Succession and soil development in man-made coastal ecosystems at the Baltic Sea

By the creation of Køge Bay Seaside Park in 1978 the opportunity was given to study the establishment of vegetation and primary succession in a man-made coastal area. As the soil consists of marine material from the Baltic Sea, no organic matter or seedbank was present. The first steps of primary succession were followed in 1980, when the initial inventories of flora immigration and soil development were carried out in coastal grasslands and plantings. The surveys were repeated in 1992 and 1993. Except for the planted woody species and a few sown grasses, all other species of plants have reached the area through natural dispersal of diaspores. The total number of species in the permanent plots has increased from 26 in 1980 to 91 in 1993. The results indicate that this number will continue to increase in the coming years until a certain level. Then it will probably decrease as a result of competition from woody species, unless the vegetation is kept in a steady state by disturbances or management. Today the area is very far from the initial situation, and the off-shore barrier has changed towards a landscape dominated by small groves and grasslands of an urban common type.