The island’s habitats are not as numerous or exotic as those found in pure tropical regions like the Caribbean and Central America. Yet, Bermuda’s ecosystems are interesting in their more subtle variety, as well as in their increasing fragility due to rampant development. The main habitats are the rocky shore; beaches and dunes; inland forest; marshes, ponds, and mangroves; karst and caves; sea grass beds; and coral reefs. All areas can be seen and explored around the island. Interpretive displays complete with audio at the Bermuda Natural History Museum (part of the Bermuda Aquarium, Museum & Zoo) at Flatts, in Smith’s Parish, describe habitats and common species found in each.
The Rocky Shore
Some of the most impressive aspects of wild Bermuda are its rocky shore and coastal environments. Climbing up and down the spray-bashed coast, where biodiverse tide pools are often large enough to swim in, you can imagine the natural setting that greeted the castaways who reached Bermuda’s shores. When the first humans arrived on the island’s shoreline in the 1500s, they encountered a reef-necklaced oasis of endemic cedar forests and palmetto palms, both of which were beneficial to survival in myriad ways: for timber to build huts and ships, for roof thatch, for berries to mull wine, and for hearts of palm, which shipwreck survivors roasted or baked.
The rocky shoreline is home to a wealth of plants and animals, a unique bridge between marine and terrestrial environments. Algae, lichens, and rockweeds drape the intertidal zone, where they have adapted to a hybrid environment with features such as attachments, or “holdfasts,” to the rock. The band lying between the lowest tide and the spray zone is darkened and made slippery by blue-green bacteria, which provide a larder of food for other animals. Among the various species found here, rainbow-hued parrotfish can be found grazing, gnawing on reef and rock with their hallmark beaked mouths. Crabs, snails, urchins, anemones, and seaweeds also thrive. The banded West Indian Top Shell (Cittarium pica) can sometimes be found; a protected species, removing this creature is illegal. Growing profusely atop the wind- and sea-eroded limestone shore are hardy, salt-resistant succulents, such as the sea purslane, coast spurge, and seaside oxeye, whose vibrant yellow flowers dot the landscape. Prickly pears, spiky Spanish bayonets with luxurious towers of white blossom, baygrape brushes, fennel, and fields of seaside goldenrod, waving feathery, butter-colored wands, cover areas above the tidal shore.
Beaches and Dunes
Sand dunes harbor a similarly tough variety of plants, whose growth effectively serves to anchor the dunes and prevent sand masses from shifting too far. Dune vegetation is peppered with the type of bright blossoms that are so striking in desert environments, although here, they are totally different varieties; these include the purple-flowered vine, seaside morning glory, wild stock, sea lavender, and the buttercup-like seaside evening primrose. Land crabs dig long burrows in dune areas to escape the prying beaks of hunting night herons; be careful when hiking the dunes not to twist your ankle in their exit holes.
Sargasso weed washes up in piles on the beaches year-round, depending on wind direction. These floating mats of brown seaweeds are found in the Sargasso Sea, a vast area east of Bermuda stretching to the Azores. Fed by the warm waters of the Gulf Stream, the seaweed got its name from Portuguese mariners of the Age of Discovery who dubbed it sargaco or “grape” since its air sacs and structure resemble the fruit. The weed comprises a self-sufficient food web that supports abundant small marinelife, including slugs, crabs, and shrimps. It often traps garbage, oil, and tar emitted by marine traffic, washing up sticky pollutants onto the sand.
As a result of residential and urban development, Bermuda’s original woodland comprising endemic cedars, palmettos, and olivewood has been whittled down over four centuries to mere remnants of its former expanse. Today, true remains of the old forest are almost nonexistent, since woodland is now dominated by introduced species. Many have proven detrimental to endemics; examples such as the Mexican pepper, whispering pine or casuarina, and the Chinese fan palm have competed for space and nutrients with cedars and palmettos—usually successfully. Yet inland forests covering uplands and interior valleys contain dense evergreen coverage, providing vital breeding and nesting areas for birds, insects, and other species.
Surviving native trees include the Bermuda cedar (Juniperus bermudiana), the palmetto (Sabal bermudiana), the yellow wood, olivewood, and hackberry. Nonendemic fiddlewoods, allspice, Surinam cherry, and Indian laurel trees are much more common and can be found in forested hillsides and valleys and in the woodland tracts of most nature reserves. The East End’s Nonsuch Island Nature Reserve, which can be visited through special tours, is the only area of the island where endemic forest has been totally restored over the past three decades. The government’s Parks Department has embarked on an islandwide restoration effort in many other protected areas to replace invasives with endemic and native saplings, a program that will take many years to achieve maturity.
