BEACH HABITATS

    


The Florida peninsula is bordered by 1900 km (1181 miles) of tidal coastline, second only to Alaska. Of this total, approximately 1200 km (746 miles), primarily along Florida’s east coast, consists of sandy beaches where high energy waves constantly break along the shoreline. In northern areas along the east coast of Florida, including the northern Indian River Lagoon area, sands are composed principally of quartz that originated in the Appalachian Mountains, and calcium carbonate from rock and shell deposits. Further south, the amount of quartz in sand decreases steadily, and sand composition becomes primarily calcium carbonate.

Beaches lie at the interface between the land and the ocean. East coast beaches in Florida, especially those in the Indian River Lagoon area, are generally dynamic, high-energy, areas. The unique topography and slope of any beach area is the result of interactions between both abiotic and biotic factors. Key physical processes in beach and dune formation are wave action, erosion, sand accretion by winds, overwash, and the deposition of salt spray (Stalter 1976; Tyndall 1985). Important biotic factors generally center around the ability of plants to colonize and grow while withstanding the adverse effects of being buried in sand and inundated by sea water. Additionally, colonizing species of plants must also be able to tolerate the xeric conditions which result from sand being generally well drained with low nutrient availability.

The slope of a beach and the shape of its dunes are heavily influenced by tides, wind patterns, storm events and the movement of sand that often accompanies these events. Sand is typically deposited on beaches as waves break on the shoreline and their energy dissipates. Whatever particulates that had been suspended in the wave are deposited on the beach and then dragged down the face of the beach again in the wave’s backwash. Since the energy of backwash tends to be far less than the initial energy of the wave, there is typically a net onshore transport of sand. However, hurricanes and their accompanying storm surges often have the effect of either eroding sands offshore, or overwashing and destabilizing dune systems, redepositing sands inland.

Wave action tends to shape the beach slope as well, with high-energy waves tending to increase the steepness of the slope, and lower-energy waves resulting in flatter beach profiles. On high-energy beaches in the IRL region, beach profiles change seasonally. In summer, waves tend to occur as swells that move sediments up the beach, building berms and providing sands for dunes. However, during fall and winter, the steep waves that accompany storms erode beaches and flatten out the beach profile, depositing eroded sands seaward on longshore bars (Bearman {ed.} 1989).

Beach Plants:
Due to sometimes intense wave action, strong winds, and the presence of sea water, most plants are unable to successfully colonize beach areas directly along the shoreline. However, several species are able to become established in the upper beach zone, thus enabling sand stabilization and subsequent development of dune systems. Plants occurring on beaches and dunes tend to occupy specific regions according to their individual growth patterns and environmental tolerances. Most beach plants occupy the area closest to the shoreline in the pioneering zone, which extends landward from the wrack line on the upper beach through the dune area. Pioneering species must be highly specialized to tolerate the severe environmental challenges they face. The most successful pioneering species in coastal zones are halophytic, meaning that they are able to thrive under highly saline conditions. Many of these same plants also have high growth rates, with some plants actually stimulated to grow faster as they become buried in sand.

Most pioneering species are also able to withstand xeric conditions, low nutrient availability, heavy winds, inundation by sea water, high soil temperatures, and burial in sand. Pioneering species are generally vine-like or succulent, having waxy or hairy coverings on their stems and leaves. They produce many seeds that are widely disbursed, helping them to become quickly established or recolonized on beach areas. Pioneering species also tend to spread rapidly as they grow, creating a network of creeping stems so if one part of the plant is uprooted or buried in shifting sand, other portions can continue to grow. Their roots also help to anchor sand, and thus assist in subsequent dune building and stabilization.

Beyond the pioneering zone, in the shelter of swales and secondary dunes, plants are generally more protected from the effects of salt spray, seawater and sand burial, and the resulting communities can be much more diverse. When dunes become established and remain stable over time, plants continue to grow and reproduce, eventually enriching the sandy soil with humus from leaf litter and decaying plants. As humus accumulates, soils become richer and hold more water. This allows other types of vegetation to take root, and begins the process of succession whereby vine-like or herbaceous pioneering species are eventually replaced by shrubs and trees.

Key species of plants that colonize the upper beach zone include salt-tolerant pioneering species such as shoreline sea purslane (Sesuvium portulacastrum), seashore dropseed (Sporobolus virginicus), beach peanut (Okenia hypogaea), railroad vine (Ipomoea pes-caprae), West Indian sedge (Remirea maritima) and knotgrass (Paspalum distichum).

