Managing complex systems: an interdisciplinary approach to modelling the effect of social and ecological interactions on carbon storage in blanket peatlands.

Abstract

Peatlands are globally important for carbon storage, water quality and biodiversity. However, many have been degraded by land use, and efforts to conserve or restore them are often contested by stakeholders with different objectives. Peat accumulates as a result of a complex network of interactions, which makes it challenging to predict the impact of climate and land use. Stakeholders’ knowledge may help to provide insights into these interactions and into the issues that underpin conflict. To investigate the impact of social and ecological factors on blanket peatland carbon storage, an interdisciplinary approach was used to couple cognitive and peatland development models. Blanket peatland stakeholders developed fuzzy cognitive maps based on their perceptions of peatland interactions, which they validated to agree on the structure of an aggregate network. To explore the impact of land–use objectives on carbon stocks, stakeholders proposed changes to a set of factors that controlled the state of the network. The changes identified to improve carbon storage and water quality had a positive effect on carbon stored, but those that were proposed to support local livelihoods had no effect on carbon. This was partly because some stakeholders perceived that supporting livelihoods was incompatible with measures that were likely to result in shallower water tables. However, further discussions between stakeholders suggested that land–use objectives could complement each other. To enrich the results of the network model, the DigiBog peatland model was modified to simulate blanket peat accumulation. Using two factors from the cognitive model, climate change and gully blocking, two novel modelling studies were produced. The first showed that existing peatland development models may overestimate peat accumulation because they aggregate climate variables into annual rather than weekly inputs; the second, that gully blocking is needed to arrest peat losses from oxidation in gullied systems, but that these losses would not be recovered 200 years after gully blocking. The combination of both cognitive and process–based modelling provides an example of how stakeholder knowledge can be incorporated into simulations of complex ecosystems which is likely to be applicable to other social–ecological systems where land use is contested. In this case, doing so provided holistic insights into how stakeholders’ perceptions, and the impacts of climatic forcing and restoration, affect carbon storage in blanket peatlands