Publications
NIBIOs employees contribute to several hundred scientific articles and research reports every year. You can browse or search in our collection which contains references and links to these publications as well as other research and dissemination activities. The collection is continously updated with new and historical material.
2024
Authors
Even Unsgård Erling Meisingset Inger Maren Rivrud Gunn Randi Fossland Pål Thorvaldsen Vebjørn Veiberg Atle MysterudAbstract
In Europe, over a third of the agricultural area is grass meadows used for livestock grazing and fodder production. Grass meadows provide a food source for wild ungulates causing human-wildlife conflicts due to forage removal. Few experimental studies have quantified biomass loss with enough replicates to determine how surrounding environments influences level of biomass removal. Using an exclosure experiment on 57 grassland meadows over five years at the northwest coast of Norway covering 10 650 km2, we quantified biomass removal by red deer (Cervus elaphus L.) and how environmental factors impacted biomass loss (Study 1). Furthermore, we examined development of biomass loss and crude protein concentration in five fields throughout the growing season (Study 2). The average predicted biomass loss to red deer grazing was 16% for the first harvest, and 7.3% for the second harvest (Study 1). Biomass loss increased with red deer density from 0% at the lowest density (0.6 red deer harvested/km2) to 31% at the highest density (4 red deer harvested/km2). Biomass loss increased from 12% to 32.8% as terrain ruggedness index (TRI) rose from 2.1 to 7.1. Absolute biomass loss increased towards time of grass harvest (Study 2). Crude protein concentration was higher in unfenced plots during the period before first harvest, but not between first and second harvest (Study 2). The quantification of biomass removal at a large spatial scale over several years in this study provides a better understanding of factors causing variation in losses.
Authors
Junbin ZhaoAbstract
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Authors
Xiao-Yan Ma Dag-Ragnar Blystad Qiao-Chun Wang Lu Tong Øyvor Stensbøl Dong Zhang Zhibo HamborgAbstract
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Nicola Bozzolan Frits Mohren Giacomo Grassi Mart-Jan Schelhaas Igor Staritsky Tobias Stern Mikko Peltoniemi Vladimír Šebeň Mariana Hassegawa Pieter Johannes Verkerk Marco Patacca Aris Jansons Martin Jankovský Petra Palátová Hanna Blauth Daniel McInerney Jan Oldenburger Eirik Ogner Jåstad Jaroslav Kubista Clara Antón Fernandéz Gert-jan NabuursAbstract
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Authors
Kim Viggo Paulsen Weiby Margrete Eknæs Angela Schwarm Håvard Steinshamn Karen Beauchemin Peter Lund Ingunn Schei Ingjerd DønnemAbstract
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Kjetil FadnesAbstract
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Erik J. JonerAbstract
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Authors
Rolf David Vogt Øyvind Aaberg Garmo Kari Austnes Øyvind Kaste Ståle Haaland James Edward Sample Jan-Erik Thrane Liv Bente Skancke Cathrine Brecke Gundersen Heleen de WitAbstract
Rising organic charge in northern freshwaters is attributed to increasing levels of dissolved natural organic matter (DNOM) and changes in water chemistry. Organic charge concentration may be determined through charge balance calculations (Org.−) or modelled (OAN−) using the Oliver and Hruška conceptual models, which are based on the density of weak acid functional sites (SD) present in DNOM. The charge density (CD) is governed by SD as well as protonation and complexation reactions on the functional groups. These models use SD as a key parameter to empirically fit the model to Org.−. Utilizing extensive water chemistry datasets, this study shows that spatial and temporal differences in SD and CD are influenced by variations in the humic-to-fulvic ratio of DNOM, organic aluminum (Al) complexation, and the mole fraction of CD to SD, which is governed by acidity. The median SD values obtained for 44 long-term monitored acid-sensitive lakes were 11.1 and 13.9 µEq/mg C for the Oliver and Hruška models, respectively. Over 34 years of monitoring, the CD increased by 70%, likely due to rising pH and declining Al complexation with DNOM. Present-day median SD values for the Oliver and Hruška models in 16 low-order streams are 13.8 and 15.8 µEq/mg C, respectively, and 10.8 and 12.5 µEq/mg C, respectively, in 10 high-order rivers.