Die Festuco-Brometea-Gesellschaften im nördlichen Harzvorland Niedersachsens
[The Festuco-Brometea-communities north of the Harz Mountains in Lower Saxony, Northwest-Germany]
The vegetation of the calcareous grasslands (Festuco-Brometea) north of the Harz Mountains in Lower Saxony was investigated with particular emphasis on the continental steppes (Festucetalia valesiacae). The investigation area is characterized by an interesting gradient from subatlantic climate in the western part to subcontinental climate in the eastern part. A characteristic feature of the Festucetalia valesiacae reaching the absolute northwestern border of their distribution is the specific and singular flora of each hill. This could be explained by the age and long isolation of these grasslands being situated in an intensively used agrarian landscape. According to the synoptic tables of the Adonido-Brachypodietum in the dry regions of Germany as well as the Festuco-Brometea-communities in Lower Saxony the following syntaxa were found: 1. The Festucion valesiacae Klika 1931 is just reaching Lower Saxony in the eastern part of the investigation area with the Stipetum capillatae (Hueck 1931) Krausch 1960. 2. Most of the vegetation in the eastern part has to be classified as Cirsio-Brachypodion pinnati Hadač et Klika 1944, partly it clearly belongs to the Adonido-Brachypodietum pinnati (Libb. 1933) Krausch 1961. 3. The Mesobromium erecti (Br.-Bl. et Moor 1938) Knapp 1942 ex Oberd. (1950) 1957 is represented by the Gentiano-Koelerietum Knapp 1942 in the western part. The structure of the vegetation and local distribution patterns of predominating species are shown by means of line-profiles.