• Centennial relationships between ocean temperature and Atlantic puffin production reveal shifting decennial trends 

      Hansen, Erpur S.; Sandvik, Hanno; Erikstad, Kjell E.; Yoccoz, Nigel; Anker-Nilssen, Tycho; Bader, Jürgen; Descamps, Sebastien; Hodges, Kevin; Mesquita, Michel d. S.; Reiertsen, Tone Kristin; Varpe, Øystein (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-05-24)
      The current warming of the oceans has been shown to have detrimental effects for a number of species. An understanding of the underlying mechanisms may be hampered by the non-linearity and non-stationarity of the relationships between temperature and demography, and by the insufficient length of available time series. Most demographic time series are too short to study the effects of climate on ...
    • Climate fluctuations and differential survival of bridled and non-bridled Common Guillemots Uria aalge 

      Reiertsen, Tone Kristin; Erikstad, Kjell E; Barrett, Robert T; Sandvik, Hanno; Yoccoz, Nigel (Journal article; Tidsskriftartikkel; Peer reviewed, 2012-06-22)
      Climate fluctuations and its effects on ecological processes are evident in most areas worldwide but whether such climatic effects are induced phenotypic plasticity or whether animals adapt to the new environment through micro‐evolutionary processes is poorly known. In this study we have analyzed long‐term data (22 years) on the relationship between climatic fluctuations and the adult survival of ...
    • Consequences of cross-season demographic correlations for population viability 

      Layton-Matthews, Kate; Reiertsen, Tone Kristin; Erikstad, Kjell E.; Anker-Nilssen, Tycho; Daunt, Francis; Wanless, Sarah; Barrett, Robert; Newell, Mark A; Harris, Mike P. (Journal article; Tidsskriftartikkel; Peer reviewed, 2023-07-12)
      Demographic correlations are pervasive in wildlife populations and can represent important secondary drivers of population growth. Empirical evidence suggests that correlations are in general positive for long-lived species, but little is known about the degree of variation among spatially segregated populations of the same species in relation to environmental conditions. We assessed the relative ...
    • Diverging phenological responses of Arctic seabirds to an earlier spring 

      Descamps, Sebastien; Ramírez, Francisco; Benjaminsen, Sigurd; Anker-Nilssen, Tycho; Barrett, Robert; Burr, Zofia; Christensen-Dalsgaard, Signe; Erikstad, Kjell E; Irons, David B.; Lorentsen, Svein Håkon; Mallory, Mark L; Robertson, Gregory J.; Reiertsen, Tone Kristin; Strøm, Hallvard; Varpe, Øystein; Lavergne, Sébastien (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-07-31)
      The timing of annual events such as reproduction is a critical component of how free‐living organisms respond to ongoing climate change. This may be especially true in the Arctic, which is disproportionally impacted by climate warming. Here, we show that Arctic seabirds responded to climate change by moving the start of their reproduction earlier, coincident with an advancing onset of spring and ...
    • 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 ...
    • Effekter av forurensning på bestandsutviklingen til måser 

      Reiertsen, Tone Kristin; Erikstad, Kjell Einar (Research report; Forskningsrapport, 2007-06)
      Måser er toppredatorer i det marine miljø, og er svært utsatt for miljøgifter. Hos arter som sildemåse (Larus fuscus), svartbak (Larus marinus) og polarmåse (Larus hyperboreus) er det dokumentert høye nivåer av organokloriner (OC), som nedsetter immunforsvaret og gir økt forekomst av sykdom, noe som medfører både redusert hekkesuksess og overlevelse av voksne. Selv om det er dokumentert en rekke ...
    • Hemispheric asymmetry in ocean change and the productivity of ecosystem sentinels 

