18 research outputs found

    Semilattices, Canonical Embeddings and Representing Measures

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    We provide conditions under which a modular function defined on a semilattice XX and with values in a commutative group is homomorphic to a modular function on a lattice LL for any embedding XLX\hookrightarrow L

    Genetic turnovers and northern survival during the last glacial maximum in European brown bears.

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    The current phylogeographic pattern of European brown bears (Ursus arctos) has commonly been explained by postglacial recolonization out of geographically distinct refugia in southern Europe, a pattern well in accordance with the expansion/contraction model. Studies of ancient DNA from brown bear remains have questioned this pattern, but have failed to explain the glacial distribution of mitochondrial brown bear clades and their subsequent expansion across the European continent. We here present 136 new mitochondrial sequences generated from 346 remains from Europe, ranging in age between the Late Pleistocene and historical times. The genetic data show a high Late Pleistocene diversity across the continent and challenge the strict confinement of bears to traditional southern refugia during the last glacial maximum (LGM). The mitochondrial data further suggest a genetic turnover just before this time, as well as a steep demographic decline starting in the mid-Holocene. Levels of stable nitrogen isotopes from the remains confirm a previously proposed shift toward increasing herbivory around the LGM in Europe. Overall, these results suggest that in addition to climate, anthropogenic impact and inter-specific competition may have had more important effects on the brown bear's ecology, demography, and genetic structure than previously thought

    Diversity of muskox Ovibos moschatus (Zimmerman, 1780) (Bovidae, Mammalia) in time and space based on cranial morphometry

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    Muskox Ovibos moschatus is a Pleistocene relic, which has survived only in North America and Greenland. During the Pleistocene, it was widely distributed in Eurasia and North America. To evaluate its morphological variability through time and space, we conducted an extensive morphometric study of 217 Praeovibos and Ovibos skull remains. The analyses showed that the skulls grew progressively wider from Praeovibos sp. to the Pleistocene O. moschatus, while from the Pleistocene to the recent O. moschatus, the facial regions of the skull turned narrower and shorter. We also noticed significant geographic differences between the various Pleistocene Ovibos crania. Siberian skulls were usually larger than those from Western and Central Europe. Eastern Europeanmuskoxen also exceeded in size those from the other regions of Europe. The large size of Late Pleistocene muskoxen from regions located in more continental climatic regimes was probably associated with the presence of more suitable food resources in steppe-tundra settings. Consistently, radiocarbon-dated records of this species are more numerous in colder periods, when the steppe-tundra was widely spread, and less abundant in warmer periods

    Winter Temperature and Forest Cover Have Shaped Red Deer Distribution in Europe and the Ural Mountains Since the Late Pleistocene

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    Aim: The Expansion-Contraction model has been used to explain the responses of species to climatic changes. During periods of unfavourable climatic conditions, species retreat to refugia from where they may later expand. This paper focuses on the palaeoecology of red deer over the past 54 ka across Europe and the Urals, to reveal patterns of change in their range and explore the role of environmental conditions in determining their distribution. Location: Europe and western Asia to 63°E. Taxon: Red deer (Cervus elaphus). Methods: We collected 984 records of radiocarbon-dated red deer subfossils from the Late Pleistocene and the Holocene, including 93 original dates. For each deer sample we compiled climatic and biome type data for the corresponding time intervals. Results: During the last 54 ka changes in red deer range in Europe and the Urals were asynchronous and differed between western and eastern Europe and western Asia due to different environmental conditions in those regions. The range of suitable areas for deer during the Last Glacial Maximum (LGM) was larger than previously thought and covered vast regions not only in southern but also in western and eastern Europe. Throughout the period investigated the majority of specimens inhabited forests in the temperate climatic zone. The contribution of forests in deer localities significantly decreased during the last 4 ka, due to deforestation of Europe caused by humans. Mean January temperature was the main limiting factor for species distribution. Over 90% of the samples were found in areas where mean January temperature was above −10°C. Main conclusions: Red deer response to climatic oscillations are in agreement with the Expansion-Contraction model but in contradiction to the statement of only the southernmost LGM refugia of the species. During the last 54 ka red deer occurred mostly in forests of the temperate climatic zone. © 2020 John Wiley & Sons Ltd.European Social Fund, Grant/Award Number: UDA-POKL.04.01.01-00-072/09-00; University of Wroclaw, Grant/Award Number: 0410/2990/18; Institute of Environmental Biology, University of Wrocław, Grant/Award Number: 0410/2990/18; Mammal Research Institute Polish Academy of Sciences; Narodowe Centrum Nauki , Grant/Award Number: DEC-2013/11/B/NZ8/00888 and UMO-2016/23/B/HS3/00387; Romanian National Authority for Scientific Research, UEFISCDI, Grant/Award Number: PN-IIIP4-ID-PCE-2016-0676; National Centre for Atmospheric Science and the Centre for Environmental Data Analysis, UK; Faunal Database of the Stage Three Project; Leverhulme Trust, Grant/Award Number: F00568W

