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Lineage distribution of the Gammarus fossarum species complex (Amphipoda) across Bohemian Massif and Western Carpathians
Rutová, Tereza ; Petrusek, Adam (advisor) ; Hulva, Pavel (referee)
Amphipods are an important component of temperate permanent freshwater macrozoobenthos. They have poor dispersal abilities, lack dormant stages, and their phylogeographies often reflect old historical processes. The genus Gammarus itself includes more than 200 described species spread in the Palearctic region. Many of the taxa previously described are, in fact, diversified species complexes, which is case of our most common Gammarus (G. fossarum). We have studied their diversity on the transect across the Bohemian Massif and the Western Carpathians, which form a significant biogeographical boundary for a number of other organisms. We tested whether the border between these areas is reflected in the phylogeography of G. fossarum as a representative of permanent aquatic fauna. Analysis of two mitochondrial markers revealed the presence of eight divergent G. fossarum lineages, which also differed in the nuclear genome. All eight lineages were found in the Western Carpathians, while the Czech Massif is inhabited only by two. The microendemic areas of some lineages and the occurrence of two apparently basal lineages of this complex, which were not found in southern regions, support the hypothesis that these amphipods survived Pleistocene glacial cycles even in West Carpathian refuges. We assume that...
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Ecological interactions and niche differentiation of coexisting freshwater amphipods
Bystřický, Pavel Karel ; Petrusek, Adam (advisor) ; Pařil, Petr (referee)
Freshwater amphipods are ecologically important crustacean group. They act mainly as shredders of detritus in fast-running and cold waters, contributing to the nutrient cycles. Ecological interactions within this group are interesting especially in connection with a considerable degree of cryptic diversity, as well as due to contacts of invasive and native species. This thesis deals with so far studied interactions between syntopic species or lineages, especially those that may affect coexistence or competitive exclusion, such as: different levels of selective predation, ecologically significant differences in morphology or behavior, varying degrees of aggressiveness or intraguild predation, and differences in habitat preferences or resource use ability. Due to the large number of newly discovered cryptic lineages, only little effort has been invested to studies of their ecological interactions. For the time being, research has been limited to sexual interactions (potential reproductive interference or hybridization), differences in habitat preferences, or infestation rates by parasites. It is worth mentioning that only a few lineages have been explored in this way, and the lessons learned from these few works cannot yet be generalized. In my work, I focus on cryptic species complexes in which at...
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Interactions between microsporidial parasites and the host cladoceran Daphnia pulex in a simple environment of a forest pond
Krylová, Pavla ; Petrusek, Adam (advisor) ; Hyliš, Miroslav (referee)
Among the most common endoparasites who infected small crustacean Daphnia pulex include microsporidia. These intracellular parasites appear to look like a simple single- celled organisms, but their cell structure and lifecycle prove the opposite. Microsporidia are species-specific. Although they infected most organisms of the animal kingdom, they are not yet sufficiently understood. This theses is inderectly followed up to the studies of waterflea Daphnia longispina and microsporidia Berwaldia schaefernai from the dam reservoirs The aim was to analyze closer microsporidian infection on host Daphnia pulex in a forest pool with simple enviroment, which included monitoring time dynamics of Daphnia population and identification infection caused by microsporidia Berwaldia singularis and yet unknown microsporidia labor-marked "HVH". Laboratory work included determination of zooplankton and parasites, calculation of prevalence, laboratory experiments with transmission of microsporidian infection between healthy and infected flea culture or by isolated spores. Genetic analysis of aquatic invertebrates from the forest pool, especially larvae of mite and mosquitos, helped make closer microsporidian life cycle and hypothesis about secondary hosts, for the presence of pathogen DNA using specific DNA...
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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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Freshwater fishless pools: from the metacommunties to the systematics
Juračka, Petr Jan ; Petrusek, Adam (advisor) ; Kotov, Alexey (referee) ; Zhai, Marie (referee)
Freshwater fishless pools: from the metacommunities to the systematics Petr Jan Juračka, Ph.D. Thesis, 2016-04-08 ABSTRACT Despite their small size, freshwater fishless pools often contain complex communities and substantially increase regional invertebrate and macrophyte biodiversity. The main core of this thesis originates from such habitats, which were newly created for the conservation purposes in the Protected Landscape Area Kokořínsko, Czech Republic. This landscape consists of deep valleys separated by steep sandstone ridges and is characteristic for very sparse stream network and low number of large water habitats, which consequents in generally low abundance of waterfowl. We studied microcrustacean metacommunities of 42 selected pools scattered over the area of approximately 220 km2 . Using variation partitioning of the species composition, analyses of the species richness and colonization experiment in the study area, we identified that spatial distribution of the habitats and number of neighbouring aquatic habitats play a major role in assembly of local communities. This led us to the conclusion that the landscape heterogeneity served as a partial barrier to dispersal of microcrustaceans. Subsequently, we compared this pattern of the microcrustacean metacommunity with other invertebrates of...
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Diversity of freshwater epigean amphipods
Rutová, Tereza ; Petrusek, Adam (advisor) ; Sacherová, Veronika (referee)
Gammarids, the most diverse group of Amphipoda are present in marine, brackish and fresh waters. In freshwater there are forms inhabiting the surface (epigean) and underground (hypogean) habitats and this thesis will be focused on epigean freshwater groups. Freshwater gammarids inhabit the continental waters of all continents, but the highest species diversity is evident in the Palearctic region. However they cannot be found in the surface waters of the tropical regions. These amphipods are characterized by the absence of any resistant or larval stages. Thus the present diversity and distribution reflects historical events like the fluctuation in sea levels, orogeny or period of glaciation from the Paleocene to the present. The goal of this thesis will be to summarize which processes and in which period the diversity of freshwater epigean amphipods were affected. One part of this thesis is dedicated to the families occurring in Australia (Chiltonidae), New Zealand (eg. Phreathogammaridae) and the North and the South America (Hyalellidae). The main focus is on family Gammaridae in which according to recent studies should include lineages occurring in the entire Palearctis including endemic groups in the Lake Baikal and across the Ponto-Caspian area. In the history of the development of gammarids...
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