The impact of cumulative stressor effects on uncertainty and ecological risk

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Estuarine and coastal systems around the world are experiencing numerous pressures on the environment. To safeguard healthy systems for the future and avoid catastrophic collapses, we must understand how systems will respond to these stressors and use this information to inform our decision-making. Multiple stressors can interact in complex ways that can result in effects much greater, and sometimes smaller, than what was expected from their individual effects. Accounting for these stressor interactions in management requires an understanding of their effects and any uncertainty should be considered in risk assessments.

Here, we studied the ecological risk and uncertainty associated with cumulative stressors effects, including local/land-derived stressors and climate change. By modelling how important organisms (e.g. shellfish, worms, etc.) respond to these stressors in estuaries across Aotearoa New Zealand, we gained insights into priority stressors, their additive or cumulative effects and the uncertainty associated with these predictions. Visualising stressor interactions (in 3D) and uncertainty estimates for complex stressor effects can help improve transparency and communication between scientist and managers, and urge for more precautionary management.