      Sydeman, William J.; Schoeman, David S.; Thompson, Sarah Ann; Hoover, Brian A.; García-Reyes, Marisol; Daunt, Francis; Agnew, Philippa; Anker-Nilssen, Tycho; Barbraud, Christophe; Barrett, Robert; Becker, Peter H.; Bell, Elisabeth; Boersma, P. Dee; Bouwhuis, Sandra; Cannell, Belinda; Crawford, Robert J. M.; Dann, Peter; Delord, Karine; Elliot, Graeme; Erikstad, Kjell E.; Flint, Elizabeth; Furness, Robert W.; Harris, Michael P.; Hatch, Scott; Hilwig, Kara; Hinke, Jefferson T.; Jahncke, Jaime; Mills, James A.; Reiertsen, Tone Kristin; Renner, Heather; Sherley, Richard B.; Surman, Christopher; Taylor, Graeme; Thayer, Julie A.; Trathan, Phil N.; Velarde, Enriqueta; Walker, Kath; Wanless, Sarah; Warzybok, Pete; Watanuki, Yutaka (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-05-28)
      Climate change and other human activities are causing profound effects on marine ecosystem productivity. We show that the breeding success of seabirds is tracking hemispheric differences in ocean warming and human impacts, with the strongest effects on fish-eating, surface-foraging species in the north. Hemispheric asymmetry suggests the need for ocean management at hemispheric scales. For the north, ...
    • 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 ...
    • Inter-population synchrony in adult survival and effects of climate and extreme weather in non-breeding areas of Atlantic puffins 

      Reiertsen, Tone Kristin; Layton-Matthews, Kate; Erikstad, K.E.; Hodges, Kevin I.; Ballesteros, Manuel; Anker-Nilssen, Tycho; Barrett, R.T.; Benjaminsen, Sigurd; Bogdanova, M.; Christensen-Dalsgaard, Signe; Daunt, Francis; Dehnhard, Nina; Harris, Michael P.; Langset, Magdalene; Lorentsen, Svein-Håkon; Newell, Mark; Bråthen, Vegard Sandøy; Støyle-Bringsvor, I.; Systad, Geir Helge Rødli; Wanless, Sarah (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-10-14)
      Seabirds are undergoing drastic declines globally and spend the non-breeding season at sea, making it challenging to study the drivers of their survival. Harsh weather and changes in climate conditions can have large impacts on seabird population dynamics through increased mortality. The intensity and persistence of extreme events are forecasted to increase with global warming. As shared conditions ...
    • Later at higher latitudes: large-scale variability in seabird breeding timing and synchronicity 

      Burr, Zofia M.; Varpe, Øystein; Anker-Nilssen, Tycho; Erikstad, Kjell E; Descamps, Sébastien; Barrett, Robert T.; Bech, Claus; Christensen-Dalsgaard, Signe; Lorentsen, Svein-Håkon; Moe, Børge; Reiertsen, Tone Kristin; Strøm, Hallvard (Journal article; Tidsskriftartikkel; Peer reviewed, 2016-05-28)
      In seasonal environments, organisms are expected to optimally schedule reproduction within an annual range of environmental conditions. Latitudinal gradients generate a range of seasonality to which we can expect adaptations to have evolved, and can be used to explore drivers of timing strategies across species’ distribution ranges. This study compares the timing of egg hatching in four seabird ...
    • Raising offspring increases ageing: Differences in senescence among three populations of a long-lived seabird, the Atlantic puffin 

      Landsem, Terje Lorentzen; Yoccoz, Nigel Gilles; Layton-Matthews, Kate; Hilde, Christoffer Høyvik; Harris, Michael P; Wanless, Sarah; Daunt, Francis; Reiertsen, Tone Kristin; Erikstad, Kjell E.; Anker-Nilssen, Tycho (Journal article; Tidsskriftartikkel; Peer reviewed, 2023-01-12)
      1. Actuarial senescence, the decline of survival with age, is well documented in the wild. Rates of senescence vary widely between taxa, to some extent also between sexes, with the fastest life histories showing the highest rates of senescence. Few studies have investigated differences in senescence among populations of the same species, although such variation is expected from population-level ...
    • A risk assessment of the effects of mercury on Baltic Sea, Greater North Sea and North Atlantic wildlife, fish and bivalves 

