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Studium problematiky nepůvodních druhů ve vybraném úseku povodí řeky Svratky
Ševčíková, Alice
This thesis deals with the issue of alien species in the selected basin of the river Svratka. The examination of selected vegetation took place near Brno, Tišnov and in Modřice. The studied areas were located on the bank of the river Svratka, on agricultural land near the bank and a few meters from the catchment on uncultivated land. My study of vegetation areas lasted from 2013 to 2015. As monitoring methods I used Zurich-Montpelier phytosociological school. Monitoring was statistically processed by analysis DCA and CCA. Total of 91 kinds of plants were founded in the selected places of the river. The highest ground cover species were Impatiens glandulifera, Plantago major, Amaranthus retroflexus, Chenopodium album, Arrhenatherum elatius, Dactylis glomerata, Urtica dioica, Convolvulus arvensis, Galinsoga parviflora, Elytrigia repens.
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Porovnání přežívání a růstu raka červeného a raka mramorovaného v teplotně suboptimálních podmínkách
DAVID, Jaroslav
Biological invasions are increasingly recognized as biological and economic threats. The numbers of these invasions continue to rise over time, disrupting the original biodiversity. In this experiment, we focused on two species of crayfish native to North America, the red swamp crayfish and the marbled crayfish, which are among the most important invasive crayfish worldwide. To determine which of these species should be dominant in permanently suboptimal temperature conditions (water temperature of 16 °C), we conducted an experiment evaluating growth, mortality, claws damage, and maturation in single-species and mixed stocks. It turned out that the faster-growing species was the red swamp crayfish, which grew the fastest in mixed stocks, at the expense of marbled crayfish, which, on the contrary, grew more slowly in these stocks than in single-species stocks. There were no large differences in survival in the individual groups, except single-species marbled crayfish stocks, for which the survival rate was about 15% higher than in other groups. The incidence of individuals with damaged claws was higher for red swamp crayfish, a large difference was recorded between marble crayfish groups, when in mixed stocks the damage was circa five times higher contrary to the single-species setup. At the end of the experiment (week 18), three mature males with gonopods and one female with glair glands were found in the red swamp crayfish.
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Zhodnocení přežívání a růstu dvou invazivních raků v teplotně suboptimálních podmínkách
MARKOVÁ, Kateřina
Biological invasions of non-native species are one of the most serious threats negatively impairing global biodiversity. The negative influence of these invasions is especially noticeable in freshwater ecosystems also exemplified by the populations of native crayfish species in Europe. Dominance of non-native species of crayfish over native ones is relatively well known and studied, but the interactions between individual non-native invasive species are significantly less explored. As the range expansion and numbers of non-native crayfish species constantly increases, it becomes apparent that the non-native species will dominate in European waters. However, it is not clear which of these invasive species, and under which conditions will perform better. The goal of this bachelor thesis was to create a literature review focusing on factors that negatively influence the population of the native species (mainly the issue of non-native species and crayfish plague which these species often transmit). Consideration was paid to the importance of the water temperature for the crayfish and to the focused species used in the experimental part the marbled crayfish Procambarus virginalis Lyko, 2017 and signal crayfish Pacifastacus leniusculus Dana, 1852. The experiment was focused on the evaluation of survival, growth, damage to the claws, and the maturation of these species at the water temperature of ~16 °C, which is in the optimal range for signal crayfish, but suboptimal for marbled crayfish (yet, within a range presumably allowing its successful reproduction). If these species should meet more frequently in the wild, it is important to understand their relationships.
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Společenstvo bentických organismů na dolním toku Ohře, Labe a jejich přítocích
MUSIL, Martin
The purpose of this work was to describe the current status of benthic communities on the main stream of Elbe River and Ohře River and their tributaries affected and non-affected by biological invasions - especially by round goby (Neogobius melanostomus) and spiny - cheek crayfish (Faxonius limosus). Sampling for this research took place from April 2018 to August 2018, while morphiologic survey of waterbodies was done in November 2017. Two tributaries of the Elbe River (Milešovský brook and Ploučnice River) and one tributary of the Ohře River (Čepel) were selected for this research. Two 100 m long sections (lower stretch potentially affected by invaders and upper stretch as referential) were monitored at each tributary. At the same time a 100 m long main flow section was monitored near the mouth of the tributaries. The following parameters were monitored: morphology of the stream and basic physical and chemical parameters of water, zoobenthos community, crayfish occurrence, and fish community. The benthic communities of the upper streams were less affected by biological invasions. The biodiversity of the benthic communities in the upper sections was richer compared to the lower sections. The occurrence of the round goby seemed to be factor affecting benthic and fish communities at the sites concerned. It was an eudominant species in the Elbe section in Děčín and becoming dominant in the lower section of Ploučnice River.
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Porovnání raka mramorovaného a raka pruhovaného: přímá interakce a kompetice o zdroje
MAN, Milan
Biological invasions of non-native species are one of the most serious factors threatening global biodiversity. Their negative impacts are particularly evident in the case of freshwater ecosystems and native crayfish populations that live there. Generally, the higher dominance of non-native crayfish species over the native species is relatively well known, but the interactions between non-native crayfish species are significantly less investigated. Although their distribution is increasingly more important and it is obvious that non-native crayfish species will dominate in European waters. However, it is not yet clear which of these crayfish will be more successful. The aim of this diploma thesis was to create a literature review on the topic of interspecific interactions in crayfish with emphasis on native and non-native crayfish species occurring in Europe. The experimental part of the thesis was focused on the comparison of direct interactions and competition for shelter between the widespread spiny-cheek crayfish Faxonius limosus (Rafinesque, 1817) and the newly increasingly occurring marbled crayfish Procambarus virginalis Lyko, 2017. These species are becoming increasingly common in the European wild, but about their mutual direct interactions and competition is largely unknown. During agonistic interactions the marbled crayfish won in significantly more fights than the spiny-cheek crayfish in the absence as well as presence of the shelter. The marbled crayfish established a significantly greater dominance over the females of the spiny-cheek crayfish in the absence and in the presence of shelter, but not over the males. It is also important to say that the presence of the shelter reduces the number of fights and their total duration. There was no significant difference in dominance established by occupation of shelter between the marbled crayfish and the spiny-cheek crayfish. Still, thanks to its aggressiveness, marbled crayfish is able to compete with other non-native species or displace them from freshwater ecosystems.
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Studium problematiky nepůvodních druhů ve vybraném úseku povodí řeky Svratky
Ševčíková, Alice
This thesis deals with the issue of alien species in the selected basin of the river Svratka. The examination of selected vegetation took place near Brno, Tišnov and in Modřice. The studied areas were located on the bank of the river Svratka, on agricultural land near the bank and a few meters from the catchment on uncultivated land. My study of vegetation areas lasted from 2013 to 2015. As monitoring methods I used Zurich-Montpelier phytosociological school. Monitoring was statistically processed by analysis DCA and CCA. Total of 91 kinds of plants were founded in the selected places of the river. The highest ground cover species were Impatiens glandulifera, Plantago major, Amaranthus retroflexus, Chenopodium album, Arrhenatherum elatius, Dactylis glomerata, Urtica dioica, Convolvulus arvensis, Galinsoga parviflora, Elytrigia repens.
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