The Ecology of Long Beach Island

“In all things of nature there is something of the marvelous.” –Aristotle

Long Beach Island is safe haven to thousands of species that live in the bays, salt marshes, mud flats, dunes, and ocean. Animal species include both full-time residents and migratory species of fish, birds, and marine mammals. Human impact from development, pollution, fishing, and species introduction is influencing the species composition of LBI and its waters.

Barrier islands consist of a number of distinct habitats. Crossing the island from the ocean side, one encounters the nearshore zone, beach, dune, maritime forest or back dune, salt marsh, and water of the bay, lagoon, or estuary.

Beach dune eco
Nearshore and Beach Zone

The LBI beach is constantly being moved by longshore and rip currents. Breakers stir up water, and sand grains are lifted and moved by currents before settling to the sea bottom. Sand particles are generally transported parallel to the shore in the direction of the prevailing longshore current. Gains and losses of sand can be affected by human activity.

A humpback whale forages right offshore. LBI. Photo by Northside Jim

A humpback whale forages right offshore. LBI. Photo by Northside Jim

The wildlife of the sandy shore habitat must deal with waves, wind, the twice daily rise and fall of the tides, and the instability of the surface. Shifting sands provide no firm surface for attachment of plants or animals. Dune grass and snow fences hold sand and prevent or at least slow wind erosion. A few species are frequently found washed onto beaches. Marine algae and seaweeds are not plants but rather members of the kingdom Protista. The most abundant marine algae are single-celled organisms called phytoplankton. Other small organisms include microscopic animals called zooplankton. The planktonic larva of crabs, barnacles, and starfish are collectively called meroplankton.

WHAT’S THAT ON THE BEACH? Seaweeds that wash up on LBI beaches include:

  • Sea lettucea paper-thin bright green alga
  • Hollow green weedsa bright green tubular alga
  • Green fleece—a dark green spongy branching alga
  • Rockweeds—algae with air bladders and flattened branching fronds that grow on rocks
  • Bladder wracka common brown alga with a flattened body and conspicuous air bladders
  • Knotted wrackalgae lacking a mid-rib
  • Red seaweedsa bushy red, hooked weed

Some LBI wildlife can be seen on the beach year round; others are seasonal—like some islanders and vacationers. Great black-backed gulls, herring gulls, and ring-billed gulls can be seen most of the year. Laughing gulls are the most abundant gull species during the summer; they move south during the winter. We also see the brown pelican during the summer. In the fall, dunlin and western sandpipers are here. A variety of diving ducks can be seen in the surf during the winter months: canvasbacks, longtails, northern pintails, buffleheads, common loons, harlequin ducks, and black surf scooters are examples.

Just off shore ~ while sitting on the beach ~ you might spot some bird activity. This is usually an indicator that a large school of menhaden is nearby, feeding on smaller bait fish. Keep an eye out for ospreys, northern gannets, bottlenose dolphins and even humpback whales who partake in this feeding frenzy right along the beach.


Island Habitats and their Inhabitants

Dune vegetation is vital to protecting shore communities from beach erosion. Photo by Ben Wurst

Dune vegetation is vital to protecting shore communities from beach erosion. Photo by Ben Wurst

Coastal Dune and Maritime Forest

Coastal dunes are unstable habitats subject to erosion by wind and waves. Our dunes are dominated by dune grass, or beach grass, which is a tall clump-forming perennial with roots that spread widely, binding the sand surface and stabilizing the dune. This native species is widely planted for dune protection. Unfortunately, most LBI dunes have been built on.

The only large undeveloped coastal dunes are in state- and Federally-owned land on the north and south ends of LBI. On the north end are Barnegat Light State Park and a wildlife area in High Bar Harbor. On the south end is the Edwin B. Forsythe National Wildlife Refuge. The only remaining maritime forest here is a small preserved area in Barnegat Light State Park, which has a short nature trail.

Salt Marsh

The coastal salt marsh in autumn. Photo by Ben Wurst.

The coastal salt marsh in autumn. Photo by Ben Wurst.

Salt marsh communities are adapted to the twice-daily tidal flooding. The endless supply of water, nutrients, and sunlight makes salt marsh communities the most productive environment on earth, converting raw materials into biomass at rates of up to 10 tons per acre per year. The roots and stems of salt marsh grasses trap sediments carried by the tides and, as this fill accumulates, the grasses grow out into the sediments creating new marsh.

The flora of the salt marsh is dominated by a few species of grass in the genus Spartina. Salt meadow grass is short with smooth delicate blades often appearing swirled; salt marsh cordgrass has wider ridged blades and grows up to 5 ft. tall. These marsh grasses have mechanisms to excrete excess salt. Low places on the marsh become too salty for cordgrass and become open mud flats that support
glasswort—a fleshy leafless plant. This edible plant is often called pickle weed because the early settlers sometimes pickled them.

Many birds including osprey, cormorants, herons, egrets, terns, various types of songbirds, ducks, and gulls use the salt marsh and bay for feeding and nesting. During the spring and fall migration, large flocks of shorebirds stop to feed and rest in salt marshes. Most shorebird species winter south of New Jersey and nest north of New Jersey. Many nest in the Arctic tundra where long days and abundant food allow them to go through their entire breeding cycle in a few weeks.