      Dietz, Rune; Fort, Jérôme; Sonne, Christian; Albert, Céline; Bustnes, Jan Ove; Christensen, Thomas Kjær; Ciesielski, Tomasz Maciej; Danielsen, Jóhannis; Dastnai, Sam; Eens, Marcel; Erikstad, Kjell E; Galatius, Anders; Garbus, Svend-Erik; Gilg, Oliver; Hanssen, Sveinn Are; Helander, Björn; Helberg, Morten; Jaspers, Veerle; Jenssen, Bjørn Munro; Jónsson, Jón Einar; Kauhala, Kaarina; Kolbeinsson, Yann; Kyhn, Line A.; Labansen, Aili Lage; Larsen, Martin M.; Lindstrøm, Ulf; Reiertsen, Tone Kristin; Rigét, Frank F.; Roos, Anna; Strand, Jakob; Strøm, Hallvard; Søndergaard, Jens; Sun, Jiachen; Teilmann, Jonas; Therkildsen, Ole Roland; Thórarinsson, Thorkell Lindberg; Tjørnløv, Rune Skjold; Wilson, Simon; Eulaers, Igor (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-11-24)
      A wide range of species, including marine mammals, seabirds, birds of prey, fish and bivalves, were investigated for potential population health risks resulting from contemporary (post 2000) mercury (Hg) exposure, using novel risk thresholds based on literature and de novo contamination data. The main geographic focus is on the Baltic Sea, while data from the same species in adjacent waters, such ...
    • Seabirds, climate and prey. A population study of two seabird species. 

      Reiertsen, Tone Kristin (Doctoral thesis; Doktorgradsavhandling, 2013-05-30)
      Many seabird populations have declined dramatically over recent decades, and studying the demography and population dynamic in seabird populations is important to gaining a better understanding of causes and mechanisms lying behind such changes and to identify targets for conservation and management. Climate and prey availability are known to affect demography and population dynamics of seabirds. ...
    • 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). ...
    • Twilight foraging enables European shags to survive the winter across their latitudinal range 

      Moe, Børge; Daunt, Francis; Bråthen, Vegard Sandøy; Barrett, Robert; Ballesteros, Manuel; Bjørnstad, Oskar; Bogdanova, Maria I.; Dehnhard, Nina; Erikstad, Kjell E.; Follestad, Arne; Gíslason, Sindri; Hallgrimsson, Gunnar Thor; Lorentsen, Svein-Håkon; Newell, Mark; Petersen, Aevar; Phillips, Richard A.; Ragnarsdóttir, Sunna Björk; Reiertsen, Tone Kristin; Åström, Jens; Wanless, Sarah; Anker-Nilssen, Tycho (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-10-14)
      Species breeding at high latitudes face a significant challenge of surviving the winter. Such conditions are particularly severe for diurnal marine endotherms such as seabirds. A critical question is therefore what behavioural strategies such species adopt to maximise survival probability. We tested 3 hypotheses: (1) they migrate to lower latitudes to exploit longer day length (‘sun-chasing’), (2) ...
    • When things go wrong: intra-season dynamics of breeding failure in a seabird 

      Ponchon, Aurore; Grémillet, David J.H.; Christensen-Dalsgaard, Signe; Erikstad, Kjell E; Barrett, Robert T.; Reiertsen, Tone Kristin; McCoy, Karen D.; Tveraa, Torkild; Boulinier, Thierry (Journal article; Tidsskriftartikkel; Peer reviewed, 2014-01-16)
      During breeding, long-lived species face important time and energy constraints that can lead to breeding failure when food becomes scarce. Despite the potential implications of intra-season dynamics in breeding failure for individual behavior, carry-over effects, dispersal decisions and population dynamics, little information is currently available on these dynamics at fine temporal scales. Here, ...
    • 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 ...
    • Your place or mine? Exploring birdwatching tourists’ behaviour disturbing birds in a nature reserve 

      Aas, Øystein; Jørgensen, Frida Marie Omma; Stensland, Stian; Reiertsen, Tone Kristin; Dybsand, Hilde Nikoline Hambro (Journal article; Tidsskriftartikkel; Peer reviewed, 2023-04-11)
      To manage for more sustainable wildlife viewing tourism, a better understanding of tourists’ behaviour that might disturb and negatively affect wildlife such as birds is needed. We conducted a qualitative case study of visitors to Hornøya, a protected bird cliff in Northern Norway. Behaviours with the potential to disturb seabirds at the site were explored using the theory of planned behaviour ...