THE EFFECT OF AIR-POLLUTION ON MOSSES IN SOUTHERN SWEDEN

The present occurrences of 10 mosses at 64 localities in southern Sweden are compared with those before 1950. Orthotrichum striatum Hedw. was confirmed at 10%, O. speciosum Nees at 17%, Antitrichia curtipendula (Hedw.) Brid. at 23%, and Neckera pumila Hedw. at 38% of their old localities. Although Ulota crispa (Hedw.) Brid was confirmed at 65% of its localities, the cushions were smaller compared to material from before 1950 kept in herbaria. Hylocomium splendens (Hedw.) B. S. G. was confirmed at 70%, Orthotrichum lyellii Hook & Tayl. at 75%, O. affine Brid. at 86%, Leucodon sciuroides (Hedw.) Schwaegr. at 94%, and Hypnum cupressiforme Hedw. at 100% of their old sites. The results are compared with the distribution of air pollution in southern Sweden, and all of the investigated species except Hypnum cupressiforme, Leucodon sciuroides and Orthotrichum affine are today more or less confined to regions with comparatively low air pollution, to sites in ravines and with a northern or eastern exposure. The epiphytes are confined to trees with high bark pH, such as Acer platanoides L., Fraxinus excelsior L. and Ulmus glabra Huds.