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

      Bjerke, Jarle W.; Elvebakk, Arve; Tømmervik, Hans (Journal article; Tidsskriftartikkel; Peer reviewed, 2017-10-27)
      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, an extreme winter warming event led to thick ground-ice layer development in the world’s northernmost botanical garden in Tromsø, in subarctic Norway, due to much rain on ...
    • Changing Arctic snow cover: A review of recent developments and assessment of future needs for observations, modelling, and impacts 

      Bokhorst, Stef; Pedersen, Stine Højlund; Brucker, Ludovic; Anisimov, Oleg; Bjerke, Jarle W.; Brown, Ross D.; Ehrich, Dorothee (Journal article; Tidsskriftartikkel; Peer reviewed, 2016-03-17)
      Snow is a critically important and rapidly changing feature of the Arctic. However, snow-cover and snowpack conditions change through time pose challenges for measuring and prediction of snow. Plausible scenarios of how Arctic snow cover will respond to changing Arctic climate are important for impact assessments and adaptation strategies. Although much progress has been made in understanding ...
    • 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; Tidsskriftartikkel; Peer reviewed, 2020-01-31)
      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 global climate change. However, a consensus is emerging that the underlying causes and future dynamics of so-called Arctic greening and browning trends are more complex, variable ...
    • Contrasting survival and physiological responses of sub-Arctic plant types to extreme winter warming and nitrogen 

      Bokhorst, Stef; Jaakola, Laura; Karppinen, Katja; Edvinsen, Guro Kristine; Mæhre, Hanne Kirsti; Bjerke, Jarle W. (Journal article; Tidsskriftartikkel; Peer reviewed, 2017-11-21)
      Evergreen plants are more vulnerable than grasses and birch to snow and temperature variability in the sub-Arctic. Most Arctic climate impact studies focus on single factors, such as summer warming, while ecosystems are exposed to changes in all seasons. Through a combination of field and laboratory manipulations, we compared physiological and growth responses of dominant sub-Arctic plant types to ...
    • 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. (Journal article; Tidsskriftartikkel; Peer reviewed, 2023-03-04)
      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- precision monitoring under variable ambient conditions. We investigated the use of handheld sensor NDVI for monitoring pale lichen cover across three study sites from boreal heathlands ...
    • Global economic drivers in the development of different industrial hubs in the European Arctic 

      Suopajärvi, Leena; Nygaard, Vigdis; Edvardsdóttir, AG; Iversen, Audun; Kyllönen, Katri-Maaria; Lesser, Pamela; Lindestav, Gun; Moioli, Sara; Nojonen, Matti; Olafsdottir, Ragnheidur; Bergström, D; Bjerke, Jarle W.; Bogadóttir, Rangheiour; Elomina, Jerbelle; Engen, Sigrid; Koivurova, Timo; Leppiaho, Toumas; Lynge-Pedersen, K; Rantala, Outi; Siikavuopio, Sten Ivar; Skum, Marja-Kristin; Tuulentie, Seija; Tømmervik, Hans (Research report; Forskningsrapport, 2022-03)
      This project report discusses global drivers affecting the development of key industries in the European Arctic (EA). Aquaculture is important for littoral states in the North, forestry and mining for northern Scandinavia, and tourism throughout the northern regions in the EA, and all are affected by globalization. Globalization is not a homogeneous, uniform phenomenon, but consists of various global ...
    • Global maps of soil temperature 

