Application of Chernobyl Caesium-137 fallout and naturally occurring Lead-210 for standardization of time in moss samples: Recent pollen-flora relationships in the Allgauer Alpen, Germany

Moss cushions were sampled in the Allgauer Alpen (Bavaria, Germany) during 1995 to compare the pollen assemblages from each site with the vegetational survey of 100 m2plots and the floristic records of bryophytes and vascular plants in a km2around the sites. Evaluation with a high resolution coaxial HPGe γ-detector of the137Cs and210Pb content in all samples permits a selection of moss cushions on the basis of the polsters already existing at the time of the Chernobyl event, exactly ten years before moss sampling. Moss cushions with high radionuclides Content thus supply information on: (1) the complete palynoflora; (2) a pollen sum that covers a more or less constant number of years; (3) a broad picture of the (past) land-use; and (4) the reconstruction of local vegetation dynamics within the last ten years. Pollen percentages computed on an (extra)regional pollen sum were compared with the quantitative abundances of the taxa in each plot. The ensuing ratio between the two parameters is a raw measure of the degree of pollen representation and contributes together with the make-up of palynomorphs to the study of plant communities in the past and to environmental impact assessments. Some pollen types indicate environmental disturbance due to acid rain and anthropogenic effects, and may be integrated into the landscape-ecology approach.