Isotopic signature in isolated south-western populations of European brown bear (Ursus arctos)

Stable isotope analysis of animal tissue samples is increasingly used to study the trophic ecology of target species. The isotopic signatures respond to the type of diet, but also to the environmental conditions of their habitat. In the case of omnivorous, seasonal or opportunistic feeding species, the interpretation of isotopic values is more complex, as it is largely determined by food selection, either due to individual choice or because of availability. We analysed C and N isotopes in brown bear (Ursus arctos) hair from four isolated populations of south-western Europe (Cantabrian, Pyrenees, Central Apennines and Alpine) accounting for the geographical and climatic differences among the four areas. We found inter-population differences in isotopic signatures that cannot be attributed to climatic differences alone, indicating that at least some bears from relatively higher altitude populations experiencing higher precipitation (Pyrenees) show a greater consumption of animal foods than those from lower altitudes (Cantabrian and Apennines). The quantification of isotopic niche space using Layman's metrics identified significant similarities between the Cantabrian and Central Apennine samples that markedly differ from the Pyrenean and Alpine. Our study provides a baseline to allow further comparisons in isotopic niche spaces in a broad ranged omnivorous mammal, whose European distribution requires further conservation attention especially for southern isolated populations

A western route of prehistoric human migration from Africa into the Iberian Peninsula

Being at the western fringe of Europe, Iberia had a peculiar prehistory and a complex pattern of Neolithization. A few studies, all based on modern populations, reported the presence of DNA of likely African origin in this region, generally concluding it was the result of recent gene flow, probably during the Islamic period. Here, we provide evidence of much older gene flow from Africa to Iberia by sequencing whole genomes from four human remains from northern Portugal and southern Spain dated around 4000 years BP (from the Middle Neolithic to the Bronze Age). We found one of them to carry an unequivocal sub-Saharan mitogenome of most probably West or West-Central African origin, to our knowledge never reported before in prehistoric remains outside Africa. Our analyses of ancient nuclear genomes show small but significant levels of sub-Saharan African affinity in several ancient Iberian samples, which indicates that what we detected was not an occasional individual phenomenon, but an admixture event recognizable at the population level. We interpret this result as evidence of an early migration process from Africa into the Iberian Peninsula through a western route, possibly across the Strait of Gibraltar

Preservation of DNA in Pleistocene and Holocene bear species samples from Northwestern Iberian Peninsula

In this paper we present 73 short mitochondrial DNA (mtDNA) sequences obtained from 30 brown bear (Ursus arctos) and 56 cave bear (Ursus spelaeus) samples in several cave sites of Northwestern Iberian Peninsula (Galicia and Asturias), of Holocene and Pleistocene ages. The technique used was PCR amplification of small mtDNA fragments and the subsequent Sanger sequencing of PCR products. In total, 6 different haplotypes were obtained for the brown bear and two for the cave bear. The high success rate of PCR amplifications (85[%], 73 positive amplifications out of a total of 86 samples) demonstrates the good conditions of the Sierra do Courel caves for the preservation of DNA in fossil bone remains, even for tens of millennia old

The cave bear’s hibernation: reconstructing the physiology and behaviour of an extinct animal

When studying an extinct species such as the cave bear (Ursus spelaeus ROSENMÜLLER 1794), it is possible to apply a variety of molecular biology techniques such as the study of stable isotopes or mitochondrial DNA (mDNA) to infer patterns of behaviour or physiology that would otherwise remain concealed. Throughout Europe and along time, differences in the isotopic values (δ 13 C and δ 15 N) of cave bears arise from environmental differences and the Pleistocene climatic evolution. The climate determines the hibernation length, during which the cave bears undergo a particular physiology that can be related to an increase in δ 15 N during climate cooling. In order to verify whether hibernation affected the isotopic values, we compared cave bears in different ontogenetic stages. The results show that perinatal values reflect the values for mothers during hibernation, while juveniles show differences in maternal investment. A previous study in the literature based on complete mitochondrial DNA sequences of several individuals collected from closely situated caves showed that each cave housed, almost exclusively, a single lineage of haplotypes. This pattern suggests extreme fidelity to the birth site, or homing behaviour, and that cave bears formed stable maternal social groups, at least for the purpose of hibernation. Studies of this type offer unexpected data on the palaeobiology of this extinct animal

Distribution and chronology of brownbear (Ursus arctos L.) in the Iberian peninsula during Upper Pleistocene and Holocene

In this paper we present 13 new radiocarbon datings of brown bear (Ursus arctos L.) remains from caves of the western half of the Cantabrian Mountains (Galicia, Asturias, Cantabria). This dates, as well as other previously reported, range from more than 40,000 years BP to 2,442 ± 61 years cal BP, belonging mostly to the early Holocene. From a whole of 26 datings, only 3 are of Pleistocene age. In order to complete the distribution in space and time in the Iberian peninsula, we review the literature on this species presence and its chronology by radiocarbon dating or archaeological culture when it exists. The presence of the brown bear has been observed in at least 143 sites. Oldest mentions are from Middle Pleistocene from the south of the Iberian peninsula. In Upper Pleistocene, sites cover the whole peninsula, with only 5 radiocarbon dates. Sites with Pleistocene fossils are a few more than the Holocene ones. There are several problems with the observed distribution. Firstly, as for the vast majority of terrestrial biocenosis, even if the species was present there are not preserv ed remains. An example of this is the lack of Holoeene remains in places we know it was present according to the historical literature. In general, there are gaps in the distribution that coincide with no limestone lithology. Furthermore, there is a bias related to the intensity of research in certain areas. It was suggested that brown bear population increased when cave bear (Ursus spelaeus ROSENMÙLLER) wiped out, but only in 12.5 % of the places in which both species are present is possible to see a substitution. The number of brown bears in every site is low before and after the extinction of its alleged competitor. Our results suggest that the denning ecology was different from the cave bear and, like nowadays, brown bears used different types of dens, like holes in the ground, inside trees or smaller natural caves. In the XVI century the population begins to decrease, till reaching its minimum in the XX century, with two surviving populations in Cantabrian Mountains and Pyrenees, but population began to drop since the Neolithic, probably due to the pressure caused by the expansion of human activities

