Preferencje help
Polish version English version Język
Widoczny [Schowaj] Abstrakt
Liczba wyników

Znaleziono wyników: 17

Liczba wyników na stronie
Pierwsza strona wyników Pięć stron wyników wstecz Poprzednia strona wyników Strona / 1 Następna strona wyników Pięć stron wyników wprzód Ostatnia strona wyników

Wyniki wyszukiwania

Wyszukiwano:
w słowach kluczowych:  freshwater habitat
help Sortuj według:

help Ogranicz wyniki do:
Pierwsza strona wyników Pięć stron wyników wstecz Poprzednia strona wyników Strona / 1 Następna strona wyników Pięć stron wyników wprzód Ostatnia strona wyników
1

Ecotypes of Amphipoda in Central European inland waters

100%
Meijering M. P. D., Jazdzewski K., Kohn J.
Polskie Archiwum Hydrobiologii
|
1995
|
tom 42
|
nr 4
2
Artykuł dostępny w postaci pełnego tekstu - kliknij by otworzyć plik
Content available

Freshwater lichens on submerged stones and alder roots in the Polish lowland

72%
Hachulka M.
Acta Mycologica
|
2011
|
tom 46
|
nr 2
The article presents the results of the studies of lichens in streams and spring areas of the escarpment zone of Wzniesienia Łódzkie Heights in Central Poland. The boulders, stones and roots of Alnus glutinosa, situated in 3 inundated zones in the streams: submerged zone, fluvial mesic zone and fluvial xeric zone, were examined in the streams. The studies have shown 23 species connected with these streams. Six species of freshwater lichens: Verrucaria aquatilis, V. hydrela, Hydropunctaria rheitrophila, V. margacea, V. praetermissa and V. madida, occupied stones in 3 different zones. Verrucaria aquatilis and Hydropunctaria rheitrophila colonized also secondary substrates – the bark of alder roots incrusted with sand grains and silt.
3

Ocena warunków hydrodynamicznych sprzyjających bytowaniu ryb na odcinku rzeki Skawy

72%
Hawrylo A., Ksiazek L., Michalik A.
Acta Scientiarum Polonorum. Formatio Circumiectus
|
2011
|
tom 10
|
nr 4
Praca przedstawia ocenę warunków hydrodynamicznych na wybranym odcinku rzeki Skawy, gdzie stwierdzono występowanie tarlisk ryb. Badany odcinek charakteryzuje się zmiennym spadkiem i zmienną morfologią oraz zróżnicowaniem lokalnym prędkości i intensywności turbulencji. Przeprowadzono pomiary geodezyjne profilu podłużnego i profili poprzecznych koryta oraz składu granulometrycznego rumowiska. Wykonano również pomiary prędkości przepływu wody ADV (Acoustic Doppler Velocimeter) na trzech stanowiskach: przed bystrzem, na bystrzu i poniżej niego. Wyniki pomiarów posłużyły do obliczenia naprężeń stycznych w korycie, rozkładów prędkości oraz rozkładów intensywności turbulencji. Dzięki tym badaniom zidentyfikowano typy siedlisk metodą MEM (Mesohabitat Evaluation Model). Według tej metody przepływy w strefie stanowisk przed bystrzem i na bystrzu sklasyfikowano jako normalne, natomiast na stanowisku poniżej bystrza jako przepływ szybki. Stwierdzenie na dwóch siedliskach przepływu normalnego pokazuje, że przyjęte kryterium w postaci szerokiego zakresu wartości naprężeń stycznych obejmującego dwa rzędy wielkości nie uwzględnia wystarczająco zmian warunków hydrodynamicznych uzyskanych w badaniach.
4

Seasonal changes in the diversity and numbers of waterbirds in a tropical river in Southern Africa

