Groupe de Recherche en Ecologie Arctique GREA

Francheville, France

Groupe de Recherche en Ecologie Arctique GREA

Francheville, France
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Gilg O.,University of Burgundy | Gilg O.,University of Helsinki | Kovacs K.M.,Norwegian Polar Institute | Aars J.,Norwegian Polar Institute | And 11 more authors.
Annals of the New York Academy of Sciences | Year: 2012

Climate change is taking place more rapidly and severely in the Arctic than anywhere on the globe, exposing Arctic vertebrates to a host of impacts. Changes in the cryosphere dominate the physical changes that already affect these animals, but increasing air temperatures, changes in precipitation, and ocean acidification will also affect Arctic ecosystems in the future. Adaptation via natural selection is problematic in such a rapidly changing environment. Adjustment via phenotypic plasticity is therefore likely to dominate Arctic vertebrate responses in the short term, and many such adjustments have already been documented. Changes in phenology and range will occur for most species but will only partly mitigate climate change impacts, which are particularly difficult to forecast due to the many interactions within and between trophic levels. Even though Arctic species richness is increasing via immigration from the South, many Arctic vertebrates are expected to become increasingly threatened during this century. © 2012 New York Academy of Sciences.

Gilg O.,University of Helsinki | Gilg O.,University of Burgundy | Strom H.,Norwegian Polar Institute | Aebischer A.,Norwegian University of Science and Technology | And 6 more authors.
Journal of Avian Biology | Year: 2010

The post-breeding movements of three northeast Atlantic populations (north Greenland, Svalbard and Franz Josef Land) of the ivory gull Pagophila eburnea, a threatened high-Arctic sea-ice specialist, were studied between July and December 2007 using 31 satellite transmitters. After leaving their breeding grounds, all birds first dispersed eastward in August-September, to an area extending from the Fram Strait to the northwestern Laptev Sea (off Severnaya Zemlya). Most returned along the same flyway in October-November, hence describing a loop migration before moving south, off east Greenland. Wintering grounds were reached in December, in southeast Greenland and along the Labrador Sea ice-edge, where Canadian birds also overwinter. One to two birds from each population however continued eastwards towards a third wintering area in the Bering Strait region, hence demonstrating a bi-directional migration pattern for the populations and elucidating the origin of the birds found in the north Pacific during winter time. Overall, all birds breeding in the northeast Atlantic region used the same flyways, had similar rates of travel, and showed a peak in migratory activity in November. Though the total length of the main flyway, to the Labrador Sea, is only and at most 7500 km on a straight line, the mean total distance travelled by Greenland birds between July and December was 50 000 km when estimated from hourly rates of travel. Our study presents the first comprehensive and complete picture for the post-breeding movements of the different ivory gull populations breeding in the northeast Atlantic. © 2010 The Authors.

Yannic G.,CNRS Alpine Ecology Laboratory | Broquet T.,Connectivity | Broquet T.,Paris-Sorbonne University | Strom H.,Norwegian Polar Institute | And 10 more authors.
Journal of Ornithology | Year: 2016

Sex identification of birds is relevant to studies of evolutionary biology and ecology and is often a central issue for the management and conservation of populations. The Ivory Gull Pagophila eburnea (Phipps, 1774) is a rare high-Arctic species whose main habitat is sea ice throughout the year. This species is currently listed Near Threatened by the IUCN, because populations have drastically declined in part of the species distribution in the recent past. Here we tested molecular sexing methods with different types of samples. Molecular sexing appeared to be very efficient with DNA extracted from muscle, blood, and buccal swabs, both for adults and young chicks. We also performed morphological analyses to characterize sexual size dimorphism in Ivory Gulls sampled in three distinct regions: Greenland, Svalbard, and Russia. Males were larger than females for all morphometric measurements, with little overlap between sexes. Discriminant analysis based on six morphometric variables correctly classified ~95 % of the individuals, even when using two variables only, i.e., gonys height and skull length. Therefore, both molecular and biometric methods are useful for sexing Ivory Gulls. Interestingly, our results indicate a male-biased sex ratio across all Ivory Gull populations studied, including two samples of offspring (67.8 % males). © 2016, Dt. Ornithologen-Gesellschaft e.V.

Yannic G.,Laval University | Yannic G.,University of Moncton | Yannic G.,CNRS Alpine Ecology Laboratory | Yearsley J.M.,University College Dublin | And 12 more authors.
Polar Biology | Year: 2015

Species may cope with rapid habitat changes by distribution shifts or adaptation to new conditions. A common feature of these responses is that they depend on how the process of dispersal connects populations, both demographically and genetically. We analyzed the genetic structure of a near-threatened high-Arctic seabird, the ivory gull (Pagophila eburnea) in order to infer the connectivity among gull colonies. We analyzed 343 individuals sampled from 16 localities across the circumpolar breeding range of ivory gulls, from northern Russia to the Canadian Arctic. To explore the roles of natal and breeding dispersal, we developed a population genetic model to relate dispersal behavior to the observed genetic structure of worldwide ivory gull populations. Our key finding is the striking genetic homogeneity of ivory gulls across their entire distribution range. The lack of population genetic structure found among colonies, in tandem with independent evidence of movement among colonies, suggests that ongoing effective dispersal is occurring across the Arctic Region. Our results contradict the dispersal patterns generally observed in seabirds where species movement capabilities are often not indicative of dispersal patterns. Model predictions show how natal and breeding dispersal may combine to shape the genetic homogeneity among ivory gull colonies separated by up to 2800 km. Although field data will be key to determine the role of dispersal for the demography of local colonies and refine the respective impacts of natal versus breeding dispersal, conservation planning needs to consider ivory gulls as a genetically homogeneous, Arctic-wide metapopulation effectively connected through dispersal. © 2015 Springer-Verlag Berlin Heidelberg

PubMed | University of Aarhus, University of Bremen, Norwegian Polar Institute, CNRS Biogeosciences Laboratory and 5 more.
Type: Journal Article | Journal: Biology letters | Year: 2016

The ongoing decline of sea ice threatens many Arctic taxa, including the ivory gull. Understanding how ice-edges and ice concentrations influence the distribution of the endangered ivory gulls is a prerequisite to the implementation of adequate conservation strategies. From 2007 to 2013, we used satellite transmitters to monitor the movements of 104 ivory gulls originating from Canada, Greenland, Svalbard-Norway and Russia. Although half of the positions were within 41 km of the ice-edge (75% within 100 km), approximately 80% were on relatively highly concentrated sea ice. Ivory gulls used more concentrated sea ice in summer, when close to their high-Arctic breeding ground, than in winter. The best model to explain the distance of the birds from the ice-edge included the ice concentration within approximately 10 km, the month and the distance to the colony. Given the strong links between ivory gull, ice-edge and ice concentration, its conservation status is unlikely to improve in the current context of sea-ice decline which, in turn, will allow anthropogenic activities to develop in regions that are particularly important for the species.

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