Blar i NTNU Open på forfatter "Speed, James David Mervyn"

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    • Airborne laser scanning reveals increased growth and complexity of boreal forest canopies across a network of ungulate exclosures in Norway 

      Kolstad, Anders Lorentzen; Snøan, Ingrid Bekken; Austrheim, Gunnar; Bollandsås, Ole Martin; Solberg, Erling Johan; Speed, James David Mervyn (Peer reviewed; Journal article, 2021)
      Large herbivores are often classed as ecosystem engineers, and when they become scarce or overabundant, this can alter ecosystem states and influence climate forcing potentials. This realization has spurred a call to ...

    • Airborne laser scanning reveals uniform responses of forest structure to moose (Alces alces) across the boreal forest biome 

      Petersen, Tanja Kofod; Kolstad, Anders Lorentzen; Kouki, Jari; Leroux, Shawn J.; Potvin, Lynette R.; Tremblay, Jean-Pierre; Wallgren, Märtha; Widemo, Fredrik; Cromsigt, Joris P. G. M.; Courtois, Coline; Austrheim, Gunnar; Gosse, John; den Herder, Michael; Hermanutz, Luise; Speed, James David Mervyn (Peer reviewed; Journal article, 2023)
      1. The moose Alces alces is the largest herbivore in the boreal forest biome, where it can have dramatic impacts on ecosystem structure and dynamics. Despite the importance of the boreal forest biome in global carbon ...

    • Assessing spatial patterns of phylogenetic diversity of Mexican mammals for biodiversity conservation 

      Aguilar Tomasini, Maria Alejandra; Martin, Michael David; Speed, James David Mervyn (Peer reviewed; Journal article, 2021)
      Phylogenetic diversity is a biodiversity measurement that describes the amount of evolutionary history contained by the taxonomic units in a region. It has proven to be an important metric for determining conservation ...

    • Background invertebrate herbivory on dwarf birch (Betula glandulosa-nana complex) increases with temperature and precipitation across the tundra biome 

      Barrio, Isabel C.; Lindén, Elin; te Beest, Mariska; Olofsson, Johan; Rocha, Adrian; Soininen, Eeva M; Alatalo, Juha M.; Andersson, Tommi; Asmus, Ashley; Boike, Julia; Bråthen, Kari Anne; Bryant, John P.; Buchwal, Agata; Bueno, C. Guillermo; Christie, Katherine S.; Denisova, Yulia V.; Egelkraut, Dagmar; Ehrich, Dorothee; Fishback, LeeAnn; Forbes, Bruce C.; Gartzia, Maite; Grogan, Paul; Hallinger, Martin; Heijmans, Monicque M.P.D.; Hik, David S.; Hofgaard, Annika; Holmgren, Milena; Høye, Toke T.; Huebner, Diane C.; Jonsdottir, Ingibjørg; Kaarlejärvi, Elina; Kumpula, Timo; Lange, Cynthia Y.M.J.G.; Lange, Jelena; Lévesque, Esther; Limpens, Juul; Macias-Fauria, Marc; Myers-Smith, Isla; Van Nieukerken, Erik J.; Normand, Signe; Post, Eric S.; Schmidt, Niels Martin; Sitters, Judith; Skoracka, Anna; Sokolov, Alexander; Sokolova, Natalya; Speed, James David Mervyn; Street, Lorna E.; Sundqvist, Maja K.; Suominen, Otso; Tananaev, Nikita; Tremblay, Jean-Pierre; Urbanowicz, Christine; Uvarov, Sergey A.; Watts, David; Wilmking, Martin; Wookey, Philip A.; Zimmermann, Heike H.; Zverev, Vitali; Kozlov, Mikhail V. (Journal article; Peer reviewed, 2017)
      Chronic, low intensity herbivory by invertebrates, termed background herbivory, has been understudied in tundra, yet its impacts are likely to increase in a warmer Arctic. The magnitude of these changes is however hard to ...

    • Biding time before breeding: flexible use of the Arctic landscape by migratory geese during spring 

      Anderson, Helen; Hübner, Christiane E.; Speed, James David Mervyn; Madsen, Jesper; van der Wal, René (Journal article; Peer reviewed, 2015)
      Many millions of long-distance migrants use pre-breeding staging sites located adjacent to breeding grounds immediately prior to nesting, presumably to improve body condition and thus reproductive success. However, in ...

