Blar i forfatter "Merkel, Benjamin"

Viser treff 1-10 av 10

    • Choose your poison – Space-use strategy influences pollutant exposure in Barents Sea polar bears 

      Tartu, Sabrina; Aars, Jon; Andersen, Magnus; Polder, Anuschka; Bourgeon, Sophie; Merkel, Benjamin; Lowther, Andrew D.; Bytingsvik, Jenny; Welker, Jeffrey Martin; Derocher, Andrew E.; Jenssen, Bjørn Munro; Routti, Heli (Journal article; Tidsskriftartikkel; Peer reviewed, 2018-01-24)
      Variation in space-use is common within mammal populations. In polar bears, Ursus maritimus, some individuals follow the sea ice (offshore bears) whereas others remain nearshore yearlong (coastal bears). We studied pollutant exposure in relation to space-use patterns (offshore vs coastal) in adult female polar bears from the Barents Sea equipped with satellite collars (2000–2014, n = 152). First, ...

    • Earlier colony arrival but no trend in hatching timing in two congeneric seabirds (Uria spp.) across the North Atlantic 

      Merkel, Benjamin; Descamps, Sebastien; Yoccoz, Nigel Gilles; Danielsen, Jóhannis; Daunt, Francis; Erikstad, Kjell E; Ezhov, Aleksey V.; Grémillet, David; Gavrilo, Maria; Lorentsen, Svein Håkon; Reiertsen, Tone Kristin; Steen, Harald; Systad, Geir Helge Rødli; Þórarinsson, Þorkell Lindberg; Wanless, Sarah; Strøm, Hallvard (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-10-23)
      A global analysis recently showed that seabird breeding phenology (as the timing of egg-laying and hatching) does not, on average, respond to temperature changes or advance with time (Keogan <i>et al.</i> 2018 <i>Nat. Clim. Change</i> <b>8</b>, 313–318). This group, the most threatened of all birds, is therefore prone to spatio-temporal mismatches with their food resources. Yet, other aspects of ...

    • Individual migration strategy fidelity but no habitat specialization in two congeneric seabirds 

      Merkel, Benjamin; Descamps, Sebastien; Yoccoz, Nigel; Grémillet, David; Daunt, Francis; Erikstad, Kjell E; Ezhov, Aleksey V.; Harris, Mike P.; Gavrilo, Maria; Lorentsen, Svein Håkon; Reiertsen, Tone Kristin; Steen, Harald; Systad, Geir Helge Rødli; Þórarinsson, Þorkell Lindberg; Wanless, Sarah; Strøm, Hallvard (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-10-30)
      Aim: In migratory species, individuals often use fixed and individual-specific migration strategies, which we term individual migration strategy fidelity (IMSF). Our goal was to test if guillemots have flexible or fixed individual migration strategies (i.e. IMSF), if this behaviour is consistent across large parts of the genus’ range and if they were philopatric to geographical sites or a habitat ...

    • Migration in seabirds: seasonal structure in space and environment across species, populations and individuals 

      Merkel, Benjamin (Doctoral thesis; Doktorgradsavhandling, 2019-05-21)
      Identifying drivers of population trends in migratory species is difficult, as they can face many stressors while moving through different areas and environments during the annual cycle. Their population response to environmental change may in addition be affected by consistent differences in individual behaviour, which are widespread in free-living populations. An understanding of the structure of ...

    • Potential misidentifications of two climate indicator species of the marine arctic ecosystem: Calanus glacialis and C. finmarchicus 

      Gabrielsen, Tove M; Merkel, Benjamin; Søreide, Janne; Johansson-Karlsson, Emma; Bailey, Allison; Vogedes, Daniel Ludwig; Nygård, Henrik Andreas; Varpe, Øystein; Berge, Jørgen (Journal article; Tidsskriftartikkel; Peer reviewed, 2012)
      Calanoid copepods of the genus Calanus represent an important, nutrient-rich food source for a multitude of Arctic marine organisms. Although morphologically very similar, their life histories and ecological roles differ. Because the distribution of Calanus glacialis and C. finmarchicus corresponds to Arctic and Atlantic water masses, respectively, they are regularly used as climate indicators. A ...

