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through contracting with universities. Natural Heritage Programs, 

 or other qualified organizations. 

 Population size estimation 



Determining the number of Coeur d'Alene salamanders at a 

 site is not straight forward. Substantial habitat exists 

 underground and not all or even a fixed percentage of salamanders 

 are above ground on any given night. In some cases, underground 

 habitat availability may be more limiting to salamanders than 

 above-ground conditions (Center et al. 1988) . 



One potential method of population estimation would involve 

 establishing a rarefaction experiment by carefully removing 

 salamanders under controlled conditions from selected sites and 

 holding them (preferably in a facility in the field) until no 

 more salamanders are found at the site (Groves 1989a) . A curve 

 could then be established based on diminishing returns as the 

 salamanders are removed, whereby the actual nxomber of salamanders 

 at a site could eventually be predicted from a few nights of 

 removals. 



During application of this procedure as a mitigation measure 

 for major highway construction at U.S. Highway 2 near Libby, 

 Montana, during the fall of 1988 (Center 1989) the curve had only 

 a small negative slope over seven nights of collecting. There 

 were two factors that seemed to complicate the population 

 estimate: drought and early, cold temperatures. The combination 

 of these adverse conditions would limit the number of salamanders 

 out foraging or breeding on any given night. Thus, temperature, 



