Wyniki wyszukiwania - AGRO

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Long-term population dynamics of African ungulates in Waterberg Plateau National Park, Namibia

100%

Kasiringua E., Proches S., Kopij G.

Polish Journal of Ecology

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2019

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tom 67

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nr 4

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The dynamics of the population of a steppe perennial Senecio macrophyllus M.BIEB. during xerothermic grassland overgrowing

100%

Czarnecka B.

Acta Societatis Botanicorum Poloniae

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2009

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tom 78

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nr 3

247-256

The study aimed to determine the long-term changes of the Senecio macrophyllus M.BIEB. population traits: the abundance, reproduction mode, individual fecundity, seed rain and recruitment of new genets in the course of xerothermic grassland overgrowing. The study had also the applied goal: to estimate the chances of "special care" species to survive in the changing environment without management regime for the maintenance of grassland. The model object was the island population of large-leaved ragwort on Biała Góra (the White Mountain) near Tomaszów Lubelski, South-East Poland. To achieve these aims I used the following sets of data: phytosociological relev,s made in plant communities in an interval of 16-18 years; repeated elaboration of the numbers and life-stage structure of the population, both by non-surface and surface method; observation of plants, life cycle in 50 labelled genets; population reproduction and seed rain amounts. The area of an open xerothermic grassland decreased due to the process of overgrowing by bushes which was accompanied by the increasing coverage of forest and meadow herbs as well as monocotyledons, mainly Brachypodium pinnatum and Calamagrostis epigejos. The abundance of the S. macrophyllus population noticable diminished. The flowering mode has been changing during years from an oscillation to a chaotic type which caused the significant decreasing of the individual fecundity, population reproduction and seed rain. In last years it was reflected in the interruption of juveniles’ recruitment.

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Long-term monitoring of Antarctic pinnipeds in Admiralty Bay [South Shetlands, Antarctica]

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Salwicka K., Rakusa-Suszczewski S.

Acta Theriologica

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2002

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tom 47

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nr 4

Year-round monitoring of five Antarctic pinnipeds was conducted in Admiralty Bay from 1988 up to 2000. Two breeding species: southern elephant seals Mirounga leonina (Linnaeus, 1758) and Weddell seals Leptonychotes weddellii (Lesson, 1826), were present throughout the year. Three other species: crabeater seals Lobodon carcinophagus (Hobron and Jacquinot, 1842), leopard seals Hydrurga leptonyx (Blainville, 1820), and Antarctic fur seals Arctocephalus gazella (Peters, 1875) visited the area only for short periods. During this study, the abundance of elephant seals was stable, whereas those of Weddell and crabeater seals declined. Leopard seals numbers fluctuated irregularly. We detected a possible immigration from South Georgia: of a stable magnitude for elephant seals, and of variable magnitude, depending on food accessibility, for Antarctic fur seals. We found a strong recurrence of the spatial distributions of elephant, Weddell, and Antarctic fur seals in the 13 oases on the shore of Admiralty Bay. Annual distribution patterns were characteristic for each species. The innermost beaches were used predominantly by the animals during their annual fasts: the breeding and the moulting seasons.

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Some remarks on recent trends in regional population dynamics in Austria

100%

Sauberer M.

Geographia Polonica

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1992

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tom 59

5

Bark beetles in the Tatra Mountains. International research 1998-2005 - an overview

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Grodzki W., Turcani M., Jakus R., Hlasny T., Rasi R., McManus M. L.

Folia Forestalia Polonica. Series A . Forestry

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2010

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tom 52

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nr 2

This paper is a review of fundamental information on bark beetles and their interactions with several predisposing factors (air pollution, drought/temperature interactions, windthrows, management activities) that are thought to contribute to the outbreaks in the High Tatra Mountains. The findings of many research projects indicate that the impact of air pollution on bark beetle populations is indirect and complex and that the disturbances in the physiology and natural resistance of trees may be of crucial importance to bark beetle population dynamics. An active forest protection approach is needed to be applied to the secondary Norway spruce forests affected in the past by human activity. Bark beetle populations in natural and near-natural forests (mainly in the upper montane zone) are regulated by natural mechanisms; bark beetles are therefore a natural factor contributing to forest development, including the transition of future generations of spruce.

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The breeding population of the Great Grey Shrike [Lanius excubitor] in Austria, 1995-2003

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Sachslehner L., Schmalzer A., Probst R.

Biological Letters

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2004

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tom 41

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nr 2

135-146

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Spirostomum teres: a long term study of an anoxic-hypolimnion population feeding upon photosynthesizing microorganisms

86%

Macek M., Sanchez Medina X., Picazo A., Pestova D., Bautista Reyes F., Montiel Hernandez J. R., Alcocer J., Merino Ibarra M., Camacho A.

