Rune Halvorsen

• Ransedokken, Yngvild Eidissen; Asplund, Johan; Morgado, Luis; Kauserud, Håvard; Mundra, Sunil & Ohlson, Mikael [Vis alle 8 forfattere av denne artikkelen] (2024). Synchronic shifts in phenolic compounds and fungal communities during litter decomposition in boreal forests. Forest Ecology and Management. ISSN 0378-1127. 554. doi: 10.1016/j.foreco.2024.121696.
• Bendiksby, Mika; Thorbek, Birgitte Lisbeth Graae; Bjorå, Charlotte Sletten & Halvorsen, Rune (2023). Improving procedures for obtaining Sanger sequences from old herbarium specimens . Bauhinia. ISSN 0067-4605. Fulltekst i vitenarkiv Vis sammendrag

  Because DNA degrades over time, extracting DNA of sufficient quality for sequencing is presumed to be more difficult from older than younger herbarium specimens. Although massive parallel sequencing techniques have clear advantages when it comes to sequencing ancient DNA, Sanger sequencing is still in frequent use, prompting us to test and improve its application on herbarium specimens. During molecular phylogenetic investigations of the subfamily Lamioideae (Lamiaceae) and subgroups, we extracted DNA from 651 herbarium specimens collected between 1826 and 2006 using regular mini-prep methods. The aim was to obtain DNA of sufficient quality for Sanger sequencing of various plastid and nuclear genetic markers. Here, we report successful Sanger sequencing of the commonly used plastid marker, rps16, as a conservative measure of DNA quality, and logistic regression to investigate the relationship between age of the material and DNA quality. Our result indicates that the upper age limit for obtaining DNA suitable for Sanger sequencing from herbarium specimens using regular mini-prep DNA extraction methods has not been reached. After simple modifications to the regular DNA mini-prep and PCR procedures, at least one genetic marker was successfully sequenced for about 90 % of the specimens tested, the oldest being 168 years old. Jointly, despite the technique's drawbacks, these results demonstrate a high success rate of Sanger sequencing of herbarium specimens.

• Auestad, Inger; Rydgren, Knut; Halvorsen, Rune; Avdem, Ingrid Hofmo; Berge, Rannveig & Bollingberg, Ina Marie [Vis alle 7 forfattere av denne artikkelen] (2023). Use climatic space-for-time substitutions with care: Not only climate, but also local environment affect performance of the key forest species bilberry along elevation gradient. Ecology and Evolution. ISSN 2045-7758. 13(8). doi: 10.1002/ece3.10401. Fulltekst i vitenarkiv Vis sammendrag

  An urgent aim of ecology is to understand how key species relate to climatic and environmental variation, to better predict their prospects under future climate change. The abundant dwarf shrub bilberry (Vaccinium myrtillus L.) has caught particular interest due to its uphill expansion into alpine areas. Species' performance under changing climate has been widely studied using the climatic space-for-time approach along elevation gradients, but potentially confounding, local environmental variables that vary along elevation gradients have rarely been considered. In this study, performed in 10 sites along an elevation gradient (200–875 m) in W Norway, we recorded species composition and bilberry performance, both vegetative (ramet size and cover) and reproductive (berry and seed production) properties, over one to 4 years. We disentangled effects of local environmental variables and between-year, climatic variation (precipitation and temperature), and identified shared and unique contributions of these variables by variation partitioning. We found bilberry ramet size, cover and berry production to peak at intermediate elevations, whereas seed production increased upwards. The peaks were less pronounced in extreme (dry or cold) summers than in normal summers. Local environmental variables explained much variation in ramet size and cover, less in berry production, and showed no relation to seed production. Climatic variables explained more of the variation in berry and seed production than in ramet size and cover, with temperature relating to vegetative performance, and precipitation to reproductive performance. Bilberry's clonal growth and effective reproduction probably explain why the species persists in the forest and at the same time invades alpine areas. Our findings raise concerns of the appropriateness of the climatic space-for-time approach. We recommend including both climatic and local environmental variables in studies of variation along elevation gradients and conclude that variation partitioning can be a useful supplement to other methods for analysing variation in plant performance.

• Økland, Tonje; Halvorsen, Rune; Lange, Holger; Nordbakken, Jørn-Frode & Clarke, Nicholas (2023). Climate change drives substantial decline of understorey species richness and abundance in Norway spruce forests during 32 years of vegetation monitoring. Journal of Vegetation Science (JVS). ISSN 1100-9233. 34(3). doi: 10.1111/jvs.13191. Fulltekst i vitenarkiv Vis sammendrag

  Questions Observations in permanent forest vegetation plots in Norway and elsewhere indicate that complex changes have taken place over the period 1988–2020. These observations are summarised in the “climate-induced understorey change (CIUC)” hypothesis, i.e. that the understorey vegetation of old-growth boreal forests in Norway undergoes significant long-term changes and that these changes are consistent with the ongoing climate change as an important driver. Seven testable predictions were derived from the CIUC hypothesis. Location Norway. Methods Vegetation has been monitored in a total of 458 permanently marked plots, each 1 m2, in nine old-growth forest sites dominated by Picea abies at intervals of 5–8 years over the 32-year study period. For each of the 52 combinations of site and year, we obtained response variables for the abundance of single species, abundance and species density of taxonomic–ecological species groups and two size classes of cryptogams, and site species richness. All of these variables were subjected to linear regression modelling with site and year as predictors. Results Mean annual temperature, growing-season length and the number of days with precipitation were higher in the study period than in the preceding ca. 30-year period, resulting in increasingly favourable conditions for bryophyte growth. Site species richness decreased by 13% over the 32-year study period. On average, group abundance of vascular plants decreased by 24% (decrease in forbs: 38%). Patterns of group abundance change differed among cryptogam groups: although peat-moss abundance increased by 39%, the abundance of mosses, hepatics and lichens decreased by 13%, 49% and 67%, respectively. Group abundance of small cryptogams decreased by 61%, whereas a 13% increase was found for large cryptogams. Of 61 single species tested for abundance change, a significant decrease was found for 43 species, whereas a significant increase was found only for 6 species. Conclusions The major patterns of change in species richness, group species density and group abundance observed over the 32-year study period accord with most predictions from the CIUC hypothesis and are interpreted as direct and indirect responses to climate change, partly mediated through changes in the population dynamics of microtine rodents. The more favourable climate for bryophyte growth explains the observed increase for a few large bryophyte species, whereas the decrease observed for small mosses and hepatics is interpreted as an indirect amensalistic effect, brought about by shading and burial in mats of larger species and accelerated by reduced fine-scale disturbance by microtine rodents. Indirect effects of a thicker moss mat most likely drive the vascular plant decline although long-term effects of tree-stand dynamics and former logging cannot be completely ruled out. Our results suggest that the ongoing climate change has extensive, cascading effects on boreal forest ecosystems. The importance of long time-series of permanent vegetation plots for detecting and understanding the effects of climate change on boreal forests is emphasised.

• Naas, Adam Eindride; Halvorsen, Rune; Horvath, Peter; Wollan, Anders Kvalvåg; Bratli, Harald & Brynildsrud, Katrine Marie [Vis alle 16 forfattere av denne artikkelen] (2023). What explains inconsistencies in field-based ecosystem mapping? Applied Vegetation Science. ISSN 1402-2001. 26(1). doi: 10.1111/avsc.12715. Fulltekst i vitenarkiv Vis sammendrag

  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.

• Simensen, Trond; Halvorsen, Rune & Erikstad, Lars (2022). Gradient analysis of landscape variation in Norway. Sommerfeltia. ISSN 0800-6865. 40(1), s. 1–193. doi: 10.2478/som-2022-0001. Fulltekst i vitenarkiv
• Bässler, Claus; Heilmann-Clausen, Jacob; Andrew, Carrie; Boddy, Lynne; Büntgen, Ulf & Diez, Jeffrey [Vis alle 17 forfattere av denne artikkelen] (2022). European mushroom assemblages are phylogenetically structured by temperature. Ecography. ISSN 0906-7590. doi: 10.1111/ecog.06206. Fulltekst i vitenarkiv
• Ariza Salazar, Maria; Fouks, Bertrand; Mauvisseau, Quentin; Halvorsen, Rune; Alsos, Inger Greve & de Boer, Hugo (2022). Plant biodiversity assessment through soil eDNA reflects temporal and local diversity. Methods in Ecology and Evolution. ISSN 2041-210X. 14(2), s. 415–430. doi: 10.1111/2041-210X.13865. Fulltekst i vitenarkiv
• Tholstrup, Ditte Wiig; Halvorsen, Rune & Dahlgren, Johan P. (2021). Age matters: Demographic senescence in the moss Polytrichastrum formosum. Journal of Ecology. ISSN 0022-0477. 109(8), s. 3024–3030. doi: 10.1111/1365-2745.13717. Fulltekst i vitenarkiv
• Horvath, Peter; Halvorsen, Rune; Simensen, Trond & Bryn, Anders (2021). A comparison of three ways to assemble wall-to-wall maps from distribution models of vegetation types. GIScience & Remote Sensing. ISSN 1548-1603. 58(8), s. 1458–1476. doi: 10.1080/15481603.2021.1996313. Fulltekst i vitenarkiv Vis sammendrag

