Richness and distribution patterns of ferns and lycopods in Los Mármoles National Park, Hidalgo, Mexico

Lycopod and fern species richness and beta diversity were analyzed along elevation gradients in different vegetation types in the Los Mármoles National Park (PNM) in the state of Hidalgo, Mexico. Sampling was conducted at 16 sites located between 1,184 and 2,702 m elevation, including eight vegetation types. Observed species richness was compared with expected species richness using non-parametric methods. The number of shared species and the lycopod and fern species replacement rate were estimated between vegetation types (beta diversity). The number of lycopod and fern species was low at the high and low extremes of the elevation gradient, while at intermediate elevations species richness ranged from low to high. This species richness and distribution pattern for lycopods and ferns is probably related to elevation (moisture), topography and vegetation type. Sampling effort efficiency was 86 to 91%, depending on the estimator used. Beta diversity of these vascular sporogenous plants between vegetation types was high, which was considered to be a reflection of the considerable micro-environmental differences related to tolerance to water availability and other environmental factors.