Known and Unknown Biodiversity, Risk of Extinction and Conservation Strategy in the Sea

  • Marjorie L. Reaka-Kudla


The ocean supports more different major kinds of organisms (phyla, classes) than any other environment on Earth. These lineages represent unique legacies that have been evolving separately for half a billion years and are more likely to contain novel genetic and chemical material than more recently evolved groups. Despite its huge expanse, the sea contains only 15% of the world’s 1.9 million described species. Empirical studies and calculations based on the species-area curve indicate that global coastal environments, tropical coastal zones and coral reefs support about 219,000, 195,000, and 93,000 described species, respectively. The pinnacle of presently known marine biodiversity, coral reefs occupy about 0.2% of the world’s oceans but contain 34% of the described marine species. Several lines of evidence suggest that as many as 90% of the species in the sea remain undiscovered and unstudied. If reefs contain the same area-specific diversity as rain forests, then coral reefs contain at least a million total (known and unknown) species. Almost half a billion people, 8% of the world’s population, live within 100 km of a coral reef, and over half of global coral reefs are under severe (about 30%) or medium (about 30%) threat. Ecological disturbances such as overfishing, overpopulation and mass mortalities of grazers, coral bleaching, outbreaks of disease, and loss of live cover due to sedimentation and other stresses plague coral reefs on a global scale. Marine environments have been considered to be less vulnerable to extinction than terrestrial and freshwater habitats due to the pervasive view that all marine organisms have long-lived pelagic stages and wide geographic distributions. It is therefore often concluded that marine conservation efforts must be of a very large, multinational scale. The present research indicates that most marine and especially coral reef species are small, inhabit holes in the bottom, produce few offspring, occupy restricted geographic distributions, and are vulnerable to extinction. If 30% of global reef habitats are degraded beyond recovery in the next few decades, we stand to lose almost 10,000 described species and at least 80,000 total (known and unknown) species (using the most conservative figures for total species). Because a significant percentage of marine species occupy restricted geographic areas, however, establishment of small marine protected areas (targeting either high species richness; rare, endemic or unique species; or unique or ecologically important habitats) can be effective. Where possible, they should be established in spatial networks that protect the critical habitats of species with broad dispersal and wider geographic ranges as well. However, these smaller marine protected areas are faster and easier to establish and maintain than large multi-national protective regions. They should be pursued relentlessly. The need has never been greater.


Coral Reef Rain Forest Coral Bleaching Systematics Agendum Mantis Shrimp 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.


