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Species and cytotype diversity of invasive Symphyotrichum species in Central Europe
Varvažovská, Adéla ; Slovák, Marek (advisor) ; Hodálová, Iva (referee)
The cytotypic variability of Aster species of the genus Symphyotrichum is relatively well-explored within the territory of North America, where this species originates. Unfortunately, in Europe, where Asters were originally introduced as ornamental plants, they have received limited attention in terms of their overall as well as cytotypic variability. The number of publications and data concerning cytotypic variability and karyology in Europe is very limited, with some reporting the occurrence of several species and higher ploidy level species complexes. Asters naturalize in many places, capable of reproducing both vegetatively and generatively, and primarily colonize habitats disturbed by human activities. As a result, they have been classified as invasive plant species. From a biosystematic perspective, Asters constitute a highly complex group due to their high morphological and karyological variability. This situation is further complicated by the phenomenon of polyploidy and intense interspecific and intraspecific hybridization. These factors contribute to the challenging task of identifying individuals and populations and assigning them to specific taxa. The aim of this thesis was to clarify the cytotypic variability of wild-growing Aster species of the genus Symphyotrichum (Asteraceae) in the...
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Koktejl invazivních druhů ve vnitrozemských vodách - ekologická charakteristika, vzájemné působení a následky
ROJE, Sara
This thesis combines four main chapters: 1) a general summary of the current knowledge of the impact of aquatic invasive species in Europe, ecological characteristics, main representatives, their interaction and the consequences of spread; 2-3) two studies addressing mutual species impacts between invaders co-occurring together in the same habitat; and 4) investigating the differences between the behaviour of native and alien fish species. Chapter 1 looks at the theoretical concept and impacts of aquatic invasive species and in particular, four chosen groups of invaders with a review on specifically chosen high-profile aquatic invasive species in freshwaters, their associated impacts and detailed descriptions of the species used in experiments. Chapter 2 focuses on the predatory impact of killer shrimp on the early developmental stages of marbled and signal crayfish, concluding that killer shrimp are almost unstoppable. They were able to feed on different developmental stages of larger freshwater crustaceans even if they were protected by their mothers. Chapter 3 observes the interactions of two invaders: the round goby and the marbled crayfish. The round goby showed dominant aggressiveness consuming all the juvenile crayfish sizes offered. The study also confirmed that the round goby was able to predate on, attack and take shelters from crayfishes. The only limiting factor in this interaction was the larger size of the crayfish. When interacting, both tested species negatively influenced each other, which can mean mutual consequences for both species. In Chapter 4, the individual behaviour during day and night activity under laboratory conditions in a flow simulator was studied. Both species showed very similar behaviour, with only slight differences towards adaptability and stress-related activity. Despite the similarities, the round goby was confirmed to be an aggressive, bottom-dwelling predator sharing a habitat with a lot of other benthic animals like amphipods, crayfish, and other fish - native or other aliens. In general, all alien species are present a threat to all populations sharing similar characteristics in their habitat, taking their shelters, attacking them, and predating on them with invasive amphipods and crayfish being no exception. One species can limit the other, or the outcompeted species can be displaced forcing it to find an alternative niche and therefore increase the overall pressure on the ecosystem. The presented thesis is submitting some new findings mainly about the interactions between invaders and also represents a baseline for future experimental work focused on more complex setups that will enable us to increase our understanding of invasive species.
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Invasive water invertebrates in Czech Republic
Kolářová, Lucie ; Tátosová, Jolana (advisor) ; Dočkalová, Kateřina (referee)
An introduction of invasive species is considered to be one of the most actual problems of these days and is also related with water environment and water invertebrates. Occurences of many non-native species has been recorded in waters of the Czech Republic and these species can be divided into two groups. Species of the first group are invasive alien species - their ecological patterns (e.g. high growing rates, high reproductive capacity or ability to transfer exotic diseases) make their spreading more successful. North-American crayfish species (Orconectes limosus and Pacifastacus leniusculus), Dreissena polymorpha or Dikerogammarus villosus are the typical representatives of this group. The spreading of these species is very remarkable, since their introduction causes many harmful effects and has negative impacts on native fauna. However, the appearance of other group of water invertebrates has been found in our waters. These are also non-indigenous species, but their spreading is very inconspicuous - they do not reach high population densities and their invasion does not cause negative impacts on native fauna and ecosystems. The evidence of these harmless invasive species has been recorded thanks to the monitoring programs and we possibly wouldn't know about them without this monitoring. The...
