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This study compares the present (1991-1993) breeding avifauna from the city of Olsztyn with that in the years 1954- 1968. Habitats changed significantly over the 25-year interval. A rise in the human population was associated with the expansion of residential and industrial districts and a consequent contraction of natural areas. Changes occurred between 1968 and 1993 in the diversity and dominance structure of the breeding avifauna. Chlidonias niger, Tringa totanus, Upupa epops, Luscinia svecica, Galerida cristata and Corvus frugilegus were lost from the city, while an additional 15 species declined. Nine species are currently endangered in the city, and will probably disappear in the near future. Urbanization meanwhile has favored 11 species that inhabit built-up areas or are undergoing synurbization. The appearance of Aythya ferina, Bucephala clangula, Mergus merganser and Columbia livia domestica as new breeding species reflects general trends towards increased populations in both Poland and the continent as a whole.
In urban areas of Łódź (Central Poland), the vertical and horizontal distributions of the Blackbird Turdus merula and Song Thrush Turdus philomelos nests were investigated in relation to running lanes and paths as places of penetration of humans. A significant effect of human penetration on vertical and horizontal distribution of Blackbird nests in parks was found. The park population of Blackbirds, unlike forest-breeding ones built nests more distantly from the lanes, lower, and under the shelter of shrubs. In the Blackbird park population, 74.2% of the nests were built in shrubs. The mean nesting height was 1.18 m. Distribution of distance between the nest and lanes are negatively skewed to = -0.57). The reverse was true of the forest population of this species where81.9% nests were built in trees. The mean nesting height was 1.29 m. Nests of the forest population of Blackbird were distributed randomly. Differentiation in nest sides between urban and forest populations of Blackbird is a statisticaly significant. Only one pair of the Song Thrush was recorded in a parks. The forest population of the Song Thrush nesting in the trees, mean nesting height was higher than those of the Blackbird. The presence of people in thef orest had a significant negative effect on the horizontal distribution of Song Thrush nests. Therefore, human disturbance is considered the factor that prevents this species from colonising urban parks (contrary to the situation in West European countries).
From 1991 to 1993 the breeding birds were censused in five types of built-up areas in the city of Olsztyn (NE Poland). The bird communities were characterized by Margalef's index of species diversity and Simpson's index of dominance structure. Areas of new construction had the lowest species diversity (d = 3.23), with a clear dominance of one species — Columba livia domestica (c = 0.44). The breeding communities of the industrial area had high species diversity (d = 10.13), but the lowest population density. The most diverse communities occurred in suburban developments of the "villa" type (d = 11.53), and in a housing estate district with older buildings and urban green space (ground cover and shrubs) (d = 9.55). Analysis of differences in indices of species diversity showed that the factors influencing diversity were the percentage cover of urban green space, the percentage cover of built-up areas and the presence of small bodies of water.
In 1987 - 1990 an investigation was made on the spatial structure of brown hare Lepus europaeus Pallas, 1778 populations using the transect routes method. The in­vestigation was carried out in two different parts of Poland that differed in the charac­ter of agriculture: 1 - northeastern with large fields of state farms, and II - east- central with small fields of individual farmers. The results indicate that independently of the agrarian structure, the distribution of hares in crops corresponds to their per­centage share in the region, with exception of rape fields, which show a tendency to be avoided. There was also a significant relationship between the spatial distribution of the hare and the habitat diversity - highly variegated fields are more consistently inhabited by hares. Besides, hares show a distinct tendency to prefer areas close to the field margins. Positively oblique distance distributions between the individuals and the margins of field crops are particularly strongly expressed in the region of a highly monotonous crop species. It may be expected that a change in type of farming by passing to the large-fields and continuous cropping is one of the factors that make it difficult for the hare to utilize the space within the habitat.
The aims of the study were determine the effects of anthropogenic pressure on the species composition and population size of amphibians of small water bodies in Olsztyn city (NE Poland). The presence of 11 amphibian species was noted in 83.5% of water bodies. The dominants were: the common frog Rana temporaria, the edible frog Rana esculenta, the pool frog Rana lessonae, the common toad Bufo bufo and the moor frog Rana arvalis. The fire-bellied toad Bombina bombina was an influent, while the common newt Triturus vulgaris, the common spadefoot Pelobates fuscus, the tree frog Hyla arborea, the green toad Bufo viridis and the crested newt Triturus cristatus were the recedents. The most frequent were "green frogs", which occur in 71.9% of water bodies inhabited by amphibians (60.0% of all water bodies). The species characterized by the lowest occurrence frequency were the tree frog (6.0% and 5.0%, respectively), the green toad (5.4% and 4.5%) and the crested newt (3.6% and 3.0%). In the paper the urban pressure on amphibian communities is widely discussed.
The morphology of the striatum (St, caudoputamen complex) and globus pallidus (GP) was studied by stereological methods in representatives of four mammalian orders (Insectivora, Rodentia, Lagomorpha, Carnivora). The aim of our study was to give the first detailed morphometric characteristics of the St and GP in the animals. The paraffin-embedded brain tissue blocks were cut in the coronal plane into 50 fim sections, which were stained for Nissl substance. The morphometric analysis of the St and GP has included such parameters as the volume, numerical density, and total number of neurons. The increase in the volume of the St and GP was accompanied by an increase in the total number of neurons and a decrease in their numerical density. The percentage contribution of the GP volume in the corpus striatum shows progressive traits in the common shrew and fox.
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