Resource allocation-based life histories: A conceptual basis for studies of ecological toxicology

Whereas ecological assessments of contaminants are concerned with populatio ns and higher levels of organization, most mechanistic work in toxicology i s directed at effects on individuals and their parts. We propose that studi es based on individuals can be useful in ecological analysis of polluted sy stems when based on the concepts of resource allocation-based life history analysis. At the heart of the resource allocation approach is the concept o f operative environments of individuals (i.e., environmental factors influe ncing birth, death, or migration). Contaminants can have strong influences on operative environments, modifying resource allocation strategies that re flect changes in energy assimilation and demands. By examining contaminant- induced responses of individuals from the perspective of changing operative environments, individual-based changes and population dynamics can be addr essed in an ecologically rigorous manner.