  1. Angel, M. 1992. Managing biodiversity in the oceans. In: Petersen, M.A., ed., Diversity of Ocean Life: An Evaluative Review, pp. 23–59. Ctr. Strategic Internat. Stud., Washington, D.C.Google Scholar
  2. Arrhenius, O. 1921. Species and area. J. Ecol. 9: 95–99.CrossRefGoogle Scholar
  3. Baillie, J., and B. Groombridge. 1996. 1996 IUCN Red List of Threatened Animals. IUCN, Gland, Switzerland. 368 pp.Google Scholar
  4. Bergh, O., K.Y. Borsheim, G. Brabtak, and M. Heldal. 1989. High abundance of viruses found in aquatic environments. Nature 340: 467.CrossRefGoogle Scholar
  5. Bischof, B. 1997. Scientists launch survey of reef health. Science 276: 1494.CrossRefGoogle Scholar
  6. Bowen, B.W., A.B. Meylan, and J.C. Avise. 1991. Evolutionary distinctiveness of the endangered Kemp’s ridley sea turtle. Nature 352: 709–711.CrossRefGoogle Scholar
  7. Brown, B.E., and J.C. Ogden. 1993. Coral bleaching. Sci. Amer. 268: 64–70.CrossRefGoogle Scholar
  8. Brown, B.E., R.R Dunne, and H. Chansang. 1996. Coral bleaching relative to elevated seawater temperature in the Andaman Sea (Indian Ocean) over the last 50 years. Coral Reefs 15: 151–152.Google Scholar
  9. Bryant, D., L. Burke, J. McManus, and M. Spalding. 1998. Reefs at Risk: A map-based indicator of threats to the world’s coral reefs. Tech. Rept., World Resources Inst., Washington, D.C. 56 pp.Google Scholar
  10. Buddemeier, R.W. 1998. Corals, carbon dioxide and co-operation. Land-Ocean Interactions in the Coastal Zone Newsletter, Internat. Geosphere-Biosphere Progr., pp. 2–3.Google Scholar
  11. Carlton, J.T., G.J. Vermeij, D.R. Lindberg, D.A. Carlton, and E.C. Dudley. 1991. The first historical extinction of a marine invertebrate in an ocean basin: The demise of the eelgrass limpet Lottia alveus. Biol. Bull. 180: 72–80.CrossRefGoogle Scholar
  12. Carlton, J.T., J.B. Geller, M.L. Reaka-Kudla, and E.A. Norse. 1999. Historical extinction in the sea. Ann. Rev. Ecol. Syst. 30: 515–538.CrossRefGoogle Scholar
  13. Chisholm, S.W., R.J. Olson, E.R. Zettler, R. Goericke, J.B. Waterbury, and N.A. Welschmeyer. 1988. A novel free-living prochlorophyte abundant in the ocean euphotic zone. Nature 344: 340–343.CrossRefGoogle Scholar
  14. Darlington, P. J., Jr. 1959. Area, climate and evolution. Evolution 13: 488–510.CrossRefGoogle Scholar
  15. Dony, J.G. 1963. The expectation of plant records from prescribed areas. Watsonia 5:377–385.Google Scholar
  16. Diamond, J.M. 1989. The present, past and future of human-caused extinctions. Phil. Trans. R. Soc. Lond. B 325: 469–477.CrossRefGoogle Scholar
  17. Dominguez, J.H., and M.L. Reaka. 1988. Temporal activity patterns in reef-dwelling stomatopods: A test of alternative hypotheses. J. Exp. Mar. Biol. Ecol. 117: 47–69.CrossRefGoogle Scholar
  18. Dunne, R.P., and B.E. Brown. 1996. Penetration of solar UV-B radiation in shallow tropical waters and its potential biological effects on coral reefs: Results from the central Indian Ocean and Andaman Sea. Mar. Ecol. Prog. Ser. 144: 109–118.CrossRefGoogle Scholar
  19. Ehrlich, P. R., and E.O. Wilson. 1991. Biodiversity studies: Science and policy. Science 253: 758–762.CrossRefGoogle Scholar
  20. Erwin, T. 1988. The tropical forest canopy: The heart of biotic diversity. In: Wilson, E.O., and F.M. Peter, eds., BioDiversity, pp. 123–129. Nat. Acad. Press, Washington, D.C.Google Scholar
  21. Feldmann, R.M., and R.B. Manning. 1992. Crisis in systematic biology in the “Age of Biodiversity.” J. Paleontol. 66: 157–158.Google Scholar
  22. Fuhrman, J.A., K. McCallum, and A.A. Davis. 1992. Novel major archaebacterial group from marine plankton. Nature 356: 148–149.CrossRefGoogle Scholar
  23. Gaston, K. 1991. The magnitude of global insect species richness. Conserv. Biol. 5: 283–296.CrossRefGoogle Scholar
  24. Gaston, K.J., and R.M. May. 1992. Taxonomy of taxonomists. Nature 356: 281–282.CrossRefGoogle Scholar
  25. Ginsburg, R.N., ed. 1993. Global Aspects of Coral Reefs: Health, Hazards, and History. Rosenstiel School Mar. Atmos. Sci., Univ. Miami, Fla.Google Scholar
