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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.

2026

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Abstract

Accurate individual tree delineation (ITD) is essential for forest monitoring, biodiversity assessment, and ecological modeling. While remote sensing (RS) has significantly advanced forest ITD, challenges persist, especially in complex forest environments. The use of imagery data is compelling given the rapid increase in available high-resolution aerial and satellite imagery data, the increasing need for image-based analysis where reliable 3D data are unavailable, the widening gap between data supply and processing capabilities, and the limited validation of state-of-the-art (SOTA) methods across diverse real-world conditions. This study aims to advance ITD research by evaluating SOTA instance segmentation approaches, including both recently developed and established methods. The analysis evaluates ITD algorithm performance using the largest forest instance-segmentation imagery dataset to date and standardized evaluation protocols. This study identifies key factors affecting accuracy, reveals remaining challenges, and outlines future research directions. Findings in this study reveal that ITD accuracy is heavily influenced by image resolution, forest structure, and method design. Findings also reveal that, while algorithm innovations remain important, robustness and transferability that ensure generalization across diverse environments are what differentiate method performances. In addition, this study highlights that commonly used evaluation metrics may fail to adequately capture precise performance in specific applications, e.g., individual-tree-crown segmentation in this study. Assessment reliability can be strengthened through the adoption of stricter criteria. Future research should focus on expanding datasets, refining evaluation protocols, and developing adaptive models capable of handling varying canopy structures. These advancements will enhance ITD scalability and reliability, contributing to more effective forest research and management at a global scale.

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Transitioning towards more circular farming systems, which prioritise using renewable and recycled resources to reduce reliance on external inputs, offers potential to improve nutrient cycling, enhance farm profitability and mitigate greenhouse gas emissions. However, widespread adoption remains limited. To support the wider adoption of circular farming practices across diverse rural and agroecological settings, we examined how psychological, contextual and motivational factors shape farmers’ sentiment and decision-making. A mixed-methods approach—combining sentiment and thematic analysis—was applied to interviews and focus groups with 96 farmers and industry stakeholders across Italy, Norway and the UK. Sentiment towards circular farming practices varied across national contexts, with UK farmers expressing more positive views overall than Norwegian farmers, and Italian farmers positioned in between. These differences reflected how well practices aligned with existing knowledge, values and farming systems, while negative sentiment was primarily associated with policy impracticalities, investment costs and local constraints, highlighting key political and structural barriers to adoption. The findings underscore the need to align circular strategies with local contexts. To support wider adoption, we recommend (1) enhancing psychological capability (e.g. aligning practices with farmers’ knowledge): through a flexible ‘toolbox’ of practices; (2) addressing physical opportunity barriers via co-designed, locally-adapted policies; and (3) strengthening reflective motivation by communicating and deliberating the broader co-benefits of circular practices. These informed insights provide more effective and inclusive strategies for sustainable agriculture and rural development across Europe.

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Edible coleopteran insects are an important source for sustainable protein and generating chitin as a significant waste (exuviae, cuticle residues, and frass), which can be valorized into value-added biopolymers. These side-streams can be diverted for chitin and chitosan production due to their biocompatibility and biodegradability in biomaterial applications which gained attention in recent times. Therefore, this review evaluates various types of chitin and chitosan extractions and their structural characterization suitable for industrial applications. The nutritional and bioactive functionalities of chitin as derived from coleoptera insect side-streams were critically discussed. Furthermore, it also distinguishes the presence of α-, β-, and γ-chitin polymorphic forms exhibited in the coleopterans order with recent research gaps was also discussed herein. Currently, there is no literature review that describes the roles of coleopteran side-streams derived chitin and chitosan. Hence, this review not only underscores the potential for chitin production from coleopteran side-streams but also outlines critical bottlenecks that warrant further investigation in biopolymer chemistry. Moreover, it provides comprehensive recommendations to facilitate the scale-up of chitin and chitosan derived from coleopteran side-streams as an added advantage for new business models.

