Biodiversity in the Gulf of Guinea: an overview

Patterns of species-richness and endemism in the Gulf of Guinea reflect the region's biogeographic history. Bioko is a continental-shelf island that was recently connected to the African mainland, whereas Príncipe, São Tomé and Annobón are truly oceanic and have never been connected with each other or with the mainland. As a result, Bioko supports a much more diverse flora and fauna but with relatively low levels of endemism at the species level, whereas the oceanic islands are relatively depauperate because of their isolation but rich in endemic taxa. Species endemism is 0–3% on Bioko for angiosperms, bats, birds, reptiles and amphibians, compared with much higher values on Principe for these same taxa of 8% (plants) to 100% (amphibians), on São Tomé between 14% (plants) and 100% (amphibians), and on Annobón 0% (bats) to 71% (reptiles). On a global scale, for their size both Príncipe and São Tomé support unusually high numbers of single-island endemic species of birds, reptiles and amphibia. For its tiny size, Annobón is also notable for its endemic birds and reptiles. Among terrestrial molluscs the rates of endemism are in general higher than for plants and vertebrates, from ca 50% on Bioko to ca 80% on the oceanic islands. In contrast and as might be expected, only Bioko supports a rich freshwater fish fauna and it contains many endemic taxa, whereas the oceanic islands support only a few salt-tolerant species. The Gulf of Guinea islands are also important for their marine organisms, amongst which coral reef fish and marginellid molluscs show high levels of endemism, though they are not especially species-rich. The Gulf of Guinea islands are of great interest to conservationists and evolutionary biologists. Each island, of greatly differing size and degree of isolation, has acquired its unique sub-set of plants and animals separately from the neighbouring mainland, followed by adaptive radiations in situ. For this reason the conservation value of the archipelago as a whole is greater than the sum of the biodiversity contained in its individual islands. Conservation initiatives in the Gulf of Guinea should therefore ensure that representative terrestrial, freshwater and marine habitats and groups of organisms are targeted in a co-ordinated manner among the islands.

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References

  1. Atkinson, P., Dutton, J. and Peet, N. (eds) (1994) A Study of the Endemic Birds and Shrews, and the Use of Turtles and Medicinal Plants in the República Democrática de São Tomé e Príncipe. Cambridge: BirdLife International.

    Google Scholar 

  2. Bibby, C.J., Collar, N.J., Crosby, M.J., Heath, M.F., Imboden, C., Johnson, T.H., Long, A.J., Stattersfield, A.J. and Thirgood, S.J. (1992). Putting Biodiversity on the Map: Priority areas for global conservation. Cambridge: International Council for Bird Preservation.

    Google Scholar 

  3. Butynski, T.M. and Koster, S.H. (1988). The Status and Conservation of Forests and Primates on Bioko island (Fernando Po) Equatorial Guinea. Kampala, Uganda: World Wildlife Fund.

    Google Scholar 

  4. Butynski, T.M. and Koster, S.H. (1989) Marine Turtles on Bioko Island (Fernando Po), Equatorial Guinea: A call for research and conservation. Unpublished report. Washington: World Wildlife Fund.

    Google Scholar 

  5. Castelo, R. (1994). Biogeographic considerations of fish diversity in Bioko. Biodiv. Conserv. 3 (9), 808–827.

    Google Scholar 

  6. Eisentraut, M. (1965) Rassenbildung bei Säugetieren und Vögeln auf der Insel Fernando Poo. Zool. Anzeiger 174, 37–53.

    Google Scholar 

  7. Fahr, J. (1993) Em Beitrag zur Biologie der Amphibien der Insel São Tomé (Golf von Guinea). Faunist. Abhandl. Staat. Mus. Tierkunde Dresden 19, 75–84.

    Google Scholar 

  8. Feiler, A. (1988) Die Saügetiere der inseln im Golf von Guinea und ihre beziehungen zur saugetierfauna des westafrikanischen festlandes. Zool. Abh. st. Mus. Tierkd. Dresden, 44, 83–8.

    Google Scholar 

  9. Fernandes, F. and Roland, E. (1992) The Marginellidae (Mollusca, Gastropoda) of Príncipe island (Republica de São Tomé e Príncipe). J. Conchol. 34, 85–90.

    Google Scholar 

  10. Gascoigne, A. (1994) The biogeography of land snails in the islands of the Gulf of Guinea. Biodiv. Conserv. 3 (9), 794–807.

    Google Scholar 

  11. Gofas, S. and Fernandes, F. (1988) The marginellids of São Tomé, West Africa. J. Conchol. 33. 1–30.

    Google Scholar 

  12. Government of São Tomé and Príncipe (1993) Decreto-Lei No. 52/93 (14 September 1993). Diário da República, São Tomé e Príncipe 13, 215–18.

