National Repository of Grey Literature 31 records found  1 - 10nextend  jump to record: Search took 0.00 seconds. 
Report on the distribution of the ichthyofauna under the natural lakes of Šumava.
Blabolil, Petr ; Hůda, J. ; Muška, Milan ; Draštík, Vladislav ; Holubová, Michaela ; Hladík, Milan ; Vrba, Jaroslav
The report describes the results of ichthyological surveys in the areas below the glacial lakes of Šumava.
Report from selected sites of the Hydrobiological Excursion in 2022.
Blabolil, Petr ; Bláha, M. ; Kajgrová, L. ; Kaštovský, J. ; Kolář, Vojtěch ; Vrba, Jaroslav
The report describes the results of sampling and determination of biological components (fish, zoobenthos, periphyton) in selected sites visited during the Hydrobiological Excursion.
Results of extended research of the ichthyofauna of lakes Laka and Čertovo, including adjacent streams.
Blabolil, Petr ; Hlaváč, J. ; Hůda, J. ; Kolařík, Tomáš ; Kortan, D. ; Muška, Milan ; Peterka, Jiří ; Vrba, Jaroslav
The report describes the results of an ichthyofauna survey in two areas of the Šumava National Park, where catches were made by an electric generator in the spring of 2021. This is the first direct evidence of natural reproduction of brown trout in the parts previously heavily affected by acidification.
Results of the autumn extended research of the ichthyofauna of the lakes Laka and Čertovo, including the adjacent streams.
Blabolil, Petr ; Bartoň, Daniel ; Draštík, Vladislav ; Jůza, Tomáš ; Hladík, Milan ; Holubová, Michaela ; Hůda, J. ; Kočvara, Luboš ; Muška, Milan ; Peterka, Jiří ; Vrba, Jaroslav
The report describes the results of a unique survey of the ichthyofauna in two areas of the Šumava National Park, where catches were made by an electric generator in the autumn of 2021.
Reintroduction of a copepod species Cyclops abyssorum (Crustacea) and its impact on zooplankton in Plešné Lake
Křenová, Radka ; Sacherová, Veronika (advisor) ; Vrba, Jaroslav (referee)
Abstract Plešné Lake is a small glacial lake in the Bohemian Forest. In the 1980th, it was heavily influenced by an acification event caused by severe atmospheric pollution. Due to some extreme parameters in the water chemistry (mainly low pH and high concentration of toxic aluminum compounds) several zooplankton species got extinct. Among these, two species important in lakes food web: Daphnia spp. and Cyclops abyssorum. They, however, survived the acidification period in one of the Bohemian Forest Lake: Prášilské. Although recovery of lakes from acidification is usually followed by return of some species or colonization by others, recolonization of Plešné Lake is assumed to be very slow or impossible from external sources thanks to the remote position of the lake. Therefore in the fall of 2004 two zooplankton species (Daphnia longispina and Cyclops abyssorum) were artificially reintroduced into Plešné Lake. In the course of 4 years that followed only Cyclops abyssorum appeared in the lake, Daphnia longispina was not recorded. My thesis focuses on several aims. First, I evaluate the development of C. abyssorum population. Second, I studied the competition between C. abyssorum and another copepod species - Heterocope saliens, acidotolerant species which never disappeared from the lake. Third, I...
Palaeoenvironmental reconstruction of the Younger Dryas based on subfubfossil cladocera
Bubenková, Anna ; Tátosová, Jolana (advisor) ; Vrba, Jaroslav (referee)
5 ABSTRACT Long-term paleoenvironmental reconstructions provides essential interpretation of environmental changes. Multiproxy analysis of lake sediments can be used for tracking the historical evolution of lakes and significant processes which formed them over time. Subfossil Cladocera play a key ecological role in freshwater ecosystems. Sedimentary cladoceran assemblages reflect environmental changes and exhibit great potential in past environmental reconstructions. The purpose of this diploma thesis is to identify climatic changes of the time interval between the Late Glacial and the early Holocene in Černé Lake. Based on the analysis of geochemical and biological proxies, determined climatic conditions of Younger Dryas (YD). The YD oscillation in Central Europe has only been briefly described. The Czech Republic is positioned between oceanic and continental climate. The results of the multiproxy analyses suggests that climate conditions of the region during YD were similar to Western Europe with moderate wet climate conditions during the first half and drier conditions during the second half of the period. In the middle of YD there was an interesting event. Observed, probably due to high precipitation and floods. These results are based on P/L ratio, geochemical proxies, pollen analyses and record of...
