Auswirkungen von saurer Beregnung und Kalkung auf die Vitalität, Artenmächtigkeit und Nährstoffversorgung der Bodenvegetation eines Fichtenbestandes

The effects of simulated sulfuric acid rain and liming on ground vegetation of a 75-year-old Norway Spruce stand were analysed since summer of 1983. During the first two growing seasons no significant change in species composition had occurred on any plot. The frequently applied acid rain injured some constant moss species, this was reflected by chlorosis, necroses, and reduced average coverage or frequency. Damaged moss segments had decreased Ca-, Mg-, Mn-, Zn- und K-concentrations. Some secondary moss species, however were more tolerant to acid precipitation. Liming with dolomite at the beginning of the experiment improved the Ca-und Mg-nutrition of all investigated species (Thuidium tamariscinum, Oxalis acetosella, spruce seedlings), lowered the intensity of injury by acid rain with mosses, and reduced the Mn- (and Zn-)uptake of the vascular plant species. The combination of liming and irrigation with acid or "normal" water strongly increased the abundance of the herb Oxalis acetosella. Without liming the same species responded to acid rain with lower Ca- (and Mg-)contents in leaves; but no visible foliar damage occurred.