  Distribution modeling methods are used to provide occurrence probability surfaces for modeled targets. While most often used for modeling species, distribution modeling methods can also be applied to vegetation types. However, surfaces provided by distribution modeling need to be transformed into classified wall-to-wall maps of vegetation types to be useful for practical purposes, such as nature management and environmental planning. The paper compares the performance of three methods for assembling predictions for multiple vegetation types, modeled individually, into a wall-to-wall map. The authors used grid-cell based probability surfaces from distribution models of 31 vegetation types to test the three assembly methods. The first, a probability-based method, selected for each grid cell the vegetation type with the highest predicted probability of occurrence in that cell. The second, a performance-based method, assigned the vegetation types, ordered from high to low model performance, to a fraction of the grid cells given by the vegetation type’s prevalence in the study area. The third, a prevalence-based method, differed from the performance-based method by assigning vegetation types in the order from low to high prevalence. Thus the assembly methods worked in two principally different ways: the probability-based method assigned vegetation types to grid cells in a cell-by-cell manner, and both the performance-based method and prevalence-based method assigned them in a type-by-type manner. All methods were evaluated by use of reference data collected in the field, more or less independently of the data used to parameterize the vegetation-type models. Quantity, allocation, and total disagreement, as well as proportional dissimilarity metrics, were used for evaluation of assembly methods. Overlay analysis showed 38.1% agreement between all three assembly methods. The probability-based method had the lowest total disagreement with, and proportional dissimilarity from, the reference datasets, but the differences between the three methods were small. The three assembly methods differed strongly with respect to the distribution of the total disagreement on its quantity and allocation components: the cell-by-cell assignment method strongly favored allocation disagreement and the type-by-type methods strongly favored quantity disagreement. The probability-based method best reproduced the general pattern of variation across the study area, but at the cost of many rare vegetation types, which were left out of the assembled map. By contrast, the prevalence-based and performance-based methods represented vegetation types in accordance with nationwide area statistics. The results show that maps of vegetation types with wall-to-wall coverage can be assembled from individual distribution models with a quality acceptable for indicative purposes, but all the three tested methods currently also have shortcomings. The results also indicate specific points in the methodology for map assembly that may be improved. area frame survey, assembly strategies, distribution modeling, spatial probabilities, vegetation mapping, vegetation types

• Bryn, Anders; Bekkby, Trine; Rinde, Eli; Gundersen, Hege & Halvorsen, Rune (2021). Reliability in Distribution Modeling—A Synthesis and Step-by-Step Guidelines for Improved Practice. Frontiers in Ecology and Evolution. ISSN 2296-701X. 9. doi: 10.3389/fevo.2021.658713. Fulltekst i vitenarkiv Vis sammendrag

  Information about the distribution of a study object (e.g., species or habitat) is essential in face of increasing pressure from land or sea use, and climate change. Distribution models are instrumental for acquiring such information, but also encumbered by uncertainties caused by different sources of error, bias and inaccuracy that need to be dealt with. In this paper we identify the most common sources of uncertainties and link them to different phases in the modeling process. Our aim is to outline the implications of these uncertainties for the reliability of distribution models and to summarize the precautions needed to be taken. We performed a step-by-step assessment of errors, biases and inaccuracies related to the five main steps in a standard distribution modeling process: (1) ecological understanding, assumptions and problem formulation; (2) data collection and preparation; (3) choice of modeling method, model tuning and parameterization; (4) evaluation of models; and, finally, (5) implementation and use. Our synthesis highlights the need to consider the entire distribution modeling process when the reliability and applicability of the models are assessed. A key recommendation is to evaluate the model properly by use of a dataset that is collected independently of the training data. We support initiatives to establish international protocols and open geodatabases for distribution models.

• Simensen, Trond; Erikstad, Lars & Halvorsen, Rune (2021). Diversity and distribution of landscape types in Norway. Norsk Geografisk Tidsskrift. ISSN 0029-1951. s. 1–23. doi: 10.1080/00291951.2021.1892177. Fulltekst i vitenarkiv Vis sammendrag

  Norwegian landscapes are changing at an increasingly rapid rate and therefore systematically structured information about observable landscape variation is required for knowledge-based management of landscape diversity. The purpose of the article is to present the first version of a complete, area covering, evidence-based, landscape type map of Norway, simultaneously addressing geoecological, bioecological and land use related variations. The type system used for the mapping is supported by systematically structured empirical evidence. The results of the mapping procedure, including the geographical distribution and descriptive statistics (abundance and areal coverage), are presented for each of the nine identified major landscape types identified based on coarse-scale landform variation. Within six inland and coastal major types, a large number of minor landscape types are defined based on the composition of geoecological, bioecological, and land use related landscape properties. The results provide new insights into the geography of Norwegian marine, coastal and inland landscapes. The authors discuss potential errors, uncertainties and limitations of the landscape type maps, and address the potential value of the new tool for research, management and planning purposes. They conclude that the results of the study might contribute to knowledge-based spatial planning and management of the unique landscape diversity of Norway.landscape diversity, landscape mapping, landscape type, Norway

• Horvath, Peter; Tang, Hui; Halvorsen, Rune; Stordal, Frode; Tallaksen, Lena M. & Berntsen, Terje Koren [Vis alle 7 forfattere av denne artikkelen] (2021). Improving the representation of high-latitude vegetation distribution in dynamic global vegetation models. Biogeosciences. ISSN 1726-4170. 18(1), s. 95–112. doi: 10.5194/bg-18-95-2021. Fulltekst i vitenarkiv Vis sammendrag

  Vegetation is an important component in global ecosystems, affecting the physical, hydrological and biogeochemical properties of the land surface. Accordingly, the way vegetation is parameterized strongly influences predictions of future climate by Earth system models. To capture future spatial and temporal changes in vegetation cover and its feedbacks to the climate system, dynamic global vegetation models (DGVMs) are included as important components of land surface models. Variation in the predicted vegetation cover from DGVMs therefore has large impacts on modelled radiative and non-radiative properties, especially over high-latitude regions. DGVMs are mostly evaluated by remotely sensed products and less often by other vegetation products or by in situ field observations. In this study, we evaluate the performance of three methods for spatial representation of present-day vegetation cover with respect to prediction of plant functional type (PFT) profiles – one based upon distribution models (DMs), one that uses a remote sensing (RS) dataset and a DGVM (CLM4.5BGCDV; Community Land Model 4.5 Bio-Geo-Chemical cycles and Dynamical Vegetation). While DGVMs predict PFT profiles based on physiological and ecological processes, a DM relies on statistical correlations between a set of predictors and the modelled target, and the RS dataset is based on classification of spectral reflectance patterns of satellite images. PFT profiles obtained from an independently collected field-based vegetation dataset from Norway were used for the evaluation. We found that RS-based PFT profiles matched the reference dataset best, closely followed by DM, whereas predictions from DGVMs often deviated strongly from the reference. DGVM predictions overestimated the area covered by boreal needleleaf evergreen trees and bare ground at the expense of boreal broadleaf deciduous trees and shrubs. Based on environmental predictors identified by DM as important, three new environmental variables (e.g. minimum temperature in May, snow water equivalent in October and precipitation seasonality) were selected as the threshold for the establishment of these high-latitude PFTs. We performed a series of sensitivity experiments to investigate if these thresholds improve the performance of the DGVM method. Based on our results, we suggest implementation of one of these novel PFT-specific thresholds (i.e. precipitation seasonality) in the DGVM method. The results highlight the potential of using PFT-specific thresholds obtained by DM in development of DGVMs in broader regions. Also, we emphasize the potential of establishing DMs as a reliable method for providing PFT distributions for evaluation of DGVMs alongside RS.

