Using biological traits to predict species sensitivity to toxic substances.

Species sensitivity distributions (SSD) assume that sensitivity to toxicants within target species is random. While the SSD approach has shown promise, it is limited by the fact that data are sparse for most compounds, and that these data are largely based on the lethal responses of a small group of testing lab species. Here we present an alternative approach, based on the hypothesis that organisms' sensitivity to stress is a function of their biology, and can be predicted from species traits such as morphology, life history, physiology and feeding ecology. Using data from the US EPA's AQUIRE database, we found that four species traits explained 71% of the variability in sensitivity to toxicants within a group of 12 species exposed to 15 chemicals. Our results indicate that this approach has promise, but effort is needed to compile species trait information to increase the power, precision and taxonomic representativeness of this approach.