The vegetal landscape of the Republic of San Marino

Here we present a phytosociological study of the vegetal landscape of the territory of the Republic of San Marino, situated in the northern Apennines, where it covers 61 km2. The bioclimate belongs to the subMediterranean variant of the temperate macrobioclimate. The vegetal landscape is here examined in relation to the characteristics of the substratum upon which it develops. On the calcareous heights, positioned on a short ridge that culminates in the peaks of Monte Titano (750 m), the forest vegetation belongs to the association of Lamiastro-Ostryetum carpinifoliae on the coldest aspects, and to the association Stellario holosteae-Quercetum pubescentis on those that are warmer. We also present the substitution phytocoenoses that are in dynamic connection with the woods. In the rocky sector of the calcareous ridge, the vegetation follows the morphology and micromorphology of the substratum, forming vegetational mosaics that are particularly complex and present rare vegetal associations, among which there is the association Crepido titani-Brassicetum robertianae colonising limited vertical portions of the calcareous cliffs, and the association Teucrio flavi-Ephedretum majoris, which is found on the microterraces that alternate with the cliffs. On the calcareous-marl conglomerate substrata and the molasses of Monte Cerreto, in part occupied by a wood that is now degraded, which is thought to be potentially referable to the association Aceri obtusati-Quercetum cerris. There is a particular vegetation coverage of Erica arborea and Ulex europaeus ssp. europaeus (this last species finds the eastern limits of its area in the location of San Marino) that is referred to the new association Crataego monogynae-Ulicetum europaei of the Rhamno-Prunetea class. The greater part of the territory of this State is formed of clay hills that have been subjected to the phenomena of rapid erosion of the substratum that has led to the formation of badlands. The vegetation is differentiated into the pioneering vegetal communities already seen for the badlands of the nearby Marecchia Valley, with the associations: Hainardio cylindricae-Salsoletum sodae, Elytrigio athericae-Artemisietum cretaceae and Arundinetum plinianae. In the areas that are no longer cultivated, however, vegetation of the association Senecio erucifolii-nuletum viscosae has developed. The study of the description of the vegetal landscape of San Marino Republic is completed by the analysis of the fragmentary river formations and the nitrophilic and anthropogenic formations.