Publication abstract

Quantifying cumulative impacts of human pressures on the marine environment: A geospatial modelling framework

Stelzenmüller, V., Lee, J., South, A.and Rogers, S.I.

Worldwide increasing pressure on the marine environment requires an integrated and ecosystem-based management such as marine planning. In turn, this calls for a sound understanding of cumulative impacts of human pressure on the marine environment. As yet, the quantification of risk of cumulative impact remains a difficult task in practice.

We developed a geospatial modelling framework that combines standardised data describing footprints and/or intensities of human activities with a measure of the sensitivity of marine landscapes to the pressures of these activities and allows quantifying the risk of cumulative impacts on the UK continental shelf.

With the help of GIS - Multi-Criteria Analysis we developed an algorithm that produced four different scenarios to quantify risk of cumulative impacts. Modelled scenarios reflected additive interactions of pressures and accounted for linear and logistic decrease of importance of ranked pressures, and we simulated expert consultation to rank the importance of the pressures. Finally, we assessed the sensitivity of the scenario outcomes to changes to input parameters.

The risk assessment framework exposed both a wide range of possible modelled scenarios and uncertainties, but all scenarios revealed similar locations with an increased risk of cumulative impacts. Results showed that the logistic weighting scheme was very sensitive to changes in the importance and ranking of pressures in comparison to the linear weighting scheme.

Synthesis and applications. For marine planning the use of a weighting scheme with more constrained values should be used in conjunction with a sensitivity analysis of the order of input parameters. Our standardised framework can be applied to identify suitable areas for the development of marine resources and therefore provides a practical tool that could support the development of sustainable marine plans.

Reference

Stelzenmüller, V., Lee, J., South, A.and Rogers, S.I.  (2010) Quantifying cumulative impacts of human pressures on the marine environment: A geospatial modelling framework. Mar Ecol Prog Ser 398: 19–32, 2010