Dynamic mapping of nature values to support prioritization of coastal oil combating

Due to the continuing demand of oil for energy production and to manufacture various consumables the threat to coastal ecosystems by maritime oil transport remains at a high level. Clearly there is a need for tools that can be used in mitigating the environmental damage incurred by oil accidents. This paper presents a dynamic mapping application for comparing the ecological value of the shoreline of the Gulf of Finland to guide decisions on where to lay oil booms after an oil spill accident. The maps were required to combine conservational value of different species occurrences, the estimated level of oil exposure, the estimated recovery potential of the occurrences following the accident, and the efficiency of oil booms to safeguard the species inhabiting the occurrences. The mapping was tested in representative cases. The results indicate that the ranking of neighbouring shoreline streches changes depending on weather conditions and on choices made in developing the significance criteria. To the authors knowledge this work represents a unique effort in combining biological and geospatial expertise to provide decision support for oil combating. Such support is essential should ecological values truly be included in oil combating planning and management.