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Williams and llodd Many turtles spend much of their time in lakes and rivers during the spring and sum- mer. hl autumn, the turtles migrate to adjacent wetlands to hibernate. One species, the Plymouth red-bellied turtle, Chrysemys rubriventris bangsi, is known only from a limited area in Massachusetts (Graham, 1969; Lazell, 1977) and there may be only 200 indivi- duals remaining (Lazell, pers. comm.). While the lakes inhabited by the species have not been seriously impacted, many of the surrounding marshes and bogs have been drained tur housing. If the activity continues, the Plymouth red-bellied turtle might disappear be- cause of the destruction of its wintering sites. Continuing destruction of isolated wetland marshes and bogs, especially in the northeast, has caused many turtle enthusiasts to voice concern fur the survival of the bog turtle, Clemmys ~~zaehlenbergi, a secretive, small, and attractive species. While recent studies on the distribution of the species reveal that it is :iot as rare as previously believed and new colonies are continually being discovered (Arndt, 1978), the rate at which known colonies have disappeared merits special concern. Mud turtles are generally considered completely aquatic although the yellow mud turtle, Kinosternor~ flm~escens, has adapted to xer%c conditions of the southwestern United States and adjacent Mexico. One isolated population, the Illinois mud turtle,Kinosternon ,flavescerzs spooneri, inhabits wetlands and sloughs of the remnant sand prairies of lllinoi's and adjacent Iowa and Missouri. Although the species was encountered in-large numbers Suring the 1940's and 1950's, it has declined to the point where it is virtually extinct in Missouri and Illinois, with only a single major remaining population on Big Sand Mound in Iowa. While all the causes of its decline are somewhat obscure, drainage of wetlands and ponds for development and agricultural purposes has eliminated most of the species in many areas (Brown and Moll, 1978; Morris, 1978). Like the Plymouth red-bellied tur- tle. a sma1.1 range coupled with drainage of the wetlands on which it depends has brought the species close to extinction. Another species confined to midwest wetlands, Kirtland's water snake, Clonophis kirtla~xdii, may be endangered because of drainage of its micro- habitat (S. Taylor, pers. comm.); studies on it are just beginning. Highway construction and development have contributed to the decline of the Santa Cruz long-toed sal~q~.r, Ambystoma macrodacty[um croceum, and San Francisco garter snake, Thamnophis sirtalis tetrataenia, both of which are confined to limited ranges in California. The salamander depends on adequate water in ponds and marshes to allow its larvae to complete their development. At one time, the only known locality of the species was almost destroyed by a freeway. Since then, other populations have been dis- covered and steps taken to restore its original habitat (U.S. Fish and Wildlife Service, 1977). The garter snake inhabits dense, continuous emergent vegetation bordering fresh water marshes in San Mateo County and appears to be semiaquatic (Barry, 1978). Like other species of reptiles, its decline has occurred in part because of drainage and modification of wetlands on which it and its prey depend. EXAMPLES FROM DESERT WETLANDS In the grid southwestern United States, wetland habitats are usually associated with lowland areas along major streams. Exceptions to this are found in the spring-fed desert areas. Wetland islands in the desert support endemic and disjunct populations of plants, fish, and wildlife which have survived there since the Pleistocene Epoch (approx. 20,000 __ years ago). Hundre,_„ ds of species_of plants fish, and wildlife are assoczate~_yy;,nt]t the v~~.t- lands,..,..,FS)~~.Pgn,„,~„em for_ survival. _ Many of the organisms are threatened wrth ex- ti~nctig~. ..~.~ .. ~~~~.,.~ 570