Case Study Sanwich Terns - a probabilistic analysis of the ecological effects of dreding

Every year, large amounts of sand are extracted from the North Sea to meet the demands for construction activities. Potential ecological effects of these sand mining activities have to be examined and reported in so called Environmental Impact Assessments (EIA’s). In the Netherlands, the potential impacts of sand mining activities on tern populations often form an important topic in these EIA’s. Sand mining causes an increase in silt concentrations. This increase will influence the turbidity of the water, which may affect populations of visual hunting birds, such as terns.