• Disturbance mapping in arctic tundra improved by a planning workflow for drone studies: Advancing tools for future ecosystem monitoring 

      Eischeid, Isabell; Soininen, Eeva M; Assmann, Jakob J.; Ims, Rolf Anker; Madsen, Jesper; Pedersen, Åshild Ø.; Pirotti, Francesco; Yoccoz, Nigel; Ravolainen, Virve T. (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-11-06)
      The Arctic is under great pressure due to climate change. Drones are increasingly used as a tool in ecology and may be especially valuable in rapidly changing and remote landscapes, as can be found in the Arctic. For effective applications of drones, decisions of both ecological and technical character are needed. Here, we provide our method planning workflow for generating ground-cover maps with ...
    • A Dynamic Occupancy Model for Interacting Species with Two Spatial Scales 

      Kleiven, Eivind Flittie; Barraquand, Frédéric; Gimenez, Olivier; Henden, John-André; Ims, Rolf Anker; Soininen, Eeva M; Yoccoz, Nigel (Journal article; Tidsskriftartikkel; Peer reviewed, 2023-04-10)
      Occupancy models have been extended to account for either multiple spatial scales or species interactions in a dynamic setting. However, as interacting species (e.g., predators and prey) often operate at different spatial scales, including nested spatial structure might be especially relevant to models of interacting species. Here we bridge these two model frameworks by developing a multi-scale, ...
    • Earlier Snowmelt Advances Breeding Phenology of the Common Frog (Rana temporaria) but Increases the Risk of Frost Exposure and Wetland Drying 

      Bison, Marjorie; Yoccoz, Nigel; Carlson, BZ; Klein, Geoffrey; Laigle, Idaline; Van Reeth, Colin; Delestrade, Anne (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-08-03)
      The alarming decline of amphibians around the world calls for complementary studies to better understand their responses to climate change. In mountain environments, water resources linked to snowmelt play a major role in allowing amphibians to complete tadpole metamorphosis. As snow cover duration has significantly decreased since the 1970s, amphibian populations could be strongly impacted by climate ...
    • 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 ...
    • Fjellrev i Finnmark” - Rapport for perioden 2008-2012. 

      Killengreen, Siw Turid; Ims, Rolf Anker; Henden, John-André; Yoccoz, Nigel; Ehrich, Dorothee (Research report; Forskningsrapport, 2013)
      Som et av to prosjekter i en stor nasjonal satsning for å redde den utrydningstruede fjellreven, ble «Fjellrev i Finnmark» startet opp våren 2004. Prosjektet har fra starten av hatt to hovedmålsettinger. 1)Å gjøre grunnleggende forskning på økosystembetingelser som begrenser fjellrevenbestandens nåværende utbredelse og bestandsvekst i Øst-Finnmark spesielt, og i sub- & lav-Arktis generelt, med ...
    • Food web approach for managing Arctic wildlife populations in an era of rapid environmental change 

      Mellard, Jarad; Henden, John-André; Pedersen, Åshild Ønvik; Marolla, Filippo; Hamel, Sandra; Yoccoz, Nigel; Ims, Rolf Anker (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-05-28)
      Scientists and wildlife managers implementing adaptive monitoring and management schemes, are tasked with providing predictions of population responses to harvest and environmental changes. Such predictions are useful not only to forecast direct effects of climate, productivity, land use, or habitat degradation, but also changes in the food web, such as expanding/increasing species that are predators, ...
    • Foraging tactics in dynamic sea-ice habitats affect individual state in a long-ranging seabird 

      Tarroux, Arnaud; Cherel, Yves; Fauchald, Per; Kato, Akiko; Love, Oliver P.; Ropert-Coudert, Yan; Spreen, Gunnar; Varpe, Øystein; Weimerskirch, Henri; Yoccoz, Nigel; Zahn, Sandrine; Descamps, Sebastien (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-07-13)
      <ol> <li>Individual heterogeneity in diet and foraging behaviour is common in wild animal populations, and can be a strong determinant of how populations respond to environmental changes. Within populations, variation in foraging behaviour and the occurrence of individual tactics in relation to resources distribution can help explain differences in individual fitness, and ultimately identify important ...
    • The ghost of development past : the impact of economic security policies on Saami pastoral ecosystems 

      Hausner, Vera Helene; Fauchald, Per; Tveraa, Torkild; Pedersen, Elisabeth; Jernsletten, Johnny-Leo L.; Ulvevadet, Birgitte; Ims, Rolf Anker; Yoccoz, Nigel; Bråthen, Kari Anne (Journal article; Tidsskriftartikkel; Peer reviewed, 2011)
      To ensure economic viability over time, any efforts to meet the Millennium Development Goals need to reconcile conservation with development interventions. Particularly, in marginal and risk prone areas erosion of resilience could make production systems more susceptible to environmental risks that compromise the economic security. By longitudinal analyses of long-term data records we investigated the ...
    • Grazing intensity drives a trophic shift in the diet of common alpine birds 

      Chiffard, Jules; Bentaleb, Ilham; Yoccoz, Nigel; Fourel, François; Blanquet, Elodie; Besnard, Aurélien (Journal article; Tidsskriftartikkel; Peer reviewed, 2023-02-18)
      Large mammalian herbivores (LMH) shape vertebrate communities and structure food webs in many terrestrial ecosystems. However, the mechanisms that underlie the effects of LMH on other vertebrates are poorly understood. In France, domestic LMH have grazed alpine and mountain grasslands for thousands of years, profoundly influencing landscapes and wildlife. As LMH modify habitat structure, favour ...
    • How spatial variation in areal extent and configuration of labile vegetation states affect the riparian bird community in Arctic Tundra 

