Epiphytic macrolichen communities in Pinus contorta peatlands in southeastern Alaska

We sampled epiphytic macrolichen communities on tree branches in 50 Pinus contorta peatlands in southeastern Alaska. We describe the natural range of variability in lichen communities in these habitats under baseline air quality and climatological conditions and interpreted how lichen community gradients related to site characteristics, tree characteristics and vascular vegetation. The most striking feature of this data set is the uniformity of species composition. Almost three-fourths of the variation was represented in an ordination axis related to variation in total lichen abundance and species richness, but without any strong gradients in the compositional mix of species. Species richness and total lichen abundance were most strongly related to geographic variables, in particular, lower values near Yakutat and the southern part of the study area. The weak compositional gradients, the small trees, their open-grown form and abundance of lichen-covered branches at a convenient height make the lichen communities ideal for biomonitoring of air quality and climate change.