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
Authors
Desalegn Chala Diress Tsegaye Alemu Habtamu Alem Belachew Asalf Tadesse Melesse Eshetu_Moges Nega Tassie Abate Ayalew Wondie Aklilu Tilahun Tadesse Abebayehu Aticho Alemu Gonsamo Lanhui Wang Erick Lundgren Jeffrey Kerby Jens Christian SvenningAbstract
Abstract Water hyacinth is among the world’s most damaging aquatic invasive plants, forming dense mats that disrupt ecosystem functioning, fisheries, navigation, and livelihoods across tropical and subtropical freshwater systems. Its rapid spread is driven by clonal propagation, short life cycles, and prolific seed production, particularly under nutrient-enriched conditions. Although mechanical, chemical, and biological control methods are widely applied, their long-term effectiveness remains uncertain when underlying eutrophication persists. Here, we present a large-scale, one-time water hyacinth removal campaign in Lake Tana, Ethiopia’s largest lake and a UNESCO Biosphere Reserve, as a representative nutrient-rich tropical freshwater system. Using high-resolution satellite imagery, we quantified coverage one month before removal, one month after removal, and one year later. We integrated SWOT (Strengths, Weaknesses, Opportunities, Threats) analysis with a socio-ecological system map to assess mitigation mechanisms and identify sustainable management pathways capable of providing long-term solutions to halt water hyacinth proliferation in freshwater bodies. The campaign removed over 75% (~1271 ha) of water hyacinth, yet within one year the plant resurged to levels ~18% higher than pre-removal. This rebound highlights the ecological resilience of water hyacinth and the limitations of short term, noncontinuous control strategies. Our analysis identifies unmanaged catchment nutrient inputs as the primary driver of proliferation. Lake Tana serves as a model system demonstrating that water hyacinth functions less as a traditional invader and more as a bioindicator of eutrophication. We propose a transferable conceptual and methodological framework combining continuous removal, catchment-based nutrient management, and circular bioeconomy approaches, offering globally relevant lessons for sustainable management of nutrient-enriched tropical freshwater systems.
Abstract
Errors in thematically detailed land-cover maps have large consequences for downstream applications. Moreover, simulation-based studies suggest that land-cover classifiers are sensitive to errors in reference data. We (1) quantified the expected error from field interpretation of land-cover types; (2) the sensitivity of classifiers to reference data errors; and (3) the error transferred from reference data to classifiers. Lastly, we (4) recommended strategies to reduce errors. The study area was mapped by 12 field interpreters divided into three equal-sized experience-level groups. The field-based land-cover maps were aggregated to three thematic resolutions and used to train 6804 land-cover classifiers by varying inputs, algorithm, and hyperparameter values. Separately from the first field campaign, four field interpreters classified validation data points, which were used to quantify error for each field interpreter and land-cover classifier, as the proportion of incorrectly classified validation points. We observed (1) generally high and varying levels of interpreter error; (2) a strong relationship between interpreter and classifier error; and (3) a net positive transfer of errors from reference data to classifiers. Because classifier error seems largely driven by interpreter error at the levels commonly observed in thematically detailed land-cover mapping, we (4) recommend strategies to reduce interpreter error before modelling.
Abstract
Aim Four different grassland types of varying land-use intensity and history were investigated for changes in plant species composition and richness over a 7- to 10-year period. Shifts in species occurrence frequencies and species-specific indicator values for nectar production were analyzed to assess how vegetation changes may influence the availability of floral rewards. Location Norwegian mainland. Methods We utilized survey (2004–2008) and resurvey (2011–2018) data from the Norwegian Monitoring Program for Agricultural Landscapes, examining vegetation in managed and unmanaged grasslands from 538 permanent vegetation plots within 97 monitoring squares across Norway. Using species-specific indicator values for nectar production, we tested how compositional changes in vascular plant communities are reflected in the occurrence frequency and cover of pollen- and nectar-providing plants. Results Grassland species composition has slightly shifted toward communities more dominated by later successional species, particularly those associated with shadier and wetter conditions. Major changes in the occurrence frequencies of individual species suggest a decline in pollen and nectar production. Specifically, 29 of 40 species (72.5%) that showed significant decreases in frequency were flowering plants important for pollinators. Across all grassland types, the average cover of pollen- and nectar-producing plants has declined over time, indicating a reduction in floral resources available to pollinating insects. Conclusions Our findings indicate a gradual transition in grassland habitats toward conditions that may be less favorable to pollinators, as reflected by changes in species occurrence frequencies and plant cover. Additionally, plant species associated with moist environments are likely to increase in abundance under continued climate change. This study highlights the value of systematic grassland monitoring within agricultural landscapes as an effective tool for detecting vegetation changes, even over short time spans. Such monitoring supports timely decision-making and the implementation of targeted management strategies to preserve ecologically and economically important habitat types.
