Blar i NTNU Open på forfatter "Austrheim, Gunnar"
-
Experimental effects of herbivore density on above-ground plant biomass in an alpine grassland ecosystem
Austrheim, Gunnar; Speed, James David Mervyn; Martinsen, Vegard; Mulder, Jan; Mysterud, Atle (Journal article; Peer reviewed, 2014)Herbivores may increase or decrease aboveground plant productivity depending on factors such as herbivore density and habitat productivity. The grazing optimization hypothesis predicts a peak in plant production at ... -
Functional traits of alpine plant communities show long-term resistance to changing herbivore densities
Vuorinen, Katariina Elsa Maria; Austrheim, Gunnar; Mysterud, Atle; Gya, Ragnhild; Vandvik, Vigdis; Grytnes, John Arvid; Speed, James David Mervyn (Peer reviewed; Journal article, 2021)Herbivores shape vegetation by suppressing certain plant species while benefitting others. By thus modifying plant species functional composition, herbivores affect carbon cycling, albedo, vegetation structure and species' ... -
A Grazer in a Browser's Habitat: Resource Selection of Foraging Cattle in Productive Boreal Forest
Spedener, Mélanie; Tofastrud, Morten; Austrheim, Gunnar; Zimmermann, Barbara (Peer reviewed; Journal article, 2024)In Norway, cattle (Bos taurus) are released to large areas of boreal forest for summer grazing. To determine to what degree this practice challenges timber production and wildlife management, we need a better understanding ... -
Growth rings show limited evidence for ungulates’ potential to suppress shrubs across the Arctic
Vuorinen, Katariina Elsa Maria; Austrheim, Gunnar; Tremblay, Jean-Pierre; Myers-Smith, Isla H.; Hortman, Hans Ivar; Frank, Peter; Barrio, Isabel C.; Dalerum, Fredrik; Björkman, Mats Peter; Björk, Robert G.; Ehrich, Dorothee; Sokolov, Aleksandr; Sokolova, Natalya; Ropars, Pascale; Boudreau, Stephane; Normand, Signe; Prendin, Angela L.; Schmidt, Niels Martin; Pacheco-Solana, Arturo; Post, Eric; John, Christian; Kerby, Jeff; Sullivan, Patrick F.; Le Moullec, Mathilde; Hansen, Brage Bremset; van der Wal, René; Pedersen, Åshild Ønvik; Sandal, Lisa; Gough, Laura; Young, Amanda; Li, Bingxi; Magnusson, Runa I.; Sass-Klaassen, Ute; Buchwal, Agata; Welker, Jeffrey; Grogan, Paul; Andruko, Rhett; Morrissette-Boileau, Clara; Volkovitskiy, Alexander; Terekhina, Alexandra; Speed, James David Mervyn (Peer reviewed; Journal article, 2022)Global warming has pronounced effects on tundra vegetation, and rising mean temperatures increase plant growth potential across the Arctic biome. Herbivores may counteract the warming impacts by reducing plant growth, but ... -
Identification of blue green structures and perceived values in public urban green spaces : a comparative case study of a natural and a constructed green space in Oslo
Fongar, Claudia (Master thesis, 2015)Population growth is increasing and further increase will occur in cities. This densification will effect and reduce urban green ecosystems. Urban ecosystems contribute to the quality of life of urban dwellers and the ... -
Increasing Cervidae populations have variable impacts on habitat suitability for threatened forest plant and lichen species
Speed, James David Mervyn; Austrheim, Gunnar; Bendiksby, Mika; Kolstad, Anders Lorentzen; Vuorinen, Katariina (Peer reviewed; Journal article, 2020)Large herbivores play a key role in temperate and boreal forest ecosystems. Cervidae (deer) population densities and community structure have undergone drastic changes in many parts of the world over the past decades, often ... -
Investigating the effect of different land use types on the presence of, and interaction between flowering plants and their pollinators in Budalen
Slettan, Frida (Master thesis, 2024)Dyrepollinering er avgjørende for økosystem funksjoner og tjenester, deriblant er insektenes rolle spesielt viktig. Det er en global nedgang i pollinator diversitet, og spesielt arter som humler er vist å være kraftig ... -
Leaf it to the professionals: Branching out to restore deciduous forests in southern Norway.
