Patterns in recent and Holocene pollen influxes across Europe; the Pollen Monitoring Programme Database as a tool for vegetation reconstruction.

The collection of modern spatially extensive pollen data are important for the interpretation of fossil pollen diagrams. Such datasets are readily available for percentage data but lacking for pollen accumulation rates (PAR). Filling this gap has been the motivation of the pollen monitoring network, whose contributors monitored pollen deposition in modified Tauber-traps for several years or decades across European latitudes. Here we present this monitoring dataset consisting of 351 trap locations with a total of 2742 annual samples covering the period from 1981 to 2017. This dataset shows that climate parameters correlating with latitude determine pollen productivity. A signal of regional forest cover can be detected in the data, while local tree cover seems more important. Pollen traps situated beyond 200 km of the distribution of the parent tree are still collecting occasional pollen grains of the tree in question. PAR's of up to 30 grains cm^-2yr^-1 in fossil diagram should therefore be interpreted as long distance transport. Comparisons to fossil data from the same areas show comparable values. Comparisons often demonstrate that similar high values for temperate taxa in fossils sites are found further south or downhill. While modern situations comparable to high PAR values of some taxa (e.g. Corylus) may be hard to find, CO2 fertilization and land use may case high modern PAR's that are not documented in the fossil record. The modern data is now publically available in the Neotoma Paleoecology Database and hopefully serves improving interpretations of fossil PAR data. [ABSTRACT FROM AUTHOR]