Presenter: Brian Katz (Oregon State University)

Description:
Multiple stressors such as ocean acidification (OA) and hypoxia combine to affect the health and growth of economically and culturally important shellfish species in the Chesapeake Bay, presenting problems for communities that are reliant on these shellfish. This aim of this study is to assess both ecological and social thresholds in the Chesapeake Bay to inform decisions on how and where to invest in adaptation strategies. How long can both organisms and the growers that rely on them persist? To understand thresholds, we identify patterns of exposure and sensitivity: where, when, and how potential thresholds affect local shellfish reliant stakeholders. The study relies on a geovisualization tool developed for mapping shellfish reliance based on observations and model outputs of estuarine stressors. These are linked to biological responses of shellfish species at various life stages. Spatiotemporal patterns of exposure and sensitivity to multiple stressors are overlaid and visually analyzed for regional and sub-regional differences. Results indicate areas where baseline stress is greater and stressor hotspots are more intense. These are contrasted with areas where the both the rate of change in stressors is faster and social sensitivity is more acute. These results have implications for the different adaptation strategies that may be necessary to increase resilience. Persistent variability and extremes may mean that stakeholders experience steady risks to shellfish growth. Conversely, faster rates of change and greater social sensitivity may mean that risk of exceeding thresholds is greater. Fast rates of change challenge the extent to which adaptation strategies may work before thresholds are crossed.