RICHNESS AND DISTRIBUTION OF FERNS AND LYCOPHYTES IN THE ELEVATIONAL GRADIENT OF THE COFRE DE PEROTE, CENTRE OF VERACRUZ, MEXICO

We present a list of ferns and lycophytes recorded along the elevational gradient (20-3,500 m a.s.l.) at the Cofre de Perote, Veracruz, including contrasting environments with different degrees of forest disturbance as well as azonal vegetation. We established 15-25 plots of 20 x 20 m each at eight elevational steps separated by 500 m in elevation. In each plot we recorded all terrestrial and epiphytic understory species (up to a height of 8 m). In the 135 plots, we found 140 species and four varieties of ferns (22 families, 58 genera) and 11 species of lycophytes (two families, three genera), representing 27.5 % of the pteridophytes of Veracruz. Two species of the genus Elaphoglossum (E. pallidum, E. squarrosum) and Polystichum muricatum, found at 2,500 m are new state records. The number of species is contrasting at different elevational steps of the gradient and mid-elevations with humid montane forest between 1,500 and 2,500 m showed maximum richness values. At the upper and lower ends of the gradient, characterized by coniferous forest and deciduous forest, respectively, the number of species decreased. The richness of the humid montane forest and its loss of species caused by anthropogenic disturbance are noteworthy. Furthermore, the azonal vegetation at ravines and riversides represents an important reservoir for the pteridophyte flora, which highlights its conservation value.