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

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

L’ours fossile du scialet de la Décroissance (Correçon-en-Vercors) et biloan du programme Oursalp

Table ronde “L’Homme dans les Alpes : de la pierre au métal” – Villard-de-Lans (Isère

2011-2013. Le Livradois-Forez

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Exploring the ancient occupation of a high altitude site (Lake Lauzon, France): Comparison between pollen and non-pollen palynomorphs

Next to Lus-la-Croix-Haute (Southern Alps, Drôme, France), Lake Lauzon is located in a small basin 1980 m above sea level, 500 m above the actual timberline, in the middle of typical sub-alpine grasslands. A drilling for samples in the wetland area bordering the lake made it possible to obtain a core of clayey fine sediments with a high organic matter content, in which pollen as well as many micro-organisms had been particularly well preserved. The pollen analysis and the non-pollen palynomorhs analysis both cover a period from ca. 8000 cal. BP to sub-recent time. The pollen analysis reveals the presence of a thriving forest vegetation dominated by Abies, and the first signs of human activity near the lake and its nearby basins in the Atlantic period. These signs become more pronounced during the Sub-boreal period from 5450 cal. BP on, with the clear presence of cereal and weed pollen. This evolution is totally confirmed by the non-pollen palynomorphs. Since the Neolithic, every time pollen analysis points to clearings or cultivation, the non-pollen palynomorphs indicate that man has burnt the vegetation to obtain openings (occurrence of Chaetomium sp.). Increased erosion during the Sub-atlantic period is revealed by the occurrence of Glomus cf. fasciculatum. Furthermore, non-pollen palynomorphs give information on eutrophication of the lake which may be explained by more nutrient-rich habitats around the lake due to grazing and possibly agriculture. The combination of both types of analysis makes it possible to prove that this elevated site has been occupied and cleared at an early stage by man to obtain pasture lands and possibly arable land. This led to deforestation, which increased during the Sub-atlantic period, and has led to the present grasslands. © 2006 Elsevier B.V. All rights reserved.Peer Reviewe

Shepherds and plants in the Alps: multi-proxy archaeobotanical analysis of neolithic dung from “La Grande Rivoire” (Isère, France)

The analysis of phytoliths, pollen, charcoal and other macroremains was carried out in the neolithic shelter of “La Grande Rivoire”, Vercors massif (French Alps). The results show the predominance of tree species, in the form of phytoliths, clustered pollen, stomata, small branches charcoal, needles, bark, buds… The practice of leaf fodder is already known in the alpine and circum-alpine area from archaeological and historical sources. The analyses of the neolithic dung levels of “La Grande Rivoire” illustrate the use of leafy and flowering tree branches as fodder. The results also suggest that some species were used for special purpose in relation with the tending of livestock (litter, dietary supplement, veterinary practices)

Comment est née Collombine: le montage du squelette du musée de l'ours des cavernes d'Entremont-le-Vieux (Savoie)

International audienc

Comment est née Collombine: le montage du squelette du musée de l'ours des cavernes d'Entremont-le-Vieux (Savoie)

International audienc

Comment est née Collombine: le montage du squelette du musée de l'ours des cavernes d'Entremont-le-Vieux (Savoie)

International audienc

Origins of European biodiversity: palaeo-geographic signification of peat inception during the Holocene in the granitic eastern Massif Central (France)

International audienceMires are rare, unique environments that greatly contribute to biodiversity and occupy key functions in the hydrological cycle, but today many of these ecosystems are menaced, making conservation measures necessary. The efficiency of these measures is partly related to our knowledge of their origins and their development, a question rarely addressed. In this paper we examine the development of mires during the 10.000 last years (Holocene) in the eastern Massif Central, France, focusing on the contributions of climate change and human activities. Radiocarbon dates of the basal layers of 63 sites show that many mires formed around 7500 BP. During the Holocene, many mires were formed in the Atlantic period, characterised by warmer and wetter climatic conditions. At shorter time scales of 103–102 years, several other factors are related to peat inception, including topography, geomorphology and superficial geology, vegetation successions and human-induced changes. There is evidence that the building of small dams in headwater streams during the Iron age induced local water logging which then lead to the initiation and growth of mires. The influence of Bronze age communities is further demonstrated by new pollen analysis results. Forest clearing and grazing also favoured soil water logging, enabling peat inception. We consider human societies to be responsible for the formation of some mires. Human activities can be considered to having taken part in the development of the European biodiversity at least during the last 5 millennium