Part 5: Ecological Thresholds can Inform Resource Management
The Ocean Tipping Points project is a collaboration of natural and social scientists, lawyers, environmental managers, and stakeholders working to understand what drives abrupt ecological shifts, and how they might be prevented or reversed. This is the fourth blog in a series highlighting the latest research and insights from our team of researchers.
Non-linear threshold responses are common in ecological systems, driven by both natural and human-induced pressures on ecosystems. However, Incorporating ecological thresholds into management can be a daunting task. In many ecosystems we have limited ability to predict if a threshold exists, when and how rapidly it will be crossed, and if positive feedback loops that entrain the new state will develop.
To help address the challenge of integrating thresholds into management, a new review published by Foley et al. in Frontiers in Marine Science this month provides an accessible overview of approaches to identify ecological thresholds and their indicators. The article, “Using Ecological Thresholds to Inform Resource Management: Current Options and Future Possibilities”, aims to facilitate the transfer of ecological threshold science out of the often technical and specialized realms of theory, modeling, and experimentation and into the realm of practical implementation. The authors also highlight new approaches and tools that are being developed that are likely to advance the identification and use of thresholds in management.
Photo: Toby Hudson
Using multiple examples, from terrestrial grassland to coral reef management, Foley et al. discuss how practitioners can manage for thresholds now using quantitative targets, responsive monitoring, and appropriately scaled management actions. The authors outline 8 different methods that can be used to estimate ecosystem thresholds, identify drivers of change, and provide early warning of threshold response. The methods include statistical approaches ranging from General Additive Models (GADs) and boosted regression trees to structural equation modeling and identifying regime shift indicators. For each method, the paper outlines when and how it can be used, its strengths and weaknesses, what software and code is necessary for its use, and where to find more information or examples of the method.
Figure: The dynamics and structure of Florida Bay before (A) and after (B) crossing a threshold. The upper gray text bubbles between states denote drivers that pushed the system across a threshold and lower bubbles denote management action taken that restored the systems to its previous state.
Threshold science is a rapidly evolving field that has many challenges to overcome, but the insights it can provide are urgently needed to address current resource use and management problems. Managing for thresholds goes hand-in-hand with increasing calls for practitioners to use an ecosystem-based management framework to address cumulative impacts of multiple stressors, account for the complexities of coupled socio-ecological systems, and sustainably manage emerging uses. This synthesis paper provides key information and perspectives necessary to retool traditional management strategies and integrate techniques that will facilitate more holistic and successful ecosystem-based management in the future.
Foley Melissa M, Martone Rebecca G, Fox Michael D, Kappel Carrie V, Mease Lindley A, Erickson Ashley L, Halpern Benjamin S, Selkoe Kimberly A, Taylor Peter, Scarborough Courtney. Using Ecological Thresholds to Inform Resource Management: Current Options and Future Possibilities. Front. Mar. Sci., 09 November 2015. http://dx.doi.org/10.3389/fmars.2015.00095