Endangered Species Handbook

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Aquatic Ecosystems

Wetland Drainage

     The drainage of wetlands has caused extinctions in some parts of the world.  The pink-headed duck (Rhodonessa caryohphyllacea), native to northeastern India, northern Myanmar (Burma) and central Nepal, was locally common during the 19th century in grassy wetlands, where it was heavily hunted by British colonials (Collar et al. 1994, Fuller 1987).  The male had very unusual coloration, with a bright pink head and brownish plumage marked in pink and white spots.  The female was a slightly less colorful version of the male.  Males and females uttered different calls, having very different trachea:  The male had a two-syllable metallic cry and the female a loud quack (Fuller 1987).  Reduced by sport and market hunting, much of its habitat was gradually converted to agriculture, causing an apparent extinction (Fuller 1987).  Although not seen in the wild since about 1936, this species is still listed by the IUCN as critical and there is some hope that it survives undetected (BI 2000, Collar et al. 1994).
     At least five species of frogs have been extinguished by wetlands drainage.  The Israel painted frog (Discoglossus nigriventer) was last seen in 1940 before its sole habitat, Lake Huleh, was drained for agriculture.  Three species of frogs that inhabited the marshes and wetlands surrounding Mexico City disappeared after the city expanded and filled in wetlands for housing and industry and used others for dumping grounds.  Leopard frogs of the genus Rana: Rana johni and Rana pueblae became extinct about 1979, and Tialoc's leopard frog (Rana tlaloci) was extinguished in 1990, according to D.M. Hillis, who wrote his Ph.D. Dissertation for the University of Kansas on the species.

Page 1 (South America & Latin America)
Page 2 (Middle East)
Page 3 (Africa)
Page 4 (Asia)
Page 5 (United States)

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