Analysis of the epiphytic bryophyte diversity of Sicily

Abstract

Sicilian epiphytic bryophyte diversity, based on literature and unpublished data, is assessed both quantitatively and qualitatively. The total number of taxa found on trees or shrubs is 133 (116 mosses and 17 liverworts). Among them, 38 are customary epiphytic, 21 cortico-saxicolous, 13 are indifferent and 61 occasionally epiphytic taxa. The most represented families are Orthotrichaceae (19.1%), which consists above all of several typically corticicolous species, Pottiaceae (19.1%) and Brachytheciaceae (12.6%) which both include many taxa that mainly colonize rock or ground substrates. From the chorological point of view, temperate taxa (33.8%) prevail, followed by oceanic-Mediterranean taxa (22.6%). An analysis of variations in species diversity along an altitudinal gradient (0-2000 m a.s.l.) shows that the number of taxa is more elevated between 800 and 1100 m. This range is especially rich in customary epiphytes. The geographical distribution of taxa highlights that the majority of taxa is found on main mountainous systems, bryoflora of which also has a high degree of diversification. The northern ranges of the Madonie and Nebrodi are particularly rich territories; however some isolated mounts also present a considerable species diversity. These areas, therefore, are of notable interest for the conservation of epiphytic bryophytes.