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Chapter 9: Extinction
Some good overviews of the current concerns over species extinction can be found in Pimm, S.L., Jones, H.L., and Diamond, J. "On the risk of evolution," American Naturalist, 132 (6) 757-785, 1988; Simberloff, D.S., "Are We on the Verge of a Mass Extinction in Tropical Rainforests?" in D.K. Elliot, ed. Dynamics of Extinction, New York: Wiley 1986; Wilson, E.O. "The current state of biological diversity." In BioDiversity, Wilson, E.O. and Peter, F.M., eds. National Academy Press, Washington D.C. 1988; Wilson, E.O. "Threats to Biodiversity," Scientific American, Sept, 1989; Wilson, E.O. "Wildlife-Legions of the Doomed," Time Magazine, 1991; Wilson, E.O., The Diversity of Life, Belknap Press, Cambridge, Mass. 1992.
May, E. M., Lawton, J.H., Stork, N.E. compare the estimated current extinction rate to the background extinction rate in "Assessing Extinction Rates" in Extinction Rates, Lawton and May, Eds., Oxford: Oxford University Press, 1995 in Biodiversity II.
T.C. Whitmore ("Tropical Forest Disturbance, Disappearance, and Species Loss," Tropical Forest Remnants: Ecology, Management, and Conservation of Fragmented Communities, W.F. Laurance and R.O. Bierregaard, Jr, Eds., Chicago: University of Chicago Press, 1997) notes that while there is little evidence of the mass extinctions predicted by the species-area curve, extinction probably has a time lag so species loss from habitat destruction in the past is not yet apparent.
In his book The Call of Distant Mammoths: Why the Ice Age Mammals Disappeared (Copernicus New York. 1997), P.D. Ward provides a popular account of the extinction of Ice Age megafauna. He explores the leading extinction theories and reviews terminology associated extinction such as "extinction debt." For more detailed examination of extinction debt, see McCarthy, M.A., Lindenmayer, D.B., and Drechsler, M. "Extinction debts and risks faced by abundant species." Conservation Biology Vol. 11 No. 1 (221-226), Feb. 1997 and Tilman, D. et al. "Habitat destruction and the extinction debt." Nature 371: 65-66. 1994. Recently Cowlishaw, G. ("Predicting the Pattern of Decline of African Primate Diversity: an Extinction Debt from Historical Deforestation." Conservation Biology, Pages 1183-1193. Vol. 13, No. 5, October 1999) examined extinction debts among west African primates, while Brooks, T.M., Pimm, S.L., and Oyugi, J.O. ("Time Lag between Deforestation and Bird Extinction in Tropical Forest Fragments." Conservation Biology, Pages 1140-1150. Vol. 13, No. 5, October 1999) surveyed the extinction debt-time lag among insular Southeast Asian bird species.
Comparing the occurrence of bird species in isolated forest fragments with the original avifauna Renjifo, L.M. ("Composition Changes in a Subandean Avifauna after Long-Term Forest Fragmentation." Conservation Biology, Pages 1124-1139. Vol. 13, No. 5, October 1999) found a reduction in diversity after fragmentation.
