Klerks, P. L. Dept. of Biology, University of Southwestern Louisiana, klerks@usl.edu

Risk assessment generally does not recognize that a stressor will exert a selective pressure on the affected population and that this may ultimately result in a genetic adaptation to the stress and thereby a possible reduction in the ecological impacts. Results on Cd-resistance in the oligochaete Limnodrilus hoffmeisteri inhabiting Cd-polluted Foundry Cove (on the Hudson River) will be presented that document that at least some natural populations adapt to some environmental contaminants. However, reported declines in species diversity in contaminated environments indicate that many populations fail to adapt. This may be a consequence of the large number of different contaminants typically present in polluted environments. Theoretical considerations will be presented that indicate that adaptation will be less likely as the number of contaminants increases. Empirical results will also be shown that are consistent with this prediction: a lack of evidence of adaptation in populations inhabiting sites in Louisiana contaminated with a large number of different contaminants. In conclusion, risk assessment should incorporate the possibility of adaptation, with the probability of adaptation not only influenced by traditional population genetic factors (e.g. selection intensity, generation time) but also by the complexity of the contamination.
Day: Friday, Feb. 5
Time: 10:30 - 10:45am
Location: Hilton of Santa Fe
Code: SS11FR1030H