From hazard to risk: introducing the vulnerability into pesticide ecotoxicology

The evaluation of site-specific ecological quality is an emerging issue in the environmental policy of the European Union. Pesticides are potentially a major stressor for ecosystems and current regulations cannot ensure the protection of real ecosystems from harmful effects due to pesticides exposure, since different ecosystems may have significantly different level of alteration in response to the same level of exposure. Different responses to a certain stressor are determined by the vulnerability of ecological systems. Despite vulnerability is a well-established concept in all the disciplines which deal with risk assessment, it is often overlooked in ecotoxicology. Nevertheless the study of ecological vulnerability is a developing branch in the field of ecotoxicology and the concept of vulnerability itself, often used in the past just like a synonymous of either sensitivity and susceptibility, is finally gaining a defined, wide acknowledged meaning. One of the key point of this view is the consideration that “Ecological vulnerability” is a term which can regard several hierarchical level of organization. Here is proposed a framework methodology for the assessment of the ecosystem vulnerability, considering the fact that ecosystem encompasses both community of living organisms and abiotic factors. Community vulnerability to a certain stressor in particular can be determined as the combination of three aspects: the susceptibility of exposure, the intrinsic sensitivity and the recovery potential (resilience). Since vulnerability depends upon the characteristics of the ecological system, a strong linkage with TERA (trait-based ecological risk assessment) is feasible.