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Abrupt cooling events in the Late Glacial and the Early Holocene
Švanda, Petr ; Vondrák, Daniel (advisor) ; Tichá, Anna (referee)
This bachelor thesis is prepared in the form of a literature review focused on abrupt cooling events in the Late Glacial Interstadial and the Early Holocene (14 700 to 8 200 cal. BP). The aim was to summarize the scientific knowledge on six such climate fluctuations and their causes and consequences. All of these events (GI-1d, GI-1c2, GI-1b, 11 400 event, 9 300 evenet, 8 200 event) lasted more than 50 years and are followed by cooling of more than 1 řC. Literature sources on this topic are based on interdisciplinary studies of various natural archives and the interpretation of so-called proxy data. For each climatic event, an assessment of its effects on ecosystems and human societies at the time was also made. The above findings are finally discussed in the context of the current climate change issues and the possible future of weakening the Atlantic Meridional Overturnig Circulation.
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Factors influencing butterfly diversity of the species-rich Submediterranean region
BARTOŇOVÁ, Alena
This thesis focuses on the history, current state, and conservation of butterfly diversity in the Submediterranean grasslands and Palaearctic steppes. The thesis is introduced with the summary of Cenozoic history of the steppe biome in Eurasia. Then it consists of three studies. The first study describes butterfly communities and microhabitat selection of a steppe specialist butterfly Proterebia afra in two relic grassland areas in the Balkans. Based on genetic markers and samples covering the whole distribution ranges, the second and third studies assess the phylogeography of two steppe butterflies, P. afra and Pseudophilotes bavius, distributed in the Irano-Anatolian region, the Balkans, as well as the northern Palaearctic steppes.
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Phylogeny of the genus Helix (Mollusca: Gastropoda: Helicidae)
Korábek, Ondřej ; Juřičková, Lucie (advisor) ; Horáček, Ivan (referee)
The land snail genus Helix comprises large gastropods distributed in from France to Iran and in North Africa. Some of them have close linkage to humans - are synanthropic or are collected and consumed. The genus is most diverse in eastern Mediterranean. Taxonomy of the genus is now being revised from morphological point of view, and a molecular study is needed as a counterpart to that study. Here I present first phylogenetic data for the genus Helix, including almost all currently recognised species. I have used samples from various sources including dried bodies and tissue remnants. I have sequenced two commonly used mitochondrial markers (16S, COI). Position of the genus within Helicidae cannot be inferred from the dataset. The genus should be delimited in a strict sense, excluding genera Maltzanella, Cantareus, Cryptomphalus and Lindholmia. Division into subgenera, as proposed by various authors until now, is not supported with the exception of a split between subgenera Pelasga and the nominotypical Helix. Relationships between species and their groups are poorly resolved. Regarding species limits, the data are largely in agreement with new opinions based on morphology. There might be surprisingly high variability in shell characters within a species, as few morphologically characteristic taxa seem to be...
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Postglacial colonization of black alder (Alnus glutinosa) and grey alder (Alnus incana) in Europe
Havrdová, Alena ; Mandák, Bohumil (advisor) ; Helena, Helena (referee)
Current species distribution in Europe was mainly influenced by massive climatic and environmental changes during the Quaternary period. Different theories concerning survival of tree species during the last ice age in Europe were proposed and up to date the position of glacial refugia and directions of migration routes are under active debate. My dissertation thesis aimed to combine information from fossil records and genetic analysis to improve knowledge on postglacial history of Alnus glutinosa and Alnus incana. The synthesis of palaeoecological data supports the idea that not only southern but also northern populations were important sources of postglacial Alnus expansion. The delayed Alnus expansion apparent in some regions was likely a result of environmental limitations. Our findings from molecular study showed differences in postglacial histories between temperate A. glutinosa and boreal A. incana. In the case of A. incana, we found an effective refugium in Central Europe located outside classical southern refugia confirming the existence of northern refugia for boreal trees in Europe. Fennoscandian populations are derived from Central-European ones that originated from populations in the Alps. For A. glutinosa, multiple southern refugia were revealed and three main directions of postglacial expansion were proposed: 1) from the northern part of the Iberian Peninsula to Western and Central Europe and subsequently to the British Isles, 2) from the Apennine Peninsula to the Alps, and 3) from the eastern part of the Balkan Peninsula to the Carpathians followed by expansion towards the Northern European plains. It has been shown that colonizing lineages have met several times and formed secondary contact zones with unexpectedly high population genetic diversity in Central Europe and Scandinavia. For the first time, we discovered tetraploid populations of A. glutinosa situated in the putative main glacial refugia on the Iberian and Balkan Peninsulas. Neither of them was probably involved in the colonization of Central and Northern Europe after glacial withdrawal. In conclusion, thanks to extensive population sampling, testing of hypothesis postulated based on fossil data by molecular data and using two molecular markers, i.e. chloroplast DNA and microsatellites, with different mode of inheritance and polymorphisms, this project revealed not only the position of glacial refugia of European tree species and discriminate between effective and non-effective ones, but also help infer the main migration routes. This approach enabled us to change some long-lasting paradigms and brought new pieces of knowledge about postglacial colonization of European tree species.
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