Large-scale changes in marine ecosystems with significant both environmental and economic consequences are observed in increasing numbers worldwide. Alterations in structure and functioning of marine ecosystems have been increasingly reported through the world in relation to overfishing, climate change and for example eutrophication. These pronounced and abrupt multi-trophic level reorganizations of large-scale ecosystems are usually termed ecosystem regime shifts. In my talk, I will provide an overview of some main reported regime shifts in marine ecosystems in relation to potential underlying mechanisms. To exemplify the existence of several potential ecosystem states, I will present the Baltic Sea as a case study, as it offers long-term monitoring data. My presentation will include results from state-of-the-art statistical analysis allowing the detection of non-linearity and thresholds in food-web interactions and their potential to recover. The results suggest that shifts in ecological and economic baselines can lead to higher economic uncertainty and costs for exploited ecosystems, in particular under climate change. Several research needs in the field of regime shifts, recovery and baselines will be discussed.

Speaker: Thorsten Blenckner

Thorsten is currently an Associate Professor and leader of the Marine Theme, at the Stockholm Resilience Centre, Stockholm University, Sweden. He has a background in aquatic ecology, climate change and ecosystem processes and function.