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.
2025
Abstract
1. Large herbivores at northern latitudes often forage on agricultural farmland. In these populations, the presence of both resident and migrant individuals (termed partial migration) is common, but how migrants and residents differ in their selection of farmland is not well-understood. Higher access to farmland may provide benefits to residents compensating for not following the ‘green wave’ of emerging vegetation such as migrants. According to sexual segregation theory, males and females differ in body-size-related nutritional needs and risk sensitivity associated with farmland. Yet, how the sexes differ in the selection of farmland through an annual cycle remains unclear. 2. We quantified seasonal variation in the selection of farmland by partially migratory red deer (Cervus elaphus) at broad, landscape scale and at fine, within-home range scale using 16 years of data (2005–2020) from 329 females and 115 males in Norway. 3. We tested predictions related to the partial migration and sexual segregation theories using resource selection functions. We predicted higher selection for farmland by residents than by migrants, and higher selection by females than by males due to higher nutritional needs, but that higher perceived predation risk would impact their diurnal selection patterns. 4. The time spent on farmland was higher in winter (14%–18%) than in summer (8%–14%). Residents selected farmland more than migrants mainly at broad, landscape scale, while differences were smaller and less consistent at a fine, within-home range scale. Females showed higher broad-scale selection for farmland in winter, whereas males showed higher selection in summer. At a fine, within-home range scale, females selected farmland more in summer during darkness, whereas sex differences were small otherwise. The fine-scale selection of farmland was markedly higher during low-light conditions than in daylight. A high population density index was correlated with high broad-scale selection of farmland, i.e. high farmland availability in the home ranges, whereas the effect of the density index was weak at a fine, within-home range scale. 5. Our study emphasises how hypotheses deriving from the theories of partial migration and sexual segregation can improve our understanding of ungulates' selection of farmland. The higher selection by residents during summer highlights the importance of retaining landscape connectivity, allowing for migration and reducing pressure on local resources.
Authors
Jo Jorem AarsethAbstract
No abstract has been registered
Abstract
The timing of migration is fundamental for species exploiting seasonally variable environments. For ungulates, earlier spring migration is expected with earlier vegetation green-up. However, other drivers, such as access to agricultural farmland and variation in local conditions, are also known to affect migration. We investigated the timing of spring migration for 96 male and 201 female red deer (Cervus elaphus) using a long-term dataset (2005–2020). Overall, the timing of migration was mainly characterized by large individual variability between and within years (95% range 6 April to 18 June). The spring migration timing was, as expected, later with colder winter and spring conditions (North Atlantic Oscillation (NAO) winter and April indices) and later peak vegetation green-up (NDVI), with a five-day delay in green-up causing a migration delay of 1.2 days. Timing was also influenced by local conditions in summer and winter home ranges. Red deer with greater access to farmland and a more variable topography (hence variable plant phenology) in winter delayed migration. Similarly, individuals with higher-elevation summer ranges (with delayed onset of plant growth) also delayed migration. Our analyses highlight that the timing of red deer migration is determined by multiple drivers affecting foraging conditions in the landscape, indicative of considerable phenotypic plasticity.
2024
Authors
Elise Lyng MonssenAbstract
Wildlife-train collisions are a widespread issue, leading to significant costs to society, reduced animal welfare and potential impacts on species' population sizes. Understanding how ungulates respond to oncoming trains and what affects their detectability is crucial for developing effective mitigation strategies. Building upon the work of Bhardwaj et al. (2022), this study investigates how various factors influence flight behaviour in fallow deer (Dama dama), roe deer (Capreolus capreolus) and moose (Alces alces), as well as wildlife detection from the train driver's perspective. By utilizing films from driver-activated scare systems (DASS) mounted on the front windshield of trains on Norwegian and Swedish railways, this study offers insights into both wildlife reactions and the viewpoints of train drivers. Based on approximately 1000 observations of ungulates, each individual encounter with trains was analysed in relation to railway features, train speed, the train driver’s use of typhoon warning, the ungulates’ location within the terrain and biotic and abiotic factors in the surrounding landscape of the railway. Detection distance and flight initiation distance (FID) was calculated based on the video footage. The results showed that with increasing distance from the railway tracks, ungulates in total were less likely to flee from an approaching train and more likely to increase their FID. Generally, there was a higher probability of flight when the typhoon was used to warn the ungulates, but the effect of this signal was not significant in any of the separate analyses on each species alone. There was also a higher likelihood of flight during dusk/dawn. Flight behaviour of fallow deer was significantly influenced by herd size, with a greater likelihood of flight in smaller groups separated from a large herd. In contrast to roe deer and fallow deer, moose were significantly affected by train speed, with flight likelihood and FID decreasing with increasing speed. All species showed a significantly higher probability of flight across track with closer distance to the track, and in areas where the rail embankment was covered by vegetation with exception of roe deer. Additionally, ungulates in total had a higher probability of an early flight, before detected by the train driver, when visibility was obstructed by vegetation, terrain and curvature of the railway. Lastly, detection distance from the train driver’s perspective was significantly obstructed by vegetation along the railroad embankment. Further studies are suggested on a warning system that could be activated before the animals are detected by the train driver to increase animals’ FID, alongside the implementation of night vision cameras for improved detection of animals during nocturnal hours.