    • Can mowing restore boreal rich-fen vegetation in the face of climate change? 

      Ross, Louise C.; Speed, James David Mervyn; Øien, Dag-Inge; Grygoruk, Mateusz; Hassel, Kristian; Lyngstad, Anders; Moen, Asbjørn (Journal article; Peer reviewed, 2019)
      Low-frequency mowing has been proposed to be an effective strategy for the restoration and management of boreal fens after abandonment of traditional haymaking. This study investigates how mowing affects long-term vegetation ...

    • Can seasonal fire management reduce the risk of carbon loss from wildfires in a protected Guinea savanna? 

      Awuah, Joana; Smith, Stuart W.; Speed, James David Mervyn; Graae, Bente Jessen (Peer reviewed; Journal article, 2022)
      Fire is fundamental to the functioning of tropical savannas and routinely used as a management tool. Shifting prescribed burning from later to earlier in the growing season has the potential to reduce greenhouse gas ...

    • Cervid Exclusion Alters Boreal Forest Properties with Little Cascading Impacts on Soils 

      Kolstad, Anders Lorentzen; Speed, James David Mervyn; Austrheim, Gunnar; Solberg, Erling Johan; Woodin, Sarah J.; Venete, Aurel M A (Journal article; Peer reviewed, 2017)
      Large herbivores are capable of modifying entire ecosystems with a combination of direct (for example browsing/grazing, trampling, defecation) and indirect (for example affecting plant species composition that then alters ...

    • Circum-Arctic distribution of chemical anti-herbivore compounds suggests biome-wide trade-off in defence strategies in Arctic shrubs 

      Lindén, Elin; te Beest, Mariska; Aubreu, Ilka; Moritz, Thomas; Sundqvist, Maja K.; Barrio, Isabel C.; Boike, Julia; Bryant, John P.; Bråthen, Kari Anne; Buchwal, Agata; Bueno, C. Guillermo; Currier, Alain; Egelkraut, Dagmar Dorothea; Forbes, Bruce C.; Hallinger, Martin; Heijmans, Monique; Hermanutz, Luise; Hik, David S.; Hofgaard, Annika; Holmgren, Milena; Huebner, Diane C.; Høye, Toke T.; Jónsdóttir, Ingibjörg S.; Kaarlejärvi, Elina; Kissler, Emilie; Kumpula, Timo; Limpens, Juul; Myers-Smith, Isla H.; Normand, Signe; Post, Eric; Rocha, Adrian V.; Schmidt, Niels Martin; Skarin, Anna; Soininen, Eeva M; Sokolov, Aleksandr; Sokolova, Natalia; Speed, James David Mervyn; Street, Lorna E.; Tananaev, Nikita; Tremblay, Jean-Pierre; Urbanowicz, Christine; Watts, David A.; Zimmermann, Heike H.; Olofsson, Johan (Peer reviewed; Journal article, 2022)
      Spatial variation in plant chemical defence towards herbivores can help us understand variation in herbivore top–down control of shrubs in the Arctic and possibly also shrub responses to global warming. Less defended, ...

    • Climate and land-use drive the functional composition of vascular plant assemblages across Norway 

      Petersen, Tanja Kofod; Vuorinen, Katariina Elsa M; Bendiksby, Mika; Speed, James David Mervyn (Peer reviewed; Journal article, 2022)
      Traditionally, biogeography has described the distribution of species. But as plant functional traits and functional diversity underpin ecosystem dynamics, understanding drivers of functional diversity at biogeographical ...

    • Competitors and ruderals go to town: plant community composition and function along an urbanisation gradient 

      Petersen, Tanja Kofod; Speed, James David Mervyn; Grøtan, Vidar; Austrheim, Gunnar (Journal article; Peer reviewed, 2021)
      Urbanisation is expected to function as a filter for plant species by changing the physiochemical environment, causing species turnover along an urbanisation gradient. Analyses of the functional traits of species characteristic ...

