Blar i NTNU Open på forfatter "Stien, Audun"
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An integrated population model for a long-lived ungulate: more efficient data use with Bayesian methods
Lee, Aline Magdalena; Bjørkvoll, Eirin Marie; Hansen, Brage Bremset; Albon, Steve D.; Stien, Audun; Sæther, Bernt-Erik; Engen, Steinar; Veiberg, Vebjørn; Loe, Leif Egil; Grøtan, Vidar (Journal article, 2015)We develop an integrated population model for Svalbard reindeer Rangifer tarandus platyrhynchus, and demonstrate how this type of model can be used to extract more information from the data and separate different sources ... -
Behavioral buffering of extreme weather events in a high-Arctic herbivore
Loe, Leif Egil; Hansen, Brage Bremset; Stien, Audun; Albon, Steve D.; Bischof, Richard; Carlsson, Anja M.; Irvine, Justin; Meland, Morten; Rivrud, Inger Maren; Ropstad, Erik; Veiberg, Vebjørn; Mysterud, Atle (Journal article; Peer reviewed, 2016)As global warming advances, there is a growing concern about the impact of extreme weather events on ecosystems. In the Arctic, more frequent unseasonal warm spells and rain-on- snow events in winter cause changes in ... -
Climate and density-dependence cause changes in adult sex ratio in a large Arctic herbivore
Peeters, Bart; Veiberg, Vebjørn; Pedersen, Åshild Ønvik; Stien, Audun; Irvine, Robert Justin; Aanes, Ronny; Sæther, Bernt-Erik; Strand, Olav; Hansen, Brage Bremset (Journal article; Peer reviewed, 2017)Variation in adult sex ratio (ASR) affects population demography and dynamics of large mammals. The mechanisms behind this variation are largely unclear, but may be partly related to climatic drivers and density dependence ... -
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 (Journal article; Peer reviewed, 2013)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, ... -
Contrasting effects of summer and winter warming onbody mass explain population dynamics in a food-limitedArctic herbivore
Albon, Steve D.; Irvine, R. Justin; Halvorsen, Odd; Langvatn, Rolf; Loe, Leif Egil; Ropstad, Erik; Veiberg, Vebjørn; van der Wal, René; Bjørkvoll, Eirin Marie; Duff, Elizabeth I.; Hansen, Brage Bremset; Lee, Aline Magdalena; Tveraa, Torkild; Stien, Audun (Journal article; Peer reviewed, 2016)The cumulative effects of climate warming on herbivore vital rates and population dynamics are hard to predict, given that the expected effects differ between seasons. In the Arctic, warmer summers enhance plant growth ... -
Demographic buffering of life histories? Implications of the choice of measurement scale
Bjørkvoll, Eirin Marie; Lee, Aline Magdalena; Grøtan, Vidar; Sæther, Bernt-Erik; Stien, Audun; Engen, Steinar; Albon, Steve D.; Loe, Leif Egil; Hansen, Brage Bremset (Journal article; Peer reviewed, 2016)Life-history theory predicts that the vital rates that influence population growth the most should be buffered against environmental fluctuations due to selection for reduced variation. However, it remains unclear whether ... -
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 (Peer reviewed; Journal article, 2021)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 ... -
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 (Peer reviewed; Journal article, 2023)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 ... -
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 (Peer reviewed; Journal article, 2023)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 ... -
Low spatial habitat overlap of herbivores in the High Arctic tundra
Ravolainen, Virve; Paulsen, Ingrid Marie Garfelt; Eischeid, Isabell; Forbey, Jennifer Sorensen; Fuglei, Eva; Hájek, Tomás; Hansen, Brage Bremset; Loe, Leif Egil; Macek, Petr; Madsen, Jesper; Soininen, Eeva M; Speed, James David Mervyn; Stien, Audun; Tømmervik, Hans; Pedersen, Åshild Ønvik (Journal article; Peer reviewed, 2024)Herbivores play a crucial role in shaping tundra ecosystems through their effects on vegetation, nutrient cycling, and soil abiotic factors. Understanding their habitat use, co-occurrence, and overlap is therefore essential ... -
Modellering av tap av tamrein til rovvilt - en risikomodell
Herfindal, Ivar; Brøseth, Henrik; Kjørstad, Morten Andre; Linnell, John Durrus; Odden, John; Persson, Jens; Stien, Audun; Tveraa, Torkild; Ersson, L. (NINA rapport;819, Research report, 2012)I januar 2011 fikk NINA i oppdrag av Direktoratet for naturforvaltning (DN) å vurdere om tilgjengelige forskningsdata kunne brukes til modellering av risikobasert erstatning for tap av tamrein til rovvilt. Oppdraget ble ... -
More frequent extreme climate events stabilize reindeer population dynamics
Hansen, Brage Bremset; Gamelon, Marlène; Albon, Steve D.; Lee, Aline Magdalena; Stien, Audun; Irvine, Robert Justin; Sæther, Bernt-Erik; Loe, Leif Egil; Ropstad, Erik; Veiberg, Vebjørn; Grøtan, Vidar (Journal article; Peer reviewed, 2019)Extreme climate events often cause population crashes but are difficult to account for in population-dynamic studies. Especially in long-lived animals, density dependence and demography may induce lagged impacts of ... -
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. (Peer reviewed; Journal article, 2020)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, ... -
Spatiotemporal patterns of rain-on-snow and basal ice in high Arctic Svalbard: detection of a climate-cryosphere regime shift
Peeters, Bart; Pedersen, Åshild Ønvik; Loe, Leif Egil; Isaksen, Ketil; Veiberg, Vebjørn; Stien, Audun; Kohler, Jack; gallet, jean-charles; Aanes, Ronny; Hansen, Brage Bremset (Journal article; Peer reviewed, 2018)Arctic winters have become increasingly warmer and rainier. Where permafrost prevails, winter rain (or rain-on-snow; ROS) is known to occasionally cause extensive ice layers at the snow/ground interface, i.e. "basal ice" ... -
Spatiotemporal variation in abundance of key tundra species: from local heterogeneity to large-scale synchrony
Le Moullec, Mathilde (Doctoral theses at NTNU;2019:20, Doctoral thesis, 2019)Summary of thesis: From local heterogeneity to large-scale synchrony of wildlife abundance in the high Arctic. The Arctic is a ‘hot-spot’ for climate change, and understanding its impacts on tundra ecosystems will ... -
Stress responses to repeated captures in a wild ungulate
Trondrud, Liv Monica; Ugland, Cassandra Regine; Ropstad, Erik; Loe, Leif Egil; Albon, Steve; Stien, Audun; Evans, Alina; Thorsby, Per Medbøe; Veiberg, Vebjørn; Irvine, R. Justin; Pigeon, Gabriel (Peer reviewed; Journal article, 2022)While capture-mark-recapture studies provide essential individual-level data in ecology, repeated captures and handling may impact animal welfare and cause scientific bias. Evaluating the consequences of invasive methodologies ...