    • A probabilistic algorithm to process geolocation data 

      Merkel, Benjamin; Phillips, Richard A.; Descamps, Sébastien; Yoccoz, Nigel Gilles; Moe, Børge; Strøm, Hallvard (Journal article; Tidsskriftartikkel; Peer reviewed, 2016-11-18)
      <p><i>Background: </i>The use of light level loggers (geolocators) to understand movements and distributions in terrestrial and marine vertebrates, particularly during the non-breeding period, has increased dramatically in recent years. However, inferring positions from light data is not straightforward, often relies on assumptions that are difficult to test, or includes an element of subjectivity ...

    • Strong migratory connectivity across meta-populations of sympatric North Atlantic seabirds 

      Merkel, Benjamin; Descamps, Sebastien; Yoccoz, Nigel; Grémillet, David; Fauchald, Per; Danielsen, Jóhannis; Daunt, Francis; Erikstad, Kjell E.; Ezhov, Aleksey V.; Harris, Mike P.; Gavrilo, Maria; Lorentsen, Svein-Håkon; Reiertsen, Tone Kristin; Systad, Geir Helge Rødli; Thórarinsson, Thorkell Lindberg; Wanless, Sarah; Strøm, Hallvard (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-03-04)
      Identifying drivers of population trends in migratory species is difficult, as they can face many stressors while moving through different areas and environments during the annual cycle. To understand the potential of migrants to adjust to perturbations, it is critical to study the connection of different areas used by different populations during the annual cycle (i.e. migratory connectivity). ...

    • The world's northern most harbour seal population - How many are there? 

      Merkel, Benjamin (Master thesis; Mastergradsoppgave, 2012-11-15)
      This study presents the first abundance estimate for the world's northernmost harbour seal (Phoca vitulina) population, which resides in Svalbard, Norway, based on three digital stereoscopic photographic surveys conducted in 2009 and 2010. The counts from these high resolution 3D images were combined with a novel method for estimating correction factors for animals that were in the water at the time ...

    • The World's Northernmost Harbour Seal Population - How Many Are There? 

      Merkel, Benjamin; Lydersen, Christian; Yoccoz, Nigel; Kovacs, Kit (Journal article; Tidsskriftartikkel; Peer reviewed, 2013)
      This study presents the first abundance estimate for the world’s northernmost harbour seal (Phoca vitulina) population, which resides in Svalbard, Norway, based on three digital stereoscopic photographic surveys conducted in 2009 and 2010. The counts from these high resolution 3D images were combined with a novel method for estimating correction factors for animals that were in the water at the ...

    • Year-round distribution of Northeast Atlantic seabird populations: applications for population management and marine spatial planning 

      Fauchald, Per; Amélineau, Françoise; Bråthen, Vegard Sandøy; Descamps, Sebastien; Ekker, Morten; Helgason, Halfdan Helgi; Johansen, Malin; Merkel, Benjamin; Moe, Børge; Åström, Jens; Bjørnstad, Oskar; Chastel, Olivier; Christensen-Dalsgaard, Signe; Danielsen, Jóhannis; Daunt, Francis; Dehnhard, Nina; Erikstad, Kjell E.; Ezhov, Alexey; Gavrilo, Maria; Hallgrimsson, Gunnar Thor; Hansen, Erpur Snær; Harris, Mike; Helberg, Morten; Jónsson, Jón Einar; Kolbeinsson, Yann; Krasnov, Yuri V.; Langset, Magdalene; Lorentsen, Svein-Håkon; Lorentzen, Erlend; Newell, Mark; Olsen, Bergur; Reiertsen, Tone Kristin; Systad, Geir Helge Rødli; Thompson, Paul; Thórarinsson, Thorkell Lindberg; Wanless, Sarah; Wojczulanis-Jakubas, Katarzyna; Strøm, Hallvard (Journal article; Tidsskriftartikkel; Peer reviewed, 2021)
      Tracking data of marine predators are increasingly used in marine spatial management. We developed a spatial data set with estimates of the monthly distribution of 6 pelagic seabird species breeding in the Northeast Atlantic. The data set was based on year-round global location sensor (GLS) tracking data of 2356 adult seabirds from 2006−2019 from a network of seabird colonies, data describing the ...