• Sulavik, Jan; Auestad, Inger; Halvorsen, Rune & Rydgren, Knut (2020). Assessing recovery of alpine spoil heaps by vascular plant, bryophyte, and lichen functional traits. Restoration Ecology. ISSN 1061-2971. s. 1–12. doi: 10.1111/rec.13257. Fulltekst i vitenarkiv
• Halvorsen, Rune; Skarpaas, Olav; Bryn, Anders; Bratli, Harald; Erikstad, Lars & Simensen, Trond [Vis alle 7 forfattere av denne artikkelen] (2020). Towards a systematics of ecodiversity: the Ecosyst framework. Global Ecology and Biogeography. ISSN 1466-822X. 29(11), s. 1887–1906. doi: 10.1111/geb.13164. Fulltekst i vitenarkiv Vis sammendrag

  Background Although a standard taxonomy of organisms has existed for nearly 300 years, no consensus has yet been reached on principles for systematization of ecological diversity (i.e., the co‐ordinated variation of abiotic and biotic components of natural diversity). In a rapidly changing world, where nature is under constant pressure, standardized terms and methods for characterization of ecological diversity are urgently needed (e.g., to enhance precision and credibility of global change assessments). Aim The aim is to present the EcoSyst framework, a set of general principles and methods for systematization of natural diversity that simultaneously addresses biotic and abiotic variation, and to discuss perspectives opened by this framework. Innovation EcoSyst provides a framework for systematizing natural variation in a consistent manner across different levels of organization. At each ecodiversity level, EcoSyst principles can be used to establish: (a) an extensive attribute system with descriptive variables that cover all relevant sources of variation; (b) a hierarchical‐type system; and (c) a set of guidelines for land‐cover mapping that is consistent across spatial scales. EcoSyst type systems can be conceptualized as multidimensional models, by which a key characteristic (the response) is related to variation in one or more key sources of variation (predictors). EcoSyst type hierarchies are developed by a gradient‐based iterative procedure, by which the “ecodiversity distance” (i.e., the extent to which the key characteristic differs between adjacent candidate types) is standardized and the ecological processes behind observed patterns are explicitly taken into account. Application We present “Nature in Norway” (NiN), an implementation of the EcoSyst framework for Norway for the ecosystem and landscape levels of ecodiversity. Examples of applications to research and management are given. Conclusion The EcoSyst framework provides a theoretical platform, principles and methods that can complement and enhance initiatives towards a global‐scale systematics of ecodiversity. iodiversity complex gradient continuum theory ecodiversity ecosystem geodiversity gradient landscape mapping typology

• Auestad, Inger; Rydgren, Knut & Halvorsen, Rune (2020). Dataset properties affect the performance of the ordination regression-based approach (ORBA) in predicting time to recovery. Ecological Engineering: The Journal of Ecotechnology. ISSN 0925-8574. 152. doi: 10.1016/j.ecoleng.2020.105875.
• Simensen, Trond; Horvath, Peter; Vollering, Julien; Erikstad, Lars; Halvorsen, Rune & Bryn, Anders (2020). Composite landscape predictors improve distribution models of ecosystem types. Diversity and Distributions: A Journal of Conservation Biogeography. ISSN 1366-9516. 26(8), s. 928–943. doi: 10.1111/ddi.13060. Fulltekst i vitenarkiv Vis sammendrag

  Aim: Distribution modelling is a useful approach to obtain knowledge about the spatial distribution of biodiversity, required for, for example, red-list assessments. While distribution modelling methods have been applied mostly to single species, modelling of communities and ecosystems (EDM; ecosystem-level distribution modelling) produces results that are more directly relevant for management and decision-making. Although the choice of predictors is a pivotal part of the modelling process, few studies have compared the suitability of different sets of predictors for EDM. In this study, we compare the performance of 50 single environmental variables with that of 11 composite landscape gradients (CLGs) for prediction of ecosystem types. The CLGs represent gradients in landscape element composition derived from multivariate analyses, for example “inner-outer coast” and “land use intensity.” Location: Norway. Methods: We used data from field-based ecosystem-type mapping of nine ecosystem types, and environmental variables with a resolution of 100 × 100 m. We built nine models for each ecosystem type with variables from different predictor sets. Logistic regression with forward selection of variables was used for EDM. Models were evaluated with independently collected data. Results: Most ecosystem types could be predicted reliably, although model performance differed among ecosystem types. We identified significant differences in predictive power and model parsimony across models built from different predictor sets. Climatic variables alone performed poorly, indicating that the current climate alone is not sufficient to predict the current distribution of ecosystems. Used alone, the CLGs resulted in parsimonious models with relatively high predictive power. Used together with other variables, they consistently improved the models. Main conclusions: Our study highlights the importance of variable selection in EDM. We argue that the use of composite variables as proxies for complex environmental gradients has the potential to improve predictions from EDMs and thus to inform conservation planning as well as improve the precision and credibility of red lists and global change assessments.conservation planning, distribution modelling, ecosystem classification, ecosystem types, IUCN Red List of Ecosystems, landscape gradients, spatial prediction, species response curves

• Jašková, Anni; Braslavskaya, Tatyana Yu.; Tikhonova, Elena; Paal, Jaanus; Rūsiņa, Solvita & Laiviņš, Māris [Vis alle 29 forfattere av denne artikkelen] (2020). European Boreal Forest Vegetation Database. Phytocoenologia. ISSN 0340-269X. 50(1), s. 79–92. doi: 10.1127/phyto/2019/0336. Vis sammendrag

  The European Boreal Forest Vegetation Database (EBFVD, GIVD ID: EU-00-027) is a repository for vegetation-plot data from the forests of the boreal and hemiboreal zones of Europe. In this report, we describe its structure, current content and future perspectives opened up by the database. In February 2019, the database contained 13 037 vegetation-plot records from Belarus, Estonia, Finland, Latvia, Norway, Russia and Sweden that are not yet stored in the databases of the European Vegetation Archive (EVA). Consequently, this database significantly improves the availability of forest plant community data from Northern Europe. The database is managed by the Vegetation Science Group, Department of Botany and Zoology, Masaryk University, Brno (Czech Republic), in the TURBOVEG 2 program. It is registered in the Global Index of Vegetation Plot Databases (GIVD) and included in EVA. The whole database, or a subset of it, can be requested via EVA, or directly from the database custodian.

• Økland, Tonje; Aarrestad, Per Arild; Bakkestuen, Vegar & Halvorsen, Rune (2019). Mengdeendringer for utvalgte plantearter 1988–2018. I Framstad, Erik (Red.), Terrestrisk naturovervåking i 2018: Markvegetasjon, epifytter, smågnagere og fugl. Sammenfatning av resultater. Norsk institutt for naturforskning (NINA). ISSN 978-82-426-3442-9. s. 96–102. Vis sammendrag

  Program for terrestrisk naturovervåking startet i 1990 og omfatter undersøkelser av vanlige planter og dyr i seks områder i bjørkeskog og elleve i granskog. Her ses resultatene fra 2018 i sammenheng med resultatene fra tidligere år. Markvegetasjonen i bjørkeskog i Gutulia har siden 1993 endret seg fra fattige lyng- og bærlyng-dominerte typer til svakt rikere lågurttyper med større innslag av urter, gras og starr. Dette skyldes trolig at lengre og mildere vekstsesong på høsten har ført til noe mer baserikhet i jorda og økt næringstilgangen til plantene. I Dividalen har bregner og urter økt i mengde, mens blåbær, fjellplanter, moser og lav har avtatt. Endringene skyldes trolig mildere klima og økt næringstilgang. Markvegetasjonen i granskog i Paulen viste betydelig tilbakegang i antall registrerte arter av karplanter og moser pr. analyseflate, både fra begynnelsen av overvåkingen i 1990 og siden forrige registrering (2010). Totalt antall registrerte plantearter er også redusert, fra 87 i 1990 til 79 i 2018. Siden 1990 var det tilbakegang i mengde for ni karplantearter og ti mosearter; ingen arter økte i mengde. Artssammensetningen har blitt mer homogen, med større likhet mellom ‘fattig’ og ‘rik’ vegetasjon. I perioden 2013–18 viste markvegetasjonen i granskog i Solhomfjell redusert mengde for moderat mineralnæringskrevende arter i rikere granskog, som på slutten av 1900-tallet. Økningen i bunnsjiktsdekning stoppet opp, men store mosearter synes å ha nådd en mengde, og mosemattene en tetthet, som har gitt vedvarende reduksjon for små moser. Populasjonsundersøkelsene av etasjemose i sju granskogsområder bekrefter at populasjonsøkningen stagnerer i områder med høy bunnsjiktsdekning, men det er fortsatt tendens til at store moser som etasjemose øker noe i mengde på bekostning av små moser. Disse mønstrene antas å ha blitt forsterket av mangelen på toppår i smågnagerbestander, slik at mosemattene blir fortettet gjennom mangel på for-styrrelse. I furuskogen i Solhomfjell ble det funnet redusert artstetthet og redusert mengde for mange lavarter og andre arter med tyngdepunkt i den mer tørkeutsatte furuskogen. Både i Gutulia og Dividalen har mengden epifytter på bjørketrær økt over overvåkingsperioden, men økningen synes nå å ha stagnert. Generelt øker dominansen av svakt varmekjære arter. Andel skadd lav er betydelig redusert fra 1993, men varierer med klimaforholdene om vinteren. Endringene reflekterer mindre svovelnedfall og gunstig klimautvikling med lengre vekstsesong, økt temperatur og nedbør. Siden 2014 har det vært utbrudd av bjørkemålere i 2014 i Dividalen, 2018 i Børgefjell og 2017 i øvrige fjellområder. Det var betydelige beiteskader på bjørkeblader i 2017/2018 i alle områdene utenom Dividalen. Smågnagere viser nokså regelmessige bestandstopper i Møsvatn, Åmotsdalen og Børgefjell, men mer uregelmessige og lavere topper i øvrige TOV-områder (Lund, Solhomfjell, Gutulia, Dividalen). I 2018 var det stor bestand av smågnagere (særlig gråsidemus, rødmus og markmus) i Dividalen, men lav eller svært lav bestand i øvrige områder. Ungeproduksjonen for kongeørn lå i 2018 noe under gjennomsnittet for overvåkingsperioden i Børgefjell, Åmotsdalen, Møsvatn og Gutulia, omtrent som snittet i Solhomfjell og noe over i Lund. Produksjonen i 2018 var noe lavere enn i 2017 for alle områdene unntatt Lund. Ungeproduksjonen for jaktfalk var betydelig lavere i 2018 enn gjennomsnitt

