Using Ecosystem Response Footprints to Guide Environmental Management Priorities

Managing cumulative effects in coastal marine ecosystems and predicting outcomes of mitigation or restorative actions represent a major challenge globally for scientists and decision-makers. Cumulative effects arise from the combined impact of individually minor yet collectively impactful activities. Each activity and the associated stressors generate distinct footprints. However, activity and stressor footprints do not necessarily inform ecosystem responses, which often occupy different space and time scales. Ecosystem responses are characterized by context dependencies (i.e., the same responses do not occur everywhere). In our critical review, we identify the challenges in characterizing ecological footprints based solely on stressors and activities and suggest a shift is needed to emphasize the "ecosystem response footprint". Our new framework lays out a series of ecological characteristics of responses that can be used to conceptualize footprints that include potential stressor legacy effects and non-additive interactions that lead to nonlinear ecosystem shifts, disturbance-recovery dynamics implicated in recoverability, and the spatial and temporal scales of stressor regimes. We use these characteristics to define the extent and depth of ecosystem response footprints (which are often different to activity and stressor footprints) and link these attributes to suitable actions for generating ecological recovery and resilience. Defining and reframing the focus on ecosystem response footprints can inform a holistic ecosystem-based approach to managing cumulative effects and inform guidelines for marine environmental management.