      Lembrechts, Jonas J.; van den Hoogen, Johan; Aalto, Juha; Ashcroft, Michael B.; De Frenne, Pieter; Kemppinen, Julia; Kopecký, Martin; Luoto, Miska; Maclean, Ilya M. D.; Crowther, Thomas W.; Bailey, Joseph J.; Haesen, Stef; Klinges, David H.; Niittynen, Pekka; Scheffers, Brett R.; Van Meerbeek, Koenraad; Aartsma, Peter; Abdalaze, Otar; Abedi, Mehdi; Aerts, Rien; Ahmadian, Negar; Ahrends, Antje; Alatalo, Juha M.; Alexander, Jake M.; Altman, Jan; Allonsius, Camille Nina; Ammann, Christof; Andres, Christian; Andrews, Christopher; Ardö, Jonas; Arriga, Nicola; Arzac, Alberto; Aschero, Valeria; Leandro de Assis, Rafael; Bjerke, Jarle W.; Cooper, Elisabeth J.; Graae, Bente Jessen; Rechsteiner, Aud Helen Halbritter; Haugum, Siri Vatsø; Lang, Simone; Lynn, Joshua Scott; Moriana Armendariz, Mikel; Petit Bon, Matteo; Smith, Stuart; Sørensen, Mia Vedel; Speed, James David Mervyn; Vandvik, Vigdis; Wedegärtner, Ronja Elisabeth Magdalene; Nijs, Ivan; Lenoir, Jonathan (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-12-29)
      Research in global change ecology relies heavily on global climatic grids derived from estimates of air temperature in open areas at around 2 m above the ground. These climatic grids do not reflect conditions below vegetation canopies and near the ground surface, where critical ecosystem functions occur and most terrestrial species reside. Here, we provide global maps of soil temperature and bioclimatic ...
    • Global maps of soil temperature 

      Lembrechts, Jonas J.; van den Hoogen, Johan; Aalto, Juha; Ashcroft, Michael B.; de Frenne, Pieter; Kemppinen, Julia; Kopecký, Martin; Luoto, Miska; Maclean, Ilya M. D.; Crowther, Thomas W.; Bailey, Joseph J.; Haesen, Stef; Klinges, David H.; Niittynen, Pekka; Scheffers, Brett R.; Van Meerbeek, Koenraad; Aartsma, Peter; Abdalaze, Otar; Abedi, Mehdi; Aerts, Rien; Ahmadian, Negar; Ahrends, Antje; Alatalo, Juha M.; Alexander, Jake M.; Allonsius, Camille Nina; Altman, Jan; Ammann, Christof; Andres, Christian; Andrews, Christopher; Ardö, Jonas; Arriga, Nicola; Arzac, Alberto; Aschero, Valeria; Leandro de Assis, Rafael; Barančok, Peter; Barrio, Isabel C; Barros, Agustina; Lenoir, Jonathan; Assmann, Jakob Johann; Bader, Maaike Y.; Bahalkeh, Khadijeh; Basham, Edmund W.; Bauters, Marijn; Bazzichetto, Manuele; Marchesini, Luca Belelli; Bell, Michael C.; Benavides, Juan C.; Alonso, José Luis Benito; Berauer, Bernd J.; Bjerke, Jarle W.; Björk, Robert G.; Björkman, Mats P.; Björnsdóttir, Katrin; Blonder, Benjamin; Boeckx, Pascal; Boike, Julia; Bokhorst, Stef; Brum, Bárbara N.S.; Brůna, Josef; Buchmann, Nina; Buysse, Pauline; Camargo, José Luís; Campoe, Otávio C.; Candan, Onur; Canessa, Rafaella; Cannone, Nicoletta; Carbognani, Michele; Carnicer, Jofre; Casanova-Katny, Angélica; Cesarz, Simone; Chojnicki, Bogdan; Choler, Philippe; Chown, Steven L.; Cifuentes, Edgar F.; Čiliak, Marek; Contador, Tamara; Convey, Peter; Cooper, Elisabeth (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-12-29)
      Research in global change ecology relies heavily on global climatic grids derived from estimates of air temperature in open areas at around 2 m above the ground. These climatic grids do not reflect conditions below vegetation canopies and near the ground surface, where critical ecosystem functions occur and most terrestrial species reside. Here, we provide global maps of soil temperature and bioclimatic ...
    • High tolerance of a high-arctic willow and graminoid to simulated ice encasement 

