The recplonization pattern of two cold-sensitive species was studied in the intertidal Wadden Sea near Sylt after their populations had been almost eliminated by the winter of 1995/96. Because of low predation pressure juvenile cockles Cerastoderma edule quickly recolonized the area in high numbers during the first summer. In contrast, the polychaete Lanice conchilega needed three years until the population reached similar densities as before the severe winter. In the first two years, coastal Lanice population was too small to release sufficient amounts of larvae to recolonize the intertidal fringe of its distributional range. These results stress that populations in the Wadden Sea, in some cases, crucially depend on exchange processes with the North Sea.