Phipps Preserve on Alligator Peninsula, Aucilla State
Preserve, and one day in the mouth of the Apalachicola River where it
all starts. Course finale is two days overnight on a beautiful Georgia
sea island. Maximum enrollment is 15 persons. This course is approved
for recertification credit.