Fernando de Noronha Archipelago

• Category: Marine and Oceanic Biomes.
• Geographic Location: Atlantic Ocean.
• Summary: The islands of Fernando de Noronha and nearby Atol das Rocas form part of the mid-Atlantic volcanic chain of islands and seamounts; they are both important nesting areas for seabirds and sea turtles.

Fernando de Noronha Archipelago is a volcanic mountain chain that developed along the east-west ocean fracture zone, forming twenty-one islands and islets in the equatorial Atlantic, approximately 224 miles (360 kilometers) off the eastern coast of Brazil. The main island, Fernando de Noronha, measures 7 square miles (18 square kilometers), or about 90 percent of the total area of the chain. The islands of Cabeluda, Rata, São Jose, and Sela Gineta together make up most of the remaining land area. The highest point on the archipelago is Morro de Pico, at 1,053 feet (321 meters).

Exotic shrublands and secondary forests, consisting of trees introduced by humans, dominate the vegetation. During the nineteenth century, when the island was used as a penal colony, the original native forests were cleared, apparently to prevent prisoners from building rafts and escaping. Only 5 percent of the original forest remains near the isolated Cape Sapata.

Due to this clear-cutting, although more than 400 plants have been recorded, today only three are endemic, or found only in this biome: the gameleira or narrow leaf fig (Ficus noronhae), mulungo (Erythrina mulungu), and burra leiteira (Apium escleratium), sometimes called milkweed. The current vegetation includes vine and shrub species that were introduced to the area, along with a few trees, principally of the families Nyctaginaceae (Four o'clocks), Bignoniaceae (Bignonias), Anacardiaceae (cashew or sumac), Rubiaceae (coffee), and Euphorbiaceae (Spurges), as well as some small planted secondary forest fragments.

The coastline is complex, with numerous high cliffs and sandy beaches used as nesting areas for seabirds and sea turtles, respectively. In fact, Fernando de Noronha is the home of one of the largest bird breeding colonies among the islands of the tropical South Atlantic, and Atol de Rocas is Brazil's second-largest nesting area for green sea turtles (Chelonia mydas).

Because of the island's volcanic origins, it has never been connected to the mainland; thus, all species arrived on wing or over water, which has resulted in fairly high species endemism among animals. Several bird species are believed to have colonized the archipelago naturally: endemic Noronha vireo (Vireo gracilirostris), endemic Noronha elaenia (Elaenia ridleyana), eared dove (Zenaida auriculata), and cattle egret (Ardea ibis). The International Union for Conservation of Nature has labeled the Noronha elaenia as vulnerable and the Noronha vireo as near threatened. Other protected birds on the island include the red-billed tropicbird (Phaethon aethereus), the Sargasso shearwater (Puffinus lherminieri), and the white-tailed tropicbird (Phaethon lepturus).

Two species of lizards are found on the islands: the endemic Noronha skink (Trachylepis atlantica) and the introduced tegu (Tupinambis teguixin). There are two terrestrial mammals found on the islands: the introduced rock cavy (Kerodon rupestris, known as mocó) and domestic sheep. The rich waters around the islands are breeding and feeding grounds for tuna, billfish, and shark, as well as the various cetaceans and turtles. There are numerous marine mammals, too, in nearby waters, including such whales as long-finned pilot (Globicephala melas), minke (Balaenoptera acutorostrata), and humpback (Megaptera novaeangliae); and such dolphin varieties as common (Delphinus delphis), spotted (Stenella attenuata), and melon-headed (Peponocephala electra).

Conservation

Fernando de Noronha Marine National Park, covering just over 42 square miles (110 square kilometers) of the archipelago, was established in 1988, and a management plan was implemented in 1990. In 2001, the Fernando de Noronha and Atol das Rocas Reserves were designated a United Nations Educational, Scientific and Cultural Organization (UNESCO) World Heritage site as the Brazilian Atlantic Islands. Despite the serious loss of terrestrial habitat that occurred during the prison era, many protective measures have been established, allowing a variety of introduced and native vegetation to recover and persist. The offshore islets remain relatively undisturbed, making them excellent seabird habitats. In 2020, the archipelago had a stable human population of about 3,100 inhabitants, concentrated on Fernando de Noronha Island, and a small transient population of tourists and researchers.

Invasive species are common on these islands, so much so that all future conservation efforts must take them into account. Among such nonnative biota are linseed, intended for use as cattle feed; the tegu lizard (Salvator merianae, known as teju), imported to control rats but now considered a plague since it feeds mostly on bird eggs; and the rock cavy, a rodent that looks like a squirrel without a bushy tail.

The Fernando de Noronha Archipelago is an important biodiversity haven for Brazil’s flora and fauna. While the area has remained relatively unaffected by climate change, researchers in the 2020s conducted risk evaluations for the island and found evidence for impending increases in maximum temperatures and decreasing minimum temperatures of the island. However, the nature and scope of changes in average temperature, moisture, and precipitation remain unknown.

Bibliography

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