Patterns on geographical distribution and taxonomic similarity of mosses in the beech forests of Mexico

Abstract

Studies on the distribution and taxonomic composition of moss floras in diverse types of vegetation and at a variety of geographical scales are useful for elucidating patterns of dispersal in space and time. Given this, the present contribution aims to (1) provide data on richness, habitat and geographical distribution of Mexican beech (F. grandifolia subsp. mexicana) forest mosses in the Sierra Madre Oriental (SMO), Mexico; (2) estimate moss species similarity among different beech forest areas in eastern Mexico; and (3) compare generic moss composition in temperate humid beech and cloud forests around the world. To do so, moss samples were obtained from Mexican beech forests and from the literature data for other regions. Jaccard's index was used to estimate floristic similarity among localities, and the distances between groups were represented by means of a dendrogram (UPGMA). The SMO beech forest moss flora in the state of Hidalgo contains 30 families, 54 genera, 71 species, and 4 varieties. The most representative families are Dicranaceae (10 species) and Pylaisiadelphaceae (6). Species richness is similar among localities, and floristic similarity is related to geographical distance. The most common substrates are epiphyte-lignicolous (20%), saxicolous (15.4 %), and lignicolous (7%). Most moss species in the beech forest of Mexico exhibit wide, Caribbean or boreal patterns of distribution. At the species and genus levels, floristic similarity is greater between closer localities while distant sites share a lower number of species (beech forests in Hidalgo) or genera (beech forests and cloud forests in various world regions), reflecting perhaps more heterogeneous environments with increasing distance between sites.