Wyniki wyszukiwania - Biblioteka Nauki

1

Geographic variation in phytochemical constituents and allelopathic potential of Pinus halepensis barks

100%

Refifa T. , Chahdoura H. , Guido F. , Achour L. , Helal A. N.

European Journal of Biological Research

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2015

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tom 05

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nr 3

2

Biomass production of different grassland communities under artificially modified amount of rainfall

84%

Holub P. , Tuma I. , Zahora J. , Fiala K.

Polish Journal of Ecology

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2015

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tom 63

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nr 3

EN

Global climate change is predicted to alter growing season rainfall patterns, potentially reducing total amounts of growing season precipitation and redistributing rainfall into fewer but larger individual events. Such changes may affect numerous soil, plant, and ecosystem properties in grasslands and ultimately impact their productivity and biological diversity. A five-year field study with regulated amount of precipitation was executed in different types of temperate grasslands (dry Festuca, wet Cirsium and Nardus grasslands) in three different regions (in lowland, highland and mountain, respectively) in the Czech Republic. Three simulated rainfall treatments were applied: reduced rainfall by 50% (dry), increased rainfall by 50% (wet), and natural rainfall of the current growing season (ambient). The addition of supplemental resources of water exhibited slightly positive relation with the above-ground production (AP), but statistically significant only in the lowland grassland. At all grasslands, both root biomass (RB) and total below-ground biomass (TBB) were significantly higher in wet compared to dry treatments. Significantly increased values of the TBB/AP ratios occurred only in the highland grassland due to enhanced rainfall. The opposite relations were found in lowland grassland where the TBB/AP ratio decreased in response to enhanced rainfall, though not significantly. In the mountain grassland, values of the TBB/AP ratios have shown less variability. The highland wet Cirsium grassland was more sensitive to altered rainfall regimes forming rather lower proportion of below-ground plant production.

3

Geographic and seasonal variability in feeding behaviour of a small herbivorous rodent

84%

Sassi P. L. , Borghi C. E. , Dacar M. A. , Bozinovic F.

Acta Theriologica

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2011

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tom 56

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nr 1

EN

Foraging strategies have traditionally been modelled as a result of food selection in response to one factor, as for instance resource availability, deterrent compounds or nutrients. Thus, a trade-off is assumed between plasticity (generalist strategy) and efficiency (specialist strategy). Nevertheless, several studies have demonstrated that animals cope behaviourally with food supply variation. For instance, desert-dwelling rodents partially compensate for nutritional bottlenecks through diet selection. The aim of our study was to test how foraging behaviour matches spatial and temporal variations in the trophic environment and how modelling hypotheses help us to understand the resultant foraging strategy. Our animal study model was the small cavy Microcavia australis, a widely distributed herbivorous rodent. Fieldwork was carried out in four places, in wet and dry seasons. We found significant differences in plant cover, plant diversity and niche breadth, and diet selection revealed a complex foraging strategy. M. australis shows a behavioural repertoire that exceeds single-criterion categories; therefore, we appeal to theoretical models that consider ecological and physiological perspectives. We classified the small cavy as a facultative specialist displaying a thoroughly opportunistic strategy based on the plasticity of the behavioural phenotype. We finally discuss the evolutionary relevance of our results and propose further investigation avenues.

4

Comparative studies on Polish and Bulgarian populations of Dactylis glomerata subsp. glomerata [ Poaceae ]

84%

Mizianty M.

Fragmenta Floristica et Geobotanica

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1996

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tom 41

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nr 1

5

Variability of helminth assemblages and populations in the bank vole Clethrionomys glareolus

84%

Haukisalmi V. , Henttonen H.

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nr Suppl.

6

Scots pine forests of the Vaccinio-Piceetea class in Europe: forest sites studied

67%

Solon J.

Polish Journal of Ecology

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2003

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tom 51

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nr 4

EN

The paper presents: a) the general differentiation of the pine forests of Europe, and b) the floristic differentiation of the ten study sites, located along the transect stretching between 50°28′ and 70°09′ N, as well as c) the relations between the geographical location and the climatic characteristics on the one hand, and the selected features of the richness and species diversity of the herb layer on the other. One can observe a dependence (p < 0.05) between the temperature and latitude on the one hand, and the number of species from some groups on the other. For the vascular plants, the indicators of linear correlation amount to, respectively, 0.64 and -0.63 (the number of the vascular species of the herb layer increases with the warming of climate and the movement towards the South), and for the numbers of lichen species: -0.81 and 0.78 (the dependencies have the opposite directions to the previous ones). The variability of the relative shares of the particular species groups is correlated with geographical location and climatic variables. Three basic patterns of spatial variability can in this context be identified. The first of these is represented by the share of the lignified chamaephytes (dwarfshrubs). In accordance with this pattern, the minimum shares are observed at the latitudes of Lithuania, Latvia, and Estonia. The second pattern of variability is represented by the shares of hemicryptophytes. In accordance with this pattern the maximum shares are observed between 53° and 56° N. The third pattern of variability is represented, in particular, by the share of the evergreen species which is proportional to the latitude.

7

Ground vegetation carbon and its relation to climate and species richness

67%

Solon J. , Roo-Zielinska E.

Polish Journal of Ecology

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2003

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tom 51

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nr 4

EN

Ten pine forest sites located along the transect between 50°28′ and 70°09′ N were studied. The purposes of the present paper are: 1) to determine the volume of the organic carbon pool in selected layers of the analysed forest ecosystems (shrubs, herb layer, mosses and lichens, litter, and the humus horizon of the soil); and 2) to elaborate the correlation-based prediction models relating the organic carbon pools in these layers with the selected variables characterising the climate and the species richness of the pine forests. The results indicate a clear horizontal heterogeneity of the ground layer in the pine forests considered. This is reflected, in particular, through the differentiation of the carbon pool in particular places within the ecosystem. There is a distinct geographical variability in the carbon pool among the sites in particular layers, with the average annual and January temperatures having the largest influence on this variability. However, in different cases there are different combinations of the factors describing these relations in the best way. The relations between the carbon pool and the species richness of the sites along the transect show that either the minimal carbon pool occurs at sites of an average species richness, or there is no relation between these variables. The analysis implies that there are two points of the transect at which various characteristics of the system undergo an abrupt shift. The first of them is equivalent to the passage of the annual +1°C isotherm, while the second at approximately 5-6°C. There is the possibility that these regularities occur within the entire range of the pine forests.

8

Rozmieszczenie i zmienność geograficzna boru trzcinnikowego (Calamagrostio villosae-Pinetum Staszkiewicz, 1958) w Polsce

51%

Cabala S.

Acta Biologica Silesiana

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1989

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tom 12