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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Vnitřní struktura balkánského refugia na modelu Erinaceus roumanicus / Internal structure of the Balkan refugium using Erinaceus roumanicus as a model organism

Eliášová, Kristýna January 2014 (has links)
The aim of this work was to describe the spatial distribution of genetic variability of the northern white-breasted hedgehog (E. roumanicus), mainly within the Balkan Peninsula and Central Europe, as these areas are crucial for understanding the effects of Pleistocene climate oscillations on the genetic architecture of the species. Based on this spatial distribution, hypotheses about the possible structuring of the Balkan refugia were formulated. A total of 260 individuals and 9 microsatellite loci were used for the analysis. Using the approach of landscape and population genetics several possible isolated subpopulations within the area surveyed were identified. Unique status was proved for a population originating from Crete, probably influenced by mechanisms of island evolution. Differences from the rest of the range were ascertained also in population from the Czech Republic, located in a secondary contact zone with the E. europeaus. The role of interspecific interactions and possible introgression should be considered in this case. In the area of Romania and the area south of the Balkan Peninsula the highest genetic distances between individuals were identified, probably associated with the occurrence of geographical barriers and the possible presence of glacial subrefugia. Other identified...
2

Late Pleistocene palaeoenvironments, archaeology, and indicators of a glacial refugium on northern Vancouver Island, Canada

Hebda, Christopher Franklin George 24 December 2019 (has links)
Recent research has revealed human settlement on the Pacific coast of Canada extending back nearly 14,000 years, but much of the late Pleistocene record is unknown due to shifting sea levels, poor understanding of Cordilleran ice extent, and limited research on the biota of the coast during this time. This study, undertaken in Quatsino First Nation and ‘Namgis First Nation territories as part of the Northern Vancouver Island Archaeology and Palaeoecology Project, employs modern multi-proxy analysis of lake sediment cores from two sites on northern Vancouver Island to reconstruct palaeoenvironments during and immediately following the Fraser Glaciation in coastal British Columbia. Evidence from radiocarbon samples, pollen, ancient environmental DNA, plant macrofossils, and diatoms indicates that Topknot Lake on the outer coast of Vancouver Island has remained unglaciated through most of the local Last Glacial Maximum since ca. 18,000 cal BP. A non-arboreal herb-shrub tundra assemblage prevailed from ca. 17,500-16,000 cal BP with taxa including willows (Salix), grasses, sedges (Cyperaceae), heathers (Ericaceae), and sagewort (Artemisia). After ca. 16,000 and into the terminal Pleistocene, Topknot Lake was dominated by pine, alder (Alnus), ferns, and aquatic plant species. In the Nimpkish River Valley deep in the Vancouver Island Ranges, Little Woss Lake also demonstrates a record extending to the late Pleistocene (ca. 14,300 cal BP). The environment comprised dry and cool conifer woodland dominated first by fir (Abies) until ca. 14,000 cal BP, then by pine, alder, and ferns from ca. 14,000-12,000 cal BP. eDNA evidence from ca. 14,000 cal BP corroborates these plant taxa as well as indicating brown bear and Chinook salmon in and around the basin at that time. A mixed-conifer assemblage consisting of pine, western hemlock, and alder followed from ca. 12,000-11,100 cal BP into the early Holocene. Collectively, these indicators demonstrate an open environment on the outer coast of northern Vancouver Island since ca. 18,000-17,500 cal BP and well-established biotic communities across the region throughout the late Pleistocene. These results inform future archaeological research for early human habitation in coastal British Columbia and provide key evidence to support the viability of the coastal migration route for the first peopling of the Americas. / Graduate / 2020-12-11

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