Geography of Bermuda - Introduced Flora and Fauna

Introduced Flora and Fauna

Since discovery by humans, numerous species have been introduced to the island, some deliberately, like the casurina, the feral pig, the Cardinal (Cardinalis cardinalis), anoles, ladybird beetles, and the Kiskadee, some incidentally, like the Norwegian rat (Rattus norvegicus) and the Black Rat (Rattus rattus), and the others accidentally, like the scale mites, and the brown widow spider (Latrodectus geometricus). Other imported species include the cane toad (Bufo marinus), and tree frogs.

In addition to casurinas, numerous other species of tree, bush, shrub, cacti, palm, and other grasses have been introduced, with many of them proving to be invasive species. Despite the decimation of the cedar, those parts of the island not covered in buildings and tarmac are now densely covered in trees and shrubbery, including allspice (Pimenta dioica ), fiddlewood, Norfolk Island pine (Araucaria heterophylla), bay grape (Coccoloba uvifera), Surinam cherry (Eugenia uniflora), poinciana (Delonix regia), fan palms, coconut palm (Cocos nucifera), royal palm (Roystonea), pittusporum, Natal plum, loquat (Eriobotrya japonica), oleander (Nerium oleander), and hibiscus. Most of the introduced species have proved to be unequal to Bermuda's frequently fierce weather. A succession of winter storms and a few powerful hurricanes that have struck over the last two decades have reduced woodlands, and available nest sites for small birds. The number of large trees, particularly, has been reduced. Although cedars are adapted to the local climate, and not so affected by stormy weather, rising sea levels are beginning to inundate the roots of old-growth cedars near low-lying marshlands, causing many to die.

Many domestic animal species have been introduced, including dogs, horses, goats, sheep, chickens, and cats, with cats long having established a large feral population. Feral chickens have recently become numerous (since the government ended its policy of allowing members of the local shotgun club to shoot them), and feral rabbits can also be found. Populations of feral guinea pigs have been established and then eradicated. Feral pigs were hunted to extinction centuries ago. Today, introduced feral species, particularly cats, are blamed for falling numbers of native birds, from bluebirds to longtails, but the primary threats are loss of habitat, due now to overdevelopment, and climate change (rising sea levels, increased hurricane activity, and rising temperatures are all having an effect on Cahow nests, particularly).