Acta Protozoologica

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2020

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tom 59

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nr 1

8

Changes in the aquatic moss Sphagnum denticulatum Brid. population abundance in a softwater lake over a period of three years

86%

Szmeja J.

Acta Societatis Botanicorum Poloniae

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2010

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tom 79

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nr 2

167-173

Changes in population abundance of submerged Sphagnum denticulatum Brid. were studied in an acidic and oligotrophic lake in NW Poland over three years. Individuals were counted in a moss carpet at a depth of 2.5 m on 4 experimental plots, 1 × 1 m each, every 30 days for 36 months using the SCUBA method. PAR intensity was seasonally variable (in winter higher than in summer). Changes in water pH, conductivity, HCO3- concentration, hydration and sediment pH were statistically insignificant (p > 0.05). In the summer of the second study year the moss carpet disappeared almost completely due to a massive bloom of filamentous green algae. Periods of growth, regression and regeneration were observed in the population. The stabilisation of population size took 24 months and followed the pattern: slight fluctuations, then rapid growth and repetition of slight fluctuations. The first stage lasted nine, the second four and the third nine months. These stages took place irrespective of seasons, temperature or PAR intensity. Each rapid increase in abundance lasted about 30 days, at PAR intensity >20% and water temperature ranging from 11 to 16oC (in winter, spring or autumn). The regression stage brought about by the algal bloom started in the second year (in summer) and lasted six months (until the end of January in the third year). The population regeneration began in winter (in February, water temperature 3.0oC, PAR about 20%, ice cover 0.15 m) and finished with the end of spring. The population of S. denticulatum shows a repetitive pattern of abundance variations, which is seriously disturbed in summer, especially after a warm spring, by a massive bloom of filamentous green algae.

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Ecology and population dynamics of yeast starter cultures in cocoa beans fermentation

86%

Gonzalez E. G., Orejuela J. H. M., Banguera J. S. S., Moreno D. I. C., Narvaez G. A., Munez A. F. O., Rodriguez C. M.

BioTechnologia. Journal of Biotechnology Computational Biology and Bionanotechnology

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2022

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tom 103

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nr 4

10

Population dynamics of the black tinder fungus beetle Bolitophagus reticulatus

86%

Lik M.

Folia Biologica

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2005

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tom 53

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nr Suppl.

11

Variation in the fecundity of roe deer in Britain: effects of age and body weight

86%

Hewison A. J. M.

Acta Theriologica

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1996

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tom 41

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nr 2

This paper investigates variation in female fecundity in relation to effects of age and body weight within and between 15 populations of roe deer Capreolus capreolus (Linnaeus, 1758) in Britain. Analyses were based on carcass material and fecundity was assessed from the presence/absence and number of fertilised ovulations (.corpora lutea) and implanted foetuses. A significant proportion (> 10%) of does ovulated in their first year in some populations, but such precocious reproductive activity rarely resulted in successful implantation of a foetus. Generally, the majority of yearling does (in their second year) conceived successfully, but average potential litter size was lower than among older animals. There was no consistent age-related variation in fecundity among does older than 2 years. Differences in fecundity between age and body weight classes suggest weight thresholds may exist for the onset of puberty and for successful conception as an adult. Fecundity of adults and yearlings was highly variable between populations and in some populations was considerably lower than previously reported for this species. Although differences between populations were correlated with differences in body weight, this relationship was insufficient to explain the wide variation in fecundity across Britain, suggesting fecundity body weight thresholds will be defined independently in separate populations.

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Population dynamics of some Lepidoptera pests on horseradish

86%

Szwejda J., Rogowska M.

Vegetable Crops Research Bulletin

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2000

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tom 52

13

Demography of woodland rodents in fragmented habitat

86%

Rajska-Jurgiel E.

Acta Theriologica

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1992

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tom 37

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nr 1-2

Populations of two species of woodland rodents were studied: Apodemus flavicollis (A. f.) and Clethrionomys glareolus (C. g.)t inhabiting a set of small wood patches, isolated from large, continuous forest. The species composition, density and population dynamics differed from those in the forest. The rodents used the entire area as a patchy habitat, moving between the woodlots. In the breeding season high mobility caused higher mortality among males, especially in C. g. Sex ratio in C. g. was female biased. In A. f. females prevailed in spring whereas there was a prevalence of males in autumn. Seasonal changes in age structure followed different patterns in females and males. Males prevailed in first spring litters in both species. Males also prevailed among numerous immigrants of A. f. but females prevailed among immigrants of C. g. The demographic processes in these species resulted from habitat fragmentation and different life strategies.

14

Spatial structure of Microtus rossiaemeridionalis during population growth

86%

Muntyanu A., Sitnik V.