Invertebrates that live in the water and mud play an important role in the functioning of the salt marsh. Bacteria break down dead plant and animal material producing detritus that feeds many of the invertebrates of the salt marsh. Mud snails and marsh snails eat detritus and are important as food in salt marsh communities. Fiddler crabs occur in large colonies feeding on the detritus during low tide and retreating to their burrows during high tide to avoid aquatic predators.

The surface and edge of marsh mud is often studded with ribbed mussels, each in its own burrow, filtering the nutrient-rich tidal water. Where these mussels grow, along the marsh edge, allows them to help stabilize shorelines from erosion. As the sea level rises, mussels may play a critical role in reducing erosion in intertidal areas. The services they provide to our estuaries are critical to their long term health and survival. Another common invertebrate of salt marsh communities is the predatory blue crab, which lives in mosquito ditches and channels and actively preys on small fish and dead organisms.

A female terrapin leaves the protection of her aquatic environment to lay eggs. Photo by Ben Wurst

A female terrapin leaves the protection of her aquatic environment to lay eggs. Photo by Ben Wurst

The only reptile commonly found in salt marshes on LBI is the northern diamondback terrapin (Malaclemys terrapin terrapin). It lives and feeds in brackish (a mix of salt and fresh) water during the warmer months and hibernates in salt marsh mud during the colder months. During the summer, female terrapins lay their eggs in nests they dig in sandy banks and road edges above the high tide line. The turtle eggs and hatchlings are vulnerable to predation by cats, raccoons, skunk, mink, crows, and gulls, and disturbance by humans walking and driving vehicles. In fact, only around 1-3% of eggs laid even produces a hatchling, and the same low number of hatchlings reach adulthood.

Mammals of the salt marsh include muskrats, mink, and river otters, which can easily make it to the Island from Island Beach State Park or Tuckerton. Raccoons, Norway rats, and opossums, all well established on LBI, seek food in the marsh. The meadow vole, a small short-tailed mouse, burrows through the grasses of the high areas of the marsh. Voles are an important food source for birds of prey that hunt in the marsh such as marsh hawks, short-eared owls, and rough-legged hawks.

Bay/ Eelgrass Community

Eelgrass, a flowering plant, grows in sandy flats and sheltered inlets. The roots penetrate the mud and the underground stems called rhizomes mat together stabilizing the substrate. Eelgrass grows just below the low tide line in shallow water. It can grow in up to 100 feet of water if there is light penetration. Beds of live eelgrass harbor large communities of marine organisms because they provide food, attachment sites, and shelter from predators. Canada geese, brant and a few ducks eat fresh eelgrass; most organisms eat decaying eelgrass. Bacteria breaks down decaying eelgrass releasing nutrients into the water. In 1930-31 an epidemic destroyed 90% of the eelgrass beds on the Atlantic coast. Today, boat traffic, pollution, and dredging take a toll on the slowly recovering eelgrass beds.

>>View interactive mapping of New Jersey’s submerged aquatic vegetation

Rocky Intertidal Community

This man-made LBI habitat came into being when the jetties were built. Tide pools form along the edge of the rocks by trapping water from the outgoing tide, twice daily. Organisms that live here must deal with extreme fluctuations in temperature, salinity, and oxygen availability. Intertidal organisms form bands on the rocks they live on because of their differing abilities to live out of water. Barnacles live higher up on the rocks than blue mussels because barnacles can seal themselves shut and avoid predation better than blue mussels can. Those organisms that live near or below the tide line cannot tolerate long periods out of the water. Starfish and sea urchins can coexist because of their different feeding niches. Starfish are carnivores that eat shellfish; sea urchins are herbivores that eat seaweed. Many Japanese crabs (introduced from Japanese fishing vessels), sand fiddler crabs, green crabs, and rock crabs also live on and around the rocks.

Bulldozers move sand on LBI. Photo by Northside Jim

Bulldozers move sand on LBI. Photo by Northside Jim

Human Impact

Humans migrate to the coastal area, too. With people come the construction of homes, motels, and marinas. Along with over-development come the problems presented by erosion-prevention structures. Jetties, or groins, interfere with long-shore current transport of sand. Breakwaters and seawalls increase turbulence and erosion. Beach replenishment, pumping sand back onto beaches, or importing sand, is a temporary solution to sand loss. Bulkheads on the bay side hold the shoreline and allow for docks but remove salt marshes,
mud flats, and bay beaches used by many breeding species.

Any species that uses the beach or dune for breeding is at risk. Examples of threatened or endangered species include: the piping plover, least tern, black skimmer, and American oystercatcher. Their eggs and young are especially vulnerable. Camouflaged eggs are vulnerable humans and vehicles. Eggs and hatchlings are preyed on by domestic pets, gulls, red fox, skunk and raccoons. Some simple solutions include restricting areas during the breeding season, and enclosures (cages surrounding nests) to further protect eggs from predators.

 

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