Abstract
Livestock production systems with ruminants are generally associated with high enteric methane emissions and thus a high carbon footprint, causing these systems to be challenged when it comes to what products to eat and wear in a sustainable future.
Abstract
No abstract has been registered
Authors
Gabriela WagnerAbstract
No abstract has been registered
Authors
Annika M. Felton Adam Felton Per-Ola Hedwall David Raubenheimer Stephen Simpson Robert Spitzer Hilde Karine WamAbstract
The moose (Alces alces) is a large-bodied, ruminant herbivore inhabiting temperate and boreal forests, where their foraging can profoundly influence ecological processes. In intensively managed landscapes, such as large parts of Scandinavia, browsing by moose can also affect human economic interests, such as commercial forestry. Deciphering the nutritional underpinnings of the moose’ foraging choices is therefore in the interest of both wildlife ecology and forest management. In this talk I will summarise findings from several studies from Scandinavia in which we have used the nutritional geometry framework to study moose foraging behavior. First, a small feeding experiment with captive moose indicated that their food choice was not governed by energy maximization as previously postulated. Instead the moose appeared to combine food to reach a target macronutritional balance. We later confirmed this pattern of macronutrient balancing by analysing rumen content (by wet chemistry and NIRS) and faeces (indirectly via by DNA metabarcoding) from a large number of wild moose during wintertime across Sweden. The moose’ tendency to maintain a stable balance between protein and non-structural carbohydrates was most recently confirmed by a detailed study of moose summer time in Norway, using camera collars and plant collections. These studies on the Scandinavian moose have also revealed patterns of complementarity, compensatory intake, linkages to damage and fitness, and valuable information about key forage plant species, and thereby help to improve our understanding of nutritional ecology.
Authors
Annika M. Felton Hilde Karine Wam Zbigniew Borowski Aksel Granhus Laura Juvany Canovas Juho Matala Markus Melin Märtha Wallgren Anders MårellAbstract
Climate change causes far-reaching disruption in nature, where tolerance thresholds already have been exceeded for some plants and animals. In the short-term, deer may respond to climate through individual physiological and behavioral responses. Over time, individual responses can aggregate to the population level and ultimately lead to evolutionary adaptations. Because responses by deer to climate change may take many paths - both positive and negative - it is generally difficult to predict outcomes. Here we take the first step to understanding these complexities by systematically synthesizing the literature (published 2000-2022) regarding direct effects of temperature, rainfall and snow on deer inhabiting boreal and temperate regions of the northern hemisphere. Our review (based on N= 219 papers) shows that while many deer populations will likely benefit from warmer winters, hotter and drier summers may exceed their physiological tolerances, causing northwards shifts in distributional ranges. We found support for deer expressing both phenotypic and behavioral plasticity in response to climate variability at different temporal and spatial scales. We identified 20 general patterns, among which some illustrate antagonistic pathways, suggesting that detrimental effects will cancel out some of the benefits of climate change. Our findings highlight the importance of local variables for any predictions of future responses by a given deer population. We identified several knowledge gaps, such as studies regarding the potential impact on these animals of extreme weather events, snow type and wetter autumns.
Abstract
Insight from new technology in rangeland grazing systems Inger Hansen, Lise Grøva, Michael Angeloff and Oddbjørn Kaasa Although digital technologies and innovations are increasingly being adopted and accepted in intensive livestock systems, they are poorly developed and implemented in extensive livestock farming systems. On-animal sensors have potential to remotely monitor and identify changes in animal behaviour, such as illness, accidents or depredation. Real time monitoring of livestock may allow farmers and ranchers to respond more rapidly when animals become ill, and by this ensure both production and welfare With the rapid increase in new data from digital technologies from livestock rangeland grazing systems, there is a need to explore the potential for new knowledge and new tools that these data may provide. The potential lies in multisource data analysis to generate new insight on sheep behaviour, interactions and possible criteria for Early Warning Systems (EWS). EWS is in high demand by farmers, authorities and all stakeholders to ensure the sustainable management of our rangeland grazing resources. In Norway we have now started a pilot work to integrate data from GPS tracking collars on free ranging sheep with individual sheep health and production data sources, as well as vegetation maps, weather conditions, human activity and predator killings. Since 2015, Meråker grazing group, consisting of 25 sheep farmers, have used GPS tracking collars on about 2000 ewes from June to September. The data set consists of more than 9 million positions, allowing analysis of the sheep's movement related to numerous environmental and production factors. Integration of these position data with production-, health-, large carnivores- and other explanatory variables, and analysis of these multisource data, has potential to be a game changer for rangeland grazing systems. This presentation will highlight the the potiential for new insight in these farming systems.