Polish Ecological Studies

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1994

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tom 20

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nr 3-4

15

Phenotypic diversity and population dynamics: another look (with particular reference to the common shrew Sorex araneus)

86%

Zakharov V. M., Pankakoski E., Sheftel B. I.

Acta Theriologica. Supplement

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1997

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nr 04

We studied temporal changes in the level of phenotypic diversity, measured by the total phenotypic variance for several characters of skull morphology, in two populations of the common shrew Sore:e araneus Linnaeus, 1758. We compared a population from central Siberia having a high-amplitude four-year cycle with a population from southern Finland having noncyclic dynamics. The level of total phenotypic diversity varied significantly among years in both populations, but was correlated neither with density nor with breeding success in either of them. We did, however, find differences between the two populations. When we compared changes in the level of phenotypic diversity with changes in the level of developmental stability, as measured by chance developmental variance (fluctuating asymmetry), the cyclic Siberian population exhibited increased developmental variability in the peak year, which was associated with relatively small proportion of other sources of variation (and genetic variation in particular). In other years, the role of chance variation was less and the proportion of other sources of variance was higher. On the other hand, in the noncyclic Finnish population, oscillations in the level of phenotypic diversity were mainly caused by changes in developmental stability. These results illustrate that not only dynamics of genotype variety, but also the alterations in the level of developmental stability can be of great importance for changes in phenotypic diversity.

16

The odour of a terrestrial predator as an olfactory risk signal detected by rodents, and its consequences

86%

Borowski Z.

Biological Bulletin of Poznań

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2000

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tom 37

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nr 1

17

Population dynamics of Liparis loeselii [L.] L.C.Rich. in the nature reserve 'Mielno' - some results from a 8 year study

86%

Bednorz L.

Electronic Journal of Polish Agricultural Universities. Series Biology

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2003

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tom 06

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nr 2

This paper presents some results of a 8 year (1995-2002) observation of Liparis loeselii population in the nature reserve Mielno. The total population numbers as well as generative and vegetative ones differ from year to year. The population grew from 73 in 1995 to 106 in 1997, falling to 29 in 2002. At the same time unfavourable changes in population environment (progressive drainage of the area and expansion of woody plants) have been observed.

18

Time of Chironomus plumosus [L.] generations in natural conditions of lowland reservoir

86%

Kajak Z., Prus P.

Polish Journal of Ecology

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2004

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tom 52

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nr 2

The time of Chironomus plu- mosus generation in the field conditions (shallow, eutrophic dam reservoir) was estimated to be about 3 weeks in the spring. This estimate has been possible due to simultaneous mass appearance of young larvae (the new generation) and the lack of older larvae at this time. Later in the season usually there was some amount of the youngest larvae, indicating the permanent emergence of imagos and the egg-laying, but without clear peaks of numbers and boundaries between successive generations. This regularity and the relatively low total numbers of larvae during the summer indicate the heavy fish pressure on the benthos, not allowing for the mass appearance of young larvae and the estimate of the generation time. Fish pressure is probably weak in spring, during a spawning period, but then increase in the summer. The generation number could be theoretically as high as 5 during the vegetation season (May–October), assuming about 3 weeks for full larval development, as it was estimated at optimal feeding and oxygen conditions and low fish pressure in the spring. However some limiting factors like: oxygen deficits, the annoyance by fish and bestrewing of larval tubes with the mud transported by the water flow (range 150–500 m³ s⁻¹ of the total inflow) increase in the summer. These factors can slow down larval development, resulting in observed lower generation number: 3 to 4 during a year.

19

Disorder effects in bridged molecular systems. Random matrix theory approach

86%

Gudowska-Nowak E., Brickmann J., Papp G.

Cellular and Molecular Biology Letters

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1999

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tom 04

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nr 1

Advances in nanotechnologies and molecular assembly techniques have brought much attention to the problem of molecular wires studied with respect to disorder and to increased electronic connectivity. In this communication we aim to use the techniques of Random Matrix Theory (RMT) in the formalism of Free Random Variables (FRV) to analyze and predict electronic properties of one-dimensional disordered bridged molecular systems. We discuss possible application of the method in biological and chemical context. As an example, based on recent achievements in the theory of nonhermitian ensembles of random matrices, we outline here an efficient procedure to calculate electron transfer matrix in electron conducting disordered materials. The approach can be applied to the variety of problems like analysis of final state-selected spectra in unimolecular chemical reactions or population dynamics of biological species.

20

Population ecology and population genetics. Expectations and limitations

86%

Falinska K.

Seria Biologiczna. Uniwersytet im. Adama Mickiewicza w Poznaniu

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2005

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tom 72

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