National Repository of Grey Literature 73 records found  1 - 10nextend  jump to record: Search took 0.01 seconds. 
Population biology and evolutionary genetics of southern right whale (Eubalaena australis)
Nevečeřalová, Petra ; Hulva, Pavel (advisor) ; Galov, Ana (referee) ; Robovský, Jan (referee)
Southern right whale (Eubalaena australis) is a species from the Balaenidae family with a range in the southern hemisphere, which evolved in connection with Neogene climate oscillations. Its population biology involves migration between coastal waters of South America, southern Africa, Australia and New Zealand to its high-latitude foraging and feeding grounds in the Southern Ocean. Intensive historical hunting from the 18th to 19th century has impacted the population dynamics of baleen whales substantially. After the whaling moratorium, the species has been recovering from the heavy exploitation, however, recently it is facing anthropogenic changes, such as climate change. The South African population, considered to be the largest one globally and intensively studied for the last several decades, is showing an increase in the calving interval, a decline in female condition and a dramatic shift in migration routes since 2010, possibly as a consequence of significant changes in marine food webs. Methods of molecular ecology were applied to monitor the population genetics and its dynamics not only in the context of the global population but also to compare different time periods - 1990s and 2010s. The majority of the samples were collected noninvasively in cooperation with commercial whale-watching...
Population connectivity and isolation in cetaceans
Žirovnický, Martin ; Hulva, Pavel (advisor) ; Choleva, Lukáš (referee)
This bachelor thesis focuses on the specifics of research in the field of population connectivity and genetic isolation of marine mammals, with an emphasis on cetaceans. The thesis is divided into three parts. The first part introduces the methods and approaches in landscape genetics and seascape genetics. The second part deals with environmental factors influencing the genetic structure of cetacean populations, such as geographic barriers, water temperature, behaviour, or human-created barriers. The last part addresses the ways of protecting cetaceans and the application of population connectivity research in the areas where cetaceans reside. The aim of the thesis is to present the issue of phylogeography of marine mammals, particularly cetaceans, and to demonstrate the significance of protecting these endangered species in the contemporary world.
Phylogeographic patterns and microevolutionary mechanisms in oceanic dolphins
Křišťanová, Žaneta ; Hulva, Pavel (advisor) ; Vokurková, Jana (referee)
This bachelor thesis discusses the current findings regarding the phylogeography of the Delphinidae family. It is mainly focused on phylogenetic structure and speciation of Delphinidae, as well as on the ways of differentiation of trophic niches and the evolution of ecotypes. In the past, the Pleistocene climate oscillation had a major influence on the development of individual species and populations. Currently, it is anthropogenic activities that cause fundamental changes in habitats and thereby change the living conditions for cetaceans. In several species of Delphinidae, the emergence of ecotypes has been recorded, where different populations of the same species use different ecological niches. This thesis is mainly dedicated to the ecotypes of the bottlenose dolphin (Tursiops truncatus). Variability in coloration, body length and spine morphology was noted for individual ecotypes. The spine is an important adaptation to the environment in Delphinidae. In this research, phylogenetic relationships between family of Delphinidae, life strategies and food niche of selected species of the genera Tursiops, Stenella and Delphinus are also described.
Population genetics of grey wolf in Western Carpathians
Veselovská, Lenka ; Hulva, Pavel (advisor) ; Suchomel, Josef (referee)
The grey wolf is a top predator that plays a keystone role in maintaining the ecological balance of forested habitats. This master thesis focuses on the population structure and demography of the grey wolves in Slovakia, using data collected over two winter seasons between 2017 and 2019. Special attention is directed to the Western Carpathians. In Slovakia, the range of the wolf may cover up to 60% of the whole area. The population size and structure of grey wolves are influenced by both natural factors, such as mountain ranges isolation and dispersal, and anthropogenic influences, such as population fragmentation caused by linear infrastructure and increased mortality from traffic collisions. Additionally, the annual culling quotas for grey wolves have had an impact on their populations until recently. Mainly a non-invasive genetics approach utilizing selected 10 nuclear microsatellite markers, a marker for sex detection and mitochondrial sequences was used. Firstly, the species determination was verified and data quality filtering was carried out under statistical control. The sex ratio of the examined sample was 1:1,3. Mitochondrial data were assigned to haplotypes to help infer population origin. Bayesian clustering analysis of microsatellite data using the STRUCTURE program was used to...
Speciation mechanisms and the role of reinforcement in mammals
Horký, Jakub ; Hulva, Pavel (advisor) ; Reifová, Radka (referee)
Speciation, the process of the formation of new species, comprises a diverse range of microevolutionary mechanisms acting in unison, which lead to the gradual formation of reproductive barriers between populations. The study of speciation has significantly progressed since its origins around the midpoint of the nineteenth century, owing to progressively improving analytical methods and the data said methods obtained, allowing us to observe previously invisible patterns and form new hypotheses on their basis. From traditional to modern research, this review's goal is to describe the contemporary understanding of speciation's concepts and mechanisms, focusing on those which are most relevant to mammals. Modern understanding of spatial contexts, prezygotic and postzygotic isolating mechanisms, and character displacement, including a type of reproductive character displacement dubbed reinforcement, are discussed. Significant emphasis is placed on the topics of maladaptive and adaptive hybridization, which, together with reinforcement and development of new genomic methods, has this review identified as the current frontier of speciation research. Keywords: reproductive isolating mechanisms, microevolution, character displacement, hybridization, reinforcement, speciation
The Current Extinction of species
Schätz, Filip ; Storch, David (advisor) ; Hulva, Pavel (referee)
This bachelor thesis deals with the current process of species extinction. The main aim of the thesis is to answer the question how we can accurately describe this process. The understanding of this process is based on the limited sample of extinct species known to us, provided by the IUCN Red List. The sheer number of extinct species is affected by the use of different species concepts, the synonymy of binomial names and the difficulty of tracking individual extinction events. The Red List sample is subject to strong selection bias, so currently there are only reliable records of extinctions of groups of birds and mammals. These extinctions are mainly associated with their occurrence on islands. For other taxa, records of extinctions are sporadic, so the status of the current extinction process in these groups is unknown. It is not possible in most cases to relate to these groups the knowledge resulting from the study of different taxa. Estimates that attempt to describe the process beyond our knowledge also suffer from shortcomings. While the problems of expressing actual extinction rates stem from our ignorance of biodiversity, the inaccuracies of the SAR curve back-extrapolation method are mainly due to the attempt to generalise the overly complex effect of range loss on species numbers. The...
