Pollen assemblage–plant community relationships on the Storbreen glacier foreland, Jotunheimen Mountains, southern Norway

Abstract

SUMMARYPresent‐day pollen assemblages from 38 sites within differing but closely juxtaposed plant communities from the Storbreen glacier foreland in southern Norway, provide evidence for the degree to which these plant communities can be characterized by distinctive pollen assemblages. Multivariate statistical analyses of the data demonstrate a broad, tripartite division in the pollen record which reflects the three major vegetation types: (i) Pioneer Poa alpina–Trisetum spicatum community; (ii) Snowbed Salix herbacea‐dominated community; (iii) Dwarf‐shrub heath community. Occasional overrepresentation of Salix, Oxyria and Cyperaceae pollen leads to assemblages that are difficult to characterize and remain outside all major groups. Four general pollen indices are derived, each of which provide maximum limiting estimates for the proportion of pollen derived from different potential source areas. Combined with isopollen mapping the indices suggest that in pioneer communities between 20–40% of pollen collected within the community could have derived locally i.e. within the 16 m2 quadrat, whereas in the dwarf‐shrub heath this figure rises to over 60%. The remaining pollen largely originates from long distance transport, i.e. < 1 km, with little movement of foreland‐derived pollen across the foreland itself. Thus the ‘extra‐local’ component appears to play a relatively insignificant role within the area of study. The ability to separate such local and long‐distance elements will prove of particular value in the reconstruction of the history of plant communities beyond the tree‐line.