Small effective population size in the long-toed salamander

The effective population sizes (N-e) of six populations of the long-toed sa lamander (Ambystoma macrodactylum) from Montana and Idaho, USA were estimat ed from allozyme data from samples collected in 1978, 1996 and 1997 using t he temporal allele frequency method. Five of the six estimates ranged from 23 to 207 (mean = 123 +/- 79); one estimate was indistinguishable from infi nity. In order to infer the actual N-e of salamander populations, we compar ed the frequency distribution of our observed N-e estimates with distributi ons obtained from simulated populations of known N-e. Our observed N-e esti mate distribution was consistent with distributions from simulated populati ons with N-e values of 10, 25, and 50, suggesting an actual N-e for each of the six salamander populations of less than 100. This N-e estimate agrees with most other N-e estimates for amphibians. We conclude by discussing the conservation implications of small N-e values in amphibians in the context of increasing isolation of populations due to habitat fragmentation.