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Island atoll off the Atlantic coast of Brazil

The archipelago of Fernando de Noronha and its neighbor Atol das Rocas belong to the Fernando de Noronha Chain of submerged east-west volcanic mountains in the equatorial Atlantic Ocean. Fernando de Noronha, farther out to sea, has a small human population and some tourism. Atol das Rocas is a Biological Reserve and is only visited by researchers. Both island groups are extremely important habitats for migratory seabird populations and for marine turtle nesting.

  • Scientific Code
    (NT0123)
  • Ecoregion Category
    Neotropical
  • Size
    50 square miles
  • Status
    Critical/Endangered
  • Habitats

Description
Location and General Description
Fernando de Noronha (3° 51' 0S, 32° 25' 0W) is a volcanic island archipelago 360 km off the eastern coast of Brazil. There is one main island, and with its adjacent islands, islets, and rocks, it constitutes part of the Pernambuco estado ("state") of Brazil. Fernando de Noronha was ‘officially’ discovered by Américo Vespúcio in 1503, though there is some dispute as to its first European visitor. In 1504, the Crown granted the archipelago to a Portuguese lord, Fernão de Loronha, from whom it takes its name (Almeida 2000). Occupied by several other European nations during the 17th and early 18th centuries, the Portuguese eventually regained control of the island and constructed several forts in order to deter further invasions. By the late 18th century, Fernando de Noronha began its service as a Portuguese penal colony. Prisoners were sent to the island as late as the Second World War, when Brazil’s Ministry of Justice used it as a destination for political prisoners. The Brazilian government allowed the U.S. to use the island from 1957–62 as a tracking station for guided missiles (Britannica 2001). Fernando de Noronha was also included as a stop on Charles Darwin’s historical Beagle expedition. His famous 1839 observations resulted in subsequent visitations by other researchers.

Fernando de Noronha Archipelago covers a total area of 18.4 km². Ninety percent of this is the main island, which is long and narrow, approximately 8 km by 3 km, with an undulating plateau at about 60 m altitude rising to the west. The highest point is 321 m at Morro do Pico, an isolated, jutting rock located on the central north coast of the island (Almeida 2000). Cliffs with sandy beaches are found along the western coastline, a tidal pool is located at Saco de Atalaia, extensive sand dunes occur in the east, and a freshwater lake is located in the southwest (Johnson 1989). Many small springs and streams disappear during the December-February dry season. The archipelago primarily consists of highly alkaline and subsatured volcanic and subvolcanic rocks and is part of a volcanic mountain that developed along an east-west oceanic fracture zone (Almeida 2000). The Quixaba and Remédios formations represent two major volcanic episodes (Almeida 2000). The substrate consists of weathered phonolytic rocks with overlying basalts and raised coral up to 30 m thick, and the island’s soil is generally fertile as a result of bird guano deposits (Johnson 1989).

Once forested, almost all of Fernando de Noronha Archipelago was cleared in the 19th century in order to prevent prisoners from building rafts. Vegetation is now dominated by vine and shrub species, though secondary forest has grown over portions of the island. Representative tree species include the families of Anacardiaceae, Nyctaginaceae, Bignoniaceae, Rubiaceae and Euphorbiaceae (BAS 2001). Many herbs and shrubs are not native to the islands. Notable shrubs are wild bean, Capparis cynophallophora, and burra leiteira (Sapium sceleratum), which is endemic and produces a caustic latex that can cause serious burns (BAS 2001). Among the herbaceous plants, the jitiranas, Ipomea spp., and Merremia spp. both occur as climbing vines. A few species of fruit trees were introduced to the archipelago, such as papaya, banana, cashew, tamarind, and guava. Introduced decorative species include the almond tree (Terminalia catappa), jasmine mango (Plumeria alba), royal poinciana (Tebebuia sp.), eucalyptus (Eucalyptus sp.), and small quantities of coconut palm (Cocos nucifera), and carnauba (Copernica prunifera) (BAS 2001). UNEP lists fifteen probable endemic plants for Fernando de Noronha. These include Capparis noronhae, Ceratosanthes noronhae, Cayaponias noronhae, Moriordica noronhae, Cereus noronhae, Palicourea noronhae, Guettarda noronhae, Bumelia noronhae, Physalis noronhae, and Ficus noronhae (Johnson 1989). In a study of the Combretum genus throughout Pernambuco, Brazil, (Loiola and Sales 1996) list Combretum rupicola as endemic to Fernando de Noronha. They also note that of nine Combretum species found in the state, only C. laxum and C. fruticosum were found in coastal as well as Atlantic forest formations.

