Odonates (Insecta: Odonata) of the ”Golczewskie Uroczysko” nature reserve (North-West Poland)

The „Golczewskie Uroczysko” nature reserve was established on 5 May 2004 to protect the raised peat bog and the dystrophic Lake Żabie with its surrounding transitional bog and adjacent forest complexes containing valuable plants. In May, July and October 2006 the research of odonates (Odonata) fauna has been conducted in this area. A total of 575 odonates individuals belonging to 29 species (366 imagines, 152 larvae, 57 exuviae) were collected and among these 489 specimens belonging to 28 species were collected in Lake Żabie, 26 specimens belonging to 7 species on the beat boog, 52 specimens belonging to 3 species in flooded alder forest and 8 specimens belonging to 2 species were collected in ditches in the forest. The eurytopic species were dominated with substantial parts of tyrphobiontic and tyrphophilous species.

Water mites (Acari: Hydrachnidia) of the „Golczewskie Uroczysko” nature reserve

The „Golczewskie Uroczysko” nature reserve was established on 5 May 2004 to protect the raised peat bog and the dystrophic Lake Żabie with its surrounding transitional bog and adjacent forest complexes containing valuable plants. In May, July and October 2006 the research of water mite (Hydrachnidia) fauna has been conducted. A total of 557 water mite specimens belonging to 41 species were collected and among these 382 specimens belonging to 31 species were collected in Lake Żabie, 83 specimens belonging to 21 species were collected in ditches in the forest, 70 specimens belonging to 15 species in a ditch on the beatboog and 22 specimens belonging to 10 species in flooded alder forest. In a ditch in the peat bog, ditches in the forest and Lake Żabie tyrphobiontic and tyrphophilous species were dominant, with a substantial part of small water body species in Lake Żabie and with similar part of small water body species and vernal astatic water body species in a ditch in the peat bog and ditches in the forest. In flooded alder forest vernal astatic water body species were dominants.

Impact of the European beaver (Castor fiber L.) population on the woody vegetation of Wigry National Park

Research on the impact of the European beaver population on the species composition of forest stands was conducted in Wigry National Park, situated in north-eastern Poland. The study was conducted in forest stands on a dystrophic lake of the ‘suchar’ type,� i.e. a dystrophic lake with high acidity and low species diversity of vegetation on its shores, on the banks of a river and a drainage ditch, and in a field environment. A ThermoPro TP8 thermal imaging camera with an uncooled microbolometer matrix of 384x288 pixels was used to confirm that the designated observation areas were inhabited by beavers. In each research area five transects four metres in width were established, where measurements were taken of five classes of trunk damage and two classes of trunk diameter. We examined the seasonal preferences of beavers in gnawing particular species of woody plants. An analysis was performed for each environment. The results indicate that after an average 15-year presence of beavers in the areas, which they inhabited rotationally, the percentage of healthy woody plants was 73.09%. Of the 17 species of woody plants, the ones most readily cut down by the beavers were grey willow (25.19%) and common hazel (32.36%). The analysis demonstrated that the rodents showed the greatest interest in plants with a trunk diameter of <10 cm (98.28%). The river and drainage ditch were the most exploited environments; here beavers cut down 40.27% and 42.70%, respectively, of the available woody plants.