The species extinction table is derived from a similar table in Biodiversity II, Reaka-Kudla, Wilson, Wilson, eds.., Washington D.C.: Joseph Henry Press, 1997. The extinction estimates come from several sources including Raven, P.H. "Our Diminishing Tropical Forests," In BioDiversity, Wilson, E.O. and Peter, F.M., eds. Washington D.C.: National Academy Press, 1988; Wilson, E.O. "Threats to Biodiversity," Scientific American, Sept, 1989; May, R.M., "How Many Species Are There on Earth?" Science, 241: 1441-49, 1988; Wilson, E.O. The Diversity of Life, Cambridge, Mass.: Belknap Press, 1992; Reid, W.V. "How Many Species Will There Be?" In Tropical Deforestation and Species Extinction, Whitmore, T.C. and Sayer, J.A., eds., London: Chapman and Hall, 1992; and Mace, G.M.; 1994; "Classifying threatened species: means and ends," Phil. Trans. R. Soc. Lond. Bulletin 344, 91-97; Lovejoy, T. E. "A projection of species extinctions," in The Global 2000 Report to the President, G.O. Barney, Study Director, Entering the twenty-first century, vol. 2. Council on Environmental Quality,U.S. Government Printing Office, Washington D.C. 1980; From Biodiversity II. Reaka-Kudla, Wilson, Wilson, eds. Joseph Henry Press. Washington D.C. 1997; and Lovejoy, Thomas E. "Biodiversity: What is it?" In Biodiversity II, Reaka-Kudla, Wilson, Wilson, eds.., Washington D.C.: Joseph Henry Press, 1997.
The worldwide decline in amphibians is discussed by Lips ("Decline of a montane amphibian fauna," Conservation Biology Vol. 12 No. 1 (106-117), Feb. 1998.), Sessions et. al. (Sessions, S.K. Franssen, R.A., Horner, V.L., "Morphological Clues from Multilegged Frogs: Are Retinoids to Blame?" Science. 284 (5415) 1999), Tangley ("The Silence of the Frogs," U.S. World and News Report 8/3/98.), and Tuxill ("The Latest News on the Missing Frogs," World Watch, May/June 1998.).
Population sinks and sources are discussed in Merenlender, A., Kremen, C., Rakotondratsima, M., and Weiss, A., "Monitoring Impacts of Natural Resource Extraction on Lemurs of the Masoala Peninsula, Madagascar," Conservation Ecology Vol. 2(2): No. 5, 1998.
Suplee, C. reported the findings of the IUCN that roughly 12% of the world's flora can be classified as being threatened with extinction ("One in Eight Plants in Global Study Threatened," The Washington Post, 4/8/98).
In their The Theory of Island Biogeography (Princeton, New Jersey: Princeton University Press, 1967) R.H. MacArthur and E.O. Wilson discuss the geographic distribution and number of species of species on islands of varying sizes and vegetation types.
Mass extinctions are defined in Sepkoski, J.J. "Mass extinctions in the Phanaerozoic oceans: A review," Geological Society America, Special Paper 190, 1982, and Ward, P.D., On Methuselah's Trail: Living Fossils and the Great Extinctions, New York: W.H. Freeman and Company, 1992 and further explored in Raup, D., The Nemesis Affair, New York: W.W. Norton, 1986 and Martin, P.S. and Klein, R.G., eds., Quaternary Extinctions: A Prehistoric Revolution, Tucson: University of Arizonia. 1984.
The role of extra-terrestrial objects in past extinction events is evaluated by Alvarez et al. (Alvarez, L., Alvarez, W., Asaro, F., and Michel, H., "Extra-terrestrial cause for the Cretaceous-Tertiary extinction," Science 208: 1094-1108, 1980), Gore (Gore, R., 1989, "Extinctions," National Geographic, Vol. 175:6, p. 662-698), Raup (Raup, D., Extinction: Bad Genes or Bad Luck? New York: W.W. Norton; 1991), Sheehan (Sheehan, P.M., 1991, "Sudden extinction of the dinosaurs: latest Cretaceous, Upper Great Plains, U.S.A.," Science, v. 236, p. 835-839), and Hecht (Hecht, J., 1993, "Asteroidal bombardment wiped out the dinosaurs" New Scientist, v. 138, p. 14).
Forces (demographic stochasticity, environmental stochasticity, and reduced genetic diversity) that can drive a species with a population under MVP to extinction are explored in The Call of Distant Mammoths: Why the Ice Age Mammals Disappeared (New York: Copernicus, 1997) by P.D. Ward and in Conservation and Biodiversity, New York: Scientific American Library, 1996 by A. Dobson.
