© 2005 Science From Israel / LPPLtd., Jerusalem Israel Journal of Plant Sciences Vol. 53 2005 pp. 115–124 *Author to whom correspondence should be addressed. E- mail: Mapping environmental effects of agriculture with epiphytic lichens SERENA RUISI, a LAURA ZUCCONI, a, * FRANCESCA FORNASIER, b LUCA PAOLI, c LUISA FRATI, c AND STEFANO LOPPI c a Dipartimento di Scienze Ambientali, Università di Viterbo, Largo dell’Università, 01100 Viterbo, Italy b ARPA Lazio (Agenzia Regionale per la Protezione Ambientale), via G. Garibaldi 114, 2100 Rieti, Italy c Dipartimento di Scienze Ambientali “G. Sarfatti”, Università di Siena, via P.A. Mattioli 4, 53100 Siena, Italy (Received 26 May 2004 and in revised form 11 July 2005) ABSTRACT 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 agricul- ture. 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. Keywords: ammonia, biomonitoring, dust, Mediterranean basin, nitrogen INTRODUCTION Agricultural activities result in increased emissions and deposition of nitrogen compounds. In Europe, the NH 3 emission from animal breeding is one of the main sources of atmospheric nitrogen (Lee and Longhurst, 1993; Fangmeier et al., 1994); with regard to total N (NO 3 , NO x , and N 2 O) emissions, agriculture is by far the largest source (Krupa, 2003). Besides the potential acidifying effect, N depositions have a fertilizing role on ecosystems, causing changes in vegetation and soil microflora and mi c ro f auna in areas where critical loads are exceeded (Rosén et al., 1992; Krupa, 2003), and significantly contributing to forest decline in Europe (Krupa, 2003). Nitrogen, mainly deposited as ammonia, ammonium, and nitrate, may strongly influence lichen-dominated ecosystems (Crittenden et al., 1994; van Dobben et al., 2001). Ammonia and ammonium, as by-product, from animal manure have a high deposition rate. Ammonia is emitted to a low altitude and thus deposited near the emission sources (Sutton and Fowler, 2002; Krupa, 2003). Ammonia, ammonium, and nitrate reach lichen thalli mainly as dry deposition, and lichens have an extraordinary capacity to capture nitrogen (Søcthing, 1995). Studies of ammonia uptake and loss by a range of lichen species have been carried out by Miller and Brown (1999). In bioindication studies of air pollution by epiphytic lichens, the inclusion of nitrophytic species has been questioned, since relatively high values could be deter- mined by eutrophication (defined by Nixon (1995) as an increase in the rate of supply of organic matter in an ecosystem), more than by air quality (van Herk, 2001). In fact, eutrophication is not necessarily associated with a decrease in lichen diversity but with a change in species composition, where acidophytic lichens are