Biogeographical outline of epiphytic lichens in a Mediterranean area: Calabria (S Italy)

Abstract

This paper aims to provide a biogeographical analysis of the epiphytic lichen flora of S Calabria by means of chorograms (i.e. distributional maps showing the joint distribution of multiple taxa). Two datasets on both local and Italian distribution were used. Local distribution is described by records of 135 epiphytic species in 14 sampling sites (5 trees per site, boles sampled from the ground to 2 m) representing the main vegetation belts of the survey area. A cluster analysis of the species, based on their commonness-rarity in the 9 main bioclimatic areas and in the 20 administrative regions of Italy, was applied. For each of the 7 clusters of species (chorotypes), a chorogram was produced. The matrix of species and sites was also submitted to numerical classification, and 5 clusters of sites were obtained, corresponding to the main altitudinal belts and tree species. For each group of sites, the frequencies of chorotypes were calculated. The results show a clear relationship between local distribution, mainly related to ecological conditions, and the Italian one. The truly Mediterranean forests of the survey area have the highest incidence of the Tyrrhenian element. Beech forests of the montane belt, dominated by broad-ranging lichens, are the most diverse biogeographically. The pine forests lying above the temperate belt do not host a peculiar lichen flora, being dominated by broad-ranging circumboreal species.