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Data-free speculation does not make for testable hypotheses: A reply to Ripple et al.

Authors

  • Karen E. Hodges

    Corresponding author
    1. Department of Biology, University of British Columbia Okanagan, 3333 University Way, Kelowna, BC, Canada V1V 1V7
    • Department of Biology, University of British Columbia Okanagan, 3333 University Way, Kelowna, BC, Canada V1V 1V7
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  • Associate Editor: Grado

Abstract

The role of top predators in structuring ecosystems is receiving substantial attention from ecologists. Ripple et al. (2011) recently posed a tentatively supported hypothesis that wolves (Canis lupus) may help restore populations of the U.S. federally Threatened Canada lynx (Lynx canadensis), a specialist predator on snowshoe hares (Lepus americanus), through 2 possible mechanisms: a) decreases in the numbers of coyotes (C. latrans), which may compete with lynx for hares as prey and may also kill lynx; or b) decreases in ungulates that might compete with hares for food. These speculative opinions are not supported by current data, either across the range or in the extended example of Yellowstone National Park (YNP) that Ripple et al. provide. The coyote hypothesis lacks the required quantification of coyote numbers and predation rates on hares, both in YNP and across the range of lynx. The browse competition hypothesis ignores substantial differences in browse and habitat preferences between elk (Cervus elaphus) or livestock and hares that prevent competition for food. Our previous work in YNP (Hodges et al. 2009) showed scattered and very low densities of snowshoe hares, with distributions driven by the substantial fire-related habitat changes YNP has experienced over the past century. Although I applaud their interest in lynx conservation, the unsupported speculations of Ripple et al. do not advance our ability to manage lynx or hares, nor do they present plausible directions for conservation research. © 2012 The Wildlife Society.

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