Dry calcareous grassland communities (Filipendula vulgaris-Helictotrichon pratense) in Western and Central Latvia

The dry calcareous grassland vegetation of Western and Central Latvia is described based on 93 relevés. All relevés could be assigned to one community type Filipendula vulgaris-Helictotrichon pratense named according to dominant species. Four variants were distinquished: typicum, Viscaria vulgaris, Astragalus danicus and Carex flacca. Ellenberg indicator values were calculated to study the ecology of communities. Floristic differences among variants are associated mainly with soil reaction (Ellenberg indicator values for soil pH range from 6.0 to 7.6), but conditions of moisture and fertility are similar among the variants. The calcareous grassland vegetation in Latvia represents transition vegetation between the classes Molinio-Arrhenatheretea and Festuco-Brometea. However, ecologically and floristically, these communities are closer to the class Festuco-Brometea and could be assigned to the order Brometalia. For designation to alliance and association, more data is required. The results are compared with similar communities in other European countries.