The concept of minimum viable populations is developed in Soulè, M.E. and Wilcox, B.A., eds., Conservation Biology: An Evolutionary-Ecological Perspective, Sunderland: Sinauer 1980; in Frankel, O. and Soulè, M.E. Conservation and Evolution, Cambridge: Cambridge University Press, 1981; and in Gilpin, M E. and Soule, M.E. (1986). "Minimum viable populations: the processes of species extinction," In Conservation Biology (pp. 19-34), Sunderland, MA.: Sinauer Associates, M. E. Soule (Ed.). Gilpin has continued to apply mathematical physics and operations research in his approach to examining island biogeography and population genetics in several books (including Restoration Ecology. (1987). J. Aber, M. Gilpin and W. Jordan, Eds. Cambridge University Press, London; Metapopulation Dynamics: Theoretical Models and Empirical Investigations. (1991). M. Gilpin and I. Hanski, Eds. Academic Press, New York; and Metapopulation Dynamics: Genetics, Evolution and Ecology. (1996). I. Hanski and M. Gilpin, Eds. Academic Press, New York).
The role of social dysfunction in population extinction is considered in Raup, D., Extinction: Bad Genes or Bad Luck? New York: W.W. Norton, 1991, and R.B. Primack, Essentials of Conservation Biology, Sunderland, MA.: Sinauer Associates, 1993.
Alfred Wallace's concerns over biodiversity loss in Indonesia during the late 19th century can be found in his classic Island Life (1881) (reprint edition (December 1997) Prometheus Books).
The complexity of ecosystem dynamics and population fluctuations is discussed in M. Gilpin and I. Hanski, Eds., Metapopulation Dynamics: Theoretical Models and Empirical Investigations (1991). Academic Press, New York; May, R. and Nowak, M. "Superinfection, metapopulation dynamics, and the volution of diversity" Journal of Theoretical Biology 170: 95-114, 1994; Leakey, R. and Lewin, R., The Sixth Extinction: Patterns of Life and the Future of Humankind. New York: Doubleday, 1995; I. Hanski and M. Gilpin, Eds. Metapopulation Dynamics: Genetics, Evolution and Ecology. (1996). Academic Press, New York; and Ward, P.D. The Call of Distant Mammoths: Why the Ice Age Mammals Disappeared (New York: Copernicus 1997).
Holdgate (Holdgate, M., "The Ecological Significance of Biological Diversity," Ambio Vol. 25 No. 6, Sept. 1996) notes that only 724 species have been recorded as going extinct since 1600, but explains actual extinction rates are acutally considerably higher given our relative ignorance of the number of species and inter-relationships between species.
Wilson (Wilson, E.O., The Diversity of Life, Cambridge, Mass.: Belknap Press 1992) and Erwin (Erwin, T. L. "Tropical Forests: Their Richness in Coleoptera and other arthropod species." Coleopterists Bulletin 36:74-75. 1982) estimate that roughly half the world's species dwell in rainforests.
Critics (see "Truth Almost Extinct in Tales of Imperiled Species," The Washington Times, September 19, 1984, and Simon, Julian, and Aaron Wildavsky (1994). Species Loss Revisited. Endangered Species Blueprint (National Wilderness Institute) 5, 1: 6-9.) have argued that the "extinction crisis [based on these theoretical projections] is alarmist and exaggerated" (Brooks, T., Pimm, S.L., Collar, N.J., "Deforestation predicts the number of threatened birds in insular southeast Asia," Conservation Biology Vol. 11 No. 2, April 1997).
In his article "The Big Goodbye" (Outside, November 1981) D. Quammen articulates that the intricate relationships between species may result in the extinction of a large number of species.
E.O. Wilson laments the loss of biological diversity in The Diversity of Life. (Cambridge, Mass.: Belknap Press, 1992) noting that as each species is lost, a unique combination of genes - which has been produced over the course of millions of year - also disappears.
