Meetings of the Royal Botanical Society of the Netherlands

The scale of temporal patterns (periodicity, succession, colonization) of multicellular green algae differs considerably from comparable patterns of higher plants. This gives a possibility to study these patterns under favourable conditions. A phycologist Can be compared with a vegetation ecologist, trying to describe a vegetation from a balloon with aid of a telescope: it is not possible to sit down beside an algal growth, sorting and investigating the organisms by simple hand movements. On the other hand, when an algal ecologist waits a few weeks, processes have evolved that take several years in higher plants. Algal growths can be collected in the field and can be kept during long periods after fixation. Only little material is collected, since the “minimum area” often is very small. Within a few decimeters, zonation patterns occur, resembling higher plant patterns which are of a much greater scale (metres, kilometres). Complete colonization of a bare area with algae is effectuated in a short time (1-3 months, including several successional stages). The same process in higher plants requires several years. The algal growth has stabilized within one or two years, higher plants need many more (5-20) years.