  26. Gleason, H.A. 1922. The individualistic concept of the plant association. Torrey Bot. Club Bull. 53: 7–26.CrossRefGoogle Scholar
  27. Gleason, D.F. 1993. Differential effects of ultraviolet radiation on green and brown morphs of the Caribbean coral Pontes asteroides. Limnol. Oceanogr. 38: 1452–1463.CrossRefGoogle Scholar
  28. Glynn, P. W. 1991. Coral bleaching in the 1980’s and possible connections with global warming. Trends Ecol. Evol. 6: 175–179.CrossRefGoogle Scholar
  29. Glynn, P. W. 1993. Coral reef bleaching: Ecological perspectives. Coral Reefs 12: 1–17.CrossRefGoogle Scholar
  30. Grassle, J.F. 1986. The ecology of deep-sea hydrothermal vent communities. Adv. Mar. Biol. 23: 301–362.CrossRefGoogle Scholar
  31. Grassle, J.F. 1989. Species diversity in deep-sea communities. Trends Ecol. Evol. 4: 12–15.CrossRefGoogle Scholar
  32. Grassle, J.F., and N.J. Maciolek. 1992. Deep-sea species richness: Regional and local diversity estimates from quantitative bottom samples. Amer. Nat. 139: 313–341.CrossRefGoogle Scholar
  33. Grassle, J.P., and J.F. Grassle. 1976. Sibling species in the marine pollution indicator, Capitella (Polychaeta). Science 192: 567–569.CrossRefGoogle Scholar
  34. Hansen, T.A. 1978. Larval dispersal and species longevity in Lower Tertiary gastropods. Science 199: 885–887.CrossRefGoogle Scholar
  35. Hansen, T.A. 1980. Influence of larval dispersal and geographic distribution on species longevity in neogastropods. Paleobiology 6: 193–207.Google Scholar
  36. Hay, M.E. 1984. Patterns of fish and urchin grazing on Caribbean coral reefs: Are previous results typical? Ecology 65: 446–454.CrossRefGoogle Scholar
  37. Hayes, R.L., and N.I. Goreau. 1998. The significance of emerging diseases in tropical coral reef ecosystems. Rev. Biol. Trop. 46 (suppl. 5): 173–185.Google Scholar
  38. Hutchings, P. A. 1986. Biological destruction on coral reefs. Coral Reefs 4: 239–252.CrossRefGoogle Scholar
  39. Hughes, TP. 1994. Catastrophes, phase shifts, and large scale degradation of a Caribbean coral reef. Science 265: 1547–1551.CrossRefGoogle Scholar
  40. Hutchinson, G.E. 1959. Homage to Santa Rosalia, or why are there so many kinds of animals? Amer. Nat. 93: 145–159.CrossRefGoogle Scholar
  41. Jablonski, D. 1982. Evolutionary rates and modes in Late Cretaceous gastropods: Role of larval ecology. Proc. 3rd N. Amer. Paleontol. Conv. 1: 257–262.Google Scholar
  42. Jablonski, D. 1986a. Larval ecology and macroevolution in marine invertebrates. Bull. Mar. Sci. 29: 565–587.Google Scholar
  43. Jablonski, D. 1991. Extinctions: A paleontological perspective. Science 253: 754–757.CrossRefGoogle Scholar
  44. Jablonski, D., and R.A. Lutz. 1983. Larval ecology of marine benthic invertebrates: Paleobiological implications. Biol. Rev. 58: 21–89.CrossRefGoogle Scholar
  45. John, D.M. 1994. Biodiversity and conservation: An algal perspective. Phycologist 38: 3–15.Google Scholar
  46. Kleypas, J. A. 1997. Modeled estimates of global reef habitat and carbonate production since the last glacial maximum. Paleoceanography 12: 533–545.CrossRefGoogle Scholar
  47. Knowlton, N., E. Weil, L.A. Weight, and H.M. Guzman. 1992. Sibling species in Montastraea annularis, coral bleaching, and the coral climate record. Science 255: 330–333.CrossRefGoogle Scholar
  48. Kuhlmann, D.H.H. 1988. The sensitivity of coral reefs to environmental pollution. Ambio 17: 13–21.Google Scholar
  49. Lovejoy, T 1980. Changes in biological diversity. In: The Global 2000 Report to the President, Vol. 2, Tech. Rept, pp. 327–332. Council Envir. Qual. and U.S. Dept. State, Washington, D.C.Google Scholar
  50. MacArthur, R.H., and E.O. Wilson. 1967. The Theory of Island Biogeography. Princeton Univ.Press, N.J. 203 pp.Google Scholar
  51. May, R.M. 1975. Patterns of species abundance and diversity. In: Cody, M.L., and J.M. Diamond, eds., Ecology and Evolution of Communities, pp. 81–120. Harvard Univ. Press, Cambridge, Mass.Google Scholar
