Geography of plants of Western La Alcarria and “Mesa” of Ocaña(I). Floristic analysis in five representative space tracts

Abstract

It carries out a systematic and exhaustive floristic inventory in order to know the composition of vascular plants of the natural region of Western La Alcarria and “Mesa” of Ocaña (Central Iberian Peninsula). The survey method was applied in the NNE-SSW transect forming for five 1 × 1-km U.T.M. grid squares (ED50) during one agricultural year (2002-2003). It allows consider almost the total richness notion of the floristic data and makes possible a geographical comparison of biodiversity in absolute terms. The Jaccard’s index is used to determine the floristic similarity between all grid cells and the taxonomic spectra is analyzed. The results show high levels of richness at all spatial levels (1634 native species at regional level; 690, in all five grid cells, and an average higher than 400 by grid cell). From highest to lowest, the regional typical spectrum presents a dominance of the daisy family, followed by grasses, legume family, crucifers and pink family; although the cells spectra have slight variations to this model.