126 



Reptiles iiHil Ainphibiiins — Ihir Li\iiiii Resutiiees 



For further information: 



R. Bnice Bury 



National Biological Service 



200 S.W. 35th St. 



Corvallis, OR 97333 



Amphibian populations also may vary in 

 size because of natural factors, pailicularly 

 extremes in the weather (Bradford 1983: Com 

 and Fogelman 1984). The size of amphibian 

 populations may vary, sometimes dramatically, 

 from year to year, so what is perceived as a 

 decline may be part of long-term tluctuations 

 (Pechmann et al. 1991). The effect of global cli- 

 mate change on amphibians is speculative, but it 

 has the potential for causing the loss of many 

 species. 



Monitoring Needs 



A profound need exists for natiimal coordi- 

 nation of regional inventories and population 

 studies, including a national effort to monitor 

 amphibians on parks, forests, wildlife refuges, 

 and other public lands. Only through long-temi 

 studies will better data on population changes 

 through time and between sites become avail- 

 able. Such data are essential to evaluating the 

 status and trends of amphibian species in the 

 United States. Some regional surveys and 

 inventories exist but only for a few species; 

 these studies should be expanded into a coordi- 

 nated effort with long-term inonitoring of popu- 

 lations at many sites across the country as the 

 goal. 



In addition, more research is needed to 

 determine the impact of natural and human- 

 caused factors on the different life-history 

 stages and environments of amphibians. Also, 

 the assumption that amphibians are good indi- 

 cators needs to be tested rigorously (Pechmann 

 and Wilbur 1994). Likewise, understanding the 

 dynamics of populations between habitats and 

 regions, and the roles amphibians play in aquat- 

 ic and terrestrial ecosystems is essential. 

 Detailed work on the ecology of species and the 

 factors implicated in declines needs to continue. 



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