• Assessing the effect of predator control on an endangered goose population subjected to predator-mediated food web dynamics 

      Marolla, Filippo; Aarvak, Tomas; Øien, Ingar Jostein; Mellard, Jarad Pope; Henden, John-André; Hamel, Sandra; Stien, Audun; Tveraa, Torkild; Yoccoz, Nigel Gilles; Ims, Rolf Anker (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-01-29)
      <ol> <li>Assessing the effectiveness of conservation actions to halt population declines is challenging when confounded by other factors. We assessed whether culling of red fox, a predator currently increasing in number in the sub‐Arctic, contributed to recent recovery of the critically endangered Fennoscandian population of Lesser White‐fronted Goose <i>Anser erythropus</i>, while controlling for ...
    • Beregning av produksjon og tap i reindriften 

      Tveraa, Torkild; Ballesteros, Manuel; Bårdsen, Bård-Jørgen; Fauchald, Per; Lagergren, Madeleine; Langeland, Knut; Pedersen, Elisabeth; Stien, Audun (Research report; Forskningsrapport, 2013-05)
      En økning i rovdyrbestandene i reinbeiteområdene regnes av næringen som den viktigste enkeltfaktoren som forårsaker lav kalvetilgang, store tap av dyr og derigjennom lav produksjon i tamreinflokkene i Norge. Endringer i reintall og klimatiske forhold er imidlertid også viktige faktorer som påvirker reproduksjon og overlevelse hos rein. Gitt at predasjon har stor innvirkning på reinens demografi ...
    • Berettiget kritikk av NMBU sin reindriftsforskning 

      Stien, Audun; Ims, Rolf Anker; Yoccoz, Nigel; Tveraa, Torkild; Stien, Jennifer (Chronicle; Kronikk, 2021-12-21)
      Det er flere elementer i artikkelen til NMBU-forskerne som fremstår som uforenlig med god vitenskapelig praksis.
    • Climate Events Synchronize the Dynamics of a Resident Vertebrate Community in the High Arctic 

      Hansen, Brage Bremset; Grøtan, Vidar; Aanes, Ronny; Sæther, Bernt-Erik; Stien, Audun; Fuglei, Eva; Ims, Rolf Anker; Yoccoz, Nigel; Pedersen, Åshild Ønvik (Peer reviewed; Research report; Forskningsrapport, 2013-01-18)
      Recently accumulated evidence has documented a climate impact on the demography and dynamics of single species, yet the impact at the community level is poorly understood. Here, we show that in Svalbard in the high Arctic, extreme weather events synchronize population fluctuations across an entire community of resident vertebrate herbivores and cause lagged correlations with the secondary consumer, ...
    • Climate variability and density-dependent population dynamics: Lessons from a simple High Arctic ecosystem 

      Fauteux, Dominique; Stien, Audun; Yoccoz, Nigel; Fuglei, Eva; Ims, Rolf Anker (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-09-09)
      Ecologists are still puzzled by the diverse population dynamics of herbivorous small mammals that range from high-amplitude, multiannual cycles to stable dynamics. Theory predicts that this diversity results from combinations of climatic seasonality, weather stochasticity, and density-dependent food web interactions. The almost ubiquitous 3- to 5-y cycles in boreal and arctic climates may theoretically ...
    • Community-wide mesocarnivore response to partial ungulate migration 

      Henden, John-André; Stien, Audun; Bårdsen, Bård-Jørgen; Yoccoz, Nigel Gilles; Ims, Rolf Anker (Journal article; Tidsskriftartikkel; Peer reviewed, 2014)
    • Congruent responses to weather variability in high arctic herbivores 

      Stien, Audun; Ims, Rolf Anker; Albon, Steve D.; Fuglei, Eva; Irvine, R.J.; Ropstad, Erik; Halvorsen, Odd; Langvatn, Rolf; Loe, Leif Egil; Veiberg, Vebjørn; Yoccoz, Nigel (Journal article; Tidsskriftartikkel; Peer reviewed, 2012-09-26)
      Assessing the role of weather in the dynamics of wildlife populations is a pressing task in the face of rapid environmental change. Rodents and ruminants are abundant herbivore species in most Arctic ecosystems, many of which are experiencing particularly rapid climate change. Their different life-history characteristics, with the exception of their trophic position, suggest that they should show ...
    • Context-dependent fitness costs of reproduction despite stable body mass costs in an Arctic herbivore 

