Die Vegetation der Abraumhalden des Steinkohlentiefbaues nördlich von Wettin (Saalkreis, Sachsen-Anhalt)

Abstract

65 of about 80 coal mine spoils north of Wettin were investigated and classified according to theirvegetation in 1998. It was decided between woody vegetation and vegetation of open sites.The woody vegetationwas classified as following: Stands of Cerasus avium!C. mahaleb, Roso-Ulmetum,Fraxinus excelsior- and Quercus robur Stands, Pruno-Sambucetum nigrae and Robinia pseudoacaciastands. In several cases a certain classification into described syntaxa is not possible because of thedominance of one and/or the Iack of characteristic species of certain communities. Because of a ratherhomogeneaus age structure of the Robinia trees and their occurrence without or with even a few otherwoody tree species it can be concluded, that these stands were planted.The vegetation of open sites can be classified into the following stand types: vegetation poor sites(steep slopes), cryptogame rich dry grassland communities, dominant stands of Festuca rupicola,Arrhentherum elatius, Elytrigia repens, Avenella .flexuosa and Melica transsylvanica.153 species of vascular plants, 40 of them woody ones, as weil as 16 moss, 1 liverwort and 16 Iichenspecies were found on the coal mine spoiles investigated.According to their ecologically preferred stands the following groups of vascular plants can be distinguished:woody species, weeds, ruderal, dry and semi dry grass1and, and forest species.The number of vascular species and the size of the coal mine spoils are positively correlated. Robiniastands contain less species despite their !arger mean size. A correlation between species number andarea does not exist in these cases.Different old stages of vegetation succession are not obvious in princip1e on the spoil mines, exceptingthe Robinia stands. Moreover, there are no differences between the woody vegetation of the spoilmines and that of adjacent stands, which do not grow on spoil mines. Thus it is assumed, that thepresent vegetation represents the final succession stage under present human influence. It is difficult tocalculate, how long this process took, because of only vague information about the end of the use of thetunnels and spoil mounds. However, 240 years is the maximum period.The coal spoil mines are partly interesting concerning their floristic and vegetation inventory ofcryptogams. Moreover they contribute to an enrichment of the countryside north of Wettin ecologicallyas well as seen from the aspect of Iandscape diversity and industry history.