|Title||De ontwikkeling van de natuurlijke vegetatie in de Wieringermeer-polder, de eerste groote droogmakerij van de Zuiderzee|
|Source||University. Promotor(en): J. Jeswiet. - Amsterdam : Mulder|
|Publication type||Dissertation, internally prepared|
|Keyword(s)||pioniersoorten - plantensuccessie - drainage - kwel - polders - ontginning - flora - wieringermeer - pioneer species - plant succession - seepage - reclamation|
|Abstract||The reclaimed sea bottom grew first a felt of blue and silicous algae, except in ditches. In very moist places unusual associations of green algae developed with some sulphur and purple bacteria.
The subsequent introduction of plants to the new land was promoted by water, by air only for a few anemochores, by birds to a slight extent and by men sometimes.
Of the 261 naturally dispersed species only about 50 could develop socially, and only a few of them over larger areas. Most species were nitriphilous, indicating the importance of N in the establishment. Dominance was studied by the Scandinavian method of plant sociology. Species distribution curves (Jaccard) were constructed.
Natural selection occurred mainly among seedlings. The reaction of the most important halophytes and glycophytes to salt concentration was examined. Musci and Hepaticae, although wind-distributed, formed associations only after a heavy leaching of salt by rainfall. Fungi appeared after a year. Finally the fauna and the usefulness of these investigations were considered.