Chasing Rainbows
By Anders Halverson
Winter 2012 / Vol. 12 No. 4
Discussion Questions
- What were the unforeseen consequences of the management decision to introduce rainbow trout, Oncorhynchus mykiss, into lakes in the Sierra Nevada range, where those fish – in some lakes any predatory fish – did not previously exist?
- What is it about the life history of amphibians, and in particular members of the family Ranidae (i.e., the mountain yellow-legged frog Rana muscosa), that makes them more productive in environments where there are fewer predatory fish?
- When Roland Knapp began his research he employed several different kinds of study design, including experimental removal studies in some lakes. What was the unifying question of all of his work? Should all of ecology be experimental, or is it important to use both observational and experimental designs?
- As the article relates, many states are investing in restoring ecological integrity including biodiversity to systems they once oversimplified with projects such as fish introductions. The recent policy shift has been accompanied by disgruntlement on the part of anglers and hunters. Do you think the states and federal government should balance the needs of different natural resource users, or should management be directed to single goals like biodiversity conservation? To you, is the restoration of the Mountain yellow-legged frog more important than a fisherman being able to catch a rainbow trout? In the end of the article, the response by the California Department of Fish and Game is described: how fair do you think this is?
Websites for Further Information
- Report from Roland Knapp on aquatic system impacts of introduced fish: http://www.highsierrahikers.org/issue_fish_main.html
- National Park Service – Yosemite: http://www.nps.gov/yose/index.htm
- USFWS Species Profile for the mountain yellow-legged frog including listing status: https://ecos-beta.fws.gov/ecp0/profile/speciesProfile?sId=8037
Frogs in the News
- Threat to world’s amphibians assessed (United Press International, November 16, 2011)
Peer-reviewed Literature
- Knapp, R.A., and K.R. Matthews 2000. Non-native fish introductions and the decline of the Mountain Yellow-Legged Frog from within protected areas. Conservation Biology 14: 428-438.
- Knapp, R.A., K.R. Matthews, and O. Sarnelle 2001. Resistance and resilience of alpine lake fauna to fish introductions. Ecological Monographs 71: 401-421.
- Knapp, R.A., D.M. Boiano, and V.T. Vredenburg 2007. Removal of nonnative fish results in population expansion of a declining amphibian (mountain yellow-legged frog, Rana muscosa). Biological Conservation 135: 11-20.
Key Concepts
- Unintended impacts of fish and wildlife management decisions
- Amphibian declines
- Invasive species in aquatic environments
- Conflicts between fishing/hunting interests and non-game wildlife management
