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1

Body size and the relative abundance of species

100%
Ulrich W.
Ecological Questions
|
2008
|
tom 10
Existing models of species abundance distributions (SADs) can be divided into those that are based on concepts of common limited niche space (niche apportionment models, neutral models) and those that invoke standard statistical distributions (e. g. log-series, lognormal). While the first type of models assumes that competitive interactions lead to observed SADs, the models of the second type appear to be mainly statistical descriptors of SADs without deeper biological meaning. None of the models explicitly includes species body size as a factor influencing species abundances. Further, with the exception of recent neutral models they are not embedded into basic ecological and evolutionary models to explain local diversity and ecosystem functioning. Here I present a new random walk model of species abundances that is based on two well known ecological distributions, the abundance - body weight distribution and the species - body weight distribution to define long-term upper abundance boundaries (carrying capacities). I show that a simple random walk of species abundances around the carrying capacities not only generates observed SADs but is also able to explain other patterns of community structure like core - satellite distributions, temporal patterns of species turnover, variance - mean ratios, and biomass distributions.
2

Biomass distribution and dynamics and food web relations in psammon community of a eutrophic lake

100%
Kalinowska K., Ejsmont-Karabin J., Gorelysheva Z., Rybak J. I.
Polish Journal of Ecology
|
2012
|
tom 60
|
nr 3
Organisms living in submerged sand along the shore and below the water’s edge in freshwater lake beaches create community called hydropsammon (see Fig. 1 in Preface). Trophic relations between psammon food web components are essential in energy flow, nutrient cycling and functioning of aquatic environments. The seasonal changes in algal, bacterial, nanoflagellate, ciliate, rotifer and crustacean biomass were investigated in hydroarenal (submerged sand) of the eutrophic Lake Mikołajskie (Poland). Sampling cores were taken once or twice a month since April till October 2005 from three layers: adjacent water layer (AWL), layer of water and sand from the transitory level (EPIH – epihydroarenal) and slice of sand (ENDOH – endohydroarenal). The meanannual phytopsammon biomass was extremely high in all microlayers. Bacterial biomass was the highest in the ENDOH. Biomass of nanoflagellates was 4 to 8 times lower than that of bacteria and was the highest in the AWL. The highest mean annual biomass of ciliates was recorded in the EPIH, whereas rotifers dominated in the ENDOH. In contrast, average biomass of Crustacea was the highest in the AWL. Crustaceans dominated heterotrophic biomass in the AWL and EPIH (92 and 54% of the total biomass, respectively) whereas bacteria definitely prevailed in the ENDOH (57%). The ratios of autotrophic to heterotrophic biomass and prey to predator biomass as well as trophic relations between the studied groups of psammon organisms differed clearly among microlayers. The AWL was characterised by the lowest autotrophic/heterotrophic and predator/prey biomass ratios (about 2) and significant positive correlations between nanoflagellates and ciliates as well as between protists and both rotifers and copepods. The highest autotrophic/heterotrophic and predator/prey biomass ratio (14 and 40, respectively) and lack of correlations was found in the ENDOH. These results may suggest that the pressure of consumers was weaker in the hydroarenal layers than in the AWL. In addition, it seems that psammon ciliates, rotifers and crustaceans inhabiting the ENDOH were probably limited by factors other than food availability. In contrast to the pelagic ecosystems, autotrophic biomass exceeded heterotrophic biomass, especially in the ENDOH.
3

Functional diversity, trophic relations and nutrient cycling in psammon community of an eutrophic lake

100%
Kalinowska K., Ejsmont-Karabin J.
Polish Journal of Ecology
|
2012
|
tom 60
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nr 3
4
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Mapping an ecosystem service: A quantitative approach to derive fish feeding ground maps

100%
Siaulys A., Daunys D., Bucas M., Bacevicius E.
Oceanologia
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2012
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tom 54
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nr 3
This study presents a quantitative approach to mapping benthophagous fish feeding grounds. This approach combines the spatial biomass distribution of benthic prey items and their importance for the diets of predators. A point based biomass data of macrozoobenthos together with a set of environmental factors was used to develop Random Forests models that produce continuous biomass distribution layers for individual prey species. Depending on the diet composition and the importance of prey for fish feeding, these layers are overlaid and an integrated GIS map of the seabed showing the quality of feeding grounds is generated. These maps provide a useful basis for conservation and marine spatial planning. In addition, this method could be applied to the mapping of resources used by other benthophagous organisms. The method is presented using the example of three common Baltic fish species: cod, flounder and viviparous eelpout.
5

Long-term trends in the macrozoobenthos of the Vistula Lagoon, Southeastern Baltic Sea. Species composition and biomass distribution

100%
Ezhova E., Zmudzinski L., Maciejewska K.
Bulletin of the Sea Fisheries Institute
|
2005
|
nr 1
6

Growth of wheat plants depending on the use of bioregulators and nitrogen supply

100%
Wierzbowska J., Nowak G. A., Mroczek A.
Natural Sciences
|
2001
|
tom 09
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