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Analysis of ichtyofauna of the Czech Republic focused on alien species
Goldstein, David ; Hanel, Lubomír (advisor) ; Andreska, Jan (referee)
This thesis analyzes the ichthyofauna in Czech Republic in historical terms, i.e. how was the data on the occurrence of native species of fishes and lampreys collected. Particular attention is given to species alien to this territory - the following species are elaborated in more detail: Carassius auratus, Ameiurus nebulosus, Pseudorasbora parva, Ctenopharyngodon idella, Hypophthalmichthys molitrix, Aristichthys nobilis, Gasterosteus aculeatus, Coregonus maraena,Coregonus peled, Acipeneser baerii, Acipeneser stellatus, Acipenser gueldenstaedtii. The history of the introductions, the current situation in the Czech Republic and the impact on native ichthyofauna are listed (a more detailed evaluation of invasiveness is included for Carassius auratus, Pseudorasbora parva). Finally, the efforts to enrich the local ichthyofauna by introducing new species are generally evaluated.
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The cytotype diversity and population demography of invasive aster from Symphyotrichum lanceolatum a S. novi-belgii groups in Central Europe.
Varvažovská, Adéla ; Slovák, Marek (advisor) ; Chrtek, Jindřich (referee)
Asters from Symphyotrichum lanceolatum and S. novi-belgii a species complexes are native to North America from where they were imported to Europe as ornamental plants during the 19th century. They were naturalized and later became invasive in the humid habitats along rivers and lakes. Both species groups are karyologically and morphologically highly variable what is reflected in their complex taxonomy. A crucial role in the formation of their intricated diversity play inter- and intraspecies hybridization, polyploid evolution as well as phenotypic plasticity. The biological and ecological diversity of Asters was thoroughly studied in their natural environment in North America, however only little is known about their variability in their new, invaded European habitats. Numerous polyploid cytotypes were reported from their native distribution range in North America, however, only a single cytogeographic study in Europe has been published to date. The outcomes of this study accompanied by occasional chromosome counts indicated the existence of higher ploidy levels only. Specifically hexaploid and octoploid cytotype was reported for S. lanceolatus while hexaploids in S. novi-belgii. The problem of the karyological variability of these taxa in Europe deserves attention and further research. Key words:...
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Interaction of non-native species of crustaceans in Czech waters: Predator or prey?
ŠVAGROVÁ, Kateřina
This diploma thesis deals with non-native species of crustaceans, which are already present not only in Europe but also successfully inhabit the territory of the Czech Republic. The species that this work deals with is the signal crayfish (Pacifastacus leniusculus), marbled crayfish (Procambarus fallax f. virginalis) and the killer shrimp (Dikerogammarus villosus). The main goal of this study was to demonstrate the ability of killer shrimp to attack and prey on the crayfish eggs and hatchlings of above mentioned species, which were used not only for theuir presencein Czech Republic but also as model representatives of families Astacidae and Cambaridae. It was therefore the confirmation of high aggressiveness of killer shrimp and point out, that this species is capable of negatively influencing even the bigger invertebrates by direct predation on their early developmental stages. Another aim was to assess whether the killer shrimp can be a suitable prey for a crayfish. As the experiments have shown, killer shrimp is able to predate on crayfish eggs and hatchlings even directly on females abdomens wehre they are incubated and protected. The results confirmed the theory of killer shrimp hazards to aquatic ecosystems and its potential to directly influence the populations of larger organisms. At the same time, it has been found that killer shrimp may be a suitable prey for adult and subadult individuals of signal crayfish and adults of marbled crayfish.
