In Rome both meadows of CentraI-European affinity and Mediterranean dry grasslands are presento We studied a site (Parco Regionale Urbano de] Pineto in Rome) with very diverse vegetation, where species belonging to both coenologica] groups oceur. Wc fertilized a grassland with a combination of phosphorus (P) and nitrogen (N). After fertilization diagDostie species of Helianthemetea guttati (Thcrophytes) dccrease while species of MolinioArrhenatheretea (Hemicriptophytes) increase. In a climate as that of Rome, transition between Mediterranean (with summer drought) and Central European (without summer drought), nutrients availability modulates the distribution of vegetation Classes with respectively Mediterranean or Central-Europe affinities.