Pollen accumulation rates as a tool for detecting land-use changes in a sparsely settled boreal forest

Abstract

A peat profile from the village of Nellim in northern Finnish Lapland was analysed at a near-annual resolution in order to test to what degree of accuracy the land-use history of the village could be reconstructed on the basis of organic microfossils. The profile was first AMS 14C dated and a robust chronology constructed to enable near-annual sampling. A set of 47 contiguous samples were treated and counted to produce a pollen accumulation rate diagram (PAR, grains cm−2 year−1). PARs enabled a better distinction of the fine-scale human induced changes in the pollen assemblages than the classical percentage representation because real changes in each pollen taxon could be followed. Changes in the accumulation rate of pine pollen reflect regional changes in forest-use in Lapland and both local events and regional logging activity could be distinguished. Local within-mire changes were deduced from the peat stratigraphy and the testate amoebae. The limitations for using PARs seem to be connected to the physiology of the plants and the taphonomy of the different pollen types and this must be taken into account when making interpretations.