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Analysis of ichtyofauna of the Czech Republic focused on alien species
Goldstein, David ; Hanel, Lubomír (advisor) ; Andreska, Jan (referee)
This thesis analyzes the ichthyofauna in Czech Republic in historical terms, i.e. how was the data on the occurrence of native species of fishes and lampreys collected. Particular attention is given to species alien to this territory - the following species are elaborated in more detail: Carassius auratus, Ameiurus nebulosus, Pseudorasbora parva, Ctenopharyngodon idella, Hypophthalmichthys molitrix, Aristichthys nobilis, Gasterosteus aculeatus, Coregonus maraena,Coregonus peled, Acipeneser baerii, Acipeneser stellatus, Acipenser gueldenstaedtii. The history of the introductions, the current situation in the Czech Republic and the impact on native ichthyofauna are listed (a more detailed evaluation of invasiveness is included for Carassius auratus, Pseudorasbora parva). Finally, the efforts to enrich the local ichthyofauna by introducing new species are generally evaluated.
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Invasive water invertebrates in Czech Republic
Kolářová, Lucie ; Tátosová, Jolana (advisor) ; Dočkalová, Kateřina (referee)
An introduction of invasive species is considered to be one of the most actual problems of these days and is also related with water environment and water invertebrates. Occurences of many non-native species has been recorded in waters of the Czech Republic and these species can be divided into two groups. Species of the first group are invasive alien species - their ecological patterns (e.g. high growing rates, high reproductive capacity or ability to transfer exotic diseases) make their spreading more successful. North-American crayfish species (Orconectes limosus and Pacifastacus leniusculus), Dreissena polymorpha or Dikerogammarus villosus are the typical representatives of this group. The spreading of these species is very remarkable, since their introduction causes many harmful effects and has negative impacts on native fauna. However, the appearance of other group of water invertebrates has been found in our waters. These are also non-indigenous species, but their spreading is very inconspicuous - they do not reach high population densities and their invasion does not cause negative impacts on native fauna and ecosystems. The evidence of these harmless invasive species has been recorded thanks to the monitoring programs and we possibly wouldn't know about them without this monitoring. The...
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The evaluation of threats resulting from Sinanodonta woodiana invasion in the Czech Rep. with focus on the fish growth modifications
Málková, Lucie ; Douda, Karel (advisor) ; Karbanová, Eva (referee)
The main task of this bachelor thesis is to inform about Chinese pond mussel (Sinanodontawoodina) invasion in the Czech Republic ecosystems of aquaculture. We provide both the literature review and risk evaluation. More we have presented impacts to other fish growth. At first we interested ourselves in the invasive species description. Then we have presented the threats for ecosystems caused with the existence of bivalve. We present the bivalve life cycle with all its impacts to the life cycle of fish. There are presented all function of bivalve in ecosystems and the risk evaluation appearing after these are overpopulated. These invasive species are worldwide problem. They are endangering the biodiversity in the nature. There are also negative impacts to economy and peoples´ health.
The bivalve are said to be ecosystem engineers. Their usefulness depends on their quantity. Invasive bivalve appear in a great densely. These produce great damages. I have presented all problems connected with the existence of threatened species and more have discussed all risks connected with extension of invasive bivalves.
We provide essential remedies and evaluate potential impacts in order to protect original species and lower damages in the economy of fishery. The essential part is the summary of legislatives.
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Socio-ekonomické a environmentální aspekty šíření vodního hyacintu na Viktoriině jezeře
Vítková, Veronika
The main aim of this thesis is an evaluation of the socioeconomic characteristics of the problems which suffer communities neighboring Lake Victoria in relation to spreading of water hyacinth. In the theoretical part lakes generally, their problems and protection will be described. This part also discusses an issue of invasive species focusing on water hyacinth. Specific part of the thesis is concentrated on geographical characteristics of the lake and its economic and social meaning to the riparian states. Another part describes the most significant problems of the lake into which somehow interferes water hyacinth. Among others, the thesis deals with methods of water hyacinth spreading regulation and socioeconomic and environmental impacts on the lake's ecosystem and surrounding population. The last part pays attention to the approaches to measures that would effectively regulate spreading of water hyacinth in the lake.
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