mcbem-2014-01-submission-wwf-en

DAY 2 – 7 JUNE 2013
V - CUMULATIVE IMPACTS AND MITIGATION/ COMPENSATION FRAMEWORKS
Ecological Risk Assessment Framework for Pacific Canada
Cathryn Clarke Murray, WWF Canada; Megan Mach, Rebecca Martone, Center for Ocean Solutions; and
Miriam O, Institute of Ocean Sciences
Cumulative Effects
Cumulative effects result from the incremental, accumulating, and/or interacting impacts of an activity
when added to other past or present impacts (Hegmann et al., 1999). We have classified cumulative
effects into three types; 1) multiple activities sum to produce a larger magnitude stressor. For example,
shipping, recreational boating and coastal construction activities all produce some degree of noise,
which together result in greater underwater noise. 2) A single activity produces multiple stressors; for
example cruise ships produce noise, chemical contaminants, nutrient waste and garbage, and 3)
multiple activities produce multiple stressors whose cumulative effects are difficult to predict and
measure (Figure 11). There can be considerable uncertainty in a single impact pathway from activity to
stressor to species response but when you have multiple pathways, it is difficult to assess impact and
the effect on species and ecosystems.
Figure 11. Multiple activities produce multiple stressors. Courtesy of Cathryn Murray.
Risk Assessment
Risk assessment is a decision making tool and ecological risk assessment uses a scientific understanding
of how human activities put species, habitats and communities at risk. Risk assessment can be used for a
number of purposes. Objectives can include 1) assess cumulative risk to species, for the Species at Risk
Act or other purposes, 2) identify high risk activities, for example, risk from shipping and 3) identify high
risk areas, for marine spatial planning, reserve design or ecosystem-based management. There are a
number of risk assessment frameworks recently developed for marine systems (Park et al., 2010;
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