Ecology of Bermuda

Bermuda's ecology has an abundance of unique flora and fauna due to the island's isolation from the mainland of North America.

The wide range of endemic species and the islands form a distinct ecoregion, the Bermuda subtropical conifer forests.

off the American East Coast, Bermuda is a crescent-shaped chain of 184 islands and islets that were once the rim of a volcano.

[1][2] Once on the island, organisms had to adapt to local conditions, such as the humid climate, lack of fresh water, frequent storms, and salt spray.

The area of the islands shrank as water levels rose at the end of the Pleistocene epoch, and fewer species were able to survive in the reduced land-area.

Many of these introduced species have posed a threat to the native flora and fauna because of competition and interference with habitat.

In the 1940s the cedar forests were devastated by introduced scale insects, which killed roughly eight million trees.

Another important component of the original forest was Bermuda palmetto (Sabal bermudana), a small palm tree.

The Jamaican anole (Anolis grahami) was deliberately introduced in 1905 from Jamaica and is now by far the most common lizard in Bermuda.

[1] The red-eared slider turtle (Trachemys scripta elegans) was introduced as a pet, but has subsequently become invasive.

Early accounts refer to wild or feral hogs, descendants of pigs left by the Spanish and Portuguese as feedstock for ships stopping at the islands for supplies.

Its ground-nesting habitats had been severely disrupted by introduced species and colonists had killed the birds for food.

In 1951, researchers discovered 18 breeding pairs, and started a recovery program to preserve and protect the species.

Other native birds include the eastern bluebird, grey catbird and perhaps the common ground dove.

The barn owl and mourning dove colonized the island during the 20th century, and the green heron has recently begun to breed.

Of the introduced birds, the European starling, house sparrow, great kiskadee, rock dove, American crow and chicken[13] are all very numerous and considered to be pests.

Other introduced species include the mallard, northern cardinal, European goldfinch and small numbers of orange-cheeked and common waxbills.

Fossil remains of a variety of species have been found on the island, including a crane, an owl and the short-tailed albatross.

Some of these became extinct as the islands' land-mass shrank by nine tenths after the Last Glacial Maximum, while others were exterminated by early settlers.

The arrival of many species is dependent on weather conditions; low-pressure systems moving across from North America often bring many birds to the islands.

Eighteen species of butterfly have been seen; about six of these breed on the islands, including the large monarch and the very common Bermuda buckeye (Junonia coenia bergi).

Large quantities of seaweed of the genus Sargassum are present and there are high concentrations of plankton, but the area is less attractive to commercial fish species and seabirds.

The thriving tourist industry creates its own challenges to preserve the wildlife and habitat that attract visitors.

Specifically, the rock pigeon often builds its nests within crevices around the island, including on rocky shorelines and cracks in Bermuda's tall cliffs.