Beach Animals:
At first glance, beaches may appear to support comparatively few animal species; however, beaches are complex habitats that support many species of animals unique to shorelines, many of them too small to notice. Successful animal inhabitants of beaches include the often overlooked but highly abundant meiofauna that live between sand grains, and the more familiar species of annelid worms that burrow into the substratum. Various bivalve and snail species, as well as many species of small crustaceans such as isopods and amphipods inhabit the wrack line along the shore. Surf clams and mole crabs are 2 species that stand out as inhabitants of the surf zone. Both of these animals are extremely fast burrowers, able to rebury themselves almost as fast as they become exposed in shifting sands. The surf clam, also known as the variable coquina (Donax variabilis), is a filter feeder that uses its gills to filter microalgae, tiny zooplankton, and small particulates out of seawater. The mole crab (Emerita talpoida) is a suspension feeder that feeds by capturing zooplankton with its antennae. Further up the beach, somewhat removed from intense wave action, is where the ghost crab (Ocypode quadrata) makes its home by burrowing into the sand.

Although many species of birds are often observed on beaches, only 5 species of shorebirds: 1) the snowy plover (Charadrius alexandrinus), 2) the black skimmer (Rynchops niger), 3) the least tern (Sterna antillarum), 4) the royal tern (Sterna maxima), and 5) the sandwich tern (Sterna sandvicensis) prefer nesting sites on bare sands in the upper beach zone. Snowy plovers, however, are known to nest only along the Gulf coast of Florida.

Additionally, of the 7 species of sea turtles, 6 are dependent on Florida beaches for nesting during the summer. In fact, the Florida coastline is the most important nesting area for sea turtles in the western Atlantic, though sites in Natal, South Africa, and the islands of the Red Sea are also utilized (Johnson and Barbour 1990). In Florida, loggerhead turtles and green turtles are by far the most commonly observed, with loggerheads laying an average of 3000-4000 nests per year on Florida beaches, and green turtles laying approximately 300 nests per year. Highest sea turtle nest densities are observed in southern Brevard County, from south of Cape Canaveral to Sebastian Inlet, though sea turtles nest even along the highly developed beaches of Broward and Dade counties. In human-impacted areas, it is often necessary to dig up turtle nests and rebury the eggs in other areas to insure successful hatching.

Many species utilize beaches as feeding areas. Sandpipers and other shorebirds, wading birds, and even some fish such as the Florida pompano employ the surf zone to prey on animals that either wash out of the sand due to wave action, or come close enough to the shore to be captured. Some mammals are also known to utilize beaches as feeding grounds. Among these are raccoons, feral cats and foxes, which are known to patrol the wrack line at the high water mark and scavenge eggs from sea turtle nests (Myers and Ewel, 1990).

Human Impacts:
Florida’s barrier islands have been extensively developed and support a large human population, leaving little of the original landscape unaltered. Florida’s beaches are rated among the finest in the U.S. and draw tourists from all over the globe. Florida’s visitors come to swim, surf, bask in the sun, snorkel, fish and sail; and as a result, tourism has become the premier industry in Florida, providing more than 845,000 jobs. In 1999 alone, approximately 58.9 million tourists visited Florida, spending 46.7 billion dollars. While development and tourism have been an economic boon to Florida, they have also brought associated problems that must be continually addressed.


Select a highlighted link below to learn more about that species:

Species  
Name:

Common  
Name:

Habitat  
Notes:

Special Status:

Beach Plants:      

Ipomoea pes-capae

Railroad vine, bayhops

Colonizes upper beach

 

Okenia hypogaea

Mexican beach peanut
burrowing four-o-clock

Colonizes upper beach

 

Paspalum distichum

Seashore paspalum
knotgrass

Colonizes upper beach

 

Remirea maritima

West Indian sedge, beachstar

Colonizes upper beach

 

Sesuvium portulacastrum

Shoreline sea purslane

Colonizes upper beach

 

Sporobolus virginicus

Beach dropseed, seashore dropseed

Colonizes upper beach

 

Beach Animals:

  

  

  

Donax variabilis

Surf clam, variable coquina

Inhabits surf zone

 

Emerita talpoida

Mole crab, Atlantic sand crab

Inhabits surf zone

 

Ocypode quadrata

Ghost crab

Inhabits beach

 

Caretta caretta

Loggerhead sea turtle

Nesting

 

Chelonia mydas

Green sea turtle

Nesting

 

Dermochelys coriacea

Leatherback sea turtle

Nesting

 

Eretmochelys imbricata

Hawksbill sea turtle

Nesting

 

Lepidochelys kempi

Kemp’s ridley sea turtle

Nesting

 

Ardea herodias

Great blue heron

Feeding

 

Arenaria interpres

Ruddy turnstone

Feeding

 

Calidris alba

Sanderling

Feeding

 

Calidris fuscicollis

White-rumped sandpiper

Feeding

 

Calidris maritima

Purple sandpiper

Feeding

 

Calidris mauri

Western sandpiper

Feeding

 

Calidris melanotos

Pectoral sandpiper

Feeding

 

Calidris minutilla

Least sandpiper

Feeding

 

Calidris pusilla

Semipalmated sandpiper

Feeding

 

Ardea alba

Great egret

Feeding

 

Charadrius alexandrinus

Snowy plover

Feeding

 

Charadrius melodus

Piping plover

Feeding

 

