What if conservation of a single species simultaneously benefited other species in the ecosystem? That is the allure of “indicator species” or “surrogate species”, particularly those that seem to occur in places of high species diversity. Unfortunately, an association between a given species’ presence and high diversity does not necessarily mean that conservation of that species will improve diversity. We demonstrated this in the latest (October) issue of Animal Conservation.
We collected fishes from a bunch of sites in the Bear River Drainage, which straddles the UT/WY border before flowing into the Great Salt Lake. The drainage is home to northern leatherside chub (NLC), a species of conservation concern. NLC is a working man’s minnow, all grays and browns, clear fins, the kind of fish that is too small to even be considered a trash fish, and so nondescript that it wasn’t described until 2004. But it knows where to live. Streams with NLC tend to have higher fish diversity than streams without NLC, a pattern that was also true for three other common fishes during our surveys.
Given those associations, we might conclude that restoring the habitat of any of those species would benefit most other species in the drainage. We would be wrong. Instead, the species we examined showed mostly idiosyncratic habitat relationships. In other words, the main habitat associated with one species was neutrally, or sometimes even negatively, associated with other species. Had we only focused on the species-diversity associations, and not examined the underlying habitat associations, we would have falsely supported using one or more of those species as “surrogates” for other fish.