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Factors influencing diurnal activity of crayfish and its seasonality
Plasová, Kateřina ; Petrusek, Adam (advisor) ; Buřič, Miloš (referee)
Crayfish is mainly but not exclusively a nocturnal animal. The crayfish aktivity is taxon specific and can be further affected by various factors. The aim of this thesis is to create an overview of factors affecting the activity and to summarize their impact. Factors can be divided into those influencing daily activity and those influencing seasonal behaviour. This thesis focuses on discussing different reactions to the factors and its intensity by individual species. Insufficient data covering activity during the winter season offers an opportunity for further research. Key words: crayfish; daily activity; abiotic factors; biotic factors; seasonality
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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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Factors associated with invasiveness in the genus Impatiens: interaction of species traits, competition and environment
Čuda, Jan ; Pyšek, Petr (advisor) ; Kollmann, Johannes (referee) ; Prach, Karel (referee)
The aim of this thesis was to identify factors that contribute to invasiveness of species in the genus Impatiens. This genus is horticulturally attractive and includes several species that are known to have naturalized outside their native ranges, while others did not escape, in spite of being frequently cultivated. When looking for traits associated with invasiveness, it is useful to focus on congeneric species. Their traits and dispersal modes are less influenced by phylogeny, than when comparing unrelated species or even complete floras. This helps to account for traits that favour invasive species over native ones and thus identify potential invaders more precisely. A superior invader performance is attributed to a competitive advantage over native species that can lead in extreme case to competitive exclusion of the latter. Invasive and native species com- pete only if their niches overlap and the strength of competition depends on niche similarity. Importantly, invasive species are considered to be able to maintain their high competitiveness over a wide range of environmental conditions, while native ones often have narrower environ- mental optima. Lastly, competitive outcome can vary over life stages and depends on the degree of species dominance, which is rarely taken into account. Spread and...
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Use of environmental DNA for detection of aquatic invertebrates
Bílek, Marek ; Petrusek, Adam (advisor) ; Černý, Martin (referee)
Environmental DNA is released genetical information from the individual to the environment. Especially in the aquatic environment, the amount of detectable DNA is sufficient to prove or refute the presence of a target organism. The method of taking samples from an aquatic environment and working with DNA is constantly evolving and bringing new insights. Especially in the area of aquatic vertebrates, very good results are found. Especially in actual researches results often correspond to reality more than traditional methods of capture. In contrast, research of an aquatic invertebrates by detection of eDNA is overlooked, especially because of eDNA production by invertebrates, which is generally much lowerthan fish andamphibians production. In this case the largest amount of eDNA is released in the form of mucus. In this work I focus on properties of eDNA in the aquatic environment, biotic and abiotic factors that affect the durability of detectable DNA. I also mention the production of DNA of aquatic invertebrates, the possibilities of collection and the laboratory procedures of its processing, I compare the different approaches of the scientific teams in the referenced research and draw attention to the most frequent problems. At the end of the thesis I compare the results of the current research...
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THE EFFECT OF AN INCREASING COVERAGE OF INVASIVE BLACK LOCUST ON BIRD COMMUNITIES IN FOREST STANDS
Kroftová, Magdalena ; Reif, Jiří (advisor) ; Ferenc, Michal (referee)
Biological invasions are one of the most important threats to global biodiversity and they were also found to negatively affect some bird species. Despite relatively large number of scientific studies dealing with the impacts of invasive plants on bird communities, their results are inconsistent, especially it is not clear how birds respond to increasing levels of expansion of invasive species in native species stands. Moreover, bird responses to plant invasions seem to depend on the ecological characteristics of individual bird species. This study contributes to elucidation of this problem; I investigated the impacts of black locust (Robinia pseudoacacia) invasion on bird communities in three types of forest stands with different levels of invasion: in stands containing solely the native oak (Quercus spp.), in partially invaded stands with different proportions of black locust and oak (mixed stands) and in pure black locust stands. Previous studies that examined birds in pure oak and pure black locust stands have found that they differ markedly in vegetation structure, but not in the total number of bird species. However, habitat specialists were associated with the oak stands, while generalists with the black locust stands. Therefore, I predicted that (1) the total species richness will be...
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Impact of polyploidy on the invasive potential of Vicia cracca
Líblová, Zuzana ; Münzbergová, Zuzana (advisor) ; Mihulka, Stanislav (referee)
This work is about diploids and tetraploids of Vicia cracca species, the two commonly occurring cytotypes. The first part is devoted to the distribution of cytotypes of this species in the secondary range in North America. It was hypothesised that polyploid species become invasive more frequently than diploid species. Their greater success may be given by greater variability of genes obtained by polyploidisation and gene subfunkcionalizing. All invasive populations of Vicia cracca species involved in this study were tetraploid. Based on this we can say that only tetraploids are invasive in this secondary colonized area. Polyploid species can be better competitors thanks to their expected better growth characteristics and stress resistance. Therefore the second part of this work is testing the hypothesis that polyploids are more variable in size of different parts of the plant body and therefore more able to grow even in conditions that are not suitable for diploids. As predicted by the EICA hypothesis (evolution of increased competitive ability), secondary colonized area also provide more space for further evolution and we can expect that growth characteristics of plants from the invasive range will differ from plants of the same ploidy from the original distribution range. This part of the work...
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Invasive alien mammal species in Europe
Hadravová, Alena ; Reif, Jiří (advisor) ; Lučan, Radek (referee)
The present thesis deals with the invasive species of mammals in Europe. Invasive mammals have far- reaching impacts both on the environment and on the economy. It is necessary to avoid the transfer and dissemination of such invasive species in the new environment. To prevent the spread of these species and to control them in general, it is crucial to know their characteristics and to strike at an initial phase of the invasion. The characteristics which make invasive species particularly successful in the new environment are, i.e., wide ecological valence, the ability to disseminate quickly, high competitive potential, and the potential to reproduce in the new environment. Another important factor which contributes to sustained existence of invasive species in the new environment is the absence of predators, parasites, and pathogens. Among the management practices which proved to be effective are shooting, trapping, and baiting, fencing and tree protectors are effective, too. In general, the management should be directed towards long-term reduction of population size to a predefined level based on mitigation of impacts and reduction of management costs. The EU Strategy on Invasive Species involves a three-stage approach, the three stages being prevention, eradication, and containment. All European states...
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Epiphytic lichens of the Czech Republic
Pelechová, Kateřina ; Svoboda, David (advisor) ; Peksa, Ondřej (referee)
This bachelor thesis researches the works of the years 1908-2013, which deal with the occurrence of epiphytic, i.e. growing on tree species, lichens in the Czech Republic. In the introduction there is briefly interpreted definition of lichens and epiphytes and the relationship between lichens and heir environment (with an emphasis on air pollution) is described. The main part is devoted to the processing of data found in the literature - when and on which tree species is the lichen growing - and is divided into two periods (1908-1970 and 1971-2013). The frequency of lichen species changes between periods - links between lichens and tree species and preference of the species and its changes over time, changes in preference of pH of bark of trees and tree species with the highest number of species of lichens. The study contains a list of 429 lichen species occurring on tree species in the Czech Republic. Powered by TCPDF (www.tcpdf.org)
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