Chlidonias niger

Black tern

Feeding

 

Felis catus

Feral cat, domestic cat

Feeding

 

Haematopus palliatus

American oystercatcher

Feeding

 

Larus atricilla

Laughing gull

Feeding

 

Larus philadelphia

Bonaparte’s gull

Feeding

 

Micropalama himantopus

Stilt sandpiper

Feeding

 

Procyon lotor 

Raccoon

Feeding

 

Rynchops niger

Black skimmer

Feeding, nesting

 

Larus argentatus

Herring gull

Feeding

 

Larus delawarensis

Ring-billed gull

Feeding

 

Larus marinus

Great black-backed gull

Feeding

 

Sterna anaethetus

Bridled tern

Feeding

 

Sterna antillarum

Least tern

Feeding, nesting

 

Sterna caspia

Caspian tern

Feeding

 

Sterna dougallii

Roseate tern

Feeding

 

Sterna forsteri

Forster’s tern

Feeding

 

Sterna hirundo

Common tern

Feeding

 

Sterna maxima

Royal tern

Feeding, nesting

 

Sterna nilotica

Gull-billed tern

Feeding

 

Sterna sandvicensis

Sandwich tern

Feeding, nesting

 

Sterna fuscata

Sooty tern

Feeding

 

Trachinotus carolinus

Florida pompano

Feeding

 

Tringa flavipes

Lesser yellowlegs

Feeding

 

Tringa melanoleuca

Greater yellowlegs

Feeding

 

Tringa solitaria

Solitary sandpiper

Feeding

 

Urocyon cinereoargenteus 

Gray fox

Feeding

 


Further Reading:  

Austin 1998. Classification of plant communities in south Florida. Internet document.
     Available at: www.fau.edu/divdept/science/envsci/communities.htm

Carter, R.W.G., T.G.F. Curtis, and M.J. Sheehy-Skeffington. 1992. Coastal dunes
     geomorphology, ecology and management for conservation. A.A.
     Balkema/Rotterdam/Brookfield.

Florida Natural Areas Inventory, Department of Natural Resources. 1990. Guide to the
     Natural Communities of Florida. Publication. 11pp. Tallahassee, FL.

Komar, P.D. and Moore, J.R., editors. 1983. CRC handbook of coastal processes and
     erosion. CRC Press, Inc. Boca Raton, Florida.

Komar, P.D. 1998. Beach processes and sedimentation, 2nd edition. Prentice Hall,
     Upper Saddle River, New Jersey.

Myers, R.L. and J.J. Ewel, eds. 1990. Ecosystems of Florida. University of Central
     Florida Press, Orlando, FL. 765 pp.

Oertel, G.F. and M. Lassen. 1976. Developmental sequences in Georgia coastal dunes
     and distribution of dune plants. Bull. GA. Acad. Sci. 34: 35 – 48.

Otvos, E.G. 1981. Barrier island formation through nearshore aggradation –
     stratigraphic and field evidence. Mar. Geol. 43:195-243.

Packham, J.R. and A.J. Willis. 1997. Ecology of dunes, salt marsh and shingle.
      Chapman and Hall, London.

Pethick, J. 1984. An introduction to coastal geomorphology. Edward Arnold, London.

Pilkey, O.H. and M.E. Feld. 1972. Onshore transport of continental shelf sediment:
     Atlantic southeastern United States. In: Swift, D.J.P., D.B. Duane and O.H. Pilkey,
     eds. Shelf Sediment Transport: Process and Pattern. Dowden, Hutchinson, Ross.
     Stroudsburg, PA

Schmalzer, P.A., B.W. Duncan, V.L. Larson, S. Boyle, and M. Gimond. 1996.
     Reconstructing historic landscapes of the Indian River Lagoon. Proceedings of
     Eco-Informa ’96. 11:849 – 854. Global Networks for Environmental Information,
     Environmental Research Institute of Michigan (ERIM), Ann Arbor, MI

Stalter, R. 1976. Factors affecting vegetational zonation on coastal dunes, Georgetown
     County, SC. In: R.R. Lewis, and D.P. Cole, eds. 3rd Proc. Annu. Conf. Restoring
     Coastal Veg. Fla. Hillsborough Comm. Coll., Tampa, FL

Stalter, R. 1993. Dry coastal ecosystems of the eastern United States of America. In:
     Ecosystems of the World. Volume 2. Elsevier Science Publications, New York, NY.

Tyndall, R.W. 1985. Role of seed burial, salt spray, and soil moisture deficit in plant
     distribution on the North Carolina Outer Banks. Ph.D. Thesis, University of
     Maryland, College Park, MD.

Wagner, R.H. 1964. The ecology of Uniola paniculata L. in the dune-strand habitat of
     North Carolina. Ecol. Monogr. 34: 79 – 96.

 

 

 

Report by:  K. Hill, Smithsonian Marine Station
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Page last updated: Dec. 17,  2001