Relative Sea-Level Changes at Shallow Coasts Inferred from Reed Bed Distribution over the Last 50 Years in Matsalu Bay, the Baltic Sea

Reed bed growth dynamics within the shallow Matsalu Bay, Baltic Sea, was studied over the last 50 years. There was expansive reed growth from the 1950s until the end of the 1970s, while over the last few decades the growth rate of the reed beds (establishment of new clones) has been considerably reduced or even ceased. Our results suggest that the distribution of the reed beds is controlled by mean sea-level variation superposed on a background of postglacial isostatic uplift. The reduced growth rate over the last decades is probably caused by an increase in the intensity of cyclonic activity (storminess) resulting in an increase of the average sea level, which has limited the suitable growth zones for the reed weakened by eutrophication.