Detailed knowledge of past vegetation change is a valuable resource that contributes to addressing a variety of problems, including the planning of forest restoration projects, it assists in archaeological surveys and sheds light on past human-environment interactions. For the time before historical maps, information on past vegetation comes from pollen preserved in lake sediments and peats. While the Netherlands are particularly rich in pollen analytical investigations, data and interpretations are difficult to access and therefore often not considered. We aim to overcome this shortcoming by collecting and collating the existing Dutch pollen data into a national atlas of past vegetation and land cover change with direct applications to forest restoration, archaeology, and education. The map series will contain detailed reconstructions for the period from 15,000 years ago to the present in 1000 to 500-year timesteps. All original data will be placed into the public domain using the international Neotoma platform to ensure ease of access and long-term storage.
In constructing the maps, we will use the constraints of the abiotic landscape on the vegetation such as soil substrate, water table depth or the location of river channels for the past and present. Based on existing algorithms (Multi Scenario and Downscaling approach) we will develop a software solution for pollen-based quantitative vegetation reconstruction using environmental constraints. The wealth of information on subsurface geology in the Netherlands is internationally unprecedented providing an ideal situation to develop this approach further. The mapping will facilitate the synthesis of the many pollen diagrams spanning only a few thousand years resulting in regionally differentiated Holocene vegetation histories for the Netherlands, hitherto not available. Prior to mapping, data compilations will be used to analyse dependencies of vegetation composition and the dynamics of change on abiotic and biotic controls such as soil substrate. Resulting quantitative vegetation reconstructions will be compared to constraints not used in the map making process such as distance to the sea and known archaeological finds. Emphasis will be on reconstructions of past vegetation openness and its dependency on substrate, coastal proximity, and peat growth. The stability and resilience of different forest types will be evaluated to assist in forest restoration projects in cooperation with Staatsbosbeheer. Relationships between past vegetation patterns and archaeological finds will be analysed with support from archaeological consultants (RCE, BIAX, ADC). TNO will support the digitization of legacy data and evaluation of age models. Staatsbosbeheer and RCA will help in the dissemination of the results.