Populationsökologische Untersuchungen an ausgewählten Zielarten des Grünlandes im Osterzgebirge als Grundlage für Schutzmaßnahmen

Abstract

ZIEVERINK, M.; HACHMÖLLER, B.: Ecological studies on populations of selected “target species” in mountain meadows of the Eastern Ore Mountains. - Hercynia N. F. 36 (2003): 75–89.Our study documents current populations of three endangered species (Arnica montana, Scorzonera humilis, Pinguicula vulgaris) typical for mountain grassland in the Eastern Ore Mountains and describes factors contributing to the decline of the populations as well as nature conservation measures necessary for their preservation. The species composition of meadows inhabited by Arnica montana, Scorzonera humilis and Pinguicula vulgaris was analysed by 50 releves, and some soil parameters (pH, N, C, and organic substance) were studied on 27 sites. The population structure (numbers of juveniles, fertile and sterile adults) was also analysed. Germination tests were conducted for 9 different populations of Arnica montana to find out if the seeds are vital. The results of the vegetation survey and soil samples confirm the preference of Arnica montana for mat-grass meadows (Violion communities) on acidic and nutrient-poor soils. These habitats are also suitable for Scorzonera humilis, a species otherwise known to prefer base-rich soils and Molinion communities. Pinguicula vulgaris, in other regions typical for base-rich fens, was found on acidic as well as neutral fens (Caricion fuscae communities). The analyses of population structure could not confirm any juvenile individuals of Arnica montana and Scorzonera humilis, whereas a high percentage of juvenile Pinguicula vulgaris was found. The germination tests for Arnica montana showed a correlation between population size and reproductive fitness, e.g. percentage of vital seeds and germination rate. The results are discussed in the light of historical and current land use patterns and demonstrate the need to protect the remaining sites of the species by nature conservation measures, especially mowing and grazing. For the fragmented populations in the Eastern Ore Mountains, the conservation of remaining populations might not be sufficient because they could be too small to survive in the long run. An increase of population size, however, can only be successful when suitable conditions for the input of diaspores and their germination can be created. This requires further studies, especially for Arnica montana and Scorzonera humilis which seem to be very slow in colonizing new habitats.