Amphibian Response to Rotenone Treatment of Ten Alpine Lakes in Northwest Montana
The piscicide rotenone is an important and widely used management tool for native fish conservation; however, long-term empirical field studies investigating potential effects on nontarget species are lacking. We tested for effects of rotenone on four native amphibian species inhabiting 10 fish-bearing alpine lakes in northwest Montana. Visual encounter amphibian surveys were conducted for 2–4 years to establish baseline species-specific detection frequencies prior to piscicide treatment to eradicate nonnative trout. Species diversity and detection frequencies varied considerably among lakes, presumably due to differences in the amount of emergent vegetation. Comparisons between baseline detection frequencies and those established from posttreatment surveys consistently revealed no significant changes in amphibian detection frequency, suggesting resiliency of amphibian populations to these piscicide treatments. These results may be explained by one or more of the following: (1) timing the rotenone application when many amphibians had metamorphosed beyond the gill-breathing life stage; (2) application of rotenone at a concentration that was sublethal to amphibians; and (3) posttreatment immigration of adults from habitats not treated with rotenone. This study provides insight into the factors that contribute to amphibian population resiliency to alpine lake rotenone treatments within the context of a watershed-scale native trout restoration program.
- Sponsoring Organization:
- USDOE
- OSTI ID:
- 1630153
- Journal Information:
- North American Journal of Fisheries Management, Journal Name: North American Journal of Fisheries Management Journal Issue: 1 Vol. 38; ISSN 0275-5947
- Publisher:
- Oxford University PressCopyright Statement
- Country of Publication:
- United States
- Language:
- English
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