DISPERSAL STRATEGIES OF DANISH SEASHORE PLANTS

The present research is based on previous surveys of primary succession in Danish seashore communities. Dispersal spectra for these communities are set up, using diaspore morphology as evidence for mode of dispersal. Dispersal spectra of species occurring in different zones and different successional phases are compared, and differences between the dispersal spectra of natural and man-made communities are investigated. The dispersal of diaspores to Danish seashore communities occurs at random because it is mostly achieved by abiotic agents or human beings. Wind is the prevalent dispersal vector, even though wind dispersal is not as common in Danish seashore communities as it is in open, disturbed, treeless vegetation throughout the world. Dispersal by water is most common among seashore plants that occur in the outer zones. As the succession progresses, it is found that plants with no special device or censer dispersal are more frequent in the intermediary stages, while dispersal by ants, adhesion, and in the digestive tract of animals increases later in the succession. No significant difference between dispersal spectra of the natural and man-made communities was found.