Current ichthyofauna of Laka Lake and connected streams
Blabolil, Petr ; Draštík, Vladislav ; Kočvara, Luboš ; Kolařík, Tomáš ; Muška, Milan ; Peterka, Jiří ; Soukalová, Kateřina ; Vrba, Jaroslav
The aim of this study was determination of Lake Laka and connected streams ichthyofauna. The obtained results, including their evaluation, are included in the report.
Palaeoenvironmental reconstruction of the Younger Dryas based on subfubfossil cladocera
Bubenková, Anna ; Tátosová, Jolana (advisor) ; Vrba, Jaroslav (referee)
5 ABSTRACT Long-term paleoenvironmental reconstructions provides essential interpretation of environmental changes. Multiproxy analysis of lake sediments can be used for tracking the historical evolution of lakes and significant processes which formed them over time. Subfossil Cladocera play a key ecological role in freshwater ecosystems. Sedimentary cladoceran assemblages reflect environmental changes and exhibit great potential in past environmental reconstructions. The purpose of this diploma thesis is to identify climatic changes of the time interval between the Late Glacial and the early Holocene in Černé Lake. Based on the analysis of geochemical and biological proxies, determined climatic conditions of Younger Dryas (YD). The YD oscillation in Central Europe has only been briefly described. The Czech Republic is positioned between oceanic and continental climate. The results of the multiproxy analyses suggests that climate conditions of the region during YD were similar to Western Europe with moderate wet climate conditions during the first half and drier conditions during the second half of the period. In the middle of YD there was an interesting event. Observed, probably due to high precipitation and floods. These results are based on P/L ratio, geochemical proxies, pollen analyses and record of...
You cannot step into the same fishpond twice - an evolution of fishpond ecosystems to hypertrophy
Vrba, Jaroslav ; Benedová, Z. ; Jezberová, Jitka ; Matoušů, Anna ; Musil, M. ; Nedoma, Jiří ; Pechar, L. ; Potužák, J. ; Řeháková, Klára ; Šimek, Karel ; Šorf, M. ; Zemanová, J.
Shallow manmade fishponds in south Bohemia were used for fish production for centuries, however, their ecosystems have changed dramatically due to excessive nutrient loading and fish stocking. Preliminary results of ten sampled fishponds suggested their hypertrophic status at present, while their plankton structure and dynamics reflected the actual size/age class of fish stock consisting predominantly of common carp. Planktivorous fish (both young carp and whitefish) remarkably reduced abundance, size, and species diversity of crustacean zooplankton, in particular large daphnids, whereas larger carp itself did not cause such a strong top-down effect. All other plankton components, i.e. phytoplankton, bacteria, protists, and rotifers showed rather high abundance and diversity, and suggested a reasonable impact of various microbial processes and interactions in the recent hypertrophic ecosystems.
Lakes of the Czech Republic physico-geographical a physico limnological characteristics
Šobr, Miroslav ; Janský, Bohumír (advisor) ; Kříž, Vladislav (referee) ; Vrba, Jaroslav (referee)
J e ze r a C e s kér ep ub l i lE fyz i c ko ge o g r af c kéa fyz i ká lně J i ntno l o gi cké p o mě ry Lakes of the Czeclt Republic physico-geographical and physicoJimnological clnracteristics (Etiglish veÍsion) IntroducÍiotl In comparison with other European regions, there are orrly a few oflakes oťnatural origin in the Czech Republic. In our country, there are neither high mountains with network of glacial lakes nor vast lowlands of northem type with tlre lďie plateau' There are neither vast, fully developed karsts regions, nor active volcanic areas nor sea shores. The fluvial lakes originated in tlre floodplains oťseveral waterways are one tlre most numerolls types of lakes ir-r the courrtry. In the river floodplains there had been massive rnining of gravel-sand alluvium sedirnents which is connected to tlre origination oť the lakes o| arrthropogenic origin. These ale also rather frequent irr the areas of coal mining, especially of lignite coal and other mineral resources. And the last numerous type of lakes includes the water bodies in the peat bog and moor land areas which are scattered alorrg the wlrole mountain border range in the Czeclr Republic (JANSKÝ, ŠosnBr AL. 2003). In comparison to the world's lakes, the lakes in the Czecir Republic are of far smaller size and volume dimensions. They are...

National Repository of Grey Literature : 31 records found   1 - 10nextend  jump to record:
See also: similar author names
2 Vrba, J.
4 Vrba, Jakub
18 Vrba, Jan
1 Vrba, Jindřich
6 Vrba, Jiří
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