Publikasjoner
NIBIOs ansatte publiserer flere hundre vitenskapelige artikler og forskningsrapporter hvert år. Her finner du referanser og lenker til publikasjoner og andre forsknings- og formidlingsaktiviteter. Samlingen oppdateres løpende med både nytt og historisk materiale. For mer informasjon om NIBIOs publikasjoner, besøk NIBIOs bibliotek.
2023
Forfattere
Adam Eindride Naas Rune Halvorsen Peter Horvath Anders Kvalvåg Wollan Harald Bratli Katrine Marie Brynildsrud Eirik Aasmo Finne Lasse Torben Keetz Eva Lieungh Christine Olson Trond Simensen Olav Skarpaas Hilde Tandstad Michal Torma Espen Sommer Værland Anders BrynSammendrag
Questions Field-based ecosystem mapping is prone to observer bias, typically resulting in a mismatch between maps made by different mappers, that is, inconsistency. Experimental studies testing the influence of site, mapping scale, and differences in experience level on inconsistency in field-based ecosystem mapping are lacking. Here, we study how inconsistencies in field-based ecosystem maps depend on these factors. Location Iškoras and Guollemuorsuolu, northeastern Norway, and Landsvik and Lygra, western Norway. Methods In a balanced experiment, four sites were field-mapped wall-to-wall to scales 1:5000 and 1:20,000 by 12 mappers, representing three experience levels. Thematic inconsistency was calculated by overlay analysis of map pairs from the same site, mapped to the same scale. We tested for significant differences between sites, scales, and experience-level groups. Principal components analysis was used in an analysis of additional map inconsistencies and their relationships with site, scale and differences in experience level and time consumption were analysed with redundancy analysis. Results On average, thematic inconsistency was 51%. The most important predictor for thematic inconsistency, and for all map inconsistencies, was site. Scale and its interaction with site predicted map inconsistencies, but only the latter were important for thematic inconsistency. The only experience-level group that differed significantly from the mean thematic inconsistency was that of the most experienced mappers, with nine percentage points. Experience had no significant effect on map inconsistency as a whole. Conclusion Thematic inconsistency was high for all but the dominant thematic units, with potentially adverse consequences for mapping ecosystems that are fragmented or have low coverage. Interactions between site and mapping system properties are considered the main reasons why no relationships between scale and thematic inconsistency were observed. More controlled experiments are needed to quantify the effect of other factors on inconsistency in field-based mapping.
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Forfattere
Karin Juul Hesselsøe Anne friederike Borchert Karin Normann Trygve S. Aamlid Pia Heltoft ThomsenSammendrag
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Forfattere
Svenja B. KroegerSammendrag
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Forfattere
Franziska Mohr Vasco Diogo Julian Helfenstein Niels Debonne Thymios Dimopoulos Wenche Dramstad Maria García-Martín Józef Hernik Felix Herzog Thanasis Kizos Angela Lausch Livia Lehmann Christian Levers Robert Pazur Virginia Ruiz-Aragón Rebecca Swart Claudine Thenail Hege Ulfeng Peter H. Verburg Tim Williams Anita Zarina Matthias BürgiSammendrag
Farming in Europe has been the scene of several important socio-economic and environmental developments and crises throughout the last century. Therefore, an understanding of the historical driving forces of farm change helps identifying potentials for navigating future pathways of agricultural development. However, long-term driving forces have so far been studied, e.g. in anecdotal local case studies or in systematic literature reviews, which often lack context dependency. In this study, we bridged local and continental scales by conducting 123 oral history interviews (OHIs) with elderly farmers across 13 study sites in 10 European countries. We applied a driving forces framework to systematically analyse the OHIs. We find that the most prevalent driving forces were the introduction of new technologies, developments in agricultural markets that pushed farmers for farm size enlargement and technological optimisation, agricultural policies, but also cultural aspects such as cooperation and intergenerational arrangements. However, we find considerable heterogeneity in the specific influence of individual driving forces across the study sites, implying that generic assumptions about the dynamics and impacts of European agricultural change drivers hold limited explanatory power on the local scale. Our results suggest that site-specific factors and their historical development will need to be considered when addressing the future of agriculture in Europe in a scientific or policy context.
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Cover crops are used to increase carbon sequestration in soils. However, an increase of organic matter in soils not only increases carbon stocks but also affects nitrogen availability. This can trigger N2O emissions, particularly during wintertime, when standing plant biomass from cover crops decays. N2O emissions associated with cover crops could potentially cancel out the carbon gain. In this study, N2O emissions were measured over two years in a field experiment in SE Norway with barley and various cover crops (perennial and Italian ryegrass, oilseed radish, summer and winter vetch, phacelia and a mixture of different herbs) and compared with controls without cover crops. Manual chambers were used in summer during the growth of the main crop, while winter emissions were measured more frequently by a field robot to capture freeze-thaw induced emission peaks. Both winters had poor snow cover and the highest N2O emissions were measured during freeze-thaw cycles in early spring. Nitrogen-rich cover crops with poor overwintering (oilseed radish) increased wintertime emissions, whereas perennial cover crops with good overwintering (perennial ryegrass and herb mixture) tended to reduce N2O emissions compared to controls. This suggests that the overall climate effect of cover crops in hemiboreal cereal production depends on cover crop species and winter conditions.
Sammendrag
We tested whether windthrow damage to Nordic conifer forest stands could be reliably detected as canopy height decrease between a pre-storm LiDAR (Light Detection and Ranging) digital surface model (DSM) and a photogrammetric DSM derived from a post-storm WorldView-3 stereo pair. The post-storm ground reference data consisted of field and unmanned aerial vehicle (UAV) observations of windthrow combined with no-damage areas collected by visual interpretation of the available very high resolution (VHR) satellite imagery. We trained and tested a thresholding model using canopy height change as the sole predictor. We undertook a two-step accuracy assessment by (1) running k-fold cross-validation on the ground reference dataset and examining the effect of the potential imperfections in the ground reference data, and (2) conducting rigorous accuracy assessment of the classified map of the study area using an extended set of VHR imagery. The thresholding model produced accurate windthrow maps in dense, productive forest stands with a sensitivity of 96%, specificity of 71%, and Matthews correlation coefficient (MCC) over 0.7. However, in sparse and high elevation stands, the classification accuracy was poor. Despite certain collection challenges during the winter months in the Nordic region, we consider VHR stereo satellite imagery to be a viable source of forest canopy height information and sufficiently accurate to map windthrow disturbance in forest stands of high to moderate density.