Nitrogen accumulation by six pleurocarpous moss species and their suitability for monitoring nitrogen deposition

This study reports on a fertilization experiment with the six pleurocarpous moss species Brachythecium rutabulum, Hylocomium splendens, Pleurozium schreberi, Rhytidiadelphus squarrosus, R. triquetrus and Scleropodium purum. The intention was to find one or more species which clearly reflected the simulated N deposition in its tissue N contents and which could therefore be regarded as valuable for an N-monitoring programme in central Europe. The mosses were fertilized over a period of 12 months with nitrogen in the form of three different compounds. The additional nitrogen was supplied at 40 kg N ha 21 year 21 in all treatments. Significant increases of tissue N content were recorded for all species with the exception of Hylocomium splendens. The curves of N accumulation distinctly differed with time among the six species. Fertilization with nitrate led to smaller increases of tissue N than solutions containing ammonium. For most of the species, at least, a trend towards N saturation was observed over the period of investigation. Some species showed injury which was probably due to toxic effects of the ammonium ion. In the unfertilized plots, seasonal variations of tissue N content were recorded. The results show that Pleurozium schreberi and Scleropodium purum, in particular, might be suitable species for monitoring N-deposition in central Europe.