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Non-fish prey in the diet of fish-eating mammals, Eurasian otter (Lutra lutra) and mink (Neovison vison)
Tuzarová, Veronika ; Čech, Martin (advisor) ; Poledníková, Kateřina (referee)
The Eurasian otter (Lutra lutra) is considered, along with the American mink (Neovison vison), a significant fish predator not only in the Czech Republic but also in other regions across Europe. One of the goals of this study is to determine, based on available literature, the types of prey that form the diet of the Eurasian otter and the American mink, specifically focusing on the non-fish component of their food and how the percentage representation of these items changes in the diet of both species depending on habitat and season. Another objective is to verify whether the American mink has a higher proportion of non-fish prey in its diet compared to the Eurasian otter. The processed data describing the diet through spraint analysis in biomass units were divided according to climatic regions, i.e., temperate, Mediterranean, and also based on the type of aquatic environment, i.e., stagnant or flowing water. The results of the study indicate that the American mink consumed, on average, three times more non-fish prey (74 % biomass) throughout the year than the Eurasian otter (24 % biomass). The seasonal variation had the most notable impact on the consumption rate of frogs and birds in the non-fish diet of both predators. According to the analyzed data, both predators especially focused on frogs,...
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Acceptance of Fish Predators by Students of Chosen High Schools
Sůva, David ; Andreska, Jan (advisor) ; Hanel, Lubomír (referee)
The thesis describes the attitude students of professionally oriented high schools have toward chosen species of fish-hunting predators, namely the eurasian otter, the american mink, the great cormorant and the sea eagle. The first part of the thesis focuses on both historical and present recognition of these species in our country, description of each species including their population and protection measures. The second part of the text analyzes the curriculum framework of chosen high schools. The third part is a field study. The field study found which textbooks are used by students to learn about the fish-hunting predators listed above as well as the student's perception of them. A sample of 191 students were questioned, out of which 98 are students of schools of forestry and 93 are students of schools of fisheries. The worst acceptance was found with the great cormorant. The best acceptance was of the sea eagle. Key words: predation, eurasian otter, american mink, great cormorant, sea eagle
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American mink (Neovison vison) - biology of an invasive species.
Hlaváčová, Petra ; Vohralík, Vladimír (advisor) ; Anděra, Miloš (referee)
The American mink is considered to be an invasive, alien species across Europe, North Asia and also in South America and now it is perceived as a permanently growing treat for native biodiversity. Mink is an extremely adaptable predator, which achieves to adapt to almost any conditions and different food niches. The aim of this study was to contribute to cognition of biology of this species in Czechomoravian highlands condition. A telemetry study was run between 2004 and 2012 during which in total six individuals (3 males and 3 females) were being monitored on the Sázava River near Havlíčkův Brod. This study was supplemented by usage of photo traps. A couple of finding can be drawn from this study. Mainly, the records show the significant differences between sexes. Males and females differ in home range size, in day/night activity and in length of day movements. The second part of this study was focused on distinguishing tracks of three different species of mustelids: American mink, European mink and Western polecat. In total, 211 tracks obtained from these three species were measured. Seven points on a track has been identified, and the computer program Measuring tracks automatically created 131 parameters. These parameters were processed with canonical discriminant analysis. The results showed...
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American mink (Neovison vison) - biology of an invasive species.
Hlaváčová, Petra ; Vohralík, Vladimír (advisor) ; Anděra, Miloš (referee)
The American mink is considered to be an invasive, alien species across Europe, North Asia and also in South America and now it is perceived as a permanently growing treat for native biodiversity. Mink is an extremely adaptable predator, which achieves to adapt to almost any conditions and different food niches. The aim of this study was to contribute to cognition of biology of this species in Czechomoravian highlands condition. A telemetry study was run between 2004 and 2012 during which in total six individuals (3 males and 3 females) were being monitored on the Sázava River near Havlíčkův Brod. This study was supplemented by usage of photo traps. A couple of finding can be drawn from this study. Mainly, the records show the significant differences between sexes. Males and females differ in home range size, in day/night activity and in length of day movements. The second part of this study was focused on distinguishing tracks of three different species of mustelids: American mink, European mink and Western polecat. In total, 211 tracks obtained from these three species were measured. Seven points on a track has been identified, and the computer program Measuring tracks automatically created 131 parameters. These parameters were processed with canonical discriminant analysis. The results showed...
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Problematika invazního druhu - norka amerického (Mustela vison) z pohledu obecné druhové ochrany
Kerouš, Karel ; Nová, Petra ; Fischer, David ; Fischerová, Jana
Práce přináší stručný přehled nejdůležitějších dosavadních poznatků o biologii, rozšíření a možných vlivech norka amerického na domácí faunu v oblastech jeho introdukce. Převážná většina informací pochází z dostupné vědecké zahraniční i domácí literatury, přičemž pozornost byla soustředěna především na území Evropy a České republiky (v případě informací z území ČR je text doplněn o některé poznatky jeho autorů). Zvláštní pozornost je věnována současné úrovni znalostí problematiky spojené s invazí norka amerického na našem území – práce se kromě rozšíření věnuje zejména vlivu vysokého predačního tlaku na některé vzácné druhy živočichů u nás, dosavadním zkušenostem s jeho odchytem a případným možnostem eliminace norků. V závěru se autoři snaží navrhnout směr, kterým by se případný pokus o redukci početního stavu norků na našem území měl v budoucnosti ubírat.
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Výzkum ekologie a rozšíření‚ návrh managementu populací a záchranných programů zvláště chráněných druhů živočichů: Ekologie norka amerického (MUSTELA VISON) a návrh jeho managementu
Agentura ochrany přírody a krajiny ČR, Praha ; Poledníková, Kateřina ; Poledník, Lukáš
Norek americký, Mustela vison patří k nově se šířícím druhům fauny savců na území České republiky. Cílem prezentované práce bylo přispět k širšímu poznání biologie norka amerického v České republice, odhadnout jeho negativní vliv na původní druhy živočichů a prověřit možnosti jeho eradikace. V rámci stanovených cílu byly studovány následující okruhy: 1. prostorové nároky norka amerického, velikost domovských okrsku a jejich základní charakteristiky, 2. pohyby norků v rámci jejich domovských okrsků v průběhu roku a v různém prostředí, 3. využití prostředí v rámci domovského okrsku, 4. vzájemné překryvy domovských okrsků mezi jednotlivými zvířaty v průběhu roku, 5. rozložení aktivity v průběhu dne a v průběhu sezón, 6. složení potravy v různých prostředích a jeho sezónnost, 7. predační tlak norka na zemi hnízdící vrubozobé ptáky, 8. úspěšnost odchytu v různých ročních obdobích.
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Comparison of efficiency of box traps and floating rafts as monitors and trap sites for mink (Musela vison) and polecat (Putorius putorius) for population control.
BARTÁKOVÁ, Daniela
The aim of my thesis was to evaluate two methods of monitoring of the American mink and polecat, monitoring with live traps and by floating rafts. While the first method is commonly used in our country, where the second method is the pilot project here, but it has been used in the UK successfully. Observation was from August to November in 2008 and from April to November in 2009. Observation took place in the area near PP Černíč near Dačice, where were chosen 4 different habitats. All detected tracks of Mustelids found on rafts were from the American mink. It corresponds with captures, where were captured also only minks and no polecat. Occupation of rafts was higher in 2008 than in 2009 because of the eradication of mink in November 2008. In both years the highest occupancy rate in rafts was in September and the lowest in October. There were differences between habitats and number of captured minks and tracks. In compare between rafts and traps, rafts were more successful method.
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