The mountain beneath Fernando de Noronha extends 4,000 m below sea level and is a small part of an alignment of submerged east-west volcanic highs along the fracture zone, which form the Fernando de Noronha Chain (Almeida 2000). Atol das Rocas is included in this chain. These island groups have an equatorial climate with a rainy season lasting from March to November and a dry season from December to February. Rainfall varies from about 180 mm to 2700 mm per month, with a monthly average of approximately 860 mm (Kikuchi 1999). Winds blow from the east, and measured at Atol das Rocas, average air temperature is 26.8ºC, and surface water temperature is 26.7ºC (WCMC 1994). Temperatures are slightly lower farther from the mainland on Fernando de Noronha.

Atol das Rocas (3°52'S, 33°49'W) is located 145 km west of Fernando de Noronha, approximately 144 miles from the mainland (Claudio et al. 1995). It is disputed whether Atol das Rocas is a true atoll, as it was formed primarily by vermetids and coralline algae (Lithothamnium spp.) rather than corals; it is termed by some sources as an annular algal reef (IUCN/UNEP 1988). The reef is elliptical, having grown upon the crater of a volcanic island as it sunk. The internal area is a shallow lagoon of about 7.5 km2, with a depth of approximately 6 m (Kikuchi 1999). Outside of the reef, the water is deep, and at low tide, portions of the reef are exposed. The two small islands of Farol and Cemitério are the only permanently exposed sections of the reef, with a total area of 0.36 km2 (WCMC 1994). These islands are composed of coarse sand and broken coral (IUCN/UNEP 1988).

Atol of the Rocas has a dense herbaceous vegetation highly resistant to salinity, extreme sunlight and constant action of the tides. Certain Blutaparon spp. (Amaranthaceae) grow adjacent to the ocean, anchoring themselves with dense tangles of rhizomes, which forms the first few meters of the substratum of the small islands (Kikuchi 1994). The herbaceous Portulaca spp. (Portulacaceae) grows farther inland, forming a mosaic with species of Cyperaceae, Graminae and Amaryllidaceae (Kikuchi 1994). Also found on the atoll are scattered coconut trees (Cocos nucifera), which were introduced on fishing boats.

Biodiversity Features
Both the Fernando de Noronha Archipelago and Atol das Rocas support large populations of migratory and resident birds, Fernando Noronha being home to the largest bird breeding colonies of all the islands of the Tropical South Atlantic. Among the migratory species found within the island group are black noddy (Anous minutus), which builds its nest in trees and on cliffs of Fernando de Noronha using algae collected from the surface of the ocean; brown noddy (Anous stolidus); sooty tern (Sterna fuscata); fairy tern or white tern (Gygis alba), a pure white bird that lays its eggs in the forks of tree branches; red-footed booby (Sula sula); masked booby (Sula dactylatra); brown booby (Sula leucogaster); magnificent frigatebird (Fregata magnificans) and red-billed tropicbird (Phaethon aethereus) (both of which are noted for their extremely long tail feathers) (BAS 2001). Atol das Rocas shelters the largest breading colonies of Sula dactylatra and Anous stolidus in Brazil and of Sterna fuscata within the South Atlantic (Schulz Neto 1998). A few land birds are found inland on Fernando de Noronha, including the endemic Noronha vireo (Vireo gracilirostris), which is abundant in forests and trees (Johnson 1989). Other land birds are cocoruta (Elainia spectabilis) and eared dove (Zenaida auriculata).