Preservación de ADN en muestras de úrsidos Pleistocenos y Holocenos del NW de la Península Ibérica

[Resumen] En este trabajo se presentan 73 secuencias cortas de ADN mitocondrial (ADN mt) obtenidas a partir de 30 muestras de oso pardo (Ursus arctos) y 56 de oso cavernario (Ursus spelaeus) procedentes de diversos yacimientos del noroeste de la Península ibérica (Galicia y Asturias) y de edades finipleistocenas y holocenas. La técnica utilizada fue la amplificación mediante PCR de pequeños fragmentos de ADNmt y la posterior secuenciación Sanger de los productos PCR. En total se han obtenido 6 haplotipos diferentes para el oso pardo y dos para el cavernario. El elevado porcentaje de éxito de las amplificaciones PCR (85%, 73 amplificaciones positivas de un total de 86 muestras) demuestra las buenas condiciones de las cuevas de la Sierra do Courel para la preservación de ADN en restos óseos fósiles, incluso de decenas de milenios de antiguedad[Abstract] In this paper we present 73 short mitochondrial DNA (mtDNA) sequences obtained from 30 brown bear (Ursus arctos) and 56 cave bear (Ursus spelaeus) samples in several cave sites of Northwestern Iberian Peninsula (Galicia and Asturias), of Holocene and Pleistocene ages. The technique used was PCR amplification of small mtDNA fragments and the subsequent Sanger sequencing of PCR products. In total, 6 different haplotypes were obtained for the brown bear and two for the cave bear. The high success rate of PCR amplifications (85%, 73 positive amplifications out of a total of 86 samples) demonstrates the good conditions of the Sierra do Courel caves for the preservation of DNA in fossil bone remains, even for tens of millennia old

Stable isotopes data (delta13C, delta15N) from the cave bear (Ursus spelaeus): a new approach to its palaeoenvironment and dormancy.

Palaeoclimatic data that can be extracted from the isotopic signatures of delta13C and delta15N, which are found in fossil bone collagen, should be analysed according to the specific metabolism of each species. Although Ursus spelaeus is an extinct species, its metabolism is assimilated to current, closely related species of bear. In this study, bone collagen isotopic signatures (delta13C and delta15N) of cave bears from Late Pleistocene Alpine sites were compared to those that have already been documented. The delta13C signature did not seem to follow a systematic trend according to climatic conditions, probably as a consequence of the high variability present in the values of C3 plants, which were the basis of feeding. On the contrary, the delta15N signature displayed higher values in sites corresponding to colder periods in which the delta15N signature appeared to be dominated by the physiology of dormancy. Then, due to the reuse of urea in synthesizing amino acids, the delta15N signature systematically increased along with dormancy duration. This was related to the length of winter and, in turn, depended on climate

Ocupacións prehistóricas e históricas nas cavidades das serras orientais galegas: Cova de Eirós (Triacastela) e Valdavara (Becerreá)

The karstic cavities of NW Iberia allow an optimal preservation of the archaeological record which helps resolving those problems identified in the open-air sites. In this sense, the recovery of faunal remains, bone industry, hearths, etc. in the caves at the Eastern Ranges of NW Iberia give us much information about the cultural and social spheres of the Prehistoric societies. Several radiocarbon dates obtained in these archaeological contexts allow us to know the the changes in the use of the caves along Prehistoric and Historic times in NWIberia.As cavidades cársticas do NW peninsular ofrecen unhas condicións de preservación do rexistro arqueolóxico que solventan as deficiencias documentadas nos xacementos ó aire libre. Neste senso, a descuberta de novos materiais como restos faunísticos, industria ósea, fogares, etc. nas cavidades das Serras Orientais están a completar moitas esferas do estudio das sociedades prehistóricas. As numerosas datacións obtidas nestes contextos permiten coñecer a evolución no uso destes hábitats ó longo da Prehistoriae Historia Antiga do NW peninsular

Isotopic signature in isolated south-western populations of European brown bear (Ursus arctos)

AbstractStable isotope analysis of animal tissue samples is increasingly used to study the trophic ecology of target species. The isotopic signatures respond to the type of diet, but also to the environmental conditions of their habitat. In the case of omnivorous, seasonal or opportunistic feeding species, the interpretation of isotopic values is more complex, as it is largely determined by food selection, either due to individual choice or because of availability. We analysed C and N isotopes in brown bear (Ursus arctos) hair from four isolated populations of south-western Europe (Cantabrian, Pyrenees, Central Apennines and Alpine) accounting for the geographical and climatic differences among the four areas. We found inter-population differences in isotopic signatures that cannot be attributed to climatic differences alone, indicating that at least some bears from relatively higher altitude populations experiencing higher precipitation (Pyrenees) show a greater consumption of animal foods than those from lower altitudes (Cantabrian and Apennines). The quantification of isotopic niche space using Layman’s metrics identified significant similarities between the Cantabrian and Central Apennine samples that markedly differ from the Pyrenean and Alpine. Our study provides a baseline to allow further comparisons in isotopic niche spaces in a broad ranged omnivorous mammal, whose European distribution requires further conservation attention especially for southern isolated populations.</jats:p