MODERN POLLEN SAMPLES FROM WEST GREENLAND AND THE INTERPRETATION OF POLLEN DATA FROM THE BRITISH LATE‐GLACIAL (LATE DEVENSIAN)

Abstract

SummarySamples of the modern pollen rain, some from lake sediment and some from moss polsters, were taken in two regions of West Greenland in which the climate is respectively low arctic continental and low arctic oceanic: (1) round the head of Söndre Strömfjord at 67° N; and (2) the south‐west of Disko Island at 70° N. The vegetation has been described and analysed by Böcher (1954, 1959, 1963). In Region 1 where the vegetation is a mosaic of xerophilous grassland with Artemisia borealis (steppe) and Betula nana heath, mean pollen percentages from 11 polsters corresponded quite closely with percentage cover for those taxa in the vegetation. Polsters from steppe could be distinguished from heath polsters by higher values for Artemisia in steppe and Ericales (Ledum, Empetrum, Vaccinium, Rhododendron) in heath, but Betula nana and grasses, with the highest values in both pollen and vegetation, showed no consistent difference between polsters of different origin‐presumably showing good pollen dispersal. In four lake samples B. nana was over‐represented by pollen values and Artemisia had a lower mean than in terrestrial samples. In Region 2 where the vegetation is a more oceanic heath in which B. nana is infrequent and Artemisia absent, the pollen samples differ from those of Region 1 in consistently higher values for Cyperaceae and lower values for Gramineae and B. nana: Artemisia is here represented by only the same few grains as the exotic taxa Pinus and Picea. When compared with vegetation cover in Region 2, sedges and B. nana appear to be over‐represented in pollen samples, especially from lakes, and Salix herbacea and the herbs of snow‐bed and heath‐mat communities to be under‐represented.These findings can be used in interpretation of Late Devensian pollen spectra which lack arboreal pollen, and make it probable that: (i) samples from the earliest Late Devensian pollen zones represent an oceanic dwarf‐shrub vegetation in which there was more Salix herbacea and fewer sedges than pollen values suggest; (ii) Betula nana did not at any time form an appreciable part of the vegetation cover; and (iii) Artemisia pollen values provide an index to local vegetation cover, which implies a vegetation mosaic correlated with snow cover during the period of the Loch Lomond Advance (c. 11000 to 10500 B.P.).