• Rydgren, Knut; Auestad, Inger; Halvorsen, Rune; Hamre, Liv Norunn; Jongejans, Eelke & Töpper, Joachim Paul [Vis alle 7 forfattere av denne artikkelen] (2019). Assessing restoration success by predicting time to recovery- But by which metric? Journal of Applied Ecology. ISSN 0021-8901. doi: 10.1111/1365-2664.13526. Fulltekst i vitenarkiv Vis sammendrag

  1. Restoration of degraded ecosystems may take decades or even centuries. Accordingly, information about the current direction and speed of recovery provided by methods for predicting time to recovery may give important feedback to restoration schemes. While predictions of time to recovery have so far been based mostly upon change in species richness and other univariate predictors, the novel ordination-regression based approach (ORBA) affords a multivariate approach based upon species compositional change. 2. We used species composition data from four alpine spoil heaps in western Norway, recorded at three time points, to predict time to recovery using ORBA. This approach uses distances between restored plots and reference plots along a successional gradient, represented by a vector in ordination space, to model linear or asymptotic relationships of compositional change as a function of time. Results from ORBA were compared with results from models of more generic univariate attributes, that is total cover, species richness and properties of the physical environment as functions of time. 3. ORBA predictions of time to species compositional recovery varied from less than 60 years with linear models to 115–212 years with asymptotic models. The long estimated time to recovery suggests that the restoration schemes adopted for these spoil heaps are likely to be suboptimal. 4. Much shorter time to recovery was predicted from some of the more generic univariate attributes, that is species richness and total cover, than from species composition. Given the current rates of recovery, most spoil heaps will reach reference levels for total cover and species richness within 50 years, whereas predictions indicate that 67–111 years are needed to restore levels of soil organic matter and pH. 5. Synthesis and applications. Species composition and soil conditions provide information of generally higher relevance for evaluation of ecosystem recovery processes than the most commonly used metric to assess restoration success, species richness. Species richness is decoupled from species compositional recovery, and likely to be a generally poor measure of restoration success. We therefore encourage further improvement of methods like the ordination-regression based approach that use species compositional data to predict time to recovery. ORBA, Ordination-Regression Based Approach, restoration ecology, soil conditions, species composition, species richness, spoil heaps, time to recovery

• Olsen, Siri Lie; Brandrud, Tor Erik & Halvorsen, Rune (2019). Tilbakegang for flueblom Ophrys insectifera i Røsskleiva naturreservat i perioden 1984-2017. Blyttia : Norsk botanisk forenings tidsskrift. ISSN 0006-5269. 77(3/2019), s. 149–157. Vis sammendrag

  The red-listed orchid Ophrys insectifera is in decline despite years of protection. One of the species’ most important habitats is seasonally moist calcareous pine forest. This characteristic and species-rich forest type is especially well developed in Røsskleiva nature reserve in Langesund, Bamble, Telemark. A cattle grazing management regime was implemented in the reserve in 2017. As a basis for evaluation the management measures, as well as to document changes in the vegetation in general and the O. insectifera population in particular, we re-analysed 10 permanent plots established in Røsskleiva in the 1980s. The re-analyses, as well as surveys outside the plots, show a sharp decline in the O. insectifera population in the reserve from 1984 to 2017. The decrease in the O. insectifera population is coupled with marked vegetation changes, including increased cover of the shrub and tree layers. These changes are most likely driven by cessation of traditional use. The new management regime will hopefully restore favourable conditions for O. insectifera and other light-demanding species, but it remains to be seen if the O. insectifera population is able to recover.

• Vollering, Julien; Halvorsen, Rune & Mazzoni, Sabrina (2019). The MIAmaxent R package: Variable transformation and model selection for species distribution models. Ecology and Evolution. ISSN 2045-7758. s. 1–14. doi: 10.1002/ece3.5654. Fulltekst i vitenarkiv
• Vollering, Julien Martin Marie; Halvorsen, Rune; Auestad, Inger & Rydgren, Knut (2019). Bunching up the background betters bias in species distribution models. Ecography. ISSN 0906-7590. 42, s. 1–11. doi: 10.1111/ecog.04503. Fulltekst i vitenarkiv
• Horvath, Peter; Halvorsen, Rune; Stordal, Frode; Tallaksen, Lena Merete; Tang, Hui & Bryn, Anders (2019). Distribution modelling of vegetation types based on area frame survey data. Applied Vegetation Science. ISSN 1402-2001. 22(4), s. 547–560. doi: 10.1111/avsc.12451. Vis sammendrag

  Aim: Many countries lack informative, high‐resolution, wall‐to‐wall vegetation or land cover maps. Such maps are useful for land use and nature management, and for input to regional climate and hydrological models. Land cover maps based on remote sensing data typically lack the required ecological information, whereas traditional field‐based mapping is too expensive to be carried out over large areas. In this study, we therefore explore the extent to which distribution modelling (DM) methods are useful for predicting the current distribution of vegetation types (VT) on a national scale. Location: Mainland Norway, covering ca. 324,000 km2. Methods: We used presence/absence data for 31 different VTs, mapped wall‐to‐wall in an area frame survey with 1081 rectangular plots of 0.9 km2. Distribution models for each VT were obtained by logistic generalised linear modelling, using stepwise forward selection with an F‐ratio test. A total of 116 explanatory variables, recorded in 100 m × 100 m grid cells, were used. The 31 models were evaluated by applying the AUC criterion to an independent evaluation dataset. Results: Twenty‐one of the 31 models had AUC values higher than 0.8. The highest AUC value (0.989) was obtained for Poor/rich broadleaf deciduous forest, whereas the lowest AUC (0.671) was obtained for Lichen and heather spruce forest. Overall, we found that rare VTs are predicted better than common ones, and coastal VTs are predicted better than inland ones. Conclusions: Our study establishes DM as a viable tool for spatial prediction of aggregated species‐based entities such as VTs on a regional scale and at a fine (100 m) spatial resolution, provided relevant predictor variables are available. We discuss the potential uses of distribution models in utilizing large‐scale international vegetation surveys. We also argue that predictions from such models may improve parameterisation of vegetation distribution in earth system models.

• Krah, Franz-Sebastian; Büntgen, Ulf; Schaefer, Hanno; Müller, Jörg; Andrew, Carrie & Boddy, Lynne [Vis alle 25 forfattere av denne artikkelen] (2019). European mushroom assemblages are darker in cold climates. Nature Communications. ISSN 2041-1723. 10:2890, s. 1–11. doi: 10.1038/s41467-019-10767-z. Fulltekst i vitenarkiv Vis sammendrag

  Thermal melanism theory states that dark-colored ectotherm organisms are at an advantage at low temperature due to increased warming. This theory is generally supported for ectotherm animals, however, the function of colors in the fungal kingdom is largely unknown. Here, we test whether the color lightness of mushroom assemblages is related to climate using a dataset of 3.2 million observations of 3,054 species across Europe. Consistent with the thermal melanism theory, mushroom assemblages are significantly darker in areas with cold climates. We further show differences in color phenotype between fungal lifestyles and a lifestyle differentiated response to seasonality. These results indicate a more complex ecological role of mushroom colors and suggest functions beyond thermal adaption. Because fungi play a crucial role in terrestrial carbon and nutrient cycles, understanding the links between the thermal environment, functional coloration and species’ geographical distributions will be critical in predicting ecosystem responses to global warming.

