Individuals versus Organisms versus Populations in the Definition of Ecological Assessment Endpoints

Abstract

Discussions and applications of the policies and practices of the U.S. Environmental Protection Agency (USEPA) in ecological risk assessment will benefit from continued clarification of the concepts of assessment endpoints and of levels of biological organization. First, assessment endpoint entities and attributes can be defined at different levels of organization. Hence, an organism-level attribute, such as growth or survival, can be applied collectively to a population-level entity such as the brook trout in a stream. Second, assessment endpoints for ecological risk assessment are often mistakenly described as "individual level," which leads to the idea that such assessments are intended to protect individuals. Finally, populations play a more important role in risk assessments than is generally recognized. Organism-level attributes are used primarily for population-level assessments. In addition, the USEPA and other agencies already are basing management decisions on population or community entities and attributes such as production of fisheries, abundance of migratory bird populations, and aquatic community composition.

Neonicotinoid insecticides negatively affect performance measures of non‐target terrestrial arthropods: a meta‐analysis

“…It is essential to understand how neonicotinoid sub‐lethal toxicity endpoints (in field and lab studies) may affect a range of species at levels of the organism (e.g., reproduction, condition) and population (e.g., abundance; Suter et al. ).…”

Polychlorinated biphenyls and hudson river white perch: implications for population‐level ecological risk assessment and risk management

“…However, as noted by DeMott et al (2005), Dearfield et al (2005), and Suter et al (2005), most ecological risk assessments performed by the US Environmental Protection Agency (USEPA) still focus on organism‐level effects. The rationale for focusing on organisms rather than on populations involves 2 elements: 1st, a focus on organism‐level attributes is practical because effects on organisms can be estimated using standard toxicity tests (Suter et al 2005); and 2nd, the use of organism‐level attributes is well supported by law, policy, and agency precedents (Dearfield et al 2005; Suter et al 2005). The organism‐level approach assumes that protection of organism‐level attributes will protect populations.…”

The need to integrate laboratory- and ecosystem-level research for assessment of the ecological impact of radiation

“…For the sake of environmental protection indeed, there is growing consensus among scientists that higher levels of organization, for example, populations, communities, and ecosystems (as opposed to individual organisms), are the appropriate targets for setting environmental protection goals for radiation. The differences between laboratory and in situ testing have been identified and discussed for many other types of environmental stressors and share a common conclusion that methodologies for assessment at an ecosystem level (as opposed to individual organisms) are deserved (Castro et al ; Anderson et al ; Suter et al ).…”