Managing the Impacts of Human Activities on Fish Habitat: The Governance, Practices, and Science

A Comprehensive Framework for Characterizing Cumulative Effects in Aquatic Ecosystems to Support Regional Environmental Assessments and Integrated Planning and Management

Roland Cormier


Abstract.—Project level regulatory review and environmental assessment processes typically assess and ascertain potential impacts of one project or human sector activity on a specific habitat or species. The scope of the assessment is usually limited to the ecological foot print or zone of influence of the project. The assessment also identifies key mitigation measures designed to reduce effects to residual levels. These measures tend to be sector or project specific with a focus on activity specific adverse environmental effects such as fish passage, flow maintenance or sedimentation control. By design, such assessments are not effective to ascertain the project’s contribution to the overall cumulative effects in a given ecosystem. In this paper, a risk analysis approach is discussed as a means to structure and facilitate the characterization of cumulative effects and in priority setting for management. As part of the hazard identification step, the risk analysis approach requires that the ecological unit and the zone of influence of relevant drivers of human activities be identified. Cumulative effects are considered as the residual effects resulting from activities operating within their respective legal and policy frameworks. In preparation for the Risk Assessment step, the paper describes the need to establish pathways of effects linking the relevant drivers of human activities to their resulting pressures and potential ecosystem goods and services Impacts. Pathways of effects are important components of risk management in identifying which pressure require new or enhanced mitigation measures.