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1

Measures of central tendency of aquatic habitat parametres: application to river macrophyte communities

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Szoszkiewicz K., Kayzer D., Staniszewski R., Dawson H. F.
Polish Journal of Ecology
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2010
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tom 58
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nr 4
The aim of this paper is to assess usefulness of different measures when determining central tendencies which characterise the environmental requirements of living organisms. Mathematical analyses were made of the environmental parameters of river macrophyte communities which were taken as a representative pattern of different levels of biological structures. To deliver a representative dataset, botanical surveys were carried out on a range of British rivers together with environmental assessment and the plant communities groups were identified based on characteristic species according to eslished phytosociological criteria. The mean values and standard univariate medians of the revealed associations were compared with means calculated on the basis of advanced transformation and also with the rarely calculated multivariate L median. Due to high variance and asymmetrical distribution, the analyses based on the mean-value appeared to be limited in application. To avoid this disadvantage transformation to obtain normality of the dataset standardisation was proposed although even this did not fully reach a satisfactory symmetry. It was concluded that each environmental variable for each single biota must be individually treated by a suile transformation to obtain approximately normal distributions. The univariate median was very resistant to the effects of outliers but gave a flattened output of the environmental dataset making the partitioning of biological units very difficult. The multivariate L median appeared to be unaffected by outliers. It enabled to obtain considerable ordering of communities against individual environmental parameters without data transformation.
2
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Distribution and composition of aquatic macrophytes in Santhapettai Lake of Villupuram district in Tamil Nadu

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Dhanam S., Elayaraj B.
International Letters of Natural Sciences
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2015
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tom 47
Macrophytes are important component of the aquatic ecosystem and broad changes in the abundance of individual species and community composition provide valuable information on how and why an ecosystem might be changing. Santhapettai lake is one of the biggest fresh water lake in Villupuram district, Tamil Nadu. The physico-chemical parameters were analysed for one year (October 2012-September 2013). Quadrates were laid randomly and extending from shoreline towards the lake center. The macrophytes falling in each quadrate were sorted species wise, identified and data were recorded. The plants have been identified from fresh materials with the help of different floras. In this present investigation, a total of 33 species belonging to 23 families and 28 genera were identified under algae, pteridophytes, dicotyledons and monocotyledons. Further, the plants were classified in morphological group as floating (7), submerged (1), submerged anchored (13), floating leaved (1) and emergent anchored (11). The coverage/spread of macrophytes along the shorelines was higher compared to the centre of the lakes where the species composition was found reduced. Assessment of biota, continuous monitoring and conservation lake are the important components to safeguard the biological wealth of lentic and lotic freshwater ecosystem.
3

Effects of grass carp introduction on macrophyte communities in a shallow lake

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Krupska J., Pelechaty M., Pukacz A., Ossowski P.
Oceanological and Hydrobiological Studies
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2012
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tom 41
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nr 1
4
Artykuł dostępny w postaci pełnego tekstu - kliknij by otworzyć plik
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The influence of increasing uncontrolled recreation on the structure of plankton and macrophyte communities in the tunnel-valley lakes located in agricultural catchment area

80%
Kuczynska-Kippen N., Messyasz B., Nagengast B.
Roczniki Akademii Rolniczej w Poznaniu. Botanika
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2003
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tom 06
In the years 1993-1995 biological research was carried out on three lakes, which are situated in a typical agricultural catchment area, along the Gołaniecka River. The hydrobiological examination carried out in 1993 revealed a stable state of eutrophy on these lakes. At that time neither of the Bukowieckie lakes was used for recreation, while at the Kobyleckie lake there were a number of buildings, including private holiday homes and holiday camps. In 1995, the year finishing the examination, recreation housing began to develop at the Bukowieckie Du?e lake and also an acceleration of tourism was observed on the Kobyleckie lake. In the spring and summer of 2000 hydrobiological research was repeated in order to find out whether the changes in the neighbourhood of the lakes had affected the chemical condition of lake waters. Although the building area by the lakes was still unfinished, particular changes of many parameters of water were already observed. Negative effects of trophic status were noted in the decrease of the visibility of water, increase of the nutrients concentration, in the outstanding blue-green algae character of the spring phytoplankton (Aphanizomenon issatschenkoi (Ussac.) Proschkina-Lavrenko; Planktothrix agardhii (Gom.) Anagn. et Kom.; Limnothrix redekei (Van Goor) Meffert) and zooplankton (Keratella cochlearis f. tecta (Lauterborn), K. quadrata (O.F. Müller), Anuraeopsis fissa (Gosse), Bosmina longirostris (O.F. Müller) and Chydorus sphaericus (O.F. Müller)), the increase of the total densities of zooplankton with the dominance of rotifers, the impoverishment of the phytolittoral, as well as quality and quantity changes in the structure of macrophytes.
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