Blar i Publikasjoner fra CRIStin - NINA på forfatter "Tømmervik, Hans"

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    • 175 years of adaptation: North Scandinavian Sámi reindeer herding between government policies and winter climate variability (1835–2010) 

      Riseth, Jan Åge; Tømmervik, Hans; Bjerke, Jarle W. (Journal article; Peer reviewed, 2016)
      Unmanaged wild reindeer populations tend to follow cyclical behaviour, and domesticatedreindeer populations often show cyclical behaviour, too. In this contribution, we intendto use the long-term development of two areas ...

    • Alpine garden plants from six continents show high vulnerability to ice encasement 

      Bjerke, Jarle W.; Elvebakk, Arve; Tømmervik, Hans (Journal article; Peer reviewed, 2017)
      Icy surfaces impose challenges for northern societies, wildlife and agriculture. However, there have been relatively few studies of the impacts of anoxic ground ice on non-agricultural plants. During the winter of 2009–2010, ...

    • Arctic greening from warming promotes declines in caribou populations 

      Fauchald, Per; Park, Taejin; Tømmervik, Hans; Myneni, Ranga B.; Hausner, Vera Helene (Journal article; Peer reviewed, 2017)
      Themigratory tundra caribou herds in North America follow decadal population cycles, and browsing from abundant caribou could be expected to counteract the current climate-driven expansion of shrubs in the circumpolar ...

    • An artificial intelligence approach to remotely assess pale lichen biomass 

      Erlandsson, Rasmus Ingel; Bjerke, Jarle W.; Finne, Eirik Aasmo; Myneni, Ranga B.; Piao, Shilong; Wang, Xuhui; Virtanen, Tarmo; Räsänen, Aleksi; Kumpula, Timo; Kolari, Tiina H.M.; Tahvanainen, Teemu; Tømmervik, Hans (Peer reviewed; Journal article, 2022)
      Although generally given little attention in vegetation studies, ground-dwelling (terricolous) lichens are major contributors to overall carbon and nitrogen cycling, albedo, biodiversity and biomass in many high-latitude ...

    • Biologisk mangfold. Bardu kommune 

      Strann, Karl Birger; Frivoll, Vigdis Irene; Iversen, Marianne; Tømmervik, Hans; Johnsen, Trond Vidar (NINA Rapport;58, Research report, 2005)
      Strann, K.-B., Frivoll, V., Iversen, M., Tømmervik, H. & Johnsen, T. 2005. Biologisk mangfold. Bardu kommune - NINA Rapport 58. 165 pp. Stortingsmelding nr. 42 (2000-2001) pålegger den enkelte sektor å gjennomføre ...

    • Bruk av fjernmåling i palsmyrovervåking 

      Lauknes, Tom Rune; Larsen, Yngvar; Høgda, Kjell-Arild; Tømmervik, Hans; Hofgaard, Annika (NINA rapport;803, Research report, 2012)
      Lauknes, T.R., Larsen, Y., Høgda, K.A., Tømmervik, H. & Hofgaard, A. 2012. Bruk av fjernmåling i palsmyrovervåking. – NINA Rapport 803. 38 s. Et fjernmålingsbasert pilotstudium som bruker flybilder, satellittbilder med ...

    • Changes in greening in the High Arctic - insights from a 30-year AVHRR max NDVI dataset for Svalbard 

      Vickers, Hannah; Høgda, Kjell Arild; Solbø, Stian; Karlsen, Stein Rune; Tømmervik, Hans; Aanes, Ronny; Hansen, Brage Bremset (Journal article; Peer reviewed, 2016)
      Satellite-aided studies of vegetation cover, biomass and productivity are becoming increasingly important formonitoring the effects of a changing climate on the biosphere. With their large spatial coverage and good temporal ...