    Winter temperature and forest cover have shaped red deer distribution in Europe and the Ural Mountains since the Late Pleistocene

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    Aim: The Expansion-Contraction model has been used to explain the responses of species to climatic changes. During periods of unfavourable climatic conditions, species retreat to refugia from where they may later expand. This paper focuses on the palaeoecology of red deer over the past 54 ka across Europe and the Urals, to reveal patterns of change in their range and explore the role of environmental conditions in determining their distribution. Location: Europe and western Asia to 63°E. Taxon: Red deer (Cervus elaphus). Methods: We collected 984 records of radiocarbon-dated red deer subfossils from the Late Pleistocene and the Holocene, including 93 original dates. For each deer sample we compiled climatic and biome type data for the corresponding time intervals. Results: During the last 54 ka changes in red deer range in Europe and the Urals were asynchronous and differed between western and eastern Europe and western Asia due to different environmental conditions in those regions. The range of suitable areas for deer during the Last Glacial Maximum (LGM) was larger than previously thought and covered vast regions not only in southern but also in western and eastern Europe. Throughout the period investigated the majority of specimens inhabited forests in the temperate climatic zone. The contribution of forests in deer localities significantly decreased during the last 4 ka, due to deforestation of Europe caused by humans. Mean January temperature was the main limiting factor for species distribution. Over 90% of the samples were found in areas where mean January temperature was above −10°C. Main conclusions: Red deer response to climatic oscillations are in agreement with the Expansion-Contraction model but in contradiction to the statement of only the southernmost LGM refugia of the species. During the last 54 ka red deer occurred mostly in forests of the temperate climatic zone. © 2020 John Wiley & Sons Ltd.European Social Fund, Grant/Award Number: UDA-POKL.04.01.01-00-072/09-00; University of Wroclaw, Grant/Award Number: 0410/2990/18; Institute of Environmental Biology, University of Wrocław, Grant/Award Number: 0410/2990/18; Mammal Research Institute Polish Academy of Sciences; Narodowe Centrum Nauki , Grant/Award Number: DEC-2013/11/B/NZ8/00888 and UMO-2016/23/B/HS3/00387; Romanian National Authority for Scientific Research, UEFISCDI, Grant/Award Number: PN-IIIP4-ID-PCE-2016-0676; National Centre for Atmospheric Science and the Centre for Environmental Data Analysis, UK; Faunal Database of the Stage Three Project; Leverhulme Trust, Grant/Award Number: F00568W

    Impact of climatic changes in the Late Pleistocene on migrations and extinction of mammals in Europe : four case studies

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    Climate changes that occurred during the Late Pleistocene had profound effects on the distribution of many plant and animal species and influenced the formation of contemporary faunas and floras of Europe. The course and mechanisms of responses of species to past climate changes are now being intensely studied by the use of direct radiocarbon dating and genetic analyses of fossil remains. Here, we review the advances in understanding these processes by the example of four mammal species: woolly mammoth (Mammuthus primigenius), cave bear (Ursus spelaeus s.l.), saiga antelope (Saiga tatarica) and collared lemmings (Dicrostonyx ssp.). The cases discussed here as well as others show that migrations, range shifts and local extinctions were the main responses to climate changes and that the dynamics of these climate-driven processes were much more profound than was previously thought. Each species reacted in its individual manner, which depended on its biology and adaptation abilities to changing environmental and climatic conditions. The most severe changes in European ecosystems that affected the largest number of species took place around 33–31 ka BP, during the Last Glacial Maximum 22–19 ka BP and the Late Glacial warming 15–13 ka BP
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