Norman Myers popularized the subject of the current extinction wave in The Sinking Ark. A New Look at the Problem of Disappearing Species, New York: Pergamon, 1979.
In his book The Future Eaters (New York: Braziller 1995.) T.F. Flannery provides a fine overview of ancient man's impact on the ecology and environment of Australia. He holds mankind largely responsible for the extinction of Australia's megafauna.
Easter Island
In his article "Easter's End" (Discover. Vol. 16, No. 8, Aug 1995) Jared Diamond evinces that the social collpase of Easter Island may be tied to its ecological degradation and subsequent impoverishment. This interesting and very readable article provides the substance for the text box on "Historical Consequences of Deforestation: Easter Island."
Steadman, D. W. ("Extinction of Birds un Eastern Polynesia: A review of the record, and comparisons with other Pacific Island groups," Journal of Archaeological Sciences, 16:177-205, 1989. From Biodiversity II, Reaka-Kudla, Wilson, Wilson, eds., Washington D.C.: Joseph Henry Press 1997). notes that only one of the original 22 species of seabird still nests on Easter Island.
For a larger scale perspective than Easter Island, C. Runnels, "Environmental degradation in ancient Greece," Scientific American 272 (3): 72-75, 1995 and R. Adams, Heartland of Cities, Chicago: University of Chicago Press, 1981 link environmental degradation with the decline of civilization in ancient Greece and Mesopotania, respectively.
"Rainforest" is used interchangeably with "rain forest" on this site. "Jungle" is generally not used.
Recent news
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Nearly 80 percent of deforestation in the Brazilian Amazon results from cattle ranching, according to a new report by Greenpeace. The finding confirms what Amazon researchers have long known – that Brazil's rise to become the world's largest exporter of beef has come at the expense of Earth's biggest rainforest.
How to save the Amazon rainforest (01/04/2009)
Environmentalists have long voiced concern over the vanishing Amazon rainforest, but they haven't been particularly effective at slowing forest loss. In fact, despite the hundreds of millions of dollars in donor funds that have flowed into the region since 2000 and the establishment of more than 100 million hectares of protected areas since 2002, average annual deforestation rates have increased since the 1990s, peaking at 73,785 square kilometers (28,488 square miles) of forest loss between 2002 and 2004. With land prices fast appreciating, cattle ranching and industrial soy farms expanding, and billions of dollars' worth of new infrastructure projects in the works, development pressure on the Amazon is expected to accelerate. Given these trends, it is apparent that conservation efforts alone will not determine the fate of the Amazon or other rainforests. Some argue that market measures, which value forests for the ecosystem services they provide as well as reward developers for environmental performance, will be the key to saving the Amazon from large-scale destruction. In the end it may be the very markets currently driving deforestation that save forests.
Amazon rainforest damage surges 67% in 2008 (12/20/2008)
The area of rainforest in the process of being deforested — razed but not yet cleared — surged in the Brazilian Amazon during 2008, according to new figures released by Brazil's National Institute for Space Research (INPE). The announcement comes shortly after the Brazilian government reported a 4 percent increase in forest clearing for the year. Using an advanced satellite system that tracks changes in vegetation cover INPE found that 24,932 square kilometers of Amazon forest was damaged between August 2007 and July 2008, an increase of 10,017 square kilometers -- 67 percent -- over the prior year.
Cutting deforestation can fight climate change, reduce poverty and conflict (09/24/2008)
Forest conservation can play a critical role in efforts to reduce greenhouse gas emissions and alleviate poverty, said a prominent group of politicians, development experts, and environmental NGOs meeting in New York City to discuss U.S. climate policy.
Future threats to the Amazon rainforest (07/31/2008)
Between June 2000 and June 2008, more than 150,000 square kilometers of rainforest were cleared in the Brazilian Amazon. While deforestation rates have slowed since 2004, forest loss is expected to continue for the foreseeable future. This is a look at past, current and potential future drivers of deforestation in the Brazilian Amazon.