    Google Scholar 

  13. Haft, J. (1993) Ein Beitrag zur Biologie der Echsen der Insel São Tomé (Golf von Guinea), mit näherer Betrachtung zur Systematik von Leptosiaphos africana (Gray). Faunist. Abhandl. Staat. Mus. Tierkunde Dresden 19, 59–70.

    Google Scholar 

  14. Harrison, M.J.S. (1990) A recent survey of the birds of Pagalú (Annobón). Malimbus 11, 135–43.

    Google Scholar 

  15. Jones, P.J. and Tye, A. (1988). A Survey of the Avifauna of São Tomé and Príncipe. ICBP Study Report No.24. Cambridge: International Council for Bird Preservation.

    Google Scholar 

  16. Jones, P.J., Burlison, J.P. and Tye, A. (1991) Conservacao dos Ecossistemas Florestais na República Democrática de São Tomé e Principe. Gland: Switzerland, International Union for the Conservation of Nature and Natural Resources.

    Google Scholar 

  17. Juste, J. and Ibañez, C. (1993a) A new Tadarida of the subgenus Chaerephon (Chiroptera: Molossidae) from São Tomé island, Gulf of Guinea (West Africa). J. Mamm. 74, 901–11.

    Google Scholar 

  18. Juste, J. and Ibañez, C. (1993b) Geographic variation and taxonomy of Rousettus aegyptiacus (Mammalia: Megachiroptera) in the islands of the Gulf of Guinea. Zool. J. Linn. Soc. 107, 117–29.

    Google Scholar 

  19. Juste, J. and Ibañez, C. (1994) Bats of the Gulf of Guinea islands: faunal composition and origins. Biodiv. Conserv. 3 (9), 837–851.

    Google Scholar 

  20. Juste, J. and Ibañez, C. (in press) Contribution to the knowledge of the bat fauna of Bioko island, Equatorial Guinea (Central Africa). Z. Saügetierkunde???

  21. Loumont, C. (1992) Les amphibiens de São Tomé et Príncipe; revisions systematiques, cris nuptiaux et caryoypes. Alytes 10, 37–62.

    Google Scholar 

  22. McAllister, D.E., Schueler, F.W., Roberts, C.M. and Hawkins, J.P. (in press). Mapping and GIS analysis of the global distribution of coral reef fishes on an equal-area grid. In Mapping the Diversity of Nature (R. Miller, ed.). London: Chapman and Hall.

  23. Moreau, R.E. (1966) The Bird Faunas of Africa and its Islands, London: Academic Press.

    Google Scholar 

  24. Nill, T. (1993) Die Schlangen der Insel São Tomé (Golf von Guinea). Faunist. Abhandl. Staat. Mus. Tierkunde Dresden 19, 71–3.

    Google Scholar 

  25. Peterson, A.T. (1992) Review of Sibley and Alquist, 1990, Faunist. Abhandl. Staat. Mus. Tierkunde Dresden 134, 204–6.

    Google Scholar 

  26. Peterson, A.T. and Stotz, D.F. (1992) Review of Sibley and Monroe, 1990, Faunist. Abhandl. Staat. Mus. Tierkunde Dresden 134, 306–8.

    Google Scholar 

  27. Pyrez (1992) Provisional check-list of the butterflies of São Tomé and Príncipe islands. Lambillionea, 92, 48–52.

    Google Scholar 

  28. Schätti, B. and Loumont, C. (1992) Ein Beitrag zur Herpetofauna von São Tomé (Golf von Guinea). Zool. Abhandl. Staat. Mus. Tierkunde Dresden 47, 23–36.

    Google Scholar 

  29. Sibley, C.G. and Alquist, J.E. (1990) Phylogeny and Classification of Birds: A study in molecular evolution. New Haven: Yale University Press.

    Google Scholar 

  30. Sibley, C.G. and Monroe, B.L. (1990) Distribution and Taxonomy of Birds of the World. New Haven: Yale University Press.

    Google Scholar 

  31. Spelda, J. (1993) Bearbeitung der im Frühjahr 1991 anf der Insel São Tomé (Golf von Guinea) gesammelten Hundert- und Tausendfüssler. Faunist. Abhandl. Staat. Mus. Tierkunde Dresden 19, 115–17.

    Google Scholar 

  32. Thys van den Audenaerde, D.F.E. (1967) The freshwater fishes of Fernando Poo. Verhandelingen van de Koninklijke Vlaamse Academie voor Wetenschappen, Letteren en Schone Kunsten van België 100, 1–167.

    Google Scholar 

  33. Williams, P.H., Humphries, C.J. and Vane-Wright, R.I. (1991) Measuring biodiversity: taxonomic relatedness for conservation priorities. Aust. Syst. Bot. 4, 665–79.

    Google Scholar 

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Jones, P.J. Biodiversity in the Gulf of Guinea: an overview. Biodivers Conserv 3, 772–784 (1994). https://doi.org/10.1007/BF00129657

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Keywords

  • Gulf of Guinea
  • biodiversity
  • endemism
  • conservation