Abstract

Agricultural production is highly dependent upon pollinators to achieve maximum yield and increase global food security. Wild pollinators, such as bees, are declining due to a loss of habitat from agricultural intensification, and the use of domesticated honeybees to supplement pollination services is increasing. Apple is an important, pollinator dependent food crop that commonly experiences pollination and production deficits worldwide. In this thesis, I explored whether pollination and production deficits occur in Norwegian apple orchards and what factors might be driving potential deficits. To test for pollination (seed set) and production (yield) deficits I conducted a supplemental pollination experiment for three cultivars, in eighteen orchards, in two distinct growing regions in Norway, over two years. I also assessed which pollinators are present in Norwegian apple orchards and how different groups of bees and their behaviour affect pollination of apple. Lastly, I studied different management practices to increase bee diversity and pollination success, by increasing alternate floral resources and evaluating orchard design that promotes cross-pollination. Pollination and production deficits were found across all locations, with differences in pollination deficits among cultivars. I also found that a high abundance of wild bees increases seed set in apples—a key indicator of pollination success. Behaviour also varied among bee groups, for example bumblebees visited more flowers, while solitary bees were slow, but potentially more thorough, foragers, which increases pollen deposition. Wild bees visited more apple flowers than dandelion flowers (Taraxacum spp.) when orchards were left unmowed. I also found that a higher abundance of dandelions increased bee visitation to apple flowers, suggesting higher floral diversity can increase pollination success and support a greater diversity of bees. In addition, block design orchards appear to limit cross-pollination among apple cultivars, and management actions to decrease the distance among compatible apple cultivars is needed to achieve sufficient pollination. Overall, my results suggest that greater pollination and production of apples in Norway is possible, and management actions should focus on increasing wild bee abundance and diversity, increasing alternate floral resources, and optimising orchard design to facilitate cross-pollination across shorter distances. Such actions have the potential to ensure greater yields of higher quality apples for human consumption and increased economic output for farmers.

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Abstract

Abstract Energy-efficient lighting solutions, while beneficial for reducing energy consumption, also pose challenges in terms of light pollution. Light pollution, defined as excessive or misdirected artificial light, has become a significant environmental issue globally. This perspective paper explores the extent, effects, and knowledge gaps related to light pollution, with a focus on its impact on human health, ecosystems, and energy consumption. This study focuses on Norway, a country that is particularly relevant for studying light pollution due to its far northern location. At high latitudes, the variation in natural light is larger over the year than at lower latitudes. Therefore, a Nordic perspective is valuable to present knowledge about effects of artificial lighting under these conditions. Under the midnight sun, minimal additional outdoor lighting is required, whereas during the winter season, outdoor lighting may be utilised continuously. The paper synthesizes findings from various studies, highlighting the rapid increase in light pollution due to urbanisation, infrastructure development, and the widespread adoption of LED technology. Human health effects include alterations of circadian rhythms, increased risk of accidents, and potential links to serious diseases such as cancer. Ecosystem impacts are profound, affecting a number of species i.e., within insects and bats, and may lead to for instance disturbances in navigation and circadian rhythms, habitat fragmentation, and altered predator–prey dynamics. This article identifies significant knowledge gaps, particularly in the measurement of light pollution, understanding its health effects, and its impact on various species. Recommendations for future research and policy development are provided, emphasising the need for interdisciplinary approaches to mitigate the adverse effects of light pollution and promote sustainable lighting practices.

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High-yielding forage grasslands frequently contain low species diversity and receive high inputs of nitrogen fertilizer. To investigate multispecies mixtures as an alternative strategy, the 26-site international LegacyNet experiment systematically varied the diversity of sown grasslands using up to six high-yielding forage species (grasses, legumes, and herbs) managed under moderate nitrogen inputs. Multispecies mixtures outyielded two widely used grassland practices: a grass monoculture with higher nitrogen fertilizer and a two-species grass-legume community. High yields in multispecies mixtures were driven by strong positive grass-legume and legume-herb interactions. In warmer sites, the yield advantage of legume-containing multispecies mixtures over grass monocultures with higher nitrogen fertilizer inputs increased. Improved design of grassland mixtures can inform more environmentally sustainable forage production and may enhance adaptation of productive grasslands to a warming climate.

