Cryptogamie, Bryologie, 2006, 27 (2): 1-20 © 2006 Adac. Tous droits réservés The bryophyte flora of the city of trento (NorthItaly) LisaPOKORNY, Francisco LARA & Vicente MAZIMPAKA 1 Universidad Autónoma de Madrid, Facultad de Ciencias, Departamento de Biología (Botánica),Ctra. Colmenar Viejo Km. 15, ES-28049 Madrid,Spain (Arrived 4 November 2004, accepted 15 June 2005) Abstract – The bryophyte flora of Trentohas been studied based on anextensive sampling. To standardize the harvesting, the city has been divided into5 zones and 12 habitats, depending on the human impact, the substratumnature and moisture state. At least 10 samples of 20 × 20 cmhave been collected in all available habitats in each zone. As a result, 136 taxa have been recorded, 12 of which were liverworts and 124 were mosses. This is the richest Italian town todate and one of the most diverse, showing an important number of new regional and national records and some remarkable threatened species. The best represented families are 6 (Pottiaceae, Brachytheciaceae, Grimmiaceae,Amblystegiaceae, Orthotrichaceae, Bryaceae and Hypnaceae) and those with only one species are 21 (comprising mosses and liverworts). Some of the species found in Trento arefrequent in urban environments, but most of them are uncommon in such environments. This outstanding bryophyte flora can bedue to the climaticconditions of Trento and to the presence of numerous microhabitats that are suitable for these cryptogams. Urban bryophytes / European towns / mosses / liverworts INTRODUCTION The urban environment is characterized by a number of features (rela- tively dry microclimate, presence of pollutants, high nutrient richness) that make it hostile and somewhat selective for most bryophytes (Heras & Soria, 1990; Suk- kop & Wurzel, 2003). However, some of these plants show ability to colonize urban areas worldwide. Most of these bryophytes often present a life strategy typ- ical of colonists with a short life span and a high reproductive effort, both in asex- ual and sexual diasporeproduction (During, 1979). They are mostly basophilous, nitrophilous, photophilous, and largely tolerant to salts and pollutants (Gilbert, 1970; Soria&Ron, 1995). For these and other reasons, the urban bryophyte flora is interesting, sinceit gives us much information on the town environmental conditions and on the biological potentiality of some bryophytes species. Several studies on Italian urban bryophytes are available. Some of them pay attention to the impact of these plants on monumental buildings (Dia & Not, 1991; Lo Giudice &Polizzi, 1997; Lo Giudice & Cristaudo, 1998; Lo Giudice et al., 1998). Others deal with biomonitoring (Aleffi et al., 1995; Gerdol et al., 2002; Adamo et al., 2003; Giordano et al., 2004; Gueli et al., 2004). Finally,a few focus * Correspondence and reprints: vicente.mazimpaka@uam.es 04_Pokorny.fm Page 1 Mercredi, 15. mars 2006 3:34 15