Rodrigo Alejandro Hernández-Cárdenas, Aniceto Mendoza-Ruiz, Libertad Arredondo-Amezcua, Victor Werner Steinmann
American Fern Journal 109 (1), 11-25, (30 April 2019) https://doi.org/10.1640/0002-8444-109.1.11
KEYWORDS: fern diversity, global warming, Mexico, Neotropics, Polypodiaceae
Alpine vegetation is one of the most restricted ecosystems in Mexico. Its greatest extent occurs on the high peaks of the Trans-Mexican Volcanic Belt (TMVB). In this study we document fern diversity of the alpine vegetation of central Mexico, generate a floristic list, provide a key for determination, and report the elevational limits of the species present. The latter information will serve as a baseline for future comparisons to determine potential upward migration of fern species, as is predicted with global warming. In comparison to the páramo vegetation of Central and South America, fern diversity in the alpine vegetation of central Mexico is surprisingly low, and only five families, 11 genera, and 12 species are documented. This represents 1.5% of the ferns species known from the country. Polypodiaceae is the most diverse family, with four genera and four species, followed by Pteridaceae (three genera and three species) and Dryopteridaceae (two genera and two species). Aspleniaceae and Woodsiaceae each have a single genus, the former with two species and the latter with one species. All of the alpine ferns growing in the TMVB are leptosporangiate, and there are no arborescent, epiphytic, aquatic, or heliophilous ferns. Asplenium castaneum, Cystopteris fragilis, and Polystichum speciosissimum are widespread in the alpine vegetation, whereas the remaining species are restricted to one or few sites. With regard to upper elevational limit, the highest occurring species were Asplenium castaneum (4,569 m), Polystichum speciosissimum (4,490 m), and Cystopteris fragilis (4,377 m).