    • Changes in growing season duration and productivity of northern vegetation inferred from long-term remote sensing data 

      Park, Taejin; Ganguly, Sangram; Tømmervik, Hans; Euskirchen, Eugénie S.; Høgda, Kjell Arild; Karlsen, Stein Rune; Brovkin, Victor; Nemani, Ramakrishna R.; Myneni, Ranga B. (Journal article; Peer reviewed, 2016)
      Monitoring and understanding climate-induced changes in the boreal and arctic vegetation is critical to aid in prognosticating their future.Weused a 33 year (1982–2014) long record of satellite observations to robustly ...

    • Changes in timing of seasonal peak photosynthetic activity in northern ecosystems 

      Park, Taejin; Chen, Chi; Macias-Fauria, Marc; Tømmervik, Hans; Choi, Sungho; Winkler, Alexander; Bhatt, Uma S.; Walker, Donald A.; Piao, Shilong; Brovkin, Victor; Nemani, Ramakrishna R.; Myneni, Ranga B. (Journal article; Peer reviewed, 2019)
      Seasonality in photosynthetic activity is a critical component of seasonal carbon, water and energy cycles in the Earth system. This characteristic is a consequence of plant’s adaptive evolutionary processes to a given set ...

    • Changes in winter warming events in the Nordic Arctic Region 

      Vikhamar-Schuler, Dagrun; Isaksen, Ketil; Haugen, Jan Erik; Tømmervik, Hans; Luks, Bartlomiej; Schuler, Thomas Vikhamar; Bjerke, Jarle W. (Journal article; Peer reviewed, 2016)
      In recent years extreme winter warming events have been reported in arctic areas. These events are characterized as extraordinarily warm weather episodes, occasionally combined with intense rainfall, causing ecological ...

    • China and India lead in greening of the world through land-use management 

      Chen, Chi; Park, Taejin; Wang, Xuhui; Piao, Shilong; Xu, Baodong; Chaturvedi, Rajiv K.; Fuchs, Richard; Brovkin, Victor; Ciais, Philippe; Fensholt, Rasmus; Tømmervik, Hans; Bala, Govindasamy; Zhu, Zaichun; Nemani, Ramakrishna R.; Myneni, Ranga B. (Journal article; Peer reviewed, 2019)
      Satellite data show increasing leaf area of vegetation due to direct factors (human land-use management) and indirect factors (such as climate change, CO2 fertilization, nitrogen deposition and recovery from natural ...

    • Complexity revealed in the greening of the Arctic 

      Myers-Smith, Isla H.; Kerby, Jeffrey T.; Phoenix, Gareth K.; Bjerke, Jarle W.; Epstein, Howard E.; Assmann, Jakob J.; John, Christian; Andreu-Hayles, Laia; Angers-Blondin, Sandra; Beck, Pieter S. A.; Berner, Logan T.; Bhatt, Uma S.; Bjorkman, Anne D.; Blok, Daan; Bryn, Anders; Christiansen, Casper Tai; Cornelissen, J. Hans C.; Cunliffe, Andrew M.; Elmendorf, Sarah C.; Forbes, Bruce C.; Goetz, Scott J.; Hollister, Robert D.; de Jong, Rogier; Loranty, Michael M.; Macias-Fauria, Marc; Maseyk, Kadmiel; Normand, Signe; Olofsson, Johan; Parker, Thomas C.; Parmentier, Frans-Jan W.; Post, Eric; Schaepman-Strub, Gabriela; Stordal, Frode; Sullivan, Patrick F.; Thomas, Haydn J.D.; Tømmervik, Hans; Treharne, Rachael; Tweedie, Craig E.; Walker, Donald A.; Wilmking, Martin; Wipf, Sonja (Journal article; Peer reviewed, 2020)
      As the Arctic warms, vegetation is responding, and satellite measures indicate widespread greening at high latitudes. This ‘greening of the Arctic’ is among the world’s most important large-scale ecological responses to ...

    • Critical seasonal conditions in the reindeer-herding year: A synopsis of factors and events in Fennoscandia and north-western Russia 

      Laptander, Roza; Horstkotte, Tim; Habeck, Joachim Otto; Rasmus, Sirpa; Komu, Teresa; Matthes, Heidrun; Tømmervik, Hans; Istomin, Kirill; Eronen, Jussi T.; Forbes, Bruce C. (Peer reviewed; Journal article, 2023)
      In this article, we identify what herders in Fennoscandia and northwestern Russia see as critical conditions and events in the annual reindeer herding cycle. Indigenous S´ami and Yamal reindeer herders identify eight ...