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Abstract

ABSTRACT Increasing drought frequency and intensity affect biophysical functions of natural ecosystems. In tropical semi‐arid savannas, while immediate drought effects are well‐studied, the drought legacy effects on vegetation composition and associated ecosystem functions remain unclear. We used data of vegetation composition, net ecosystem CO 2 exchange, surface albedo and evapotranspiration (ET) in 2017–2022 from a savanna ecosystem, Southwest China, to investigate the legacy effect of an extreme drought event that occurred in 2019. Vegetation declined continuously for 3 post‐drought years. While tree numbers declined by 12%, shrub numbers dropped by 50% compared with pre‐drought levels, shifting vegetation dominance toward trees. This structural change caused sustained reductions in albedo and ET, which remained below pre‐drought levels, despite gross primary production recovering in the years immediately post‐drought. Vegetation shifts disproportionately impact ecosystem functions, with energy and water fluxes exhibiting greater vulnerability and potentially enhancing regional warming as droughts increase in Asian savannas.

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Sewage sludge-derived biochar, a carbon-rich material produced by the pyrolysis of sewage sludge, has emerged as a promising amendment for enhancing the fertility and biological quality of nutrient-poor sandy soils in tropical regions. We investigated the effects of sewage sludge (SS) and its biochar (SSB) on microbial indicators, nutrient dynamics, and sugarcane biomass growth in sandy soil over 120 days. Treatments included individual applications of SS (40 Mg ha−1) and SSB (20 Mg ha−1), their combinations at 75:25, 50:50, and 25:75 SS:SSB ratios, a mineral fertilizer, and an unfertilized control. Microbial biomass carbon (Cmic), basal C-CO2 flux, metabolic (qCO2) and microbial (qMic) quotients were monitored, along with ammonium and nitrate levels, available phosphorus (P), and carbon stock. SS promoted a rapid rise in microbial activity and Cmic, whereas SSB sustained these effects over time, demonstrating complementary roles. The 75:25 combination exhibited the strongest synergistic response, enhancing microbial efficiency (higher qMic and lower qCO2), P availability, and carbon storage. Ammonium and nitrate peaked during early and mid-stages, respectively, with the highest values under SS. At the same time, P availability and soil carbon stocks were maximized under 75:25. Sugarcane biomass increased significantly in this treatment, despite foliar N and P concentrations remaining below sufficiency levels. These results highlight clear synergistic interactions between SS and SSB, emphasizing that the 75:25 combination offers a balanced strategy to improve nutrient cycling, microbial functionality, and carbon stabilization in tropical sandy soils.

Abstract

Cover crops enhance soil quality and organic matter stability, yet the mechanisms linking belowground inputs to persistent soil organic matter (SOM) remain unclear. This study examined the effects of diversified cover cropping in barley systems on root biomass, SOM fractions, soil structure, microbial activity, and yield in central Norway (63.9° N), three years post-implementation. Six treatments were tested: (1) Control (barley without NPK), (2) Biochar-Fertilizer (barley + NPK + 3 Mg ha⁻¹ biochar), (3) Monocrop (barley), (4) Ryegrass (barley + ryegrass), (5) Clover (barley + ryegrass + white/red clover), and (6) Chicory (barley + ryegrass + red clover + chicory + bird’s-foot trefoil). Ryegrass and Clover systems produced 28.65 g m-² more root biomass at 0–13 cm (p < 0.05) and, along with Monocrop, stored 2.2 Mg ha-¹ more mineral-associated organic matter (MAOM) carbon and 0.2 Mg ha-¹ more MAOM nitrogen at 0–20 cm than other treatments. The Chicory system improved soil structure and biology, with higher aggregate stability, lower bulk density, and greater microbial abundance. Barley yields remained consistent across treatments, suggesting that cover cropping and low biochar inputs do not reduce productivity. Strong correlations (p < 0.01) between root biomass and MAOM stocks highlight root development as a key driver of SOM stabilization via organo-mineral associations. These findings underscore the role of root-enhancing cover crops in promoting MAOM formation and long-term SOM persistence, offering valuable insights for sustainable soil management.