      Pigeon, Gabriel; Albon, Steve; Loe, Leif Egil; Bischof, Richard; Bonenfant, Christophe; Ropstad, Erik; Veiberg, Vebjørn; Stien, Audun (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-09-20)
      1.The cost of reproduction on demographic rates is often assumed to operate through changing body condition. Several studies have found that reproduction depresses body mass more if the current conditions are severe, such as high population densities or adverse weather, than under benign environmental conditions. However, few studies have investigated the association between the fitness components ...
    • Determinants of heart rate in Svalbard reindeer reveal mechanisms of seasonal energy management 

      Trondrud, Liv Monica; Pigeon, Gabriel; Albon, Steve; Arnold, Walter; Evans, Alina; Irvine, R. Justin; Król, Elżbieta; Ropstad, Erik; Stien, Audun; Veiberg, Vebjørn; Speakman, John R.; Loe, Leif Egil (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-06-28)
      Seasonal energetic challenges may constrain an animal's ability to respond to changing individual and environmental conditions. Here, we investigated variation in heart rate, a well-established proxy for metabolic rate, in Svalbard reindeer (Rangifer tarandus platyrhynchus), a species with strong seasonal changes in foraging and metabolic activity. In 19 adult females, we recorded heart rate, ...
    • Direct and indirect effects of environmental drivers on reindeer reproduction 

      Henden, John-André; Tveraa, T.; Stien, Audun; Mellard, Jarad; Marolla, Filippo; Ims, Rolf Anker; Yoccoz, Nigel (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-05-27)
      The impact of climate change on the dynamics of populations has been well documented and is widespread. However, weather variability influences populations both directly and indirectly, and is mediated by species interactions. This complexity may impede proper climate impact assessments. Hence, predicting the consequences of climate change may require including processes that occur both with time ...
    • Don't go chasing the ghosts of the past: habitat selection and site fidelity during calving in an Arctic ungulate 

      Paulsen, Ingrid M.; Soininen, Eeva M; Ravolainen, Virve; Loe, Leif Egil; Hansen, Brage Bremset; Irvine, Justin R; Stien, Audun; Ropstad, Erik; Veiberg, Vebjørn; Fuglei, Eva; Pedersen, Åshild Ønvik (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-04-01)
      Predator avoidance and food availability are both factors known to influence habitat selection and site fidelity around calving in caribou and reindeer. Here, we assess habitat selection and site fidelity during the calving period in the solitary, Arctic Svalbard reindeer Rangifer tarandus platyrhynchus, which is subject to limited predation risk and human disturbance. In this largely predator-free ...
    • Effect of scavenging on predation in a food web 

      Mellard, Jarad; Hamel, Sandra; Henden, John-André; Ims, Rolf Anker; Stien, Audun; Yoccoz, Nigel (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-04-26)
      <ol> <li>The fasting endurance hypothesis (FEH) predicts strong selection for large body size in mammals living in environments where food supply is interrupted over prolonged periods of time. The Arctic is a highly seasonal and food-restricted environment, but contrary to predictions from the FEH, empirical evidence shows that Arctic mammals are often smaller than their temperate conspecifics. ...
    • End-user involvement to improve predictions and management of populations with complex dynamics and multiple drivers 

      Henden, John-André; Ims, Rolf Anker; Yoccoz, Nigel; Asbjørnsen, Einar Johannes; Stien, Audun; Mellard, Jarad Pope; Tveraa, Torkild; Marolla, Filippo; Jepsen, Jane Uhd (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-03-11)
      Sustainable management of wildlife populations can be aided by building models that both identify current drivers of natural dynamics and provide near-term predictions of future states. We employed a Strategic Foresight Protocol (SFP) involving stakeholders to decide the purpose and structure of a dynamic state-space model for the population dynamics of the Willow Ptarmigan, a popular game species ...
    • Estimating the cumulative impact and zone of influence of anthropogenic features on biodiversity 

      Niebuhr, Bernardo Brandão; Van Moorter, Bram; Stien, Audun; Tveraa, Torkild; Strand, Olav; Langeland, Knut; Sandstrom, Per; Alam, Moudud; Skarin, Anna; Panzacchi, Manuela (Journal article; Tidsskriftartikkel; Peer reviewed, 2023-06-02)
      1. The concept of cumulative impacts is widespread in policy documents, regu-lations and ecological studies, but quantification methods are still evolving. Infrastructure development usually takes place in landscapes with preexist-ing anthropogenic features. Typically, their impact is determined by computing the distance to the nearest feature only, thus ignoring the potential cumulative impacts of ...
    • Fat storage influences fasting endurance more than body size in an ungulate 

