Relationship Between Atmospheric Ammonia Concentration and Nitrogen Content in Terricolous Lichen (Cladonia portentosa)

From April 2006 to April 2007, the geographical and seasonal variation in nitrogen content in terricolous lichen (Cladonia portentosa) and atmospheric ammonia concentrations were measured at five heathland sites. The seasonal variation in the nitrogen content of the lichen was small, even though there was a large seasonal variation in the air concentration of ammonia. A sizable local variation in the nitrogen content of the lichen was found even at the scale of a few kilometres. The nitrogen content in the lichen showed a high correlation to the yearly mean value of the measured ammonia concentration in air at the different locations. This investigation is part of a larger attempt to incorporate effects of nitrogen in the conservation status of terrestrial habitat types.