  52. May, R.M. 1978. The dynamics and diversity of insect faunas. In: Mound, L.A., and N. Waloff, eds., Diversity of Insect Faunas, pp. 188–204. Blackwell Sci. Pub., Oxford!Google Scholar
  53. May, R.M. 1994. Biological diversity: Differences between land and sea. Phil. Trans. R. Soc. Lond.B 343: 105–111.CrossRefGoogle Scholar
  54. Mayr, E. 1969. Principles of Systematic Zoology. McGraw-Hill, N.Y.Google Scholar
  55. Moran, D.P., and M.L. Reaka. 1988. Bioerosion and the availability of shelter for benthic reef organisms. Mar. Ecol. Progr. Ser. 44: 249–263.CrossRefGoogle Scholar
  56. Moran, D.P., and M.L. Reaka-Kudla. 1991. Effects of disturbance: Disruption and enhancement of coral reef cryptofaunal populations by hurricanes. Coral Reefs 9: 215–224.CrossRefGoogle Scholar
  57. National Science Board, Task Force on Biodiversity. 1989. Loss of biological diversity: A global crisis requiring international solutions. National Science Foundation, Washington, D.C.Google Scholar
  58. Norse, E.A. 1993. Global Marine Biological Diversity: A Strategy for Building Conservation into Decision Making. Island Press, Washington, D.C. 383 pp.Google Scholar
  59. Norse, E.A., and L. Watling. 1999. Impacts of mobile fishing gear: The biodiversity perspective. Amer. Fish. Soc. Symp., Amer. Fish. Soc. 22.Google Scholar
  60. Pauly, D., V. Christensen, J. Dalsgaard, R. Froese, and F. Torres, Jr. 1998. Fishing down marine food webs. Science 279: 860–863.CrossRefGoogle Scholar
  61. Pearse, V.B. 1987. Living Invertebrates. Blackwell Sci. Pub., Oxford.Google Scholar
  62. Poore, G.C.B., and G.D.F. Wilson. 1993. Marine species richness. Nature 361: 579.CrossRefGoogle Scholar
  63. Porter, G. 1998. Too much fishing, too few fish. World Wildlife Fund, Washington, D.C. 28 pp.Google Scholar
  64. Ray, G.C. 1985. Man and the sea: The ecological challenge. Amer. Zool. 25: 451–468.Google Scholar
  65. Ray, G.C. 1988. Ecological diversity in coastal zones and oceans. In: Wilson, E.O., and F.M. Peter, eds., BioDiversity, pp. 36–50. Nat. Acad. Press, Washington, D.C.Google Scholar
  66. Ray, G.C. 1991. Coastal zone biodiversity patterns. Bioscience 41: 490–498.CrossRefGoogle Scholar
  67. Raven, P.H., and E.O. Wilson. 1992. A fifty-year plan for biodiversity surveys. Science 258: 1099–1100.CrossRefGoogle Scholar
  68. Reaka, M.L. 1979. The evolutionary ecology of life history patterns in stomatopod Crustacea. In: Stancyk, S., ed., Reproductive Ecology of Marine Invertebrates, pp. 235–260. Univ. S. Carolina Press, Columbia.Google Scholar
  69. Reaka, M.L. 1980. Geographic range, life history patterns, and body size in a guild of coral-dwelling mantis shrimps. Evolution 34: 1019–1030.CrossRefGoogle Scholar
  70. Reaka, M.L. 1985. Interactions between fishes and motile benthic invertebrates on reefs: The significance of motility vs. defensive adaptations. Proc. Fifth Internat. Coral Reef Congr. 5: 439–144.Google Scholar
  71. Reaka, M.L. 1986. Biogeographic patterns of body size in stomatopod Crustacea: Ecological and evolutionary consequences. In: Gore, R.H., and K.L. Heck, eds., Biogeography of the Crustacea, pp. 209–235. Balkema Press, Rotterdam.Google Scholar
  72. Reaka-Kudla, M.L. 1991. Processes regulating biodiversity in coral reef communities on ecological vs.evolutionary time scales. In: Dudley, E.C., ed., The Unity of Evolutionary Biology, pp. 61–70. Dioscorides Press, Portland, OregonGoogle Scholar
  73. Reaka-Kudla, M.L. 1997. The global biodiversity of coral reefs: A comparison with rain forests. In: Reaka-Kudla, M.L., D.E. Wilson, and E.O. Wilson, eds., Biodiversity II: Understanding and Protecting Our Natural Resources, pp. 83–108. Joseph Henry/Nat. Acad. Press, Washington, D.C.Google Scholar
  74. Reaka-Kudla, M.L., J.S. Feingold, and P.W. Glynn. 1996. Experimental studies of rapid bioerosion of coral reefs in the Galapagos Islands. Coral Reefs 15: 101–107.Google Scholar
  75. Reaka-Kudla, M.L., D.S. O’Connell, J.D. Regan, and R.I. Wicklund. 1993. Effects of temperature and UV-B on different components of coral reef communities. In: Ginsburg, R.N., ed., Global Aspects of Coral Reefs: Health, Hazards, and History, pp. 126–181. Rosenstiel School Mar. Atmos. Sci., Univ. Miami, Fla.Google Scholar