• Kistenich, Sonja; Halvorsen, Rune; Schrøder-Nielsen, Audun; Thorbek, Birgitte Lisbeth Graae; Timdal, Einar & Bendiksby, Mika (2019). DNA Sequencing Historical Lichen Specimens . Frontiers in Ecology and Evolution. ISSN 2296-701X. 7. doi: 10.3389/fevo.2019.00005. Fulltekst i vitenarkiv
• Rydgren, Knut; Halvorsen, Rune; Töpper, Joachim Paul; Auestad, Inger; Hamre, Liv Norunn & Jongejans, Eelke [Vis alle 7 forfattere av denne artikkelen] (2019). Advancing restoration ecology: A new approach to predict time to recovery . Journal of Applied Ecology. ISSN 0021-8901. 56(1), s. 225–234. doi: 10.1111/1365-2664.13254. Fulltekst i vitenarkiv Vis sammendrag

  1. Species composition is a vital attribute of any ecosystem. Accordingly, ecological restoration often has the original, or “natural,” species composition as its target. However, we still lack adequate methods for predicting the expected time to compositional recovery in restoration studies. 2. We describe and explore a new, ordination regression-based approach (ORBA) for predicting time to recovery that allows both linear and asymptotic (logarithmic) relationships of compositional change with time. The approach uses distances between restored plots and reference plots along the successional gradient, represented by a vector in ordination space, to predict time to recovery. Thus, the approach rests on three requirements: (a) the general form of the relationship between compositional change and time must be known; (b) a sufficiently strong successional gradient must be present and adequately represented in a species compositional dataset; and (c) a restoration target must be specified. We tested the approach using data from a boreal old-growth forest that was followed for 18 years after experimental disturbance. Data from the first 9 years after disturbance were used to develop models, the subsequent 9 years for validation. 3. Rates of compositional recovery in the example dataset followed the general pattern of decrease with time since disturbance. Accordingly, linear models were too optimistic about the time to recovery, whereas the asymptotic models provided more precise predictions. 4. Synthesis and applications. Our results demonstrate that the new approach opens for reliable prediction of recovery rates and time to recovery using species compositional data. Moreover, it allows us to assess whether recovery proceeds in the desired direction and to quantitatively compare restoration speed, and hence effectiveness, between alternative management options. ordination, prediction, recovery, reference, restoration ecology, species composition, successional gradient, time to recovery

• Støa, Bente; Halvorsen, Rune; Mazzoni, Sabrina & Gusarov, Vladimir (2018). Sampling bias in presence-only data used for species distribution modelling: theory and methods for detecting sample bias and its effects on models. Sommerfeltia. ISSN 0800-6865. 38, s. 1–53. doi: 10.2478/som-2018-0001. Fulltekst i vitenarkiv
• Eriksen, Eva Lieungh; Ullerud, Heidrun Asgeirsdatter; Halvorsen, Rune; Aune, Sigrun; Bratli, Harald & Horvath, Peter [Vis alle 9 forfattere av denne artikkelen] (2018). Point of view: error estimation in field assignment of land-cover types. Phytocoenologia. ISSN 0340-269X. 49(2), s. 135–148. doi: 10.1127/phyto/2018/0293. Fulltekst i vitenarkiv Vis sammendrag

  Questions: Substantial variation between observers has been found when comparing parallel land-cover maps, but how can we know which map is better? What magnitude of error and inter-observer variation is expected when assigning land-cover types and is this affected by the hierarchical level of the type system, observer characteristics, and ecosystem properties? Study area: Hvaler, south-east Norway. Methods: Eleven observers assigned mapping units to 120 stratified random points. At each observation point, the observers first assigned a mapping unit to the point independently. The group then decided on a ‘true’ reference mapping unit for that point. The reference was used to estimate total error. ‘Ecological distance’ to the reference was calculated to grade the errors. Results: Individual observers frequently assigned different mapping units to the same point. Deviating assignments were often ecologically close to the reference. Total error, as percentage of assignments that deviated from the reference, was 35.0% and 16.4% for low and high hierarchical levels of the land-covertype system, respectively. The corresponding figures for inter-observer variation were 42.8% and 19.4%, respectively. Observer bias was found. Particularly high error rates were found for land-cover types characterised by human disturbance. Conclusions: Access to a ‘true’ mapping unit for each observation point enabled estimation of error in addition to the inter-observer variation typically estimated by the standard pairwise comparisons method for maps and observers. Three major sources of error in the assignment of land-cover types were observed: dependence on system complexity represented by the hierarchical level of the land-cover-type system, dependence on the experience and personal characteristics of the observers, and dependence on properties of the mapped ecosystem. The results support the necessity of focusing on quality in land-cover mapping, among commissioners, practitioners and other end users.

• Botnen, Synnøve Smebye; Davey, Marie Louise; Halvorsen, Rune & Kauserud, Håvard (2018). Sequence clustering threshold has little effect on the recovery of microbial community structure. Molecular Ecology Resources. ISSN 1755-098X. 18(5), s. 1064–1076. doi: 10.1111/1755-0998.12894. Fulltekst i vitenarkiv
• Andrew, Carrie Joy; Halvorsen, Rune; Heegaard, Einar; Kuyper, Thomas W.; Heilmann-Clausen, Jacob & Krisai-Greilhuber, Irmgard [Vis alle 15 forfattere av denne artikkelen] (2018). Continental-scale macrofungal assemblage patterns correlate with climate, soil carbon and nitrogen deposition. Journal of Biogeography. ISSN 0305-0270. 45(8), s. 1942–1953. doi: 10.1111/jbi.13374. Vis sammendrag

  Aim:Macroecological scales of species compositional trends are well documentedfor a variety of plant and animal groups, but remain sparse for fungi, despite theirecological importance in carbon and nutrient cycling. It is, thus, essential to under-stand the composition of fungal assemblages across broad geographical scales andthe underlying drivers. Our overall aim was to describe these patterns for fungiacross two nutritional modes (saprotrophic and ectomycorrhizal). Furthermore, weaimed to elucidate the temporal component of fruiting patterns and to relate theseto soil carbon and nitrogen deposition. Location:Central and Northern Europe.Methods:A total of 4.9 million fungal fruit body observations throughout Europe,collected between 1970 and 2010, were analysed to determine the two main envi-ronmental and geographical gradients structuring fungal assemblages for two mainnutritional modes, saprotrophic and ectomycorrhizal fungi. Results:Two main gradients explaining the geography of compositional patternswere identified, for each nutritional mode. Mean annual temperature (and relatedcollinear, seasonal measures) correlated most strongly with the first gradient forboth nutritional modes. Soil organic carbon was the highest correlate of the second compositional gradient for ectomycorrhizal fungi, suspected as an indicator of vege-tation- and pH-related covariates. In contrast, nitrogen deposition constituted asecond gradient for saprotrophic fungi, likely a proxy for anthropogenic pollution.Compositional gradients and environmental conditions correlated similarly whenthe data were divided into two time intervals of 1970–1990 and 1991–2010.Evidence of compositional temporal change was highest with increasing elevationand latitude. Main conclusions:Fungal assemblage patterns demonstrate clear biogeographicalpatterns that relate the nutritional modes to their main environmental correlates oftemperature, soil organic carbon and nitrogen deposition. With respect to globalchange impacts, the highest rates of compositional change by time suggest targetinghigher latitudes and elevations for a better understanding of fungal dynamics. We,finally, suggest further examination of the ranges and dispersal abilities of fungi tobetter assess responses to global change.

Se alle arbeider i Cristin

• Edvardsen, Anette; Halvorsen, Rune; Bratli, Harald; Bryn, Anders; Dervo, Børre Kind & Erikstad, Lars [Vis alle 11 forfattere av denne artikkelen] (2024). Natur i Norge. Variasjon satt i system. Universitetsforlaget. ISBN 978-82-15-06986-9. 434 s.