72%
Kopij G., Paxton M.
Polish Journal of Ecology
|
2018
|
tom 66
|
nr 3
Although freshwater habitats play a crucial role in most ecosystems in the world, little is known on their functioning in tropical regions even in regard to the most often studied avian communities. In this study, counts on waterbirds were conducted in dry and wet season (in years 2001–2008) in a riverine habitat in southern Africa (Shamvura stretch of the Okavango River). In total, 84 waterfowl species were recorded. The birds were assigned to different guilds according to their migration activity, diet and nesting site selection. In overall, the species number was almost the same (74 vs. 73) in the wet and dry season. The abundance of all resident species recorded was lower in wet (N = 5992) than in dry seasons (N = 6965)(χ²= 73.1, P < 0.01). In both seasons Palearctic migrants were represented by seven species, which comprised 1–2% of all waterbirds. Six species were classified as dominants: African reed cormorant Phalacrocorax africanus, African openbill stork Anastomus lamelligerus, cattle egret Bubulcus ibis, wattled lapwing Vanellus senegallus, African darter Anhinga rufa and white-faced duck Dendrocygna viduata. In the wet season the dominant species comprised 68%, while in dry season – 52.5% of all birds recorded. Significant seasonal differences in the numbers of individuals were shown for the following species: African reed cormorant, great egret, squacco heron, wattled lapwing and pied kingfisher. Insectivorous and omnivorous birds were more abundant in wet season, while piscivorous, carnivorous and plant eating birds in dry season. These differences can be related mainly to seasonal variation in the availability of food as well as to the timing of breeding.
5

A description of Cochliopodium megatetrastylus n. sp. isolated from a freshwater habitat

72%
Anderson O. R., Tekle Y. I.
Acta Protozoologica
|
2013
|
tom 52
|
nr 2
6

Testate amoebae as sea-level indicators in Northwestern Norway: developments in sample preparation and analysis

72%
Barnett R. L., Charman D. J., Gehrels W. R., Saher M. H., Marshall W. A.
Acta Protozoologica
|
2013
|
tom 52
|
nr 3
7

High genetic diversity of amoebae belonging to the genus Mayorella (Amoebozoa, Discosea, Dermamoebida) in natural habitats

72%
Glotova A., Bondarenko N., Smirnov A.
Acta Protozoologica
|
2018
|
tom 57
|
nr 1
8

The interface between taxonomy and ecology in modern studies on the protists

72%
Corliss J. O.
Acta Protozoologica
|
1992
|
tom 31
|
nr 1
9

Invertebrate reproduction in astatic water bodies: egg number - body weight relationship in Viviparus viviparus (L.) from oxbow lakes

58%
Jakubik B.
Polish Journal of Ecology
|
2012
|
tom 60
|
nr 2
Reproduction is the most important factor in population dynamics and invading freshwater habitats by Viviparus viviparus. This is largely associated with ovoviviparity of these snails. Some traits like steered reproduction, the appearance of young snails during the whole year, protection of embryos by female and delayed reproduction were fixed by natural selection as adaptations increasing the chance for progeny survival. In variable habitats like oxbow lakes seasonally joined to the river channel, Viviparidae start reproducing in the early stage of their life hence increasing a chance for population to survive. Studies on fecundity, embryonic development of V. viviparus and the relationships between these parameters and females’ body size and weight, were carried out in oxbow lakes periodically connected to the river (the Bug River, Central Poland). The Bug River is one of a few European rivers which preserved their nearly natural character. No larger hydrotechnical works have been made in its valley, therefore, the river flows in a natural, meandering channel and forms numerous oxbow lakes. The surrounding of studied oxbow lakes is flat and of lowland character with mixed land use structure (arable lands, grasslands, settlements). Oxbow lakes are fed by the runoff from flood terrace, hence their waters are more fertile than those of the river. Two lakes were selected: Lake Szumin, area 17 ha, Lake Wywłoka – area 23 ha. Maximum depth of both lakes is ca 3 m. Samples of V. viviparus were collected in the years 2003–2007 with a bottom drag during the successive seasons from five sites in each oxbow lake. The embryos were found in females of the II (8.1–12.0 mm of width and height), III (12.1–20.0 mm width and 12.1–25.0 mm height) and IV (over 25.0 mm height and over 20.0 mm width) size classes. Three developmental stages were distinguished in embryonic growth: the oval transparent egg capsules (called the youngest embryos), egg capsules with visible contour of a shell (called medium embryos) and snails with a shell (the oldest embryos). The youngest growth stages of embryos (in a form of oval transparent egg capsules) dominated in all size classes of females. Medium growth stages (egg capsules with visible outlines of the shell) and the oldest ones (with shell) were represented in smaller proportion. The highest number of the youngest embryos per female were found in females of the II size class. The proportions of the embryo growth stages varied seasonally. The number of embryos per female and the degree of their development increased with the increase of shell (height, width, dry weight) and body (dry weight) parameters. High fecundity of the youngest females of V. viviparus is probably an adaptation to unstable habitat conditions of oxbow lakes.
10

