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Parameterisation of a population model for Acartia spp. in the Southern Baltic Sea. Part 2. Egg production

100%
Dzierzbicka-Glowacka L., Lemieszek A., Zmijewska M. I.
Oceanologia
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2009
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tom 51
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nr 2
185-201
The paper describes the modelling ofeg g production in Acartia spp. under changing environmental conditions in the southern Baltic Sea (Gdańsk Deep). The hypothesis (Sekiguchi et al. 1980) that the food-saturated rate of egg matter production is equivalent to specific growth rate ofco pepods is applied. The average number ofeggs produced per day by one Acartia female is obtained as a function ofg rowth rate, i.e. by multiplying exp gN3 − 1 from the growth rate of the nauplius stage equation by Wfemale/Wegg. The copepod model, reduced to a zerodimensional population model calibrated for Acartia spp. under the environmental conditions typical ofthe southern Baltic Sea, was used to determine the effects of temperature and food concentration on the growth rate ofeac h oft he model stages (see Part 1 – Dzierzbicka-Głowacka et al. 2009 – this issue). In this part, egg production as a function of the above parameters is evaluated. The rate of reproduction during the seasons in the upper layer ofthe Gdańsk Deep is also determined.
2

Localization of breeding origin of migrants according to biometrical data: the methodological problem

100%
Busse P.
The Ring
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1997
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tom 19
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nr 1-2
3
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Parameterisation of a population model for Acartia spp. in the Southern Baltic Sea. Part 1. Development time

84%
Dzierzbicka-Glowacka L., Lemieszek A., Zmijewska M. I.
Oceanologia
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2009
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tom 51
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nr 2
165-184
The copepod model (see Dzierzbicka-Głowacka 2005b),red uced to a zero-dimensional population model (Fennel 2001,S tegert et al. 2007),i s calibrated for Acartia spp. under the environmental conditions typical of the southern Baltic Sea. Most of the coefficients used in the model are taken from the literature,co ntaining values from various published studies and parameters derived for similar species. The parameters for growth are presented in Part 1; those for population dynamics are given in Part 2. Ingestion rates,whic h are dependent on developmental stage, food supply,temp erature and weight of the animals, are estimated for Acartia bifilosa at 15◦C from the Gdańsk Deep after the experimental data of Ciszewski & Witek (1977). In Part 1 the model presents the change in mean individual mass in successive stages. Quantitative formulae are obtained describing the effects of temperature and food concentration on the development time of Acartia spp. for each of the model stage groups. The generation time during the seasons in the upper layer of the Gdańsk Deep is also determined. The simulations computed here are similar to the experimental results. Part 2 (Dzierzbicka-Głowacka et al. 2009 – this issue) will evaluate egg production as a function of the above-mentioned parameters,temp erature and food availability.
4

The decline of the Bullfinch Pyrrhula pyrrhula in Britain: is the mechanism known?

84%
Siriwardena G. M., Freeman S. N., Crick H. Q. P.
Acta Ornithologica
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2001
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tom 36
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nr 2
The Bullfinch has declined in Britain and elsewhere in Europe, but definitive evidence about the cause and demographic mechanism has yet to be published. We review current knowledge, concentrating on analyses of demography, and present new integrated population modelling analyses designed to reveal the demographic changes most important in the decline. It is likely that changes in brood size and clutch size have not been important and our models suggest that the decline can be explained without invoking variation in numbers of breeding attempts or post-fledging survival rates. However, although changes in the egg period daily nest failure rate provide the best explanation for population change during the years of steepest decline, nestling period failures, adult survival and first-year survival could all have been equally important. Egg period nest failure rates have been higher in the preferred habitat, woodland, than in farmland and have fallen over time in farmland, where a larger decline has occurred (65% versus 28%), arguing against a causal link with abundance. Despite evidence for a negative effect of agricultural intensification on Bullfinch presence, little evidence exists clearly linking any demographic rate to environmental change and agricultural land-use has had little effect on nest failure rates. Predation appears to have had no significant impact. Future work should focus on contemporary investigations of the importance of hedgerow structure and woodland understorey vegetation.
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