Se alle arbeider i Cristin

• Storaunet, Ken Olaf; Rolstad, Jørund; Skarpaas, Olav & Halvorsen, Rune (2023). Hva er naturlig dynamikk i skoglandskapet? Norsk Skogbruk. ISSN 0029-2087. s. 52–54.
• Øien, Dag-Inge; Halvorsen, Rune; Lyngstad, Anders & Moen, Asbjørn (2023). Atlantisk høgmyr.
• Øien, Dag-Inge; Halvorsen, Rune; Lyngstad, Anders & Moen, Asbjørn (2023). Terrengdekkende myr.
• Øien, Dag-Inge; Halvorsen, Rune; Lyngstad, Anders & Moen, Asbjørn (2023). Øyblandingsmyr.
• Øien, Dag-Inge; Halvorsen, Rune; Lyngstad, Anders & Moen, Asbjørn (2023). Strengblandingsmyr.
• Øien, Dag-Inge; Halvorsen, Rune; Lyngstad, Anders & Moen, Asbjørn (2023). Strengmyr.
• Øien, Dag-Inge; Halvorsen, Rune; Lyngstad, Anders & Moen, Asbjørn (2023). Innsjøflommyr.
• Øien, Dag-Inge; Halvorsen, Rune; Lyngstad, Anders & Moen, Asbjørn (2023). Elveflommyr.
• Øien, Dag-Inge; Halvorsen, Rune; Lyngstad, Anders & Moen, Asbjørn (2023). Flarkmyr.
• Øien, Dag-Inge; Halvorsen, Rune; Lyngstad, Anders & Moen, Asbjørn (2023). Saltflommyr.
• Øien, Dag-Inge; Halvorsen, Rune; Lyngstad, Anders & Moen, Asbjørn (2023). Torvkilde.
• Lyngstad, Anders; Halvorsen, Rune; Moen, Asbjørn & Øien, Dag-Inge (2023). Eksentrisk høgmyr.
• Lyngstad, Anders; Halvorsen, Rune; Moen, Asbjørn & Øien, Dag-Inge (2023). Skogshøgmyr.
• Lyngstad, Anders; Halvorsen, Rune; Moen, Asbjørn & Øien, Dag-Inge (2023). Konsentrisk høgmyr.
• Lyngstad, Anders; Halvorsen, Rune; Moen, Asbjørn & Øien, Dag-Inge (2023). Platåhøgmyr.
• Lyngstad, Anders; Halvorsen, Rune; Moen, Asbjørn & Øien, Dag-Inge (2023). Kanthøgmyr.
• Lyngstad, Anders; Halvorsen, Rune; Moen, Asbjørn & Øien, Dag-Inge (2023). Mellomstillingsmyr.
• Lyngstad, Anders; Halvorsen, Rune; Moen, Asbjørn & Øien, Dag-Inge (2023). Palsmyr.
• Lyngstad, Anders; Halvorsen, Rune; Moen, Asbjørn & Øien, Dag-Inge (2023). Høgmyrmassiv.
• Lyngstad, Anders; Halvorsen, Rune; Moen, Asbjørn & Øien, Dag-Inge (2023). Ombrogent ikke-hvelvet torvmassiv.
• Lyngstad, Anders; Halvorsen, Rune; Moen, Asbjørn & Øien, Dag-Inge (2023). Mellomstillingsmassiv.
• Lyngstad, Anders; Halvorsen, Rune; Moen, Asbjørn & Øien, Dag-Inge (2023). Blandingsmyrtorvmassiv.
• Lyngstad, Anders; Halvorsen, Rune; Moen, Asbjørn & Øien, Dag-Inge (2023). Flommyrtorvmassiv.
• Lyngstad, Anders; Halvorsen, Rune; Moen, Asbjørn & Øien, Dag-Inge (2023). Kildetorvmassiv.
• Lyngstad, Anders; Halvorsen, Rune; Moen, Asbjørn & Øien, Dag-Inge (2023). Bakkemyr.
• Lyngstad, Anders; Halvorsen, Rune; Moen, Asbjørn & Øien, Dag-Inge (2023). Gjennomstrømningsmyr.
• Lyngstad, Anders; Halvorsen, Rune; Moen, Asbjørn & Øien, Dag-Inge (2023). Slakmyr.
• Lyngstad, Anders; Halvorsen, Rune; Moen, Asbjørn & Øien, Dag-Inge (2023). Soligene torvmassiv.
• Lyngstad, Anders; Halvorsen, Rune; Moen, Asbjørn & Øien, Dag-Inge (2023). Topogene torvmassiv.
• Lyngstad, Anders; Halvorsen, Rune; Moen, Asbjørn & Øien, Dag-Inge (2023). Flatmyr.
• Lyngstad, Anders; Halvorsen, Rune; Moen, Asbjørn & Øien, Dag-Inge (2023). Gjenvoksningsmyr.
• Schuuring, Sil; Halvorsen, Rune; Eidesen, Pernille Bronken; Nyttinen, Pekka; Kemppinen, Julia & Lang, Simone (2023). No need to be bushy: Low-statured high arctic vegetation slows early season active layer thaw.
• Vloon, Catharina Caspara; Halvorsen, Rune; Nordbakken, Jørn-Frode; Auestad, Inger & Rydgren, Knut (2023). Restoration of a boreal ombrogenous mire: predicting time to recovery after ditch blocking.
• Halvorsen, Rune (2023). Peatlands: origin, dynamics, pattern and processes.
• Töpper, Joachim Paul; Bakkestuen, Vegar; Evju, Marianne; Halvorsen, Rune; Jokerud, Mari & Kvamme, Mons [Vis alle 9 forfattere av denne artikkelen] (2023). Fire tiår med og for naturen – Per Arild Aarrestad. Blyttia : Norsk botanisk forenings tidsskrift. ISSN 0006-5269. 81(1), s. 12–19.
• Halvorsen, Rune & Bryn, Anders (2023). Hvorfor mangler naturkartlegging tillit? Altinget - Alt om politikk: [nettavis].
• Halvorsen, Rune; Brenn, Odd Arne; Framstad, Erik; Gaarder, Geir; Gjerde, Ivar & Schei, Fride Høistad [Vis alle 9 forfattere av denne artikkelen] (2022). Framlegg til revidert beskrivelse av skogdynamikk i NiN. I Skarpaas, Olav & Halvorsen, Rune (Red.), Skogens dynamikk, struktur og artsmangfold - bakgrunnskunnskap for en ny beskrivelse av skogbestandsdynamikk i NiN. Naturhistorisk museum, UiO. ISSN 978-82-7970-141-5. s. 85–115.
• Skarpaas, Olav; van Son, Thijs Christiaan; Halvorsen, Rune & Storaunet, Ken Olaf (2022). Samvariasjon mellom strukturvariabler i norsk skog – en analyse basert på Landsskogtakseringens data. I Skarpaas, Olav & Halvorsen, Rune (Red.), Skogens dynamikk, struktur og artsmangfold - bakgrunnskunnskap for en ny beskrivelse av skogbestandsdynamikk i NiN. Naturhistorisk museum, UiO. ISSN 978-82-7970-141-5. s. 58–68.
• Bendiksby, Mika; Thorbek, Birgitte Lisbeth Graae; Bjorå, Charlotte Sletten & Halvorsen, Rune (2022). Simple procedures for obtaining DNA sequences from old herbarium specimens .
• Velle, Liv Guri; Töpper, Joachim Paul; Chipperfield, Joseph; Halvorsen, Rune; Seddon, Alistair William Robin & Vandvik, Vigdis (2022). ECoMAP: Modelling Ecological state and Condition Maps to support knowledge-based decision-making in Area management and spatial Planning.
• Velle, Liv Guri; Töpper, Joachim Paul; Chipperfield, Joseph; Halvorsen, Rune; Seddon, Alistair William Robin & Vandvik, Vigdis (2022). ECoMAP: Modelling Ecological state and Condition Maps to support knowledge-based decision-making in Area management and spatial Planning .
• Vollering, Julien; Aakre, Gina & Halvorsen, Rune (2022). Sitkagranen har de mest produktive årene foran seg og stortrives i norsk klima. [Internett]. titan.uio.no.
• Schuuring, Sil; Eidesen, Pernille Bronken; Halvorsen, Rune & Lang, Simone (2021). High Arctic Bryophytes: A green Blanket?
• Økland, Tonje & Halvorsen, Rune (2020). TOV granskog: Utvikling i bakkevegetasjonen og dens artsmangfold i ni områder med gammel, vernet granskog. Utvalgte overvåkingsresultater 1988–2019. , Skogens helsetilstand i Norge. Resultater fra skogskadeovervåkingen i 2019. NIBIO. ISSN 978-82-17-02387-6. s. 39–46. Vis sammendrag

  Skogens helsetilstand påvirkes i stor grad av klima og værforhold, enten direkte ved tørke, frost og vind, eller indirekte ved at klimaet påvirker omfanget av soppsykdommer og insektangrep. Klimaendringene og den forventede økningen i klimarelaterte skogskader gir store utfordringer for forvaltningen av framtidas skogressurser. Det samme gjør invaderende skadegjørere, både allerede etablerte arter og nye som kan komme til Norge i nær framtid. I denne rapporten presenteres resultater fra skogskadeovervåkingen i Norge i 2019 og trender over tid.....

