Sekundär-progressive Sukzession eines aufgelassenen Kalkmagerrasens: Dauerflächenuntersuchungen 1987 – 2002

Abstract

Dierschke, H.:Secondary progressive succession of an abandoned calcareous grassland – research on permanent plots 1987 – 2002 . – Hercynia N. F. 39 (2006): 223 –245.Since 1972 experimental studies have been carried out on the regeneration and succession of abandoned calcareous grassland dominated by Bromus erectus and partially mixed with shrubs. The study area is situated on the south-western slope of the Feldbornberg near Göttingen (Germany) with a total of 32 quadrats of 2 x 2 m size arranged in a grid. Species-rich grassland assemblages had developed especially in quadrats subjected to mowing two to three times a year. In 1988 the experiment was concluded, the entire area uniformly mowed in summer and the entire above-ground biomass removed. Following this the area was left to secondary progressive succession. The present publication deals mainly with the successional trends on 16 of the plots until 2002 on which succession has progressed through some interim phases into a dense scrub. The species turnover, which was characterized by an initially slight and later rapid decrease of species, is analysed in detail for several species groups. Grid maps show the behavior of selected species in a fine-scale differentiation in space and time. The extensive discussion deals with the broader issues of secondary succession of calcareous grasslands. The spread of graminoids (‘Vergrasung’), herbaceous forest edge species (‘Versaumung’), and shrubs (‘Verbuschung’) and reversion to woodland are mentioned as the main processes. Finally, successional series with phases and stages are discussed and the present results placed within this context.