A review of prehistoric and early historic mainland salt marsh vegetation in the northern-Netherlands based on the analysis of plant macrofossils

The article presents an overview of archaeobotanical research on artificial dwelling mounds, so-called 'terps', in the northern-Netherlands. A total of 40 studies carried out over the past 40 years is evaluated. The vegetation diversity in the area as well as the differences with the present marsh are studied. Seriation, Principal Component Analysis and Sorensen similarity indices are used to assess the diversity of both individual samples and sites. For comparison with the present marshes, an index based on the TMAP vegetation typology was defined. Based on these methods, a selection of the individual samples was analyzed phytosociologically. It is found that all samples represent a mixture of vegetation types, but that the salt marsh species are a constant factor. The variation in the sample composition is not related to their dating, except for some of the latest samples that reflect the earliest endikements. Great similarity to the present marshes is found, but the analysis also testifies of a landscape profoundly disturbed by human activities throughout history.