Effects of chemical contaminants an genetic diversity in natural populations: implications for biomonitoring and ecotoxicology

The conservation of genetic diversity has emerged as one of the central iss ues in conservation biology. Although researchers in the areas of evolution ary biology, population management, and conservation biology routinely inve stigate genetic variability in natural populations, only a handful of studi es have addressed the effects of chemical contamination on population genet ics. Chemical contamination can cause population reduction by the effects o f somatic and heritable mutations, as well as non-genetic modes of toxicity . Stochastic processes in small populations, increased mutation load, and t he phenomenon of mutational meltdown are compounding factors that cause red uced fitness and accelerate the process of population extirpation. Although the original damage caused by chemical contaminants is at the molecular le vel, there are emergent effects at the level of populations, such as the lo ss of genetic diversity, that are not predictable based solely on knowledge of the mechanism of toxicity of the chemical contaminants. Therefore, the study of evolutionary toxicology, which encompasses the population-genetic effects of environmental contaminants, should be an important focus of ecot oxicology. This paper reviews the issues surrounding the genetic effects of pollution, summarizes the technical approaches that can be used to address these issues, and provides examples of studies that have addressed some of them. (C) 2000 Elsevier Science B.V. All rights reserved.