Browsing NINA Brage by Author "Tømmervik, Hans"
Now showing items 21-40 of 90
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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- ... -
Feasibility of hyperspectral vegetation indices for the detection of chlorophyll concentration in three high Arctic plants: Salix polaris, Bistorta vivipara, and Dryas octopetala
Zagajewski, Bogdan; Kycko, Marlena; Tømmervik, Hans; Bochenek, Zbigniew; Wojtun, Bronislaw; Bjerke, Jarle W.; Klos, Andrzej (Peer reviewed; Journal article, 2018)Remote sensing, which is based on a reflected electromagnetic spectrum, offers a wide range of research methods. It allows for the identification of plant properties, e.g., chlorophyll, but a registered signal not only ... -
Focus on recent, present and future Arctic and boreal productivity and biomass changes
Tømmervik, Hans; Forbes, Bruce C. (Peer reviewed; Journal article, 2020)The reduction of cold temperature constraints on photosynthesis in recent decades has led to extended growing seasons and increased plant productivity (greening) in significant parts of Polar, Arctic and Boreal regions, ... -
Forsøk med forsterkning og revegetering av kjøretraséer i Porsangmoen - Hálkavárri skytefelt
Tømmervik, Hans; Bakkestuen, Vegar; Erikstad, Lars (NINA Rapport;341, Research report, 2008)Tømmervik, H., Bakkestuen, V. og Erikstad, L. 2008. Forsøk med forsterkning og revegetering av kjøretraséer i Porsangmoen - Hálkavárri skytefelt. NINA Rapport 341, 35 s. Rapporten oppsummerer forsøk gjort med forsterkning ... -
Future forest distribution on Finnmarksvidda, North Norway
Karlsen, Stein Rune; Tømmervik, Hans; Johansen, Bernt; Riseth, Jan Åge (Journal article; Peer reviewed, 2017)Finnmarksvidda is Norway’s largest mountain plateau, located in the Arctic/alpineboreal transition area. The area is also a central winter grazing area for the reindeer herds of the indigenous Sámi people. This study ... -
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; Peer reviewed, 2018)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 ... -
Historiske tamreintall i Norge fra 1800-tallet fram til i dag
Tømmervik, Hans; Riseth, Jan Åge (NINA rapport, Research report, 2011)Tømmervik, H. & Riseth, J. Å. 2011. Historiske tamreintall i Norge fra 1800-tallet fram til i dag - NINA Rapport 672. 36 s. På oppdrag for Direktoratet for naturforvaltning har vi sammenstilt tilgjengelige data for ... -
Impact of Multiple Ecological Stressors on a Sub-Arctic Ecosystem: No Interaction Between Extreme Winter Warming Events, Nitrogen Addition and Grazing
Bokhorst, Stef; Berg, atty P.; Edvinsen, Guri K.; Ellers, Jacintha; Heitman, Amber; Jaakola, Laura; Mæhre, Hanne K.; Phoenix, Gareth K.; Tømmervik, Hans; Bjerke, Jarle W. (Peer reviewed; Journal article, 2018)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 ... -
Impacts of snow season on ground-ice accumulation, soil frost andprimary productivity in a grassland of sub-Arctic Norway
Bjerke, Jarle W.; Tømmervik, Hans; Zielke, Matthias; Jørgensen, Marit (Peer reviewed; Journal article, 2015)Europe’s and the World’s northernmost agriculture is very vulnerable to harsh overwintering conditions. It is important from both an economic and societal standpoint to have accurate methods of predicting the severity ... -
