Biodiversity

The coastal zone is characterised by strong gradients of environmental factors causing a continuous decrease in the number of marine species towards the landward side. However, this is only true for larger species. Small sized meiofauna attained a broad maximum of abundance and species richness at mid tide level (meiofaunal biodiversity).

Introduced species

During the past decades, the number of species introductions from other parts of the world has strongly increased. This is mainly due to increases in trans-oceanic traffic with faster ships. Up to now, most of the newcomers were harmless and fitted into the native communities in the North Sea. However, long-term effects of the newcomers are still unknown and deserve further attention. This is particularly true for species like American razor clams Ensis americanus which became a dominant member of the North Sea benthos, American slipper limpets Crepidula fornicata, or Pacific oysters Crassostrea gigas which spread by now and may have the capacity to displace the native mussel beds. In addition, the next species to be introduced might be disastrous. Therefore, we study the effects introduced species may exert on the established communities.