There Is No Substitute
When it comes to conservation research, a study suggests that surrogate or model species do not “stand-in” for endangered species.
An article in the latest issue of Conservation Biology examines the use of surrogate animals to predict or target what is endangering another 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.
The sensitivity of specific taxa to environmental stresses is illustrated in the recent recognition that military mid-frequency sonars under certain circumstances have a history of injuring and killing certain species of beaked whales, while other toothed whale species and baleen whales in the same areas are little affected.
