Conservation

The biota of islands is often unique—for example, the islands of the Pacific have been designated a biodiversity hot spot. Assessing this diversity, particularly for arthropods, is problematic. The major impediment is a lack of taxonomic understanding of arthropods on many islands, particularly those that are more remote. New species are being collected at a remarkable rate in areas such as French Polynesia, Madagascar, and even the relatively well-studied Canary Islands, New Zealand, Hawaii, and the Galapagos, yet the training of arthropod systematists has lagged behind.

Anthropogenic disturbance has also had its impact not only in present times, but historically, as witnessed through the colonization of the Pacific by Polynesians several thousands of years ago. A number of characteristics of arthropods populations on islands, including high local endemism, limited dispersal abilities, and small population sizes, make them particularly vulnerable to both demographic accidents and environmental change. In addition, islands have been impacted heavily by invasive species, many of which are also arthropods. The impact has been both direct, such as through the extirpation of species by invasive predatory ants, and indirect, such as through diseases of vertebrates having mosquitoes as vectors.

Although islands have long served as extraordinary laboratories for studying processes associated with the generation of diversity, they are now contributing to understanding of processes leading to the loss of diversity. For example, studies of invasive species on islands have shown the importance of environmental factors as well as species-specific attributes that facilitate biological invasions and its negative effects. New tools are urgently needed: rapid biodiversity assessment techniques that bypass traditional taxonomic identification will be important in recognizing areas of high conservation priority, as will genetic or ecological approaches that can distinguish native species from those introduced in more recent history.

See Also the Following Articles

Biodiversity • Biogeographical Patterns • Cave Insects • Introduced Insects

Further Reading

Darwin, C. (1859). "The Origin of Species by Means of Natural Selection."

John Murray, London. Gillespie, R. G., and Roderick, G. K. (2002). Arthropods on islands: Colo-

niziation, speciation, and conservation. Annu. Rev. Entomol. 47, 595—632. Howarth, F. G., and Mull, W. P. (1992). "Hawaiian Insects and Their Kin."

University of Hawaii Press, Honolulu.

MacArthur, R. H., and Wilson, E. O. (1967). "The Theory of Island

Biogeography." Princeton University Press, Princeton, NJ. Wagner, W. L., and Funk, V. A. (eds.). (1995). "Hawaiian Biogeography, Evolution on a Hot Spot Archipelago." Smithsonian Institution Press, Washington, DC. Wallace, A. R. (1902). "Island Life." 3rd ed., Macmillan, London. Whittaker, R. J. (1998). "Island Biogeography: Ecology, Evolution, and

Conservation." Oxford University Press, Oxford, U.K. Williamson, M. H. (1981). "Island Populations." Oxford University Press, Oxford, U.K.

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