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The purposes of the present paper are: a) to show the synusial structure of the herb layer often sites, located in Norway, Finland, Estonia, Latvia, Lithuania and Poland along the transect stretching between 50°28′ and 70°09′ N, and b) to characterise the species-area curves for all the sites studied. The number of types of synusiae on the particular sites ranges from three to ten, though only one or two have the dominating character, that is, occupy at least 20% of surface. From the point of view of synusial differentiation three geographical groups of sites could be established: the most distinctly different are the northern sites. The second subset of sites, though featuring relatively weak internal mutual similarities, encompasses the sites located in the middle part of the transect. The third subset of sites, represents a more southern character. For each of the sites separately the dependence between the number of vascular species of the herb layer and the area of the site considered (the species-area relationship) is described by the formula y = axb. Correlation coefficients between the model and the actual number of species are very high, from 0.902 to 0.998.
The applicability of Mean Individual Biomass (MIB) of Carabidae as an indicator of succession stage was tested on 35 forest stands in western Poland. The differences in MIB values as well as similarity indices (Jaccard index, Wainstein index) were calculated between two inventories at the study sites separated by a time span of 13 years. The hypotheses were set that (1) MIB values increase with time on the study areas and (2) the differences in MIB values are negatively correlated with the corresponding similarity indices. The results show an increase in numbers of species and individuals of big sized carabids in the total samples. MIB values increase at the vast majority (85.7%) of the individual study sites between the two inventories. The increase in MIB shows a significant negative correlation with both similarity indices. The correlation is more pronounced when using the Wainstein index. The results verify the applicability of MIB of Carabidae as an indicator of stage of succession. Based on the results we suggest MIB as a useful tool in forest research and forest management.
The toxicity and bioaccumulation of cadmium in a marine benthic protist community were examined at different depths within the sediment. For this purpose, sediment-water microcosms with 1000 μgCd dm−3 of the pollutant were used in two assays. The addition of cadmium caused a significant reduction in protist density, number of species and biomass. There was also a decrease in these three parameters with depth. During the treatment the density of protist groups was strongly depth-dependent. The dominant groups of protists at the different depths during the assay were also considered. The most dominant protist group in terms of density were the heterotrophic flagellates, both in the control and in the treatment with cadmium. In the treatments with cadmium, these were followed by ciliates and by dinoflagellates in both assays. In the control, all protist groups were present during the assay, whereas in the treatments with cadmium, autotrophic flagellates, diatoms and sarcodines were found in reduced proportion or not at all. Cadmium bioaccumulation increased towards the end of the assay. At any time during the assay, the proportion of cadmium bioaccumulated was an increasing function of depth.
Knowledge of bat diets may be important for the conservation of small Atlantic Forest fragments because these animals play an important role in seed dispersal and natural recovery of tropical forests. The ‘Reserva Particular do Patrimônio Natural Feliciano Miguel Abdala’ (RPPN-FMA) is a 886-hectare Atlantic forest fragment consisting of a mosaic of distinct successional phases resulting from logging and natural causes, in the state of Minas Gerais, Brazil. We collected 216 fecal samples containing blood, arthropods, pollen-nectar, vegetation (leaflets and fruit peel), fruit pulp (fibers and juice) and seeds, from 18 bat species at the RPPN-FMA. Piperaceae, Solanaceae, Cecropiaceae, and Guttiferae were the most important food resources for frugivorous bats at RPPN-FMA. Piper infrutescences were consumed by Artibeus obscurus, A. fimbriatus, Carollia perspicillata, and Sturnira lilium throughout the year, functioning as key species, as already observed for other tropical rainforest sites.
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