• Økland, Tonje; Aarrestad, Per Arild; Bakkestuen, Vegar & Halvorsen, Rune (2020). Mengdeendringer for utvalgte plantearter 1988–2019. I Framstad, Erik (Red.), Terrestrisk naturovervåking i 2019: Markvegetasjon, epifytter, smågnagere og fugl. Sammenfatning av resultater. Norsk institutt for naturforskning (NINA). ISSN 978-82-426-4557-9. s. 48–54.
• Halvorsen, Rune; Økland, Tonje & Nordbakken, Jørn-Frode (2019). Videreføring av TOV granskog.
• Halvorsen, Rune; Bratli, Harald & Wollan, Anders Kvalvåg (2019). Vegetasjonsundersøkelser av boreal barskog i Solhomfjell 2018. I Framstad, Erik (Red.), Terrestrisk naturovervåking i 2018: Markvegetasjon, epifytter, smågnagere og fugl. Sammenfatning av resultater. Norsk institutt for naturforskning (NINA). ISSN 978-82-426-3442-9. s. 46–79. Vis sammendrag

  Overvåking av markvegetasjonen i gran- og furuskog har pågått i Solhomfjell-området siden 1988 (R. Økland & Eilertsen 1993). Overvåkingen i Solhomfjell ble i 2001 samorganisert med tilsvarende overvåking i regi av NIJOS (seinere Norsk institutt for skog og landskap og NIBIO) i granskog og NINA i bjørkeskog. Fra 2004 har alle disse vegetasjonsovervåkingsaktivitetene vært del av Program for terrestrisk naturovervåking (TOV). De tre overvåkingsaktivitetene for markvegetasjon som nå er samlet i TOV, var i utgangspunktet basert på ulike metoder for plassering av prøveflater (R. Økland & Eilertsen 1993, T. Økland 1996, Bakkestuen et al. 2010), men er seinere samordnet med sikte på å maksimere sammenliknbarhet (f.eks. T. Økland et al. 2001, 2004a, 2004b). Undersøkelsen i Solhomfjell skiller seg imidlertid (fortsatt) fra undersøkelsene i de øvrige områdene som inngår i TOV på tre måter: (1) Prøveflatene er plassert langs transekter i stedet for i 50-m2 makroruter. (2) I tillegg til å utspenne den lokale komplekse miljøgradienten kalkinnhold (mineralnæringsinnhold; KA i NiN-terminologi, jf. Halvorsen et al. 2015), fra kalkfattig via intermediær til (svakt) kalkrik, favner Solhomfjell-materialet hele uttørkingsfare-gradienten (UF i NiN) fra frisk, blåbærdominert granskog, inkludert fuktmarksutforminger [se R. Økland & Eilertsen (1993) og T. Økland (1996) for definisjon av begrepet 'blåbærdominert granskog'] via bærlyngskog (blandingsskog av gran og furu) og furu-dominert lyngskog, til svært tørkeutsatt, furudominert lavskog. Flater med svak kildevannspå-virkning (KI; overganger mellom lågurtskog og høgstaudeskog) inngår også. (3) Prøveflateantallet er 100 (et utvalg av de 200 flatene som opprinnelig ble plassert og analysert i 1988 og 1993) og ikke 50 flater som i de andre TOV-områdene. Vegetasjonen i prøveflatene i Solhomfjell ble første gang analysert i 1988. Deretter har 100 flater blitt analysert hvert 5. år: i 1993, 1998, 2003, 2008, 2013 og foreløpig siste gang i 2018. 50 av prøveflatene ble dessuten analysert hvert år mellom 1988 og 1993, samt i 1995. I 1988 og 1993 ble grundige registreringer av økologiske forklaringsvariabler registrert i tilknytning til hver av de 200 analyserte prøveflatene. For å identifisere hovedgradienter i artssammensetning og å relatere disse til komplekse miljøgradienter, ble det foretatt en vegetasjonsøkologisk basisundersøkelse av datamaterialet innsamlet i 1988 (R. Økland & Eilertsen 1993). De årlige undersøkelsene av vegetasjon fram til og med 1993 dannet grunnlag for undersøkelser av artenes persistens (R. Økland 1995a, 1995b). Gjenanalysedatasettet fra 1993 ble også grundig analysert med hensyn til endringer i vegetasjon og miljøvariabler (R. Økland 1995c, 1995d, R. Økland & Eilertsen 1996). Seinere gjenanalyser er, med unntak av datamaterialet som ble samlet inn i 1998, og som er grunnlag for artikkelen T. Økland et al. (2004a), rapportert i enklere form (R. Økland 1997a, R. Økland et al. 2000, R. Økland & Nordbakken 2004, Halvorsen et al. 2009b, 2014). I denne rapporten oppsummeres endringsmønstre for arter og vegetasjon i Solhomfjell-området 1988–2018, med særlig vekt på femårsperioden 2013–18. Parallelt med vegetasjonsundersøkelsen har det siden 1990 blitt gjennomført populasjonsbiologiske undersøkelser av etasjemose i granskog i Solhomfjell og i seks andre overvåkingsområder (R. Økland 1995e). Disse undersøkelsene blir rapportert i kapittel 7.

• Økland, Tonje; Halvorsen, Rune & Nordbakken, Jørn-Frode (2019). VEGETASJONSOVERVÅKING I GAMMEL GRANSKOG I TOV Hva kan den mer enn 30 år lange tidsserien bidra med til «Fagsystem for god økologisk tilstand»/ANO/Naturindeks? .
• Dolan, Margaret; Bekkby, Trine; Buhl-Mortensen, Pål; Andersen, Guri Sogn; van Son, Thijs Christiaan & Thormar, Jonas [Vis alle 11 forfattere av denne artikkelen] (2019). Phasing in use of the “Nature in Norway” (NiN) system for classification and description of nature in the marine environment – experiences, challenges and international relevance. .
• Økland, Tonje; Aarrestad, Per Arild; Bakkestuen, Vegar & Halvorsen, Rune (2019). Mengdeendringer for utvalgte plantearter 1988–2017. I Framstad, Erik (Red.), Terrestrisk naturovervåking i 2017: Markvegetasjon, epifytter, smågnagere og fugl. Sammenfatning av resultater. Norsk institutt for naturforskning. ISSN 978-82-426-3349-1. s. 50–56. Vis sammendrag

  Program for terrestrisk naturovervåking startet i 1990 og omfatter undersøkelser av vanlige planter og dyr i 6 områder i bjørkeskog og 11 i granskog. Her ses resultatene fra 2017 i sammenheng med resultatene fra tidligere år. Markvegetasjonen i Møsvatn har siden 1997 endret seg fra fattige lyng- og bærlyngdominerte typer til svakt rikere lågurttyper med større innslag av gras og starr. Dette skyldes dels påvirkning av langtransportert nitrogen. Flere bjørkemålerangrep har også tilført nitrogen fra ekskrementer og gitt mer lys til bakken. Sammen med lengre og mildere vekstsesong på høsten har dette ført til noe mer baserikhet i jorda og økt næringstilgangen til plantene. Markvegetasjonen i granskog i Gutulia nasjonalpark viste i 2017 betydelig tilbakegang i antall registrerte arter av karplanter, moser og lav, både fra begynnelsen av overvåkingen i 1989 og siden forrige registrering (2009). Siden 1989 var det tilbakegang i mengde for 14 karplantearter og 16 mosearter; bare én torvmoseart økte i mengde. Artssammensetningen har endret seg mot vegetasjon på næringsfattige voksesteder. I Møsvatn har mengden epifytter på bjørketrær økt over overvåkingsperioden og er nå over 100 %. Mengde busklav har økt også siden 2012, mens økning i bladlav har stagnert. Andel skadd lav er liten og lavere enn i 2012. Endringene tyder på mindre svovelnedfall og gunstig klimautvikling med lengre vekstsesong, økt temperatur og nedbør. I perioden 2014-2017 har Dividalen hatt utbrudd av bjørkemålere i 2014, mens det har vært en økning i forekomst i øvrige områder, med betydelige beiteskader på bjørkeblader i Åmotsdalen i 2017. Smågnagere viser nokså regelmessige bestandstopper i Møsvatn, Åmotsdalen og Børgefjell, men mer uregelmessige og lavere topper i øvrige TOV-områder. I 2017 var det forholdsvis høye bestander av smågnagere i Møsvatn og Åmotsdalen, lavere topper i Solhomfjell, Finse og Gutulia, og bunnår i Børgefjell og Dividalen. Få smågnagere ble fanget i Lund, men en del individer ble observert. I de fleste områdene dominerte klatremus og til dels markmus i fangstene, bortsett fra på Finse der lemen og fjellmarkmus dominerte. Ungeproduksjonen for kongeørn lå i 2017 noe under gjennomsnittet for overvåkingsperioden for Børgefjell, Møsvatn, Gutulia og Lund og noe over for Åmotsdalen og Solhomfjell. Produksjonen i 2017 var likevel noe høyere enn i 2016 for de fleste områdene i Sør-Norge, trolig pga. større smågnagerbestander og bedre tilgang på ryper og annet bytte. Ungeproduksjonen for jaktfalk var lavere i 2017 enn i 2016, omtrent som gjennomsnittet for overvåkingsperioden i Møsvatn og lavere i Børgefjell og Åmotsdalen. Rypetakseringene i 2017 viste få endringer fra 2016 for de fleste TOV-områdene. I Børgefjell og Lund ble få ryper observert. Også i Dividalen ble det estimert nokså lave tettheter, mens estimatene for Åmotsdalen var ganske høye. For Møsvatn ble det observert flere ryper og høyere unge-produksjon enn i noen tidligere år. NØKKELORD : terrestrisk miljø, overvåking, klimavariasjon, forurensinger, naturlig dynamikk, markvegetasjon, epifytter, smågnagere, fugl, reproduksjon, bestandsvariasjoner, artssammensetning, Norge, KEY WORDS : terrestrial environment, monitoring, climate variation, pollution, natural Dynamics, ground vegetation, epiphytes, small rodents, birds, reproduction, population variation, species composition, Norway

