Natural islands and habitat islands as refuges of vegetation cover and wild bees. The case of the Lednica Landscape Park in western Poland

摘要

The study has contributed to the identification of the apifauna of central Wielkopolska. The study identified 161 bee species, accounting for 34.2% of the Polish bee fauna. The highest contribution (28.7% of the fauna) comes from four species, namelyAndrena haemorrhoa, A. helvola, Evylaeus calceatus and Osmia rufa, while Bombus terrestris and Evylaeus pauxillus are two subdominants. The assemblages of Apiformes in the study area are characterised by a significant contribution of spring-associated species, which is probably an effect of the presence of numerous willow thickets offering abundant host plants (mainly Salix sp. div.). Both the islands and the surroundings of the lake have a unique species composition, and there are differences in the proportions of the individual dominant species. The overall abundance of bees varies greatly, with mean seasonal density figures on Ostr6w Lednicki Island being more than twice as high as that on the mainland grassland, with a distinct predominance of bumblebees. The exceptional richness of Apiformes, including bumblebees, on Ostrow Lednicki should be regarded as the basis for treating this island as a life refuge for bumblebees and including it and its environs in the list of sites of Community importance (SCI). A simultaneous study of the vegetation cover contributed significant data on the vascular plant flora and plant communities of the Lednica Landscape Park. For example, it was the first such investigation of Mewia Island. The study revealed the importance of marginal habitats (natural islands and habitat islands) for the preservation of protected and endangered plant species and plant communities receding from an agricultural landscape.