      Henden, John-André; Yoccoz, Nigel; Ims, Rolf Anker; Langeland, Knut (Journal article; Tidsskriftartikkel; Peer reviewed, 2013)
      The Arctic tundra is currently experiencing an unprecedented combination of climate change, change in grazing pressure by large herbivores and growing human activity. Thickets of tall shrubs represent a conspicuous vegetation state in northern and temperate ecosystems, where it serves important ecological functions, including habitat for wildlife. Thickets are however labile, as tall shrubs respond ...
    • Impact of climatic change on alpine ecosystems: inference and prediction 

      Yoccoz, Nigel; Delestrade, Anne; Loison, Anne (Journal article; Tidsskriftartikkel; Peer reviewed, 2011-01-26)
      Alpine ecosystems will be greatly impacted by climatic change, but other factors, such as land use and invasive species, are likely to play an important role too. Climate can influence ecosystems at several levels. We describe some of them, stressing methodological approaches and available data. Climate can modify species phenology, such as flowering date of plants and hatching date in insects. It ...
    • The importance of willow thickets for ptarmigan and hares in shrub tundra : the more the better? 

      Ehrich, Dorothee; Henden, John-André; Ims, Rolf Anker; Doronina, Lilyia O; Killengreen, Siw Turid; Lecomte, Nicolas; Pokrovsky, Ivan; Skogstad, Gunhild; Sokolov, Alexander A.; Sokolov, Vasily A.; Yoccoz, Nigel (Journal article; Tidsskriftartikkel; Peer reviewed, 2012)
    • In-situ Temperature Stations Elucidate Species’ Phenological Responses to Climate in the Alps, but Meteorological and Snow Reanalysis Facilitates Broad Scale and Long-Term Studies 

      Laigle, Idaline; Carlson, Bradley Z.; Delestrade, Anne; Bison, Marjorie; Van Reeth, Colin; Yoccoz, Nigel (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-07-22)
      Linking climate variability and change to the phenological response of species is particularly challenging in the context of mountainous terrain. In these environments, elevation and topography lead to a diversity of bioclimatic conditions at fine scales affecting species distribution and phenology. In order to quantify in situ climate conditions for mountain plants, the CREA (Research Center ...
    • Incorporating capture heterogeneity in the estimation of autoregressive coefficients of animal population dynamics using capture–recapture data 

      Nicolau, Pedro Guilherme; Sørbye, Sigrunn Holbek; Yoccoz, Nigel (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-08-31)
      Population dynamic models combine density dependence and environmental effects. Ignoring sampling uncertainty might lead to biased estimation of the strength of density dependence. This is typically addressed using state‐space model approaches, which integrate sampling error and population process estimates. Such models seldom include an explicit link between the sampling procedures and the true ...
    • 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 ...
    • Influence of reproductive output on divorce rates in polar seabirds 

      Mercier, Guillaume; Yoccoz, Nigel; Descamps, Sébastien (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-09-15)
      The high occurrence of social monogamy in birds has led to questions about partner fidelity, or the perennial nature of monogamy from one breeding season to another. Despite the evolutionary advantages of partner fidelity, divorce occurs among 95% of bird species. We aimed to describe patterns of divorce and partner fidelity in five seabird species breeding in Arctic and Antarctic regions and ...
    • Integrated Methods for Monitoring the Invasive Potential and Management of Heracleum mantegazzianum (giant hogweed) in Switzerland 

      Shackleton, Ross T.; Petitpierre, Blaise; Pajkovic, Mila; Dessimoz, Florian; Brönnimann, Olivier; Cattin, Loïc; Čejková, Šárka; Pergl, Jan; Pyšek, Petr; Yoccoz, Nigel; Guisan, Antoine (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-03-23)
      Biological invasions are a major driver of human-induced global environmental change. This makes monitoring of potential spread, population changes and control measures necessary for guiding management. We illustrate the value of integrated methods (species distribution modelling (SDM), plant population monitoring and questionnaires) for monitoring and assessing invasions of Heracleum mantegazzianum ...
    • Intrapopulation variability shaping isotope discrimination and turnover : experimental evidence in Arctic Foxes 

      Lecomte, Nicolas; Ahlstrøm, Øystein Jan; Ehrich, Dorothee; Fuglei, Eva; Ims, Rolf Anker; Yoccoz, Nigel (Journal article; Tidsskriftartikkel; Peer reviewed, 2011)
      Tissue-specific stable isotope signatures can provide insights into the trophic ecology of consumers and their roles in food webs. Two parameters are central for making valid inferences based on stable isotopes, isotopic discrimination (difference in isotopic ratio between consumer and its diet) and turnover time (renewal process of molecules in a given tissue usually measured when half of the tissue ...
    • Kunnskapsstatus for bruk av molekylære verktøy i kartlegging og overvåkning av biologisk mangfold i marine miljø 

      Dunshea, Glenn; Martell, Luis; Bakken, Torkild; Budaeva, Nataliya; Ekrem, Torbjørn; Tandberg, Anne Helene S.; Baussant, Thierry; de Boer, Hugo; Hestetun, Jon Thomassen; Hobæk, Anders; Kallioniemi, Eveliina; Larsen, Aud; Markussen, Stine Svalheim; Mauvisseau, Quentin; Ray, Jessica Louise; Yoccoz, Nigel; Willassen, Endre (Research report; Forskningsrapport, 2021-06-02)
      Denne rapporten er bestilt av Miljødirektoratet fra NorBOL (Norwegian Barcode of Life), et nasjonalt nettverk av forskningsinstitusjoner som koordineres av NTNU Vitenskapsmuseet. Universitetsmuseet i Bergen har hatt prosjektledelsen. Rapporten gir en oppsummering av dagens status på DNA-basert metodikk som verktøy i kartlegging og overvåking av biologisk mangfold i det marine miljø. Fokus har vært ...