Mapping environmental effects of agriculture with epiphytic lichens

The present paper reports the results of a study designed to check the feasibility of epiphytic lichens as biomonitors of the effects of agriculture in an area of central Italy without heavy industrialization and with an economy mainly based on agriculture. The exclusion of nitrophytic species (objectively selected using the on-line check-list of Italian lichens) from the calculation of the index of lichen diversity, which is supposed to reflect air quality, led to more realistic results. Conversely, the use of only nitrophytic species allowed us to map the eutrophication in the area, which resulted in lichens heavily affected by agricultural activities. Mapping using only strictly nitrophytic species showed two "hot spots" where ammonia emission from animal husbandry plays an important role. Two sites emerged as suffering at the same time from ammonia and NO(x) pollution. It is concluded that epiphytic lichens are an effective tool to detect and map the effects of agriculture also in Mediterranean countries, at least in areas without heavy industrialization, given the proper species selection.