Modelowanie fizyczne i numeryczne przepływu wody w przepławce biologicznej

58%
Ksiazek L., Struzynski A., Leja M., Pilch E.
Acta Scientiarum Polonorum. Formatio Circumiectus
|
2011
|
tom 10
|
nr 4
W pracy przedstawiono wyniki modelowania numerycznego warunków przepływu wody w przepławkach biologicznych w formie kanału stanowiącego obejście budowli hydrotechnicznej naśladującego naturalny strumień, z funkcją kanału tarłowego. Wyniki modelowania porównano z wynikami pomiarów laboratoryjnych rozkładu prędkości w różnych typach siedlisk występujących w naturalnych strumieniach, od przepływu spokojnego do przepływu szybkiego. Uzyskano rozkłady trzech składowych prędkości vx, vy i vz w charakterystycznych punktach profilu podłużnego i przekroju poprzecznego: (1) na zbystrzeniu, (2) w strefie oraz (3) poza strefą turbulencji dla różnych konfiguracji dna i wielkości rumowiska. Wielkości te posłużyły do wyznaczenia profili prędkości, prędkości średnich oraz charakterystyki lokalnych warunków przepływu. Podjęto próbę przeniesienia wyników uzyskanych przy użyciu modelu fizycznego na obiekty rzeczywiste z wykorzystaniem teorii podobieństwa zjawisk fizycznych.
11

Seasonal variations and changes in the diet of southern river otter in different freshwater habitats in Chile

58%
Medina G.
Acta Theriologica
|
1998
|
tom 43
|
nr 3
The diet of southern river otter Lutra provocax Thomas, 1908 was determined from 605 scats collected from four sites in Southern Chile between 1990-1991. Crustacean remains were the most common item found in scats. Crustacean species that were the most common in scats collected from lakes, became less important in the river outlets. Fish remains were all from fish less than 100 mm in length and were found more frequently in scats collected at the river sites than at the lake sites. Differences in the diet between otter's scats collected in lakes and their river outlets may be related to prey availability and vulnerability. Diet was more diverse in river habitats than in the lakes. The diet of southern river otter appears to be closer to that described for Aonyx capensis and Lutra maculicollis in South Africa. The southern river otter is heavily dependent on the abundance of three crustacean species. Dif­ferences in the diets observed between lake and their river outlets suggest important differences in habitat conditions. This may have future implications for prioritising habitat protection in the conservation of southern river otter.
12

Adaptations of pupae of Chironomidae [Insecta: Diptera] to oxygen-poor habitats

58%
Marziali L., Lencioni V., Rossaro B.
Polish Journal of Ecology
|
2006
|
tom 54
|
nr 4
Morphological, behavioural and physiological adaptations of chironomid pupae to oxygen-poor habitats, such as the profundal zone of lakes, are discussed. Lentic and oxy-regulator species possess developed respiratory organs (thoracic horns) and an extensive anal fringe to perform respiratory movements, whereas in rheophilic and oxy-conformer species these structures are reduced or absent. This led to the hypothesis that the number of thoracic horn branches, the number of anal macrosetae and the body size could consititute a measure of a species’ oxygen requirements. These characters were analyzed in 12 species groups collected in 39 Italian lakes. Numbers were correlated to the optimum value of oxygen level, total phosphorus concentration and transparency calculated for each taxon. Taxa with plumose thoracic horns, extensive anal fringe and large body size (Chironomus) inhabited habitats poorer in oxygen than those inhabited by taxa with less extensive respiratory surface and fringe and small body size (Paratendipes, Polypedilum, Microtendipes). Stictochironomus was less tolerant than expected. Further studies are needed into the physiological adaptations of chironomid pupae.
13

The effect of salinity of freshwater crustaceans

58%
Grzesiuk M., Mikulski A.
Polish Journal of Ecology
|
2006
|
tom 54
|
nr 4
Recent advancing industrialization and urbanization have increased salt concentrations in formerly-freshwater habitats. Freshwater animals are being affected, especially those like crustaceans that are unable to emigrate to escape the problem. The effects of increased salinity, first observed at the molecular level, are found to extend to the levels of the individual, population, community and ecosystem. Crustacean morphology, behaviour and life histories may be influenced, with growth rate, and age and size at first reproduction, being disturbed, along with clutch and neonate size. Mortality rates are also elevated where the salt concentration is high, though susceptibility to salt differs both between species and between clones of the same species. The effect may be to modify the composition of crustacean assemblages in terms of the species and clones present.
14

