Studying Substitute Animals Will Not Save Endangered Species

Researchers often use similar, often called umbrella or flagship, species to identify the cause of endangerment to others. These substitutes may be chosen because they are biologically similar representatives of the troubled species, or they may be used to develop a predictive model to which the original species can be related.

The authors find that using these substitutes cannot create reliable information about population responses; human induced disturbances will not always affect common and rare species in the same fashion. "After all, target species are the ones that are doing poorly, whereas other taxa continue to persist or even thrive despite human disturbance," authors Tim Caro, John Eadie, and Andrew Sih state.

The authors suggest three criteria that must be met in order to use substitute species with confidence. The first is to establish the relationship between the level of the disturbance and vitality rate of the substitute. Second, the trait(s) that affect both species' viabilities must be identified. Third, the trait value and the disturbance threshold must be established for the substitute. The authors see these hurdles as almost insurmountable, especially in a field as cautious as conservation.

"Where at all possible, we advocate making every possible effort to examine the target species directly before resorting to substitute species," the authors conclude.

This study is published in the December issue of Conservation Biology.

Conservation Biology is a top-ranked journal in the fields of Ecology and Environmental Science and has been called, "required reading for ecologists throughout the world." It is published on behalf of the Society for Conservation Biology.

Lead author Tim Caro is a professor in the Department of Wildlife, Fish and Conservation Biology at the University of California at Davis. He has investigated the utility of surrogate species in conservation biology. His interest is in the way in which many people study common species in the hope that they will tell us something about endangered species. 

Co-author John Eadie is at the Department of Wildlife, Fish and Conservation Biology at University of California at Davis.

Co-author Andrew Sih is at the Department of Environmental Science and Policy at University of California at Davis.

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