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Evolutionary history, genetic diversity and human impact on selected leuciscids from the southern Balkans
Viñuela Rodríguez, Nuria ; Vukićová, Jasna (advisor) ; Perea, Silvia (referee) ; Kalous, Lukáš (referee)
- ABSTRACT - Fishes represent the most diverse group of vertebrates on Earth, with freshwater fishes accounting for half of this diversity, and occupying a mere 0.01 % of the world's water surface. The Balkans are considered a European hotspot of biodiversity, and its southern section is recognized as centre of ichthyological diversity, characterized by its exceptional richness and endemicity. Within the southern Balkans, the Ionian ecoregion stands out as one of the most isolated ichthyological regions in Europe due to its very complex geological history and the variety of events that influenced its ichthyofaunal composition. All fish species inhabiting the Ionian region are endemic, and most of them display reduced distribution areas with a marked geographic pattern. The western Aegean region, on the contrary, is considered a species-poor ecoregion within the southern Balkans, despite also harbouring a significant number of endemic species. However interesting the region of the southern Balkans is in terms of its ichthyofauna, there is a lack of knowledge for many of the fish species inhabiting them. In this thesis, we address some of these knowledge gaps for two representative genera, Pelasgus and Telestes, of the most diverse family in the area (Leuciscidae), with the aim to better understand the...
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Telestes perspective on the karstic poljes of eastern Herzegovina
Doulíková, Tereza ; Vukićová, Jasna (advisor) ; Choleva, Lukáš (referee)
The Dinaric karst region in the Balkans is one of the hot spots of biodiversity with a high number of endemic freshwater fish. The major cause of the high degree of endemism are numerous paleoclimatic and geological events that have affected the formation of the entire area. Flows of karst poljes represent a specific ecosystem to which some fishes have adapted. The poljes have been periodically flooded and these floods may activate different underground channels, which lead to interconnection of poljes. These fish species spend a part of the year in surface water and a part in groundwater and they may use the underground flows between poljes for migration. The aim of this thesis is to evaluate the genetic variability of two endemic fish species of the genus Telestes living in karst poljes in the region of eastern Herzegovina, and to detect a possible current gene flow between populations of these species due to the connection of underground flows. For this purpose, the DNA from 102 individuals from five different localities was isolated. The mitochondrial marker cytochrom b and 16 microsatellite loci were used for the analyses. The results point to very low variability between species and populations. Based on mitochondrial marker analysis, no link between populations of the species was detected,...
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How to become a critically endangered species: a review of the distribution and status of the crucian carp (Carassius carassius)
Janda, Benedikt ; Choleva, Lukáš (advisor) ; Lojkásek, Bohumír (referee)
The Crucian carp (Carassius carassius) is the native species of fish in European standing and slowly flowing waters. Thanks to their high resistance to adverse abiotic conditions, they also inhabited dead arms of river, ponds and floodplains. Despite its resilience, this species has been declining or completely retreating from the most of natural habitats since the middle of the 20th century. The negative direct human interventions into the species populations were, intensive fishing and the elimination of suitable habitats as a result of landscape defragmentation, which was part of flood control measures. Secondly, the human-made introductions of non-native species, the Gibel carp (Carassius gibelio), capable of gynogenetic reproduction, strongly competes with the native species for resources. The extent to which the situation of the native Cruvian carp is critical and ow it has historically occured is revised in the formo f literaly search by this bachelor's Thesis. Keywords The Crucian carp, gynogenesis, molecular genetic methods, cytochrome b gene, taxonomy, hybridization, introduction, microsatellites
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Aquatic fauna of karstic fields in the Balkans
Doulíková, Tereza ; Vukićová, Jasna (advisor) ; Kalous, Lukáš (referee)
Dinaric Karst region of the Balkan Peninsula is one of the hot spots of biodiversity, and it is characterized by a high degree of endemism of freshwater fishes. Numerous geological and climatic events have influenced the formation of the area and speciation. Karst poljes are the specific features of Dinaric Karst. They represent a specific ecosystem full of endemic species, where hydrogeological processes play an important role. The periodic flooding appears on poljes. It leads to activation of various underground channels and their interconnection. Twenty two endemic fish species have adapted to this regime. They live in underground waters or in surface waters part of the year and they can migrate between poljes through karst channels. They show significant reduction in size and change in complexity of scaliness. Scales are small and they are barely visible in some species. All these species and abundant underground karst fauna are threatened primarily by pollution, habitat destruction, and drainage of poljes.