    • Distribution and population characteristics of the soil mites Diapterobates notatus and Svalbardia paludicola (Acari: Oribatida: Ceratozetidae) in High Arctic Svalbard (Norway) 

      Seniczak, Stanislaw; Seniczak, Anna; Graczyk, Radomir; Tømmervik, Hans; Coulson, Stephen James (Journal article; Peer reviewed, 2017)
      The Oribatida of High Arctic Svalbard are faunistically relatively well known, but the distribution, density, stage structure and other population parameters of most species are unknown. Here we focus on two ceratozetid ...

    • Ecosystem change and stability over multiple decades in the Swedish subarctic: complex processes and multiple drivers 

      Callaghan, Terry V.; Jonasson, Christer; Thierfelder, Tomas; Yang, Zhenlin; Hedenås, Henrik; Johansson, Margareta; Molau, Ulf; Van Bogaert, Rik; Michelsen, Anders; Olofsson, Johan; Gwynn-Jones, Dylan; Bokhorst, Stef; Phoenix, Gareth K.; Bjerke, Jarle Werner; Tømmervik, Hans; Christensen, Torben R.; Hanna, Edward; Koller, Eva K.; Sloan, Victoria L. (Journal article; Peer reviewed, 2013)
      The subarctic environment of northernmost Sweden has changed over the past century, particularly elements of climate and cryosphere. This paper presents a unique geo-referenced record of environmental and ecosystem ...

    • The ecosystem effects of reindeer (Rangifer tarandus) in northern Fennoscandia: Past, present and future 

      Stark, Sari; Horstkotte, Tim; Kumpula, Jouko; Olofsson, Johan; Tømmervik, Hans; Turunen, Minna (Peer reviewed; Journal article, 2022)
      The semi-domesticated nature of the reindeer (Rangifer tarandus L.) makes it a distinct case among the world’s herbivores. Here, we review the literature on how reindeer shape vegetation and soil carbon and nitrogen cycles ...

    • Ecosystem response to climatic change: the importance of the cold season 

      Bokhorst, Stef; Bjerke, Jarle Werner; Tømmervik, Hans; Preece, Catherine; Phoenix, Gareth K. (Journal article; Peer reviewed, 2012)
      Winter climate and snow cover are the important drivers of plant community development in polar regions. However, the impacts of changing winter climate and associated changes in snow regime have received much less attention ...

    • Estimating lichen volume and reindeer winter pasture quality from Landsat imagery 

      Falldorf, Tobias; Strand, Olav; Panzacchi, Manuela; Tømmervik, Hans (Peer reviewed; Journal article, 2014)
      Reindeer and caribou are keystone species in the circumpolar region, and rely on lichens as their main winter forage to survive in some of the most extreme environments on Earth. Lichen mats, however, can be heavily ...

    • Extreme event impacts on CO2 fluxes across a range of high latitude, shrub-dominated ecosystems 

      Treharne, Rachael; Bjerke, Jarle W.; Tømmervik, Hans; Phoenix, Gareth K. (Peer reviewed; Journal article, 2020)
      The Arctic is experiencing an increased frequency of extreme events which can cause landscape-scale vegetation damage. Extreme event-driven damage is an important driver of the decline in vegetation productivity (termed ...

    • Feasibility of active handheld NDVI sensors for monitoring of lichen ground cover 

      Erlandsson, Rasmus; Arneberg, Marit Klemetsen; Tømmervik, Hans; Finne, Eirik Aasmo; Nilsen, Lennart; Bjerke, Jarle W. (Peer reviewed; Journal article, 2023)
      Vegetation indices are corner stones in vegetation monitoring. However, previous field studies on lichens and NDVI have been based on passive sensors. Active handheld sensors, with their own light sources, enables high- ...