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.
2023
Authors
Mélanie Spedener Karen Marie Mathisen Marie Vestergaard Henriksen Anders Nielsen Gunnar Austrheim Barbara ZimmermannAbstract
No abstract has been registered
Authors
Linn Vassvik Anders Nielsen Erik Trond Aschehoug Bjørn Arild Hatteland Joseph Chipperfield Michael P. D. GarrattAbstract
No abstract has been registered
Abstract
Questions During the winter of 2014, an intense drought combined with sub-zero temperatures resulted in a massive Calluna dieback in Norwegian heathlands. We studied the initial vegetation recovery under two management approaches: natural recovery and prescribed burning. We hypothesized that natural recovery will be slower in more drought-affected sites, whereas burning will facilitate post-fire recovery in all sites by effectively removing dead and damaged heath. Both natural recovery and post-fire succession will be slower in the north. Location Calluna heath in seven sites spanning an approx. 600-km latitudinal gradient along the coast of Norway (60.22–65.69° N). Methods After a natural drought, 10 permanent plots per site were either burnt or left for natural recovery. Vegetation data were recorded annually in 2016 (pre-fire) and 2017–2019 (post-fire) reflecting a factorial repeated-measures design (n = 280). The data were analyzed using mixed-effects models. Results Two years after the drought, we observed high but variable Calluna damage and mortality. Over the four years of study, damaged Calluna recovered, whereas dead Calluna showed little recovery. Both the extent of the damage and mortality, as well as the rate of natural recovery, are only weakly related to site climate or environmental factors. Fire efficiently removed dead and damaged Calluna and facilitated post-fire successional dynamics and recovery in a majority of sites. Conclusions Extreme winter drought resulted in substantial and often persistent damage and dieback on Calluna along the latitudinal gradient. In sites with high mortality, prescribed burning removed the dead biomass and, in some cases, facilitated vegetation recovery. Traditional heathland management, which uses burning to facilitate all-year grazing by Old Norse sheep in Atlantic coastal heathlands, can be an efficient tool to mitigate dieback events and more generally to increase resistance to and resilience after extreme drought events in the future.
Abstract
No abstract has been registered
Authors
Svenja B. KroegerAbstract
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Authors
Linn VassvikAbstract
No abstract has been registered
Authors
Linn VassvikAbstract
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Abstract
No abstract has been registered
Authors
Ruben Erik Roos Johan Asplund Tone Birkemoe Aud Helen Halbritter Rechsteiner Siri Lie Olsen Linn Vassvik Kristel van Zuijlen Kari KlanderudAbstract
No abstract has been registered
Authors
Julie Sørlie Paus-Knudsen Henrik Andersen Sveinsson Merete Grung Katrine Borgå Anders NielsenAbstract
Bumblebees carry out the complex task of foraging to provide for their colonies. They also conduct pollination, an ecosystem service of high importance to both wild plants and entomophilous crops. Insecticides can alter different aspects of bumblebee foraging behavior, including the motivation to leave the hive, finding the right flowers, handling flowers, and the ability to return to the colony. In the present study, we assessed how the neonicotinoid imidacloprid affects bumblebees' foraging behavior after exposure to four different treatment levels, including field-realistic concentrations (0 [control], 1, 10, and 100 μg/L), through sucrose solution over 9 days. We observed the behavior of several free-flying bumblebees simultaneously foraging on artificial flowers in a flight arena to register the bees' complex behavior postexposure. To conduct a detailed assessment of how insecticides affect bumblebee locomotor behavior, we used video cameras and analyzed the recordings using computer vision. We found that imidacloprid impaired learning and locomotor activity level when the bumblebees foraged on artificial flowers. We also found that imidacloprid exposure reduced sucrose solution intake and storage. By using automated analyses of video recordings of bumblebee behavior, we identified sublethal effects of imidacloprid exposure at field-realistic doses. Specifically, we observed negative impacts on consumption of sucrose solution as well as on learning and locomotor activity level. Our results highlight the need for more multimodal approaches when assessing the sublethal effects of insecticides and plant protection products in general.