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Development of endemic freshwater ichthyofauna of Greece
Kyralová, Eva ; Vukićová, Jasna (advisor) ; Švátora, Miroslav (referee)
The Balkans is one of the hot spots of biodiversity, and is known for a high diversity and endemism of freshwater fishes. The development of Greece was significantly affected by the climatic, geologic and orogenetic events resulting in high concentration of freshwater fish endemism. Some of the important historical events were the emergence of land bridges during the early Oligocene and Miocene, through which freshwater fishes dispersed to the Balkans from Asia and subsequently to Africa, the freshwater phase of the Paratethys sea or Alpine orogeny, which began 65 million years ago, and which gradually formed the Greek mountain systems, leading to a long-term isolation of local freshwater ichthyofauna and subsequent speciation. Other major events include Messinian salinity crisis and Pleistocene climate oscillations. Most of the freshwater fish families occurring in Greece most probably originated in the Southeast Asia, from where they colonized the Balkans by several routes. These colonizations took place repeatedly at different times and by different routes. The dispersion of freshwater fishes from Asia to Europe through Siberia started before the uplift of the Ural Mountains about 33 million years ago and continued until Pliocene. Another important colonization route from Asia was via the...
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Methods of study habitats and microhabitats preferences of freshwater fishes of Central Europe
Žák, Jakub ; Švátora, Miroslav (advisor) ; Drozd, Bořek (referee)
Small streams are a common habitat in Central Europe with unstable, rapidly-changing conditions. We can examine habitats on three different scales: microhabitat, mesohabitat and macrohabitat. Habitat preferences were among the fields of interest of Antonín Frič as he tried to describe the changing gradient of fish assemblages from source to the river's mouth on the macrohabitat scale. Habitat preferences are examined from a spatial point of view (substrate, depth, shelter), temporal point of view (season, day/night), biotic point of view (interspecies and intraspecies competition) and abiotic point of view (dissolved chemicals, velocity). For obtaining data of good quality, it is necessary to choose the right location and select the opti- mal strategy of examining fish assemblages (e.g. electrofishing, radiotelemetry, cameras). All variables which can affect habitat preferences in fish are measured. Multivariate statistical methods (e.g. PCA, RDA, CCA, CA) are used for evaluation of obtained datasets. Currently, we live in a fast developing period of this scientific area because of the need of evaluation of the human impact on freshwater biotope. The aim of this bachelor thesis is to introduce variables which influence habitat pref- erences of fish, to propose a modern review of methods commonly...
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Trophic structure of fish communities in the tributaries upstream of the Lipno Reservoir
Kofentová, Nikola ; Horká, Petra (advisor) ; Slavík, Ondřej (referee)
River obstacles, especially dams, are known to alter the natural environment in streams, which significantly impacts fish communities. The cyprinid species migrate from the reservoirs upstream to the reservoir's tributaries, where they may cause changes in the trophic structure of native fish communities. The aim of this study was to evaluate the trophic structure of the fish community composed mainly of cyprinid and salmonid species throughout seven localities in the Vltava River upstream of the Lipno reservoir. Stable isotope analysis was used to identify trophic positions, trophic niche width and trophic niche overlap between species. Trophic relationships of individual species were then evaluated to assess the potential for food competition. The trophic niche width of the salmonid species was significantly higher than that of the cyprinid species. Trophic niche overlap between salmonids and cyprinids was observed, with the most significant overlap being with both common dace Leuciscus Leuciscus and common roach Rutilus rutilus, suggesting a potential competition for food. The effect of the presence of cyprinids on the trophic niche width of salmonids was shown not to be statistically significant. From the perspective of protecting native salmonid species, there should be special attention paid...
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