734 research outputs found
Effect of riverbed morphology, stream order and season on the structural and functional attributes of caddisfly assemblages (Insecta: Trichoptera)
We tested the individual and joint effects of stream order, riverbed morphology (i.e. pool-riffle sequence), and season on the structural (i.e. species composition, density and richness) and functional (i.e. percent ratio of shredders, collectors, scrapers, and predators) properties of caddisfly assemblages in a closely natural headwater system (Börzsöny Mts., North Hungary). Each factor, both individually and in interaction had a significant effect on caddisfly assemblages as shown by MANOVA analyses. To clarify the effects of stream order, riverbed morphology and season on caddisflies, assemblage properties were also separately
studied by ANOVAs. Percent ratio of shredders and collectors were strongly affected by all factors, whereas other attributes were not always sensitive to stream order, season and riverbed morphology. In contrast, species compositions of the reaches differing in stream order and riverbed morphology were significantly different. Our findings on the contrasting differences in shredder composition between riffles and pools may suggest that not only riparian vegetation, but also instream habitat features could
shape the accumulation and retention of particulate organic matter (in streams with pool-riffle heterogeneity)
Estimating sample representativeness in a survey of stream caddisfly fauna
Obtaining an adequate and representative sample is a continuing challenge of community ecology. The present study focuses on what sample area represents adequately the structural composition of the caddisfly fauna of a riffle, at a given sampling occasion. Sixty-two Surber samples were collected from a riffle in a second-order reach of the Bernecei Stream (Börzsöny Mountains, Hungary). This data set was used to estimate sample representativeness at different sample sizes (from 1 to 31 Surber samples, 0.09 m2 - 2.79 m2) generated a re-sampling procedure. Sample representativeness was measured with mean Jaccard
Coefficient and Bray-Curtis Index between samples for species presence-absence data and abundance data, respectively. We found that a sample size of 2.25 m2 represented well (mean similarity 0.998) the species composition of the caddisfly fauna if rare species were excluded from the analysis. In contrast, sample representativeness of species composition proved to be relatively low (0.719) if rare species were included in the analysis. Curves of sample representativeness based on both raw-, or transformed abundance data were less sensitive to the presence of rare species and showed lower representativeness than sample representativeness based on presence/absence data
VĂzi Ă©lĹ‘lĂ©nyközössĂ©gek jellemzĂ©se szerkezeti Ă©s funkcionális jellemvonások alapján – hasonlĂłságok Ă©s kĂĽlönbözĹ‘sĂ©gek = Taxonomic vs. trait based approaches for characterizing aquatic communities – consistency, disharmony or complementarity?
A kutatások a vĂzi Ă©lĹ‘lĂ©nyközössĂ©gek taxonĂłmiai Ă©s funkcionális szervezĹ‘dĂ©sĂ©t meghatározĂł tĂ©nyezĹ‘k feltárására irányultak. A pályázat keretĂ©ben bevezettĂĽnk egy Ăşj funkcionális diverzitási indexet, amelynek segĂtsĂ©gĂ©vel meghatározhatĂł a közössĂ©get alkotĂł fajok hozzájárulása a vizsgált közössĂ©g funkcionális sokfĂ©lesĂ©gĂ©hez. Kimutattuk, hogy mely környezeti tĂ©nyezĹ‘k határozzák meg leginkább a halegyĂĽttesek Ă©s a makroszkĂłpikus gerinctelen szervezetek taxonĂłmiai Ă©s funkcionális szervezĹ‘dĂ©sĂ©t változatos Ă©desvĂzi Ă©lĹ‘helyeken (tavak, vĂzfolyások). Rámutattunk arra, hogy a taxonĂłmiai Ă©s a funkcionális alapĂş Ă©rtĂ©kelĂ©sek közötti összhang nagymĂ©rtĂ©kben fĂĽgg attĂłl, mikĂ©nt jellemezzĂĽk a közössĂ©geket a funkcionális változĂłk alapján. Vizsgáltuk a közössĂ©gek reprezentatĂv mintavĂ©telĂ©nek számos kĂ©rdĂ©sĂ©t. Ăšj Ă©rtĂ©kelĹ‘ eljárást vezettĂĽnk be a folyĂłvĂzi ökolĂłgiában a konnektivitás mĂ©rĂ©sĂ©re. A kutatások számos eredmĂ©nye segĂti a környezetvĂ©delmi Ă©s termĂ©szetvĂ©delmi Ă©rtĂ©kelĹ‘ eljárások kialakĂtását. | In this research project we have dealt with the taxonomic and function (trait) based organization of aquatic communities, with special regard to the congruence between the evaluation methods. We introduced a new functional diversity index, with the help of which the contribution of individual species to the (total) functional diversity of the community can be quantified. We examined what environmental variables drive taxon and trait based community patterns in a variety of freshwater habitats (streams and lakes) in several papers. We revealed that the congruency between taxon and function based approaches depends largely on how the functional roles of community members are quantified. We published several articles in the representative sampling of and its influence on community patterns. We introduced a novel framework for quantifying connectivity relationships in freshwaters, with special regards to stream ecology and conservation. Our results help the development of bioassessment evaluation methods and conservation oriented landscape design and management
Nemzetpolitikai lélektantól tudományos fajelméletig : A magyar pszichológia történetének szürke zónája
Egy szociálpszichológiai tanmese
OktĂłberben mutatták be a magyarországi mozikban A hullám cĂmű nĂ©met filmet, Dennis Gansel alkotását. Nem sokkal korábban kerĂĽlt a könyvesboltokba egy amerikai szerzĹ‘, Todd Strasser A hullám cĂmű ifjĂşsági regĂ©nye. MindkĂ©t mű közös forrása egy több, mint negyven Ă©vvel ezelĹ‘tt, 1967-ben törtĂ©nt esemĂ©ny. Egy Ron Jones nevű amerikai közĂ©piskolai törtĂ©nelemtanár pedagĂłgiai „kĂsĂ©rletet” vĂ©gzett a kaliforniai Palo Alto egyik közĂ©piskolájában. Jones meg akarta magyarázni diákjainak, hogyan is törtĂ©nhetett, hogy NĂ©metország polgárainak többsĂ©ge aktĂvan támogatta Hitlert Ă©s a náci pártot, s hogy sokan közĂĽ- lĂĽk rĂ©szt vettek – a parancsoknak vakon engedelmeskedve – a legkĂĽlönfĂ©lĂ©bb kegyetlensĂ©gekben, tömeggyilkosságokban
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