Spatial molecular ecology of the brown bear in Western Carpathians
Šrutová, Jana ; Hulva, Pavel (advisor) ; Hájková, Petra (referee)
In the current human-dominated landscape, wildlife populations are more often exposed to the island effect, loss of genetic variation and the associated risk of extinction vortex. Landscape genetics studies microevolutionary processes in populations and their relationships to landscape features. Integration of the results of genetic analyses and the results of habitat modeling of the species under study helps to identify transition zones between suitable habitats or anthropogenic barriers to gene flow in the landscape. Analysis of the spatial population structure of wildlife populations is an important tool for the conservation and management of populations. Between 2019-2021, 2172 mostly non-invasive brown bear (Ursus arctos) samples were collected in Slovakia, mostly collected in the Western Carpathian region. Using a microsatellite panel containing 10 polymorphic loci and the SRY gene for sex determination, a total of 1036 genotypes were identified, including 632 unique genotypes. The population seems to be relatively diversified and the observed heterozygosity is comparable to other demographically stable bear populations in Europe. Using STRUCTURE, a Bayesian clustering analysis was performed, which divided the population into three or four subpopulations according to the selected method. The...
Molecular demography of brown bear in the Western Carpathians
Tkáčová, Nikola ; Hulva, Pavel (advisor) ; Tkadlec, Emil (referee)
Reliable estimates of population size are an essential tool for effective species conservation and management. The aim of this master thesis was to estimate the census population size and describe genetic variability and structure of the brown bear (Ursus arctos) using non-invasive genetics in Slovakia, which includes the majority of the West Carpathian population. A total of 2,172 samples were obtained during 2019-2021. The majority of the samples were non-invasive, mainly stool samples, which were complemented with tissue samples from roadkills or legally culled animals. Subsequently, DNA was purified and 12 microsatellite loci and the SRY sex marker were amplified. 1036 genotypes were successfully determined, of which 632 were unique. The Slovak population of bears posses a relatively high genetic diversity and similar values of heterozygosity as populations in areas with good state of conservation and relatively intact landscape. Based on Bayesian clustering analysis, population was divided into four clusters, with a certain level of gene flow. Only one cluster was detected in the eastern part of Slovakia (Eastern Carpathians). In the central part of Slovakia (Western Carpathians) all clusters were represented. Observed male to female ratio was 1.006. In males, a higher recapture rate was...
Phylogeography and conservation genetics of rare palearctic megaherbivores
Červeňák, Jakub ; Hulva, Pavel (advisor) ; Robovský, Jan (referee)
This review is focused on the surviving species of Pleistocene megaherbivores in the Palearctic realm. It describes a basic classification of herbivores depending on their trophic niche, the adaptations associated with diet and an application of Cope's rule in evolution of ungulates. This is followed by a description of different approaches in defining megafauna and causes of large animals extinctions at the end of the Pleistocene and during the Holocene. At the end of the general part of this work, the importance of megafaunal elements as keystone species and concepts of downsizing, associated trophic downgrading and the idea of rewilding are being emphasized. In the second part of the work, Pleistocene history, phylogeography and marked reduction of range during the Holocene are described for elk (Alces alces), European bison (Bison bonasus) and Przewalski's horse (Equus przewalskii) according to the available literature. Finally, a history of the efforts to save the species and current knowledge on conservation genetics related to an overcome bottleneck effect are ascertained. Key words: Pleistocene megafauna, bottleneck, reintroduction, rewilding, browsing, grazing
Phylogeography of Rousettus aegyptiacus in the Mediterranean region
Dundarova, Cheliana ; Hulva, Pavel (advisor) ; Janko, Karel (referee)
The genus Rousettus has distributional pattern unique among fruitbats comprising both Asia and Africa and reaching northern distributional limits of the family in Persia, Arabia and Mediterranean basin. This could be ascribed to the ability of echolocation, consequent cave dwelling, and presumably other site-specific adaptations, which enabled dispersal independent of forest block and surviving in Mediterranean type of climate. Using fastly evolving mitochondrial marker, we aimed to assess genetic variability, its geographic distribution and demography of northern populations of the Egyptian fruitbat (Rousettus aegyptiacus). Mitochondrial network indicates deep genetic divergence between disjunct Mediterranean and eastern African parts of the range. Basal position of Sinaic and Jordanian haplotypes within northern clade indicate important role of these regions in colonization of eastern Mediterranean. Generally, the northern haplogroup is moderately diversified with partial geographic localization of particular haplotypes. Significant isolation by distance pattern suggests relatively pronounced site fidelity of particular colonies, at least in terms of maternal gene flow. Landscape genetics analyses indicate discontinuities in distribution of mitochondrial genetic variability, in some cases correlating with...

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