Untersuchungen zu Struktur und Erhalt der Segetalvegetation im östlichen Teil der „Karstlandschaft Südharz“ (Sachsen-Anhalt)

Abstract

Meyer, S.; Mahn, E.-G.: Analysis of the structure and preservation of the segetal vegetation in the eastern part of the “Karstlandschaft Südharz” (Saxony-Anhalt). – Hercynia N.F. 39 (2006): 247 –267.The existence of some segetal weed communities with rare species characterizes the fields on shallow calcareous soils of the hilly karst land forming the southern edges of the Harz mountains. With a specified vegetational analysis of selected sites by relevées, based on the Braun-Blanquet method, it was tended to evaluate the role of agricultural measures with different intensity on the structural diversity of these units. It turned out that fields with an extensive degree of management measures distinguished by a distinct higher structural diversity and species number compared with those submitted to measures of conventional intensity. This refers to the borders as to the interior parts of the fields in a similar way. On conventionally cultivated fields the characteristic species of the Caucalidion have been disappeared or remained restricted to the field borders. Sites, formerly occupied by different Caucalidion communities appear dominated actually by stands of the Euphorbio-Melandrietum, a community with a significant lower number of indicative and rare species. Based on the existing federal, national and European guidelines and decrees are possibilities discussed to avoid a further structural and floristical impoverishment of the named, regionally seen more or less strongly endangered vegetation. A decisive role should play in this context the ELER-decree (European landscape development area), edited by the European Union (2005). In evaluating the results of our investigations different measures have been proposed to be realized within the frame of a regionally planned agricultural environmental program. The main concern should be to sustain the conditions for the development of extensively used agro-ecosystems within an economically – ecologically well balanced system compound. This conception should include the installation of a special field flora reservation, accompanied by measures to protect selected field border lines, representative for the fields along the karst land of southern Harz mountains.