Weak recovery of epiphytic lichen communities in Sweden over 20 years of rapid air pollution decline

Abstract Epiphytic lichens are sensitive to deteriorating air quality, but levels of nitrogen and especially sulphur deposition have been in decline over most Europe recent decades. We assessed the response epiphytic this decline, using data from long-term monitoring sites Sweden. analyzed 20 years investigate temporal trends lichen communities’ sensitivity sulphur, preference, species richness alpha beta diversity. found only limited partial evidence recovery area that previously had high deposition, a mean at northern site with low throughout period. The slow recolonization species, even where environmental conditions now suitable, is probably result impoverished regional pools inherent dispersal capacity many species. suggest due consideration these factors use as indicators period improving quality.