      Bjerke, Jarle W.; Elverland, Ellen; Jaakola, Laura; Lund, Leidulf; Zagajewski, Bogdan; Bochenek, Zbigniew; Kłos, Andrzej; Tømmervik, Hans (Journal article; Tidsskriftartikkel; Peer reviewed, 2018-12-17)
      Climate change-induced snow thaw and subsequent accumulation of ice on the ground is a potential, major threat to snow-dominated ecosystems. While impacts of ground-ice on arctic wildlife are well explored, the impacts on tundra vegetation is far from understood. We therefore tested the vulnerability of two high-arctic plants, the prostrate shrub <i>Salix polaris</i> and the graminoid <i>Luzula ...
    • Impact of Multiple Ecological Stressors on a Sub-Arctic Ecosystem: No Interaction Between Extreme Winter Warming Events, Nitrogen Addition and Grazing 

      Bokhorst, Stef; Berg, Matty P.; Edvinsen, Guro Kristine; Ellers, Jacintha; Heitman, Amber; Jaakola, Laura; Mæhre, Hanne K; Phoenix, Gareth K.; Tømmervik, Hans; Bjerke, Jarle W. (Journal article; Tidsskriftartikkel; Peer reviewed, 2018-11-30)
      Climate change is one of many ongoing human-induced environmental changes, but few studies consider interactive effects between multiple anthropogenic disturbances. In coastal sub-arctic heathland, we quantified the impact of a factorial design simulating extreme winter warming (WW) events (7 days at 6–7∘C) combined with episodic summer nitrogen (+N) depositions (5 kg N ha-1) on plant winter physiology, ...
    • The lichen Allocetraria madreporiformis in high-arctic steppes on Svalbard: a result of out-of-Tibet migration? 

      Elvebakk, Arve; Bjerke, Jarle W.; Nilsen, Lennart (Journal article; Tidsskriftartikkel; Peer reviewed, 2018-01-29)
      <i>Allocetraria madreporiformis</i> is a small, finger-like, fruticose lichen with isolated occurrences in the inner fiord section of the long, straight fiord Wijdefjorden in Svalbard. Several new localities are added and mapped here, and we show that the species is confined to exclusive high-arctic steppe habitats on finetextured, moderately alkaline soil, exposed to wind erosion and aeolian transport ...
    • The northernmost hyperspectral FLoX sensor dataset for monitoring of high-Arctic tundra vegetation phenology and Sun-Induced Fluorescence (SIF) 

      Tømmervik, Hans; Julitta, Tommaso; Nilsen, Lennart; Park, Taejin; Burkart, Andreas; Ostapowicz, Katarzyna Anna; Karlsen, Stein Rune; Parmentier, Frans-Jan W.; Pirk, Norbert; Bjerke, Jarle W. (Journal article; Tidsskriftartikkel; Peer reviewed, 2023-09-16)
      A hyperspectral field sensor (FloX) was installed in Adventdalen (Svalbard, Norway) in 2019 as part of the Svalbard Integrated Arctic Earth Observing System (SIOS) for monitoring vegetation phenology and Sun-Induced Chlorophyll Fluorescence (SIF) of high-Arctic tundra. This northernmost hyperspectral sensor is located within the footprint of a tower for long-term eddy covariance flux measurements ...
    • Snefjord Vindpark. Vurdering av konsekvenser for landskap, flora, fauna, friluftsliv, kulturminner og reindriftsnæring 

      Tombre, Ingunn; Andersen, Oddgeir; Barlindhaug, Stine; Bjerke, Jarle W.; Erikstad, Lars; Frivoll, Vigdis Irene; Johnsen, Trond Vidar; Sloreid, Svein Erik; Strann, Karl Birger; Svestad, Asgeir; Tømmervik, Hans (Research report; Forskningsrapport, 2005-02)
      This report summarises consequences of a planned wind park at the Sneqord peninsula, Måsøy municipality. Impact assessments are conducted for landscape perspectives, flora, fauna, outdoor recreation, cultural heritage and reindeer herding. The whole peninsula, 150 km2. is evaluated, with the main focus on higher parts where the potential wind turbines will be located. For the landscape, a wind park ...
    • Sub-arctic mosses and lichens show idiosyncratic responses to combinations of winter heatwaves, freezing and nitrogen deposition 