Atol das Rocas is Brazil's second largest reproductive area for green turtles (Chelonia mydas), after Trindade Island (Moreira et al. 1995). Chelonia mydas also reproduce on Fernando de Noronha, and juvenile hawksbill (Eretmochelys imbricata) use the islands for feeding and growth. The TAMAR-IBAMA Project has been monitoring areas of major concentrations of these turtles in the archipelago since 1987 (Sanches and Bellini 1999). Two species of lizards occur on the island, mabuia (Mabuya maculata), which is endemic and teju (Tupinambis teguxim), which was introduced to control rat populations, but prefers prey such as the eggs and the young of birds and turtles (BAS 2001). UNEP lists two endemic invertebrates, a wasp (Polistes ridleyi), and a species of Gammarus, endemic in lake and streams; an endemic worm lizard, (Amphisbaena ridleyi), abundant on Morro do Pico; and an endemic genus of Dactyloscopidae fish found in a tide pool (Johnson 1989). There are no extant indigenous mammals on Fernando de Noronha, and no mammals at all occur on Atol das Rocas. A large school of resident dolphins are a tourist attraction of Fernando de Noronha. The waters surrounding Atol das Rocas harbor a great abundance of commercial fishes as well as lobsters, which were one cause of heavy fishing activity around the atoll in the past (Kikuchi 1999).

Current Status
Fernando de Noronha Marine National Park, covering 112.7 km2 of the archipelago, was established in 1988. Despite the serious loss of habitat that occurred when the island was cleared of trees, many protective measures have been established, allowing the habitat of the archipelago to recover and persist. The offshore islets are relatively undisturbed. The archipelago has a stable human population of less than 3,000 inhabitants, concentrated on the principal island, and a small transient population of tourists and researchers (Almeida 2000). With its interesting landscape, pleasant climate, and morning visitations by the resident dolphins, Fernando de Noronha Island is considered by many as Brazil’s most beautiful island. Tourism began in the 1970’s, and currently there are daily flights to the island from Natal and Recife. However, the total number of tourists on the island is subjected to limits, and visitors must pay a daily "environment" tax, which increases incrementally as the visit progresses. There is little tourism infrastructure. The sole hotel was adapted from the North-American Airforce base in operation during the World War II, a few guest houses operate near Remédios Village on the eastern end of the island, and there is only one paved, seven-kilometer road (Almeida 2000). In addition to the limitations imposed on tourism, two research organizations, the Instituto Brasileiro do Meio Ambiente e dos Recursos Naturais Renováveis (IBAMA), of the Rotator Dolphins Project, and the Tamar Project (a marine turtle nesting project) are involved in monitoring ecological impact on the archipelago (Almeida 2000).

Atol das Rocas was the first site designated as a Brazilian Marine Protected Area (1979). As a Biological Reserve, the only human activity allowed there is scientific research (Kikuchi 1999). Atol das Rocas lies in a heavily fished area of the Atlantic, and before protective measures were in place, many ships were grounded off of the atoll, which causes considerable physical damage to shallow reef areas, particularly at low tide (IUCN/UNEP 1988). Though spear fishing and blast fishing is prohibited by the Federal Department of National Parks, it does occur, and the reef connecting these island groups is stressed by fishing and spearfishing, particularly at Fernando de Noronha (IUCN/UNEP 1988).

Types and Severity of Threats
Tourism must continue to be monitored on Fernando de Noronha. Invasive species, includingrats, mice, and feral cats, have been a serious detriment to the islands’ native habitat (Johnson 1989). A "new", though extinct, species of rat, Noronhomys vespuccii, was described from Fernando de Noronha in 1999 (Carleton and Olson 1999). This species may have disappeared since the time of human presence on the archipelago due to the common anthropogenic causes that extirpate many vertebrate species on islands. The isolation of island ecosystems make them particularly sensitive to human pressures and the introduction of exotic species.

