Meadows and pastures of the Mézenc massif: phytosociological characterization and diagnosis of agroecological variables

Abstract

The Mézenc massif, located in the Massif central, is known for its production of «Fin gras» meat, which is promoted by a Protected Designation of Origin (PDO). The permanent mown and grazed meadows of the PDO, habitats of European interest (6520 and 6230*), are still little known because little prospected in this territory. As part of this study, these vegetations were characterized by classification analyses (MTC) in two reference systems of 376 and 225 surveys of the Massif central. The 79 surveys of Mézenc were also analyzed by classification then by ordination (DCA and CCA) to determine the variations present. In addition, the groups highlighted were compared by ANOVA based on the ecological indices of Ellenberg et al., pastoral values, diversity and specific richness. The pastures have shown that they are floristically richer, with a diversity and pastoral values similar to the hay meadows; they therefore contribute to the quality of the meat produced on the AOP air. These pastures correspond to the association of Diantho pseudocollini-Meetum athamantici (Luquet 1926) B.Foucault 1986 mut. Le Hénaff et al. 2021 but higher in altitude than in the monts Dore. They lead us to differentiate a new sub-association specific to Mézenc named bellardiochloetosum variegatae, reflecting its more mountainous character. Four variants have been highlighted: one on granite, one more thermoxerophilic and two others showing a difference in the more or less extensive livestock loading. As for the Mézenc mowings, their floristic and biogeographical originality is highlighted by naming a new plant association of Triseto flavescentis-Polygonion bistortae Braun-Blanq. & Tüxen ex Marschall 1947: Campanulo scheuchzeri-Trisetetum flavescentis. The latter is located on basaltic summit plateaus, higher in altitude and more eastern of the volcanic mountains of Auvergne.