Evolutionary consequences for ecological risk assessment and management

The human health risk assessment (HRA) paradigm is being used as a basis for developing ecological risk assessment (ERA). The modification of the HRA paradigm to ERA will be most useful in an ecotoxicological sense, to assess the effect of hazards to single indicator species and populations, rather than to ecosystems. However, even for single species and population assessments, there are major differences in HRA and ERA. One such difference derives from the HRA tenet that human impairment at any age is important, and that each individual is important. For ERA, individuals are less important, and it is the population and its survival and interactions that are of concern. One exception is in the case of endangered species where every individual is critical because of its potential impact on survival and genetic diversity of the species. We suggest that ERA must take into account the relative reproductive value of the potentially impacted individuals in assessing hazards. This will involve adding additional steps to evaluate the value of the individual to current population levels, assessing reproductive value, and assessing recovery potential. Although ecologists recognize the importance of these factors, we suggest that they should be integral parts of ecological risk assessment.