      Trondrud, Liv Monica; Pigeon, Gabriel; Król, Elżbieta; Albon, Steve; Evans, Alina; Arnold, Walter; Hambly, Catherine; Irvine, R. Justin; Ropstad, Erik; Stien, Audun; Veiberg, Vebjørn; Speakman, John R.; Loe, Leif Egil (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-04-26)
      <ol> <li>The fasting endurance hypothesis (FEH) predicts strong selection for large body size in mammals living in environments where food supply is interrupted over prolonged periods of time. The Arctic is a highly seasonal and food restricted environment, but contrary to predictions from the FEH, empirical evidence shows that Arctic mammals are often smaller than their temperate conspecifics. ...
    • High goose abundance reduces nest predation risk in a simple rodent-free high-Arctic ecosystem 

      Pedersen, Åshild Ønvik; Stien, Jennifer; Eidesen, Pernille Bronken; Ims, Rolf Anker; Jepsen, Jane Uhd; Stien, Audun; Tombre, Ingunn; Fuglei, Eva (Journal article; Tidsskriftartikkel; Peer reviewed, 2017-12-13)
      Breeding geese are the preferred prey of the Arctic fox Vulpes lagopus in the high-Arctic Svalbard archipelago. According to the <i>apparent competition hypothesis (ACH)</i>, less-abundant prey species (e.g. ptarmigan, waders and small passerines) will experience higher predation rates when breeding in association with the more common prey (geese), due to spill-over predation by the shared predator. ...
    • High seasonal overlap in habitat suitability in a nonmigratory High Arctic ungulate 

      Pedersen, Åshild Ønvik; Soininen, Eeva M; Hansen, Brage Bremset; Le Moullec, Mathilde; Loe, Leif Egil; Paulsen, I.M.G.; Eischeid, Isabell; Karlsen, Stein Rune; Ropstad, Erik; Stien, Audun; Tarroux, Arnaud; Tømmervik, Hans; Ravolainen, Virve (Journal article; Tidsskriftartikkel; Peer reviewed, 2023-05-26)
      Understanding drivers of space use and habitat selection is essential for management and conservation, especially under rapid environmental change. Here, we develop summer and winter habitat suitability models for the endemic wild Svalbard reindeer (Rangifer tarandus platyrhynchus). The High Arctic Svalbard tundra is currently subject to the fastest temperature increases on Earth, and reindeer ...
    • How Many Reindeer? UAV Surveys as an Alternative to Helicopter or Ground Surveys for Estimating Population Abundance in Open Landscapes 

      Paulsen, Ingrid M.; Pedersen, Åshild Ø; Hann, Richard; Blanchet, Marie-Anne; Eischeid, Isabell; van Hazendonk, Charlotte Maartje; Ravolainen, Virve; Stien, Audun; Le Moullec, Mathilde (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-12-20)
      Conservation of wildlife depends on precise and unbiased knowledge on the abundance and distribution of species. It is challenging to choose appropriate methods to obtain a sufficiently high detectability and spatial coverage matching the species characteristics and spatiotemporal use of the landscape. In remote regions, such as in the Arctic, monitoring efforts are often resource-intensive and there ...
    • Kongeørn i Finnmark. Årsrapport 2012 

      Jacobsen, Karl Otto; Johnsen, Trond Vidar; Stien, Audun; Nygård, Torgeir; Kleven, Oddmund; Opgård, Olaf; Johansen, kenneth; Østlyngen, Arve; Myklevoll, Vidar (Research report; Forskningsrapport, 2013)
      Målet med prosjektet er å framskaffe økt kunnskap om bestanden av kongeørn i Finnmark. Gjennom å studere atferd, valg av byttedyr, reproduksjon og trekkmønster er kunnskapen nå betydelig forbedret. Kongeørna er studert over tolv feltsesonger (2001-2012) i de indre områdene av Porsanger, Karasjok og Tana. Det er også gjennomført studier i Alta og Kautokeino av rovfuglgruppa i Alta. I perioden ...
    • The neglected season: Warmer autumns counteract harsher winters and promote population growth in Arctic reindeer 

      Loe, Leif Egil; Liston, Glen E.; Pigeon, Gabriel; Barker, Kristin; Horvitz, Nir; Stien, Audun; Forchhammer, Mads C.; Getz, Wayne M.; Irvine, Robert Justin; Lee, Aline Magdalena; Movik, Lars K.; Mysterud, Atle; Pedersen, Åshild Ønvik; Reinking, Adele K.; Ropstad, Erik; Trondrud, Liv Monica; Tveraa, Torkild; Veiberg, Vebjørn; Hansen, Brage Bremset; Albon, Steve D. (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-11-24)
      Arctic ungulates are experiencing the most rapid climate warming on Earth. While concerns have been raised that more frequent icing events may cause die‐offs, and earlier springs may generate a trophic mismatch in phenology, the effects of warming autumns have been largely neglected. We used 25 years of individual‐based data from a growing population of wild Svalbard reindeer, to test how warmer ...