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
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Authors
Catharina Caspara Vloon Rune Halvorsen Jørn-Frode Nordbakken Adam Eindride Naas Inger Auestad Knut RydgrenAbstract
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Clear-cutting can resemble natural disturbances like forest fire, but key differences exist in biological legacy. One way to enhance similarity is by preserving structural features of old-forests, such as retention trees, within harvested areas. The latest Programme for the Endorsement of Forest Certification (PEFC) standards require not only the preservation of retention trees but also their mapping for centralized reporting. This study evaluates the accuracy of retention tree density and volume predictions using airborne laser scanning (ALS) data with low (2 pulses/m2) and high (~100 pulses/m2) pulse densities, with and without spectral data. We also assess the feasibility of large-area predictions with minimal field data by testing both in-situ and ex-situ sources. The study was conducted in a managed 1300 ha forest in southeast Norway. Three reference datasets were used: (1) 630 in-situ retention trees across 27 stands (for species and DBH predictions), (2) 1604 ex-situ sample trees (for DBH predictions), and (3) 150 ex-situ annotated segments (for species predictions). Retention trees were identified using an individual tree segmentation approach, using adaptive local maxima window size and applying an adaptative height threshold to filter regeneration. ALS at 2 pulses/m2 alone provided reliable total density and volume predictions, while adding spectral data improved species-specific predictions. Species predictions were relatively stable across data source (kappa=0.556 for in-situ, 0.519 for ex-situ), but DBH predictions were notably underpredicted with ex-situ data (RMSE=9.40 cm, MSD=-4.55 cm) compared to in-situ data (RMSE=8.84 cm, MSD=0.20 cm). Using adaptive segmentation methods enhances scalability. We recommend sampling ~40 in-situ retention trees to develop DBH-height models and delineating ex-situ annotated segments for species predictions. This approach balances accuracy and efficiency while enabling retrospective analysis using national ALS datasets and orthophotos.
Authors
Johan Sjöström Ragni Fjellgaard Mikalsen Marius Hauglin Ellen Synnøve Skilbred Frida vermina Plathner Ana María De Lera Garrido Edvard Aamodt Kemal Sarp ArsavaAbstract
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Authors
Özgün Candan Onarman Umu Knut Espevig Simeon Rossmann Inger-Lise Akselsen Carl-Henrik Lensjø Alvin Marit Larssen SekseAbstract
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Reducing diffuse nutrient losses to water bodies remains a major problem in the agricultural areas of the Nordic countries. The transition towards a bioeconomy and ongoing climate change raise questions on the future of water quality and freshwater ecosystems and what kind of adaptation strategies could be implemented to maintain both food and environmental safety. The objective of our study was to evaluate the effectiveness of Natural Soil Water Retention Measures (NSWRMs) under current and future climate conditions in retaining water, soil particles and nutrients within the landscape. The hydro-biochemical model SWAT+ was implemented in the Krakstad catchment in southern Norway using the novel approach developed within the EU H2020 project OPTAIN. This approach enables an improved spatial representation of NSWRMs in the landscape. Available discharge and water quality monitoring data were used as reference data for model calibration. The effectiveness of reduced tillage, grassed waterways, sedimentation ponds established in the forested areas and buffers on water retention and nutrient loads was evaluated. Our simulation results indicate that conservation tillage, which maintains stubble on the soil surface during winter, has the strongest impact on reducing soil and nutrient losses towards surface water bodies. Grassed waterways, established in existing erosion prone gullies, could also significantly contribute to water and nutrient retention within the landscape. The implemented NSWRMs did not appear to increase the soil moisture content in early spring even under future climate conditions, which is an important aspect for ensuring soil trafficability and the timing of sowing spring cereals
Abstract
Fresh water quality problems in Norway are largely caused by high phosphorus (P) inputs from the catchments. The need for measures in the agricultural landscape, such as constructed wetlands (CWs), are needed and the importance of the measures will most probably increase due to the consequences of climate changes. In agricultural areas in South-Eastern Norway, several hundred small vertical flow CWs were established in the streams during the last two decades, to reduce downstream losses of sediments (SS) and nutrients. The focus of the CWs has been on reducing losses of P and SS, due to the naturally P-rich clay soils of marine origin in lowland areas. Whereas our study included 11 CWs altogether, we here present the data from the CW with the most intensive monitoring, i.e., the Skuterud CW, around 20 years after it was constructed. The catchment’s total area was 450 ha with 61% agricultural land. The CW occupies 0.05% of the catchment area. The methods included analyses of waterflow-proportional water composite