THE USE OF SIMULATION MODELS IN RECONSTRUCTING PAST LANDSCAPES FROM FOSSIL POLLEN DATA: EXAMPLES FROM THE POLLANDCAL RESEARCH NETWORK

There is a great need of quantitative reconstruction of past vegetation and landscapes within the fields of climate change, archaeology, and ecology/landscape management. This poster aims at demonstrating the potentials and advantages of the modelling and simulation approach in pollen analytical research, and at the same time presents the NorFA (Nordic Academy for Advanced Study) international research-network POLLANDCAL (POLlen-LANDscape CALibration). The major goals of this network are the exchange of ideas and expertise, and the organisation of research training. The network includes scientists from twelve countries (the five nordic countries, Estonia, Britain, Switzerland, France, The Netherlands, Japan, and USA), and the necessary areas of expertise (palaeoecology, plant ecology, modelling, Geographical Information System GIS). The long-term aim of the network is to achieve of a robust calibration tool for the quantitative reconstruction of past landscapes using fossil pollen assemblages. The POLLANDCAL network has adopted the simulation model POLLSCAPE, as a working framework, aiming to develop the approach and train a group of palynologists in its application. POLLSCAPE enables the calculation of pollen assemblages and source area of pollen using a pollen dispersal and deposition function, vegetation data (either hypothetical or actual), and estimates of pollen productivity for the taxa involved. The model has been validated for forested landscape. Within the POLLANDCAL network, estimates of pollen productivity for northwest European herbs have been produced, which enables the application of POLLSCAPE to an open to semi-open mosaic landscape including both herbs and trees, and allows the group to tackle questions related to cultural landscape history. We illustrate the potentials of the simulation approach with two distinctly different examples: (1) testing the effect of differing vegetation composition and species distribution on the pollen assemblages and source area of pollen, and (2) assessing various hypothetical past landscape scenarios in order to identify the most plausible quantitative interpretation(s) of pollen data in terms of past landscape mosaic.