  76. Reaka, M.L., and R.B. Manning. 1981. The behavior of stomatopod Crustacea, and its relationship to rates of evolution. J. Crust. Biol.l: 309–327.CrossRefGoogle Scholar
  77. Reaka, M.L., and R.B. Manning. 1987. The significance of body size, dispersal potential, and habitat for rates of morphological evolution in stomatopod Crustacea. Smithsonian Contr. Zool. 448: 1–46.Google Scholar
  78. Richardson, L.L. 1998. Coral diseases: What is really known? Trends Ecol. Evol. 13:438–443.Google Scholar
  79. Roberts, CM. 1997. Connectivity and management of Caribbean coral reefs. Science 278:1454–1457.CrossRefGoogle Scholar
  80. Schick, J.M., M.F. Lesser, and RL. Jokiel. 1996. Effects of ultraviolet light radiation on corals and other coral reef organisms. Global Change Biol. 2: 527–545.CrossRefGoogle Scholar
  81. Simberloff, D.S. 1974. Equilibrium theory of island biogeography and ecology. Ann. Rev. Ecol. Syst. 5: 161–182.CrossRefGoogle Scholar
  82. Simberloff, D.S. 1976. Experimental zoogeography of islands: Effects of island size. Ecology 57: 629–648.CrossRefGoogle Scholar
  83. Smith, S.V. 1978. Coral-reef area and the contribution of reefs to processes and resources of the world’s oceans. Nature 273: 225–226.CrossRefGoogle Scholar
  84. Smith, F.D.M., R.M. May, R. Pellew, T.H. Johnson, and K.S. Walter. 1993. Estimating extinction rates. Nature 364: 494–96.CrossRefGoogle Scholar
  85. Spalding, M., and A.M. Grenfell. 1997. New estimates of global and regional coral reef areas. Coral Reefs 16: 225–230.CrossRefGoogle Scholar
  86. Strathmann, R.R., and M.F. Strathmann. 1982. The relationship between adult size and brooding in marine invertebrates. Amer.Nat.119: 91–101.CrossRefGoogle Scholar
  87. Strong, A.E., TJ. Goreau, and R.L. Hayes. 1998. Ocean hotspots and coral reef bleaching, January–July, 1998. Reef Encounter 24: 20–22.Google Scholar
  88. Systematics Agenda 2000.1994. Systematics Agenda 2000: Charting the Biosphere. Tech. Rept., Systematics Agenda 2000, a Consort, of Amer. Soc. Plant Taxon., Soc, Syst. Biol, Willi Hennig Soc, Assoc. Syst. Coll., N.Y. 34 pp.Google Scholar
  89. Vermeij, G.J. 1991. Marine extinctions and their implications for conservation and biogeography. In: Dudley, E.C., ed., The Unity of Evolutionary Biology, pp. 143–148. Dioscorides Press, Portland, Oregon.Google Scholar
  90. Vermeij, G.J. 1993. Biogeography of recently extinct marine species: Implications for conservation. Conserv. Biol. 7: 391–397.CrossRefGoogle Scholar
  91. Watling, L., and E.A. Norse. 1998. Disturbance of the seabed by mobile fishing gear: A comparison to forest clearcutting. Conserv. Biol. 12: 1180–1197.CrossRefGoogle Scholar
  92. Wilkinson, C.R. 1992. Coral reefs of the world are facing widespread devastation: Can we prevent this through sustainable management practices? Proc. 7th Internat. Coral Reef Symp. 1: 11–24.Google Scholar
  93. Williams, E.H., Jr., and L. Bunkley-Williams. 1990. The worldwide coral reef bleaching cycle and related sources of coral mortality. Atoll Res. Bull. 335: 1–71.CrossRefGoogle Scholar
  94. Wilson, E.O. 1985. Time to revive systematics. Science 230: 1227.CrossRefGoogle Scholar
  95. Wilson, E.O. 1988. The current state of biological diversity. In: Wilson, E.O., and F.M. Peter, eds., Bio Diversity, pp. 3–18. Nat. Acad. Press, Washington, D.C.Google Scholar
  96. Wilson, E.O. 1989. Threats to biodiversity. Sci. Amer. (September): 108–116.Google Scholar
  97. Wilson, E.O. 1992. The Diversity of Life. Harvard Univ. Press, Cambridge, Mass.Google Scholar
  98. Wright, S.J. 1981. Intra-archipelago vertebrate distributions: The slope of the species-area relation. Amer. Nat. 118: 726–748.CrossRefGoogle Scholar

Copyright information

© Springer Science+Business Media New York 2001

Authors and Affiliations

  • Marjorie L. Reaka-Kudla
    • 1
  1. 1.Department of BiologyThe University of MarylandCollege ParkUSA

Personalised recommendations