Intraspecific differences in spectral reflectance curves as indicators of reduced vitality in high-arctic plants
Zagajewski, Bogdan; Tømmervik, Hans; Bjerke, Jarle W.; Raczko, Edwin; Bochenek, Zbigniew; Kłos, Andrzej; Jarocińska, Anna Maria; Lavender, Samantha; Ziółkowski, Dariusz (Journal article; Peer reviewed, 2017) -
Jakt på kortnebbgås i Nord-Trøndelag 2008. En evaluering og forslag til fremtidig forvaltningspraksis
Tombre, Ingunn; Madsen, Jesper; Eythórsson, Einar; Søreng, Siri Ulfsdatter; Tømmervik, Hans; Kristiansen, Amund (NINA Rapport;431, Research report, 2009)Tombre, I.M., Madsen, J., Eythorson, E., Søreng, S.U., Tømmervik, H. & Kristiansen, A. 2009. Jakt på kortnebbgås i Nord-Trøndelag 2008. En evaluering og forslag til fremtidig forvaltningspraksis. - NINA Rapport 431. 36 s. ... -
Kartlegging av lavbeitenes biomasse tilbake i tid
Erlandssong, Rasmus; Ostapowicz, Katarzyna; Langeland, Knut; Tveraa, Torkild; Finne, Eirik Aasmo; Tømmervik, Hans (NINA Rapport;2426, Research report, 2024)Erlandsson, R., Ostapowicz, K., Langeland, K., Tveraa, T., Aasmo Finne, E. & Tømmervik, H. 2024. Kartlegging av lavbeitenes biomasse tilbake i tid. NINA Rapport 2426. Norsk institutt for naturforskning. http://hdl.handle ... -
Klassifisering av 14 ikke-nasjonale villreinområder etter kvalitetsnorm for villrein. Første klassifisering – 2023
Rolandsen, Christer M.; Tveraa, Torkild; Gundersen, Vegard; Røed, Knut H.; Tømmervik, Hans; Våge, Jørn; Skarin, Anna; Strand, Olav; Hansen, Brage B. (NINA Rapport;2372, Research report, 2023)Rolandsen, C.M., Tveraa, T., Gundersen, V., Røed, K.H., Tømmervik, H., Våge, J., Skarin, A., Strand, O. & Hansen, B.B. 2023. Klassifisering av 14 ikke-nasjonale villreinområder etter kvalitetsnorm for villrein. Første ... -
Klassifisering av de ti nasjonale villreinområdene etter kvalitetsnorm for villrein. Første klassifisering – 2022
Rolandsen, Christer M.; Tveraa, Torkild; Gundersen, Vegard; Røed, Knut H.; Tømmervik, Hans; Kvie, Kjersti; Våge, Jørn; Skarin, Anna; Strand, Olav (NINA Rapport;2126, Research report, 2022)Rolandsen, C.M., Tveraa, T., Gundersen, V., Røed, K.H., Tømmervik, H., Kvie, K., Våge, J., Skarin, A. & Strand, O. 2022. Klassifisering av de ti nasjonale villreinområdene etter kvalitetsnorm for villrein. Første klassifisering ... -
Kommunedelplan Tømmerneset, Sør-Varanger kommune - Konsekvensutredning for reindrift
Tømmervik, Hans; Danielsen, Inge E.; Langeland, Knut (NINA rapport;1083, Research report, 2015)Multiconsult er engasjert av Forsvarsbygg til å utarbeide en områdereguleringsplan med kon-sekvensutredning for Høybuktmoen skyte- og øvingsfelt. Parallelt pågår arbeidet med område-reguleringsplaner for Kirkenes Maritime ... -
Langtidsvirkninger på naturmiljøet av Forsvarets virksomhet i Troms
Tømmervik, Hans; Erikstad, Lars; Jacobsen, Karl-Otto; Strann, Karl Birger; Bakkestuen, Vegar; Aarrestad, Per Arild; Yoccoz, Nigel Gilles; Hagen, Dagmar; Johnsen, Trond Vidar; Johansen, Bernt; Høgda, Kjell Arild; Ahmed, Said Hassan; Dahl, Rolv; Bargel, Terje Harald; Olsen, Lars (NINA Rapport;49, Research report, 2005)Tømmervik, H., Erikstad, L., Jacobsen, K.-O., Strann, K.-B., Bakkestuen, V., Aarrestad, P.A., Yoccoz, N., Hagen, D., Johnsen, T.V., Johansen, B., Høgda, K.A., Ahmed, S.H., Dahl, R., Bargel, T.H., Olsen, L. 2005. ...