Marshes, Ponds, and Mangroves
Peat marshes, freshwater and salt ponds, and mangroves are some of the most fascinating natural environments for amateur or professional biologists to explore. Such wetlands provide a vital feeding ground for bird species and also nurture insects, toads, lizards, and other animals. Bermuda’s mangrove swamps—wet forests that can tolerate saltwater—are the Atlantic’s most northerly.
Red and black mangrove trees, with a dense tangle of roots, many submerged, thrive in coastal swamps such as Hungry Bay on the South Shore, Blue Hole Park, and Ferry Reach Park. There are also brackish pond mangroves at Spittal Pond and Walsingham. Bees and other insects are attracted to the yellow or white flowers of mangroves. Black mangroves have air-breathing roots, which rise like alien fingers from the water. These atmospheric environments are home to numerous species of snail, mollusk, and crab, as well as lizards, crab spiders, large hurricane spiders, dragonflies, tiny whistling frogs, and giant toads. Birdlife includes herons, kiskadees, migrating warblers, and waterfowl. The only plant to avoid when exploring nature reserves, particularly swamp forests, is poison ivy (Rhus radicans), a red-veined crawling vine that can leave a nasty rash after contact with skin.
Karst and Caves
Scientists have discovered diverse plant and animal life inside the island’s honeycomb of marine and terrestrial caves. Most are located in Smith’s and Hamilton Parishes, where karst scenery is characterized by limestone terrain containing sinks, underground caves, and pinnacle rock. The dark, still, isolated environment inside caves has fed interesting biological adaptations and fostered endemic forms of life, some of which may have evolved from deep-sea creatures that inhabited Bermuda’s seamount in prehistoric times. Unusual crustaceans, similar to shrimp, have been found in marine caves, and numerous more common biota, including sea squirts (sea cucumbers), sponges, and mollusks, also make their homes here. Cave mouths on land have helped keep alive many endemic species and are populated by ferns, herbs, and mosses.
Sea Grass Beds
Many of Bermuda’s bays and shallow offshore areas are covered by sea grass beds, which are prime nurseries and feeding grounds for fish, turtles, invertebrates, and other species. Flounders, crabs, and crustaceans—and often, protected green turtles—can be spotted feeding on sea grass. The mud underlying sea grass beds is home to marine worms and other species. Snorkeling over sea grass beds can be fascinating, but watch out for spiny sea urchins if you put your feet down in these shallow areas.
The marine equivalent of rainforests, coral reefs are precious ecosystems whose rich biodiversity of plants and animals supports a complex web of interdependence. Coral reef organisms, including hard and soft coral species, construct their own environment and thrive in areas near the Equator that receive even temperatures and sunlight year-round. Fed by the warm Gulf Stream, Bermuda’s coral reefs are the world’s most northerly; thanks to legislative protection, they have not been destroyed like so many in other regions.
Bermuda’s coral reefs take various forms. Rim reefs encircle the island inside a shallow plateau that drops off beyond to the deep ocean. This reefy necklace, the bane of ships over the centuries, lies fairly close to the South Shore coastline, several hundred feet off in places; on the North Shore, by contrast, rim reefs are located about 10 miles out. Patch reefs are scattered across the shallow plateau, covering some 290 square miles around the island. Boiler reefs are “micro atolls”—wineglass-shaped structures that rise from the sea floor and harbor coral-based ecosystems in miniature. They are particularly visible just a few meters off the entire length of the South Shore and West End. At low tide, boiler reef rims can sit just above the surface. At high tide, you can actually swim down inside these mushroom-like formations to investigate various plant and animal life within.
Bursting with life, coral reefs are continually decaying and rebuilding naturally, as organisms such as stony corals create the framework that other limestone-skeletoned creatures like forams, sea mosses, and bristle worms cement together. Anemones, sea fans, and soft corals then fill in the gaps—in turn, providing food on which other creatures come to graze. Boring clams, sponges, and barnacles undermine the reef structure in the meantime, a process that sees honeycombed chunks break off, providing fresh surfaces for new growth.
© Rosemary Jones from Moon Bermuda, 2nd Edition