Vegetation series as a tool for Biogeography: a case study of the central Iberian Peninsula
Dynamic phytosociological studies are becoming increasingly important tools in biogeography. Our main goal is to establish the basis for separating biogeographical units, and to ascertain biogeographical boundaries, using primarily synphytosociological criteria in addition to climatological and floristic data. The study area is the central Iberian Peninsula comprising the Spanish Central System and the adjoining Tajo river basin.For the vegetation series study we used dynamic-integrated phytosociology procedures, where the basic unit is the sigmetum. We made 198 synphytosociological relevés distributed throughout the area, including 159 associations. The data were also organised in a synoptic table for cluster analysis. Climatic data were compiled from 70 weather stations for bioclimatic diagnosis. The plant communities and plants used as bioindicators were ordered in phytogeographical sectors and bioclimatic belts. The phytogeographical diagnosis was also done for each taxon.The synphytosociological relevés belong to 22 sigmeta which are represented in the cluster analysis. The greatest dissimilarity can be seen at the biogeographical province level, followed by the clusters showing the relation between climate and vegetation. This level not only separates the mesomediterranean vegetation series from the others, but also biogeographic units at the subprovince level. The bioclimatic belts identified in the area are: mesomediterranean, supramediterranean, supratemperate submediterranean, orotemperate submediterranean and cryorotemperate submediterranean. This study is an analytical confirmation that vegetation series can be used to establish sectorialization schemes and, with the help of bioindicator taxa, the limits between biogeographical units.