The diversity and abundance of bumblebees (Bombus Latr.) in eight parks of Warsaw city and the impact of park size (range from 1.9 to 73 ha) as well as other selected characteristics (the percentage of the area covered by tree and the quality of park surroundings) on the bumblebee community were evaluated. In each park, bumblebees were observed along designated paths for 30 minutes. In total, 12 species of bumblebees were recorded, of which four belonged to cuckoo bumblebees (Psithyrus subgenus). We found: B. terrestris (L.), B. lapidarius, (L.), B. pascuorum (Scop.), B. hortorum (L.), B. semenoviellus (Skorikov), B. hypnorum (L.), B. ruderarius (Müller), B. pratorum (L.) and four cuckoo bumblebee species: B. (Ps.) bohemicus (Seidl.), B. (Ps.) campestris (Pz.), B. (Ps.) rupestris (F.), B. (Ps.) vestalis (Fourc.). The size of parks, percentage of area covered by trees, and characteristics of the areas surrounding the parks were found to be not significant for the diversity and abundance of bumblebees in urban parks. However, our results indicate the importance of the semi-natural areas within the parks for the species diversity.
Taking into account high organic matter content in the orchid reserve soils of the Roztoczański National Park, the present authors tried to adapt the method worked out by Rice-Evans and Miller to estimate a soil extract antioxidant activity. This method is used to compare antioxidant activity of complex substances with various organic compounds. The method corroborated the occurrence of antioxydation substances in the tested soil samples.