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Shell-abounding thanatocenoses were collected from recent sediments of the Vistula River near Cracow formed during a few flood episodes. They are composed of 65 species of aquatic and terrestrial molluscs. Considerable differences between particular mollusc assemblages deposited on the river banks are controlled by both the intensity of flood and the changes of the fauna inhabiting the catchment area, mainly the floodplain and the river itself. Living specimens and empty shells of Potamopyrgus antipodarum (Gray) were found for the first time in thanatocenoses accumulated in Tyniec in 1999 and 2000.
Shells and opercula of an aquatic snail Bithynia tentaculata (L.) occur commonly in Quaternary deposits as a substantial component of subfossil malacocenoses. They have been noted mainly in lacustrine chalk and calcareous gyttja, as well as in silts and muds accumulated in fluviatile environments. The contemporary geographical range of this taxon is very wide, comprising the whole Palaearctic except areas extending north of the Arctic Circle. In subfossil assemblages of molluscs B. tentaculata (L.) has been described almost exclusively from Holocene and Interglacial deposits, apart from a few localities of sediments accumulated during the cold periods of Pleistocene, particularly in Late Glacial phases. As the range of the mentioned species is limited to the zones of the temperate, boreal and Mediterranean climate, it can be pointed out as a climatic- stratigraphic indicator, useful in malacological analysis of Quaternary deposits. Only a few taxa of aquatic molluscs have such a value. The proportion of shells and opercula characterizes sedimentary environments.
Land snail assemblages found among the most famous and popular historical monuments of ancient Rome are the subject of this study. Malacocoenoses found beneath walls of ruins in antique places, among grass and other short vegetation, in places visited by thousands of tourists, are usually ignored by naturalists and thus are only rarely examined. They develop in specific habitats, being under constant and strong human impact. The living fauna is accompanied by thanacocoenoses composed of numerous shells. Species associated with open or even xerothermic habitats as well as mesophile ones, accepting both sunny and shaded habitats, are the main components of these assemblages.
A rich population of Planorbella duryi (Wetherby) has been found in Lake Albano near Rome. It is a pulmonate aquatic snail inhabiting the zone of tropical climate, and heated artificial reservoirs outside this zone. It has migrated from its area of origin – Florida – to Africa, South America and some islands, has been introduced in a few botanical gardens in Europe, and also found a favourable habitat in a small crater-lake Albano in Italy where it is now abundant.
Przedstawiono rezultaty szczegółowej analizy zespołów subfosylnych mięczaków znalezionych na obszarze Kampinoskiego Parku Narodowego i w jego najbliższym otoczeniu. Umożliwiły one zestawienie i podsumowanie pełnego kompletu danych dotyczących występowania holoceńskiej malakofauny na omawianym terenie. Prezentowana fauna obejmuje 51 gatunków ślimaków i małży oraz wieczka zagrzebek i wapienne płytki ślimaków bezskorupowych, a ponadto kilka taksonów reprezentowanych przez ułamki skorupek lub pojedyncze okazy, najczęściej niekompletnie zachowane. Przedstawione wyniki badań podsumowują pierwszy etap poznania czwartorzędowej fauny Parku jako wskaźnika zmian środowiska naturalnego w epoce holocenu, a zarazem wskazują na celowość kontynuowania tu analizy malakologicznej osadów najmłodszego okresu geologicznego
A shell-abounding thanatocenosis was found on the valley floor of the Osam River near Muselievo. It is composed of 42 taxa of land snails and aquatic molluscs. Six species of rheophile water snails, Lithoglyphus naticoides (C. Pfeiffer) being the dominant, are the main components of the assemblage, together constituting 57%. Land snails are represented mainly by open-country species, including the most numerous shells of Helicopsis striata (O. F. Müller). All the taxa of the thanatocenosis are known from the recent fauna of Bulgaria and adjacent countries. The percentage of particular components corresponds to thanatocenoses deposited in the lower course of the river. The shell material was displaced by the flood flow over a relatively short distance and deposited close to environments inhabited by molluscs. Differences in abundance of some species between the thanatocenosis and the malacocenosis can be explained by differences in the hillwash intensity controlled by local conditions.
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