Tuesday 6
Building a foundation for managing for tipping points in marine ecosystems
Carrie Kappel, Courtney Scarborough, Mary Hunsicker, Adrian Stier
› 11:35 - 12:30 (55min)
A global review of marine ecosystem regime shifts (part of 'Building a foundation for managing for tipping points in marine ecosystems' session)
Courtney Scarborough  1, *@  , Carrie Kappel  1, *@  
1 : National Center for Ecological Analysis and Synthesis  (NCEAS)  -  Website
735 State Street, Suite 300 Santa Barbara, CA 93101 -  États-Unis
* : Corresponding author

A growing body of scientific evidence suggests that marine ecosystems around the world can experience dramatic and abrupt shifts. Ecosystem shifts are often unforeseen, can be difficult to reverse, and have direct impacts on people's livelihoods and wellbeing. As a result, these non-linearities in system dynamics have important implications for ocean management. As managers around the world shift to ecosystem-based approaches to marine management, an understanding of potentially irreversible non-linearities is critical to effective decision-making. Though interest in tipping points and ecosystem shifts has been on the rise, a comprehensive synthesis of these shifts and their drivers and consequences in marine ecosystems has not been published. Building upon existing efforts (e.g., databases from the Resilience Alliance and Stockholm Resilience Centre), we have compiled a comprehensive, systematic global database of examples of marine tipping points across various systems from the intertidal to the open ocean. This dataset includes both examples of systems that have shifted due to changes in climatic or oceanic conditions and those that have shifted due to human pressures, such as overharvest of key species or nutrient input. Through analysis of over 100 case examples we have found numerous commonalities across systems and scales as well as some potential early warning indicators that may assist managers in anticipating shifts before they occur. We have identified ecosystem characteristics that may make a system more prone to abrupt shifts, factors that confer more or less resilience to these shifts, and have developed a comprehensive list of drivers, response variables, underlying mechanisms, and implications for goods and services in these case studies. We are also beginning to develop an assemblage of potential early warning indicators, or variables that are sensitive and respond quickly to changes in environmental stressors, that may provide advance warning that a shift is approaching and have the potential to be considered in habitat-specific portfolios of indicators. Finally, to better understand the variety of ecosystem shifts that are possible and match their dynamics to appropriate models and indicators, we have categorized the observed shifts based on their underlying ecosystem dynamics, when known (i.e. smooth/linear tracking vs. abrupt/threshold vs. discontinuous/regime shift). This effort will contribute significantly to the broader goal of helping managers recognize where ecosystem shifts have the potential to occur and how to best anticipate, avoid, or respond to these changes.

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