samples, water grab samples, sensor monitoring (turbidity), bed sediments, and biological quality elements (invertebrates and benthic algae). Analyses of three years of composite samples showed a retention of 47 % for SS, 41 % for total phosphorus (TP), 4.2 % for total nitrogen (TN), 0.8 % for ortho-phosphate, and a negative retention for nitrate (i.e., nitrate leaching). Monitoring by turbidity sensors (correlations to SS and TP; R2 = 0,7802) during a 5 - month period showed that retention during episodes of elevated water discharges was 26 % for SS and 11 % for TP. Grab sampling gave more confusing results. It was revealed by the sensor monitoring that to assess the retention in CWs by grab sampling at the in- and outlet can be misleading, even if the sampling is done at the same time. The reason is the rapid variation in concentrations. Bed sediments have been removed from the CW several times since it was established, and in total approx. 1140 tons of SS and approx. 1090 kg of particle bound P. However, it is difficult to assess the total amount of retention, as we did not know the extent of leaching of nutrients from the bed sediments over the years. The analysis of invertebrates and benthic algae revealed that the ecological condition was better at the inlet and worse at the outlet (similar for five CWs). The reason is probably that the oxygen levels and substrate conditions are better at the inlet, where the running creek enters, whereas the outlet would have still-standing waters with lower oxygen contents and a clayey substrate. Moreover, this can be due to the method used, as the outlet area had fewer stones where the benthic algae could grow. Hence, it would be better to sample biology a bit more downstream, but that is often not practical, as the CWs often have their outlet into another stream or directly into a drainage system. In summary therefore, our recommendation is to use composite sampling and/or sensor monitoring (combined with grab sampling for correlation purposes), to assess the retention capacity of a CW. However, for cost-effective assessment of the effect of sediments and particle bound nutrients, bed sediments are recommended.
Abstract
Fertilizers and pesticides contribute to the pollution of water resources. The areas along streams are affected by climate change as stream bank failures often occur following floods or during prolonged rainfalls. In addition to BMP (best management practices) on the fields, grassed cover buffer zones are one of the most common measures for improving water quality in Norway’s agricultural catchments. Increased focus on buffer zones is important in a future climate perspective, both for food production, natural diversity and water quality. The efficiency of vegetation cover is composed of a variety of factors; therefore, effectives of these measures are to a large degree site specific. Recently, increased attention is given to the buffer zones efficiency, depending on both conditions in the catchments and the design of the buffer zones itself. However, most research is focusing in investigating the effect of buffer zones looking mostly at the surface runoff. According to our knowledge there is no previous research investigating the efficiency of the buffer zones with flower mixture. We focus on these types of vegetation as they also stimulate increased biodiversity. Moreover, previous investigations show that more than 50% of simulated runoff infiltrates into buffer zones with grass and bushes, while within buffer zones with trees there all the water infiltrates into the soil. Herein we show the results of 3 years monitoring surface runoff from buffer zones with different types of plant cover (grass and flower mixture). The idea was to monitor real live surface runoff from the field with autumn tillage (as “worst case scenario”). The results show significant differences, especially in the runoff quality. The visual differences are confirmed by water quality analysis.
Authors
Martyn Futter Emma Lannergård Katrin Bieger Csilla Farkas Jens Fölster Pia Geranmayeh Anastasija Isidorova Brien Kronvang Dominika Krzeminska Katarina Kyllman Ainis Lagzdins Anu Lähteenmäki-Uutela Hannu Marttila Michael Peacock Katri Rankinen Eva Skarbøvik Anne Lyche Solheim Pasi Valkama Joachim AudetAbstract
Society increasingly expects that food will be produced in a sustainable, climate-smart manner. Nature based solutions (NBS), including ponds and constructed wetlands are widely promoted by researchers as a class of measures promoting healthy agricultural landscapes. However, a range of trade-offs associated with NBS influence practitioner’s decisions about their implementation and use. Making the right decisions about NBS requires, amongst other things, access to data from environmental monitoring programmes. The value of monitoring programmes depends on how well the data they collect and curate can be used to support decision-making. Here, we present a conceptual framework for assessing the value of monitoring programmes based on the relevance of the data they collect to decision maker needs, their overall running costs and their levels of uncertainty in characterizing the state of the environment. We demonstrate how our proposed framework can be used to assess the value of a range of monitoring programmes for quantifying trade-offs between nutrient load reduction and climate impacts from artificial wetlands in agricultural landscapes.