Authors
Ming Yu Sebastian Kepfer-Rojas Yamina Micaela Rosas Teresa Gómez de la Bárcena Inger Kappel Schmidt Per Gundersen Ludovica D'Imperio Carsten W. Mueller Lars VesterdalAbstract
Afforestation of agricultural land is widely promoted as a nature-based solution to enhance carbon (C) sequestration and mitigate atmospheric CO2 levels. However, the temporal dynamics of soil organic carbon (SOC) after afforestation, particularly in mineral soils, remain uncertain due to the complex interaction of biogeochemical processes and their spatial variability. We investigated changes in SOC sequestration over five decades of afforestation on former cropland by extending the chronosequence approach with three repeated soil inventories in oak (Quercus robur L.) and Norway spruce (Picea abies (L.) Karst.) stands. Aboveground biomass C stocks were also quantified to evaluate the contribution of SOC to post-agricultural ecosystem C stocks. Forest floor C stocks increased rapidly in the early years and stabilized after approximately three decades, with consistently higher accumulation under Norway spruce than oak. In contrast, mineral SOC stocks in 0-25 cm depth increased with forest age by 0.18 ± 0.06 Mg ha−1 yr−1 under oak and 0.44 ± 0.07 Mg ha−1 yr−1 under Norway spruce. These contrasting trends in forest floor and mineral soil indicated a shift in C source-sink strength over time and between species. After 50 years of afforestation, total ecosystem C stocks in afforested stands reached up to 75% of those in a 200-year-old forest, with most new C stored in biomass (84-86%), followed by mineral soil (10-11%) and forest floor (4-5%). Despite higher sequestration of new C in Norway spruce stands, the relative distribution across ecosystem compartments was similar between tree species.
Authors
Adam Eindride Naas Trond Simensen Lasse Torben Keetz Ingrid Vesterdal Tjessem Anders Bryn Rune Halvorsen Peter Horvath Ida Marielle Mienna Olav Skarpaas Joachim Paul Töpper Vigdis Vandvik Liv Guri Velle Catharina Caspara VloonAbstract
Field-based ecosystem maps are often used to support environmental impact assessments (EIAs) in later stages of spatial planning. During the early stages, however, information on geographical distributions of ecosystems is typically unavailable. This can result in uninformed decisions, with negative consequences for biodiversity and ecosystem services. Although model-based maps offer low-cost wall-to-wall coverage, they are rarely used for spatial planning. Using Norway as a study system, we aimed to: (1) quantify the coverage of field-based ecosystem maps in areas reserved for development; (2) use a model-based map to assess ecosystem extents in these areas; and (3) provide guidance on how model-based maps can support spatial planning. We first collated municipality-level land-use plans and intersected these with existing field-based ecosystem maps created for EIAs. Then, we constructed a model-based map for 17 ecosystem types with a 10 m × 10 m resolution that was intersected with the unsurveyed land-use plans. We estimated that 4.2 km2 of land is reserved for development in an average municipality, of which 0.3 km2 is covered by field-based maps. Our model-based map indicates, with moderate uncertainty, that 260 km2 covered by red-listed ecosystem types is at risk of being affected if unsurveyed land reserves are developed. However, improvements in model training and uncertainty quantification methodology should be considered to increase utility of the maps. We provide guidelines for using model-based ecosystem maps in spatial planning, especially in early planning stages, aiming to support decision-making while taking the limitations of model-based maps into account.
Authors
Gaute Velle Anders Bryn Kyrre Kausrud Lawrence R. Kirkendall Martin Malmstrøm Brett Kevin Sandercock Paul Ragnar Berg Kjetil Hindar Johanna Järnegren Erlend Birkeland Nilsen Eva Bonsak Thorstad Anders NielsenAbstract
This report examines how co-occurring non-native species can interact to create cumulative impacts on ecosystems. Non-native species may interact in additive, antagonistic, or synergistic ways. Through literature review, we found theoretical foundations and empirical examples showing that such interactions often occur. Synergistic interactions are of particular concern. Certain ecosystems appear particularly susceptible, including agricultural landscapes, urban environments, riparian systems, shipping-influenced marine areas, and islands with naïve fauna. We conclude that cumulative effects are ecologically important, and that it would be beneficial to incorporate multispecies interactions into risk assessments of non-native species in Norway.
Authors
Terje Christensen Are Røysamb Ulrike Bayr Dieu Tien Bui Guðrún Helgadóttir Nina Johansen Joern Klein Mieke Cornelia Louwe Randi Mork Kyung Binn Noh Stefanie Reinhardt Trude Eid Robsahm Kristin Helen Roll Øyvind Steifetten Per Strömberg Gry Tengmark Østenstad Veronika ZaikinaAbstract
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.
2025
Abstract
No abstract has been registered
Abstract
Presentasjon av kartbasert klimagasskalkulator.
Authors
Teresa Gómez de la Bárcena Tatiana Francischinelli Rittl Eva Farkas Daniel Rasse Christophe Moni Cédric Plessis Loiuse Malot Helge Meissner Trond Henriksen Randi Berland FrøsethAbstract
Background and aims Cover crops are an important measure for carbon (C) sequestration in agriculture. However, little is known about the potential of cover crops to increase C under Nordic conditions and the efficiency of this measure over time. Here, we quantify the potential contribution of different cover crops to soil organic carbon (SOC) and organic matter fractions, and study how this is affected by the origin of the C input (aboveground or belowground residues). Methods We conducted a 13 CO 2 pulse-labelling experiment during the growing season of four cover crops adapted to Nordic conditions, representing different plant functional types. The assimilated 13 C was traced in soil during the following two years. We investigated the fate of cover crop C in two organic matter fractions, Particulate Organic Matter (POM) and Mineral-Associated Organic Matter (MAOM), known to have different persistence in soil. Results Carbon derived from aboveground residues decayed two to three times faster as compared to belowground C. Belowground C inputs were similar among cover crops despite their contrasting root traits and differences in root biomass C. Rhizodeposited-C was consistently the largest belowground C input. Cover crop species affected the quantity of POM-C and MAOM-C, but MAOM-C was preferentially formed from belowground C (ranging from 0.63 ± 0.2 to 0.25 ± 0.1 Mg MAOM-C ha −1 across different cover crops), regardless of the species. Conclusions Cover crop species that can combine large belowground biomass production with root traits that promote physical and physico-chemical protection of OM will contribute most effectively to the long-term SOC pool. These aspects need to be balanced with considerations related to agricultural management.