Justification of Ecoregion Delineation
The Fernando de Noronja and Atoles de Rocas islands were classified as their own ecoregion due to the great distance seperating them from the mainland and by the presence of endemic species, including two birds (Stattersfield et al. 1998).

References
Almeida, F. M. 2000. The Fernando de Noronha Archipelago. Geological and Paleontological Sites of Brazil 066. SIGEP. Retrieved 2001, from the World Wide Web: http://www.unb.br/ig/sigep/sitio066/sitio066english.htm.

BAS. 2001. A Discourse on Fernando de Noronha. British Antarctic Survey - Natural Environment Research Council. Retrieved 2001, from the World Wide Web: http://www.antarctica.ac.uk/Diaries/es/antarctic2000_2001/esdiary27.html.

Carleton, M. D. and S.L. Olson, 1999. Amerigo Vespucci and the rat of Fernando de Noronha: A new genus and species of Rodentia (Muridae: Sigmodontinae) from a volcanic island off Brazil's Continental Shelf. American Museum Novitates 0: 2.

Claudio, B., M. A. Marcovaldi, T. M. Sanches, A. Grossman, and G. Sales. 1995. Atol das Rocas Biological Reserve: Second Largest Chelonia Rookery in Brazil. Marine Turtle Newsletter 72: 1-2.

IUCN/UNEP. 1988. UNEP Regional Seas Directories and Bibliographies. Volume 1: Atlantic and Eastern Pacific. IUCN, Gland, Switzerland and Cambridge, U.K./UNEP, Nairobi, Kenya.

Johnson, T. H. 1989. Unpublished ICBP profiles of Atlantic islands. UN System-wide Earthwatch Coordination, (UNEP) United Nations Environment Programme, Geneva, Switzerland. Retrieved 2001, from the World Wide Web: http://www.unep.ch/earthw.html.

Kikuchi, R. K. P. 1999. Atol das Rocas, Southwestern Equatorial Atlantic, Brazil. SIGEP- Geological and Paleontological Sites of Brazil 033. Retrieved 2001, from the World Wide Web: www.unb.br/ig/sigep/sitio033/sitio033english.htm.

Kikuchi, R. K. P. 1994. Geomorfologia, estratigrafia and sedimentologia of the Atol of the Rocas (Rebio/Ibama/RN), South Atlantic Equatorial Occidental person. Dissertação de Mestrado.

Loiola, M. I. B. and M.F. Sales, M. F. 1996. Taxonomic studies of the genus Combretum Loefl. (Combretaceae R.Br.) in Pernambuco, Brazil. Arquivos do Jardim Botanico do Rio de Janeiro 34: 173-188.

Moreira, L., C. Baptistotte, J. Scalfone, J. C. Thomé, and A. P. L. S. de Almeida. 1995. Occurrence of Chelonia mydas on the Island of Trindade, Brazil. Marine Turtle Newsletter 70: 2.

Sanches, T. M. and C. Bellini, 1999. Juvenile Eretmochelys imbricata and Chelonia mydas in the Archipelago of Fernando de Noronha, Brazil. Chelonian Conservation and Biology 3: 308-311.

Schulz Neto, A. 1998. Aspects of seabird biology at Atol das Rocas Biological Reserve, Rio Grande do Norte, Brazil. Hornero 15: 17-28.

Stattersfield, A.J., M.J. Crosby, A.J. Long, and D.C. Wege. 1998. Endemic bird areas of the world: priorities for conservation. Birdlife International Conservation Series No.7. BirdLife International, Cambridge, UK.

WCMC. 1994. Protected Areas Database, World Conservation Monitoring Center. Retrieved 2001, from the World Wide Web:

Prepared by: Leann Trowbridge
Reviewed by: In process

 

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