      Bokhorst, Stef; Bjerke, Jarle W.; Phoenix, Gareth K.; Jaakola, Laura; Mæhre, Hanne; Tømmervik, Hans (Journal article; Tidsskriftartikkel; Peer reviewed, 2023-02-25)
      Arctic ecosystems are increasingly exposed to extreme climatic events throughout the year, which can affect species performance. Cryptogams (bryophytes and lichens) provide important ecosystem services in polar ecosystems but may be physiologically affected or killed by extreme events. Through field and laboratory manipulations, we compared physiological responses of seven dominant sub-Arctic ...
    • Use of unmanned aircraft systems (UAS) in a multi-scale vegetation index study of arctic plant communities in Adventdalen on Svalbard 

      Tømmervik, Hans; Karlsen, Stein-Rune; Nilsen, Lennart; Johansen, Bernt; Storvold, Rune; Zmarz, Anna; Beck, Pieter S.; Høgda, Kjell Arild; Goetz, Scott; Park, Taejin; Zagajewski, Bogdan; Myneni, Ranga B.; Bjerke, Jarle W. (Journal article; Tidsskriftartikkel; Peer reviewed, 2014)
      Use of Unmanned Aircraft Systems (UAS) gives the opportunity to carry out research with a re-duced environmental footprint. Unmanned aircraft, including both fixed wing and multi rotor types (helicopters) allow us to collect very high resolution image data for vegetation mapping without the need for any personnel walking into the site and thereby potentially disturbing the sensitive Arctic ecosystems. ...
    • Winters are changing: snow effects on Arctic and alpine tundra ecosystems 

      Rixen, Christian; Høye, Toke Thomas; Macek, Petr; Aerts, Rien; Alatalo, Juha; Andeson, Jill; Arnold, Pieter; Barrio, Isabel C.; Bjerke, Jarle W.; Björkman, Mats P.; Blok, Daan; Blume-werry, Gesche; Boike, Julia; Bokhorst, Stef; Carbognani, Michele; Christiansen, Casper Tai; Convey, Peter; Cooper, Elisabeth J.; Cornelissen, J. Hans C.; Coulson, Stephen; Dorrepaal, Ellen; Elberling, Bo; Elmendorf, Sarah; Elphinstone, Cassandra; Forte, T'ai Gladys Whittingham; Frei, Esther R.; Geange, Sonya Rita; Gehrmann, Friederike; Gibson, Casey; Grogan, Paul; Rechsteiner, Aud Helen Halbritter; Harte, John; Henry, Greg H.R.; Inouye, David W.; Irwin, Rebecca; Jespersen, Gus; Jónsdóttir, Ingibjörg Svala; Jung, Ji Young; Klinges, David H.; Kudo, Gaku; Lämsä, Juho; Lee, Hanna; Lembrechts, Jonas; Lett, Signe; Lynn, Joshua Scott; Mann, Hjalte Mads; Mastepanov, Mikhail; Morse, Jennifer; Myers-Smith, Isla; Olofsson, Johan; Semenchuk, Philipp; Vandvik, Vigdis (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-02-18)
      Snow is an important driver of ecosystem processes in cold biomes. Snow accumulation determines ground temperature, light conditions and moisture availability during winter. It also affects the growing season’s start and end, and plant access to moisture and nutrients. Here, we review the current knowledge of the snow cover’s role for vegetation, plant-animal interactions, permafrost conditions, ...
    • Økologiske konsekvenser av restaurering av elveforbygninger og avsnørte meandre ved Bones, Salangselva. Sluttrapport 2003-2009 

      Strann, Karl Birger; Rikardsen, Audun H.; Bjerke, Jarle W.; Dahl-Hansen, Geir (Research report; Forskningsrapport, 2010-04)
      I 2006 og 2007 ble deler av de eldre elveforbygningene ved Bones i Salangselva i Troms restaurert. Et eldre elveløp samt et større meander ble igjen åpnet for vann-gjennomstrømning samt at det ble gjennomført flere mindre justeringer på det gam-le inngrepet. NINA og Akvaplan-niva ble engasjert av NVE for å vurdere eventuelle miljøeffekter av restaureringstiltaket. Det ble gjennomført for- og ...