Berg, Elise (Master thesis, 2023)While restoration endeavors in Scandinavia and Northern Europe have predominantly concentrated on boreal forests, the often-overlooked boreonemoral forests, sharing similar characteristics, demand equal attention. These ... -
Legacy effects of herbivory on treeline dynamics along an elevational gradient
Mienna, Ida Marielle; Austrheim, Gunnar; Klanderud, Kari; Bollandsås, Ole Martin; Speed, James David Mervyn (Peer reviewed; Journal article, 2022)Treelines are expected to expand into alpine ecosystems with global warming, but herbivory may delay this expansion. This study quantifies long-term effects of temporally varying sheep densities on birch recruitment and ... -
Long term effects of red deer browsing and an extreme winter drought event on bilberry in boreal forests
Hafsås, Hallvard (Master thesis, 2022)Forandringer i klima, arealbruk og viltforvaltning har ført til endringer i nivå og type av forstyrrelser i norske boreale skoger. Blåbær er en nøkkelart i boreale økosystem og det er kjent at den blir påvirket av beiting ... -
Long-term changes in northern large-herbivore communities reveal differential rewilding rates in space and time
Speed, James David Mervyn; Austrheim, Gunnar; Kolstad, Anders Lorentzen; Solberg, Erling Johan (Journal article; Peer reviewed, 2019)Herbivores have important impacts on ecological and ecosystem dynamics. Population density and species composition are both important determinants of these impacts. Large herbivore communities are shifting in many parts ... -
Long-term Effects of Shifts in Grazing Pressure on Alpine Plant Species along an Elevational Gradient
Maurset, Marie Uhlen (Master thesis, 2015)Sheep (Ovis aries) are the main large herbivore in Norwegian mountains during summer and these herbivores have shaped alpine plant communities over a long land-use history. Sheep are selective feeders, and increased livestock ... -
Long-Term Increase in Aboveground Carbon Stocks Following Exclusion of Grazers and Forest Establishment in an Alpine Ecosystem
Speed, James David Mervyn; Martinsen, Vegard; Mysterud, Atle; Mulder, Jan; Holand, Øystein; Austrheim, Gunnar (Journal article; Peer reviewed, 2014)Ecosystem stores of carbon are a key component in the global carbon cycle. Many studies have examined the impact of climate change on ecosystem carbon storage, but few have investigated the impact of land-use change and ... -
Long-term land-use and landscape dynamics in Budalen, central Norway
Solem, Thyra Lise; Aune, Egil Ingvar; Daverdin, Marc; Hassel, Kristian; Sjøgren, Per Johan E; Stenvik, Lars; Tretvik, Aud Mikkelsen; Øien, Dag-Inge; Austrheim, Gunnar (Journal article; Peer reviewed, 2012)Humans have used resources in mountain landscapes for thousands of years, but the intensity and continuity of different land uses and the corresponding landscape changes are not well understood. This study examined long-term ... -
Mapping and Estimating Aboveground Biomass in an Alpine Treeline Ecotone under Model-Based Inference
Mukhopadhyay, Ritwika; Næsset, Erik; Gobakken, Terje; Mienna, Ida Marielle; Candelas Bielza, Jaime; Austrheim, Gunnar; Persson, Henrik Jan; Ørka, Hans Ole; Roald, Bjørn-Eirik; Bollandsås, Ole Martin (Peer reviewed; Journal article, 2023)Due to climate change, treelines are moving to higher elevations and latitudes. The estimation of biomass of trees and shrubs advancing into alpine areas is necessary for carbon reporting. Remotely sensed (RS) data have ... -
Mapping large carnivores in Norway across 175 years of changing policy
Sobocinski, Anna (Master thesis, 2022)Large carnivores serve important ecosystem functions, but have broad ecological requirements that often bring them into conflict with modern human society. Heavy persecution in Europe has led to a dramatic reduction in ... -
Moose browsing effects on boreal production forests – implications for ecosystems and human society
Kolstad, Anders Lorentzen (Doctoral theses at NTNU;2019:286, Doctoral thesis, 2019)Sammendrag: Den viktige elgen Utmarkbeite er trolig den mest utbredte arealbruken i Norge, som i verden forøvrig. Etter at mengden beitende husdyr begynte å ned på midten av forrige århundre har ville hjortedyr tatt ... -
Moose effects on soil temperatures, tree canopies, and understory vegetation: a path analysis
Kolstad, Anders Lorentzen; Austrheim, Gunnar; Graae, Bente Jessen; Solberg, Erling Johan; Strimbeck, Richard; Speed, James David Mervyn (Journal article; Peer reviewed, 2018)Large vertebrate herbivores are ubiquitous and increasingly numerous in boreal forests where they are known to influence ecosystems in many ways. However, separating the direct effects of herbivores from their indirect ... -
Mowing Impacts on Urban Biodiversity: A study of Plant- Pollinator dynamics in Mowed vs Unmowed grasslands
Subedi, Pooja (Master thesis, 2024)Mowing, as a management practice, can impact the species richness and abundance of both plants and pollinators and the interaction between them by altering the plant-pollinator dynamics and their relationship. The main aim ... -
Natural and cultural heritage in mountain landscapes: towards an integrated valuation
Speed, James David Mervyn; Austrheim, Gunnar; Birks, Harry John Betteley; Johnson, Sally; Kvamme, Mons; Nagy, Laszlo; Sjøgren, Per Johan E; Skar, Birgitte; Stone, Duncan; Svensson, Eva; Thompson, Des B.A. (Journal article; Peer reviewed, 2012)Mountain areas of Europe have been managed by humans for a long time, leading to a prevalence of semi-natural habitats in mountain landscapes today. These landscapes contain both natural and cultural heritage; however, ...