US Geological Survey


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Published on the NRC Research Press Web site at on 1 December 2006.


Wildfire is a potential threat to many species with narrow environmental tolerances like the Rocky Mountain tailed frog (Ascaphlls montanlls Mittleman and Myers, 1949), which inhabits a region where the frequency and intensity of wildfires are expected to increase. We compared pre- and post-fire counts of tadpoles in eight streams in northwestem Montana to determine the effects of wildfire on A. montanus. All streams were initially sampled in 2001, 2 years before four of them bumed in a large wildfire, and were resampled during the 2 years follo\ving the fire. Counts of tadpoles were similar in the 1\\'0 groups of streams before the fire. After the fire, tadpoles were almost twice as abundant in unbumed streams than in bumed streams. The fire seemed to have the greatest negative effect on abundance of age-l tadpoles, which was reflected in the greater variation in same-stream age-class structure compared with those in unbumed streams. Despite the apparent effect on tadpoles, we do not expect the wildfire to be an extirpation threat to populations in the streams that we sampled. Studies spanning a chronosequence of fires, as well as in other areas, are needed to assess the effects of fires on streams with A. montallus and to determine the severity and persistence of these effects.