Análisis de la brioflora riparia de un bosque atlántico gallego. Razones para la conservación de A Fraga Gorda (Muras-Ourol, Lugo)

Abstract

A Fraga Gorda (Tras da Serra river Valley, Muras-Ourol, Lugo) is an acidophilous, Atlantic forest (Blechno spicanti-Quercetum roboris) located in Galicia (NW Iberian Peninsula). This area is known for its diversity of threatened, termophilous, relictic ferns. Despite this, the enclave remains largely unprotected. The bryoflora of A Fraga Gorda is poorly known, and its study could provide further arguments for its protection. Preliminary analyses, limited to the banks of the Tras da Serra river and their adjacent areas, revealed the existence of 55 species of bryophytes in the forest (22 liverworts and 33 mosses), with suboceanic and european-eurosiberian elements being the most frequent. The bryoflora of A Fraga Gorda is similar to that found in other geographically and ecologically close enclaves, although with a higher diversity of Sphagnum species. Likewise, the bryoflora of A Fraga Gorda reflects the ecological characteristics of the site, especially with regard to the pH of the substrate and the oceanic influence. Several species of bryophytes of conservation concern have been identified. More specifically, 6 species were observed that are under some degree of threat according to the Catálogo Galego de Especies Ameazadas and the Atlas y Libro Rojo de los briófitos amenazados de España. Also, three taxa were recorded in Galicia for the first time. Although it is necessary to expand our analysis of the bryophyte diversity of this forest, our preliminary results already provide new reasons for its conservation.