    • Contrasting spatial, temporal and environmental patterns in observation and specimen based species occurrence data 

      Speed, James David Mervyn; Bendiksby, Mika; Finstad, Anders Gravbrøt; Hassel, Kristian; Kolstad, Anders Lorentzen; Prestø, Tommy (Journal article; Peer reviewed, 2018)
      Species occurrence data records the location and time of an encounter with a species, and is valuable for many aspects of ecological and evolutionary analyses. A key distinction within species occurrence data is between ...

    • Contrasting spatial, temporal and environmental patterns in observation and specimen based species occurrence data 

      Speed, James David Mervyn; Bendiksby, Mika; Finstad, Anders Gravbrøt; Hassel, Kristian; Kolstad, Anders Lorentzen; Prestø, Tommy (Journal article; Peer reviewed, 2018)
      Species occurrence data records the location and time of an encounter with a species, and is valuable for many aspects of ecological and evolutionary analyses. A key distinction within species occurrence data is between ...

    • Cool as a moose: How can browsing counteract climate warming effects across boreal forest ecosystems? 

      Vuorinen, Katariina; Kolstad, Anders Lorentzen; De Vriendt, Laurent; Austrheim, Gunnar; Jean-Pierre, Tremblay; Solberg, Erling Johan; Speed, James David Mervyn (Peer reviewed; Journal article, 2020)
      Herbivory has potential to modify vegetation responses to climatic changes. However, climate and herbivory also affect each other, and rarely work in isolation from other ecological factors, such as plant–plant competition. ...

    • Developing common protocols to measure tundra herbivory across spatial scales 

      Barrio, Isabel C.; Ehrich, Dorothee; Soininen, Eeva M; Ravolainen, Virve; Bueno, C. G.; Gilg, Olivier; Koltz, Amanda; Speed, James David Mervyn; Hik, David S.; Mörsdorf, M.; Alatalo, Juha M.; Angerbjørn, A.; Bêty, Joël; Bollache, L.; Boulanger-Lapointe, N.; Brown, G. S.; Eischeid, Isabell; Giroux, M. A.; Hajek, T.; Hansen, Brage Bremset; Hofhius, S. P.; Lamarre, J.-F.; Lang, J.; Latty, C.; Lecomte, N.; Macek, P.; McKinnon, L.; Myers-Smith, I. H.; Pedersen, Åshild Ønvik; Prevey, J. S.; Roth, J. D.; Saalfeld, S. T.; Schmidt, N. M.; Smith, P.; Sokolov, A.; Sokolova, N.; Stolz, C.; van Bemmelen, R.; Varpe, Øystein; Woodard, P. F.; Jonsdottir, I. S. (Peer reviewed; Journal article, 2021)
      Understanding and predicting large-scale ecological responses to global environmental change requires comparative studies across geographic scales with coordinated efforts and standardized methodologies. We designed, ...

    • Differential patterns of floristic phylogenetic diversity across a post-glacial landscape 

      Mienna, Ida M.; Speed, James David Mervyn; Bendiksby, Mika; Thornhill, Andrew H.; Mishler, Brent D; Martin, Michael David (Journal article; Peer reviewed, 2019)
      Aim: In this study, we explored spatial patterns of phylogenetic diversity (PD) and end-emism in the flora of Norway and tested hypothesized post-glacial environmental drivers of PD, including temperature, precipitation, ...

    • Effects of hydropeaking on benthic invertebrate community composition in two central Norwegian rivers 

      Kjærstad, Gaute; Arnekleiv, Jo Vegar; Speed, James David Mervyn; Herland, Anne Karine (Journal article; Peer reviewed, 2018)
      Hydropower regulations can have dramatic impacts on river ecological communities. The operation of hydropower stations is related to power demands, but their releases in the receiving water body causes sudden changes in ...

    • Evidence of effects of herbivory on Arctic vegetation: a systematic map protocol 

      Soininen, Eeva M; Barrio, I.; Jepsen, Jane Uhd; Ehrich, Dorothee; Ravolainen, Virve; Speed, James David Mervyn (Journal article; Peer reviewed, 2018)
      Background: Along with climate change, herbivory is considered a main driver of ecosystem change in terrestrial Arctic environments. Understanding how herbivory influences the resilience of Arctic ecosystems to ongoing ...

    • 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' ...