Bog Woodland geobotanical characterisation in the central Pyrenees

Abstract

Here, we present a detailed study of the diversity, species composition, ecology and phytosociological characterization of the Habitat of Community Interest (priority type) at a European level Bog woodland (HIC 91D0*) in the Pyrenees, carried out through 23 inventories taken according to the Braun-Blanquet methodology, from the Benasque valley (central Pyrenees) to the Cerdanya region (eastern Pyrenees). The results show a clear separation of communities according to the dominant tree and to hydrology. We recognize a birch wooded mire of Betula pubescens Ehrh. as a new association: Blechno spicanti-Betuletum pubescentis ass. nov. within the alliance Betulion pubescentis Lohmeyer et Tüxen ex Scamoni et H. Passarge 1959. We also include in this alliance the Abies alba Mill wooded mires. The mires with open pine populations of Pinus uncinata Ramond ex DC. subsp. uncinata have been differentiated into two new associations characterized mainly by bryophytes: Sphagno papillosi-Pinetum uncinatae ass. nov., within the Betulion pubescentis alliance Lohmeyer et Tüxen ex Scamoni et H. Passarge 1959, and Sphagno capillifolii-Pinetum uncinatae ass. nov., within the Eriophoro vaginati–Piceion abietis H. Passarge 1968 alliance. These communities always occupy small areas and have no direct threats, but they are influenced by the forest dynamics of the adjacent forests and by livestock activity, both with notable changes in recent decades. The particularities of these forests and the presence of some bryophytes included in the Spanish red list or rare in Catalonia (Sphagnum squarrosum Crome, S. centrale C.E.O. Jensen, S. fallax H. Klinggr., S. flexuosum Dozy & Molk., S. medium Limpr.) demand protection and monitoring to guarantee their conservation.