AbstractsGeography &GIS

Nisäkkäiden levinneisyyteen, niiden morfologisiin ja ekologisiin piirteisiin vaikuttavat ympäristön sekä lyhyet että pitkäkestoiset muutokset, etenkin ilmaston ja kasvillisuuden vaihtelut. Työssä tutkittiin nisäkkäiden sopeutumista ilmastonmuutoksiin Euraasiassa viimeisen 24 miljoonan vuoden aikana. Tutkimuksessa keskityttiin varsinkin viimeiseen kahteen miljoonaan vuoteen, jonka aikana ilmasto muuttui voimakkaasti ja ihmisen toiminta alkoi tulla merkittäväksi. Tämän takia on usein vaikea erottaa, kummasta em. seikasta jonkin nisäkäslajin sukupuutto tai häviäminen alueelta johtui. Aineistona käytettiin laajaa venäjänkielistä kirjallisuutta, josta löytyvät tiedot ovat kääntämättöminä jääneet aiemmin länsimaisen tutkimuksen ulkopuolelle. Työssä käytettiin myös NOW-tietokantaa, jossa on fossiilisten nisäkkäiden löytöpaikat sekä niiden iät. Short and long term environmental changes, variations in climate and vegetation during the late Neogene shaped the geographical ranges of large terrestrial mammals by allowing origination, distribution and dispersal of certain species that make up faunas. Climatic fluctuations were intensified during the latest Neogene, Pleistocene (1.8-0.01 Ma), at the end of which also human presence became more conspicuous. Both climate and humans have been linked to extensive alteration and extinctions in mammalian faunas across the world. This dissertation consists of a set of papers that examine different periods of the Neogene and associated faunas in northern Eurasia. Major trends in changing environments and climate were studied by means of the tooth crown height (hypsodonty) and dietary structure in herbivorous terrestrial mammals or/and species commonness (locality coverage, abundance proxy). This study was also intended to bring to light a great deal of information contained in Russian literature to fill in the gap between the European literature and not translated Russian records. Since the middle Miocene (~15-11 Ma), central Asia has been the focal point of the transformation in Eurasia towards more open and dry environment. The drying of the central part of Eurasia hampered the spread of temperate or mesophilic species between western and eastern sides of the continent, and created conditions for origination of the cold and arid adapted grazing fauna in north-eastern Eurasia. Throughout the climatically unstable late middle and late Pleistocene, Europe that was more maritime during interglacials than Siberia, experienced the most drastic faunal alternations between the interglacial Palaeoloxodon antiquus and glacial Mammuthus primigenius assemblages that permanently inhabited the Mediterranean and Siberia, respectively. During more climatically equable middle part of the middle Pleistocene (Holsteinian interglacial) that was climatically similar to the current Holocene, the interglacial species could have spread eastwards. The origins, dispersal and cohesiveness of the Palaeoloxodon antiquus assemblage in Eurasia are examined. During the latest Weichselian Glaciation (Late…