Science Advisory Report 2015/020
A science-based approach to assessing the impact of human activities on ecosystem components and function
Summary
- This Science Advisory Report (SAR) provides a structured approach for assessing the impact of an anthropogenic pressure on an ecosystem component and its function. The impact is assumed to result from a change in the status of an ecosystem component caused by a pressure. This approach is merely one aspect of a larger, multi-step risk management process.
- This advice incorporates previous advice related to assessing how pressures may impact fisheries productivity and how fishing may impact stock status. This approach can be applied consistently to any ecosystem component, pressure, and ecosystem function, and is independent of time and space.
- The relationships between any ecosystem component and any pressure, as well as the ecosystem function provided by the ecosystem component will often be non-linear and usually sigmoidal. In cases where data is limited, informed inferences will be necessary and should include a measure of uncertainty.
- This advice includes three categories of impact that characterise the status of ecosystem function as a result of changes to an ecosystem component. The boundaries between these categories represent transition points that indicate where an incremental change in the status of an ecosystem component substantially affects its ability to perform its function. Depending on risk tolerance levels, management action may be appropriate at any point along the spectrum of pressure (i.e. negligible impact to high impact). However, at the transition points the nature or necessity of management action may change more than incrementally.
- Integral to this advice are the Pathways of Effects (POEs) models that have been developed for major classes of anthropogenic pressures. In cases where POEs do not already exist, these (or other similar analyses, e.g. interaction matrices) will be required to identify the potential impacts of human activities on ecosystem components of concern.
- In addition to understanding the interaction between pressures and the ecosystem, an understanding of the relative contributions of different ecosystem components to the ecosystem function of interest and of the amplitude of variability linked to natural factors improves the ability to apply the approach provided in this advice.
- The likelihood of an ecosystem component being exposed to a pressure and the level of risk tolerance in policy and decision-making must be considered in a broader risk management process; however neither of these aspects is discussed in this advice.
This Science Advisory Report is from the December 9-11, 2014 National Science Advisory Process titled Ecological Risk Criteria for Integrated Oceans Management. Additional publications from this meeting will be posted on the Fisheries and Oceans Canada (DFO) Science Advisory Schedule as they become available.
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