Invasive plant species - threat to grasslands in river valleys

River valleys are areas of transition between aquatic and terrestrial communities, with complex biological structure. As ecotones they have high biodiversity as a result of the occurrence of species with different requirements according to soil moisture. They create ecological corridors, allowing migration of the organisms in human disturbed landscape. With these migration routes, species of foreign origin which spread to a new area also benefit. Numerous alien species are considered as invasive, and described as a threat to biodiversity due to strong competitive abilities. To describe the relationships between a number of invasive species, biodiversity and size of a river, the vegetation of 750 m fragments of the Odra and Dobra river valleys on the area of the Wrocław city were analysed. The comparison of plant communities in the valley of a large, managed river (Odra) and its small tributary (Dobra) was carried out. The plant assemblages, occurring in study areas, determined the habitat conditions on the basis of Ellenberg’s indicator values (EIV’s), as well as Shannon-Wiener biodiversity index was defined. The designed sites differed according to Shannon-Wiener biodiversity index, as well as soil properties: moisture, reaction, and fertility. In the study side of the Odra river ruderal and scrub species were dominated, whereas in case of study site of the Dobra river – meadows and ruderal species. The invasive plant species occurring in the Odra valley are: Symphoricarpos albus, Solidago gigantea, S. canadensis, Robinia pseudoacacia, Clematis vitalba, Quercus rubra, Reynoutria japonica, Parthenocissus inserta and Echinocystis lobata, and in the Dobra valley: Solidago gigantea, S. canadensis. The analysis of correlation between Shannon-Wiener biodiversity index and share of invasive species revealed statistically significant influence of occurrence of invasive species on biodiversity of plant communities in case of the Odra river

The effect of long-term peatlands drainage on the properties of soils in microrelief in the Długie Mokradło bog (Central Sudetes - SW Poland)

The aim of the study was to assess the impact of long-term drainage on the morphology and selected properties of shallow peatland soils in microrelief. The study was conducted within strongly drained peatland (Długie Mokradło bog) located on elevated plateau in the Central Sudetes. The study area is covered by spruce stands introduced by man. Long-term drainage has changed morphology of study soils which were classified as Ombric Fibric Dystric Histosols or Histic Dystric Gleysols. Some peat horizons were strongly silted. The depth of organic materials varied within the range 30-55 cm. Peat humification process showed greater - activity in surface horizons, than in a deeper ones. This phenomenon were especially visible in the shallow places in drainage ditches. Soil reaction was strongly acidic. In soil horizons in old drainage ditches higher values of effective cation exchange capacity (CECe) were recorded, whereas base saturation (BS) did not exceed 20%

The assessment of usable features of football pitch turf on the example of KS AZS Wrocław

The aim of the study was to evaluate the utility as well as visual and functional characteristics of intensively exploited football pitch, with consideration of the impact of used pratotechnics. In the assessment of the football turf fundamental traits according to the COBORU methodology, in the tested multi-year period the best results were obtained during the spring measurements. Overall aspect of turf as well as sodding level was defined as a good to very good. Turf color was natural between light green, and bluish, however the color of turf on the playing field, was not monochromatic. The turfgrass was characterized by a very low susceptibility to diseases. The range of the grasses root system of in different parts of the field remained at a low level. The grass tillering proceeded best during the spring

Off-resonance Photosensitization of a Photorefractive Polymer Composite Using PbS Nanocrystals

The photosensitization of photorefractive polymeric composites for operation at 633 nm is accomplished through the inclusion of narrow band gap semiconductor nanocrystals composed of PbS. Unlike previous studies involving photosensitization of photorefractive polymer composites with inorganic nanocrystals, we employ an off-resonance approach where the first excitonic transition associated with the PbS nanocrystals lies at ~1220 nm and not the wavelength of operation. Using this methodology, internal diffraction efficiencies exceeding 82%, two-beam-coupling gain coefficients of 211 cm-1, and response times of 34 ms have been observed, representing some of the best figures of merit reported for this class of materials. These data demonstrate the ability of semiconductor nanocrystals to compete effectively with traditional organic photosensitizers. in addition to superior performance, this approach also offers an inexpensive and easy means by which to photosensitize composite materials. the photoconductive characteristics of the composites used for this study will also be considered