RELATIONSHIP BETWEEN ACIDIFICATION AND MA CROPHYTE COMMUNITIES IN SOFT-WATER IN THE NORTHERN VOSGES - FIRST RESULTS

In the Northern Vosges (Northeastern, France), a study has clearly sho wn that several weakly mineralized streams were characterised by a ver y low alkalinity. To determine water chemistry of 40 sites, physico-ch emical factors were measured each season during 1994. To follow the ac idification status, parameters of mineralization were analysed each mo nth on 15 sites. The first results have shown that 11 sites were acidi fied and temporal variations of Al concentrations were demonstrated. T he vegetation of these 11 stations was composed of Bryophyta, and some times of Potamogeton polygonifolius. They seem to have (at least tempo rally) the ability to survive under extremely acid conditions.