Effects of liming on forest soil algal communities

The effects of the application of dolomite lime (5 t ha-1) on soil algal communities were investigated in sessile oak (Quercus petraea (MATT.) LIEB.) and Norway spruce (Picea abies (L.) KARST.) plots situated in the Belgian Ardenne. Chlorophyta (60 taxa) were by far the most diverse group, followed by Xanthophyceae (10 taxa), Bacillariophyceae (3 taxa), Cyanophyceae (2 taxa) and Euglenophyceae (1 taxon). In both forest types, liming lead to a significant increase in soil pH, exchangeable magnesium and calcium. In the limed Quercus plots available phosphorus and soil solution nitrate concentrations were also increased. The soil algal diversity was similar in oak and spruce control plots and in limed spruce plots. However, in the limed oak plots a significantly higher algal diversity was observed. On the basis of a CCA analysis, three clusters of plots could be distinguished: a) Picea control plots, b) limed Picea and control Quercus plots, c) limed Quercus plots. Both soil pH and nutrient availability seem to be important in determining algal species composition in these forest soils