One of the most over-used reasons amphibians are endangered is that they are more sensitive to environmental changes and contaminants than other groups, making them “canaries” for the environment. This reason is mentioned without evidence and only backed with the reasoning that they have permeable skin and many are exposed to more environments due to their amphibious life history. A recent paper by Jacob L. Kerby, Kathryn L. Richards-Hrdlicka, Andrew Storfer, and David K. Skelly, tested this idea, apparently for the first time, by comparing the response of amphibians to toxins like pesticides and heavy metals.
The study found that amphibians are not more sensitive in at least three of the groups evaluated, which calls into question the justification of portraying them as canaries for the environment. Hopefully this study will force some to test their justifications, since, in my opinion, amphibian declines have been exaggerated in some cases by abusing poor quality data. Better data sets and better analyses will yield possible answers and research questions while poor quality research will only lead to more confusion.
Kerby, Jacob L., Kathryn L. Richards-Hrdlicka, Andrew Storfer, and David K. Skelly. 2009. An examination of amphibian sensitivity to environmental contaminants: are amphibians poor canaries? Ecology Letters 12: 1-8. doi: 10.1111/j.1461-0248.2009.01399.x