Desmids and associated algae of terrestrial small water bodies in the Admiralty Bay area [King George Island, maritime Antarctic]

58%
Mrozinska T., Czerwik-Marcinkowska J., Smykla J.
Oceanological and Hydrobiological Studies
|
2007
|
tom 36
|
nr Suppl.1
15

Ireland's changing freshwater habitats: anthropogenic impacts, fishery management problems and ecohydrological perspectives

58%
McCarthy T. K., Cullen P.
International Journal of Ecohydrology and Hydrobiology
|
2002
|
tom 02
|
nr 1-4
The adverse changes to Ireland’s rivers and lakes, that result from deterioration in water quality, channelization and alteration of natural hydrological features, have impacted on the habitats of a variety of important fish stocks. These anthropogenic effects, and the recent changes in landscape management, which also threaten the other aspects of aquatic biodiversity of many Irish river catchments are reviewed. The importance of conserving ecotone features and of adopting an integrated ecological approach to monitoring of aquatic environmental change is discussed. Application of ecohydrological principles, for fish conservation and fisheries management is recommended. Further interdisciplinary studies and elaboration of new strategies for sustainable development of Ireland’s freshwater resources are outlined.
16

Morphology, phylogeny and evolution of the superfamily Plectoidea Orley, 1880 [Nematoda: Plectida]

58%
Holovachov O.
Annales Zoologici
|
2004
|
tom 54
|
nr 4
The phylogeny and classification of the superfamily Plectoidea Örley, 1880 is revised on the basis of published and updated morphological data for 35 ingroup and 2 outgroup species. The following features are here considered to support the monophyletic origin of the superfamily: 1) stegostom developed and differentiated into two sections; 2) dorsal gland orifice opening into the second stegostom section; 3) pharynx cylindrical, with distinct subdivision into corpus and postcorpus by the orifices of the subventral pharyngeal glands and a discontinuity in the muscular pharyngeal tissue; 4) corpus cylindrical, with subdivision into procorpus and metacorpus homologues; 5) pharyngeal radii of the corpus with prominent pharyngeal tubes along the procorpus; 6) cuticular lumen of the basal part of postcorpus (within basal bulb if latter is present) is modified to form a valvular apparatus. In addition the inner labial sensilla open inside the cheilostom. New data on postembryonic development of Anaplectus grandepapillatus (Ditlevsen, 1928), Plectus parietinus Bastian, 1865, P. decens Andrássy, 1985 and P. communis Bütschli, 1873 are given and supplemented with a discussion of the phylogenetic significance of the ontogeny in Plectoidea. Following the proposal of a phylogeny, some key events in the evolution of Plectidae Örley, 1880 are discussed. It is suggested that the superfamily Plectoidea includes four families: Pakiridae Inglis, 1983, Chronogastridae Gagarin, 1975, Metateratocephalidae Eroshenko, 1973 and Plectidae. Plectolaimus supplementatus Keppner, 1988 is transferred to the genus Caribplectus Andrássy, 1973. The genus Keralanema Siddiqi, 2003 is considered a junior synonim of Chronogaster Cobb, 1913. The genus Chiloplectus Andrássy, 1984 is considered a junior synonim of Plectus Bastian, 1865. The family Anaplectidae Zell, 1993 is downgraded to the subfamily level.
17
Artykuł dostępny w postaci pełnego tekstu - kliknij by otworzyć plik
Content available

Destroyed and threatened localities of rissooid snails (Gastropoda: Rissooidea) in Greece

51%
Szarowska M., Falniowski A.
Folia Malacologica
|
2011
|
tom 19
|
nr 1
In September 2003 we visited localities of rissooid snails in continental Greece, known from the literature. Nine springs (type localities included), situated in urbanized or cultivated areas, were destroyed, changed or under stress. Localities of Rissooidea in Greece need urgent protection, otherwise the snails may disappear altogether.
Pierwsza strona wyników Pięć stron wyników wstecz Poprzednia strona wyników Strona / 1 Następna strona wyników Pięć stron wyników wprzód Ostatnia strona wyników
JavaScript jest wyłączony w Twojej przeglądarce internetowej. Włącz go, a następnie odśwież stronę, aby móc w pełni z niej korzystać.