• Simensen, Trond; Halvorsen, Rune; Erikstad, Lars & Bakkestuen, Vegar (2018). A gradient perspective on landscape classification.
• Sulavik, Jan; Boudreau, Stephane; Halvorsen, Rune; Rydgren, Knut; Jongejans, Eelke & Auestad, Inger (2018). Spatio-temporal patterns of crowberry (Empetrum nigrum ssp. hermaphroditum) colonisation at an alpine spoil heap.
• Rydgren, Knut; Halvorsen, Rune; Töpper, Joachim Paul; Auestad, Inger; Hamre, Liv Norunn & Jongejans, Eelke [Vis alle 7 forfattere av denne artikkelen] (2018). ORBA - a new approach to predict time to recovery in restoration ecology.
• Bryn, Anders; Andersen, Guri Sogn; Bekkby, Trine; Bratli, Harald; Dervo, Børre Kind & Dolan, Margaret [Vis alle 14 forfattere av denne artikkelen] (2023). Hovedveileder for feltbasert kartlegging. Terrestrisk, limnisk og marin naturvariasjon etter NiN (3.0). Artsdatabanken. ISSN 978-82-92838-61-7. Fulltekst i vitenarkiv
• Lyngstad, Anders; Moen, Asbjørn; Halvorsen, Rune & Øien, Dag-Inge (2023). Beskrivelser av torvmassivenheter. Kunnskapsgrunnlag for NiN 3.0. NTNU Vitenskapsmuseet. ISSN 978-82-8322-353-8. 2023(4). Fulltekst i vitenarkiv
• Skarpaas, Olav & Halvorsen, Rune (2022). Skogens dynamikk, struktur og artsmangfold - bakgrunnskunnskap for en ny beskrivelse av skogbestandsdynamikk i NiN. Naturhistorisk museum, UiO. ISSN 978-82-7970-141-5.
• Dervo, Børre Kind; Brabrand, Åge; Erikstad, Lars; Halvorsen, Rune; Mjelde, Marit & Schartau, Ann Kristin [Vis alle 7 forfattere av denne artikkelen] (2022). Metodehåndbok: Kartleggingsmetodikk for NiN limnisk med vekt på natursystemet. NINA Temahefte 84. Norsk institutt for naturforskning. Norsk institutt for naturforskning. ISSN 978-82-426-4865-5.
• Dervo, Børre Kind; Brabrand, Åge; Erikstad, Lars; Halvorsen, Rune; Mjelde, Marit & Schartau, Ann Kristin [Vis alle 7 forfattere av denne artikkelen] (2022). Metodehåndbok - Kartleggingsmetodikk for NiN limnisk med vekt på natursystemet. Norsk institutt for naturforskning (NINA). ISSN 978-82-426-4865-5.
• Bratli, Harald; Halvorsen, Rune; Høitomt, Torbjørn; Ihlen, Per G. & Brynjulvsrud, John Gunnar (2021). Utvikling av kunnskapsgrunnlaget for beskrivelse av fossesprutsoner i Natur i Norge (NiN). Naturhistorisk museum. ISSN 978-82-7970-125-5. Fulltekst i vitenarkiv
• Halvorsen, Rune; Wollan, Anders Kvalvåg; Bryn, Anders; Bratli, Harald & Horvath, Peter (2021). Naturtypekart etter NiN for området omkring Veia (Nedre Eiker og Øvre Eiker, Buskerud). Naturhistorisk museum. ISSN 978-82-7970-126-2. Fulltekst i vitenarkiv
• Bryn, Anders; Bekkby, Trine; Dervo, Børre Kind; Dolan, Margaret & Halvorsen, Rune (2020). Hovedveileder for feltbasert kartlegging av terrestrisk, limnisk og marin naturvariasjon etter NiN. Artsdatabanken. ISSN 978-82-92838-54-9. Fulltekst i vitenarkiv Vis sammendrag

  Formålet med veilederen er å fylle det kunnskapsrommet som trengs for å bruke natursystemnivået i NiN til feltbasert kartlegging; både til opplæring av nye kartleggere, til hjelp ved utlysning av oppdrag, og som veiledning for ulike brukere av naturtypekart. Feltbasert kartlegging etter NiN brukes og lyses ut for mange ulike formål, og veilederen bærer derfor preg av å skulle dekke mange ulike behov. Veilederen inkluderer kartlegging av terrestriske, limniske og marine økosystemer. Veilederen definerer ikke hvordan de enkelte sektorer skal løse sine kartleggingsbehov, men viser hvordan ulike behov og utfordringer kan løses. Formålet med veilederen er å bidra til at resultatene av praktisk kartlegging blir så gode som mulig. Naturtypekartenes kvalitet styres imidlertid i stor grad av rammer utenfor denne veilederen. Det er de ulike sektorene som organiserer og lyser ut oppdrag som avgjør hvordan kartleggingen i praksis foregår. Dette dokumentet er derfor en veileder, ikke en instruks.

• Framstad, Erik; Bakkestuen, Vegar; Halvorsen, Rune; Ihlen, Per Gerhard; Nilsen, Erlend Birkeland & Olsen, Siri Lie [Vis alle 10 forfattere av denne artikkelen] (2020). TOV etter 2020. Utvikling av TOV som økosystembasert overvåking. Norsk institutt for naturforskning (NINA). ISSN 978-82-426-4649-1. Vis sammendrag

  Overvåking, terrestriske økosystemer, vegetasjon, epifytter, fauna, modeller, integrasjon, adaptiv, monitoring, terrestrial ecosystems, vegetation, epiphytes, fauna, models, integration, adaptive

• Timmermann, Volkmar; Andreassen, Kjell; Beachell, Andreas Myki; Børja, Isabella; Brurberg, May Bente & Clarke, Nicholas [Vis alle 18 forfattere av denne artikkelen] (2020). Skogens helsetilstand i Norge. Resultater fra skogskadeovervåkingen i 2019. NIBIO. ISSN 978-82-17-02387-6. 6(119). Fulltekst i vitenarkiv Vis sammendrag

  Skogens helsetilstand påvirkes i stor grad av klima og værforhold, enten direkte ved tørke, frost og vind, eller indirekte ved at klimaet påvirker omfanget av soppsykdommer og insektangrep. Klimaendringene og den forventede økningen i klimarelaterte skogskader gir store utfordringer for forvaltningen av framtidas skogressurser. Det samme gjør invaderende skadegjørere, både allerede etablerte arter og nye som kan komme til Norge i nær framtid. I denne rapporten presenteres resultater fra skogskadeovervåkingen i Norge i 2019 og trender over tid.....

• Halvorsen, Rune; Bryn, Anders; Bratli, Harald & Horvath, Peter (2020). Naturtypekart etter NiN for et område omkring Unsetsætra (Biri, Gjøvik, Oppland). Naturhistorisk Museum. ISSN 978–82–7970–120–0. Fulltekst i vitenarkiv
• Framstad, Erik; Bakkestuen, Vegar; Halvorsen, Rune; Kålås, John Atle; Myklebost, Heidi Elin & Nilsen, Erlend Birkeland [Vis alle 10 forfattere av denne artikkelen] (2020). Program for terrestrisk naturovervåking (TOV). Dokumentasjon av overvåkingsområder, metoder og data. Norsk institutt for naturforskning (NINA). ISSN 978-82-426-4586-9. Vis sammendrag

  Norge, terrestrisk naturovervåking, dokumentasjon, områder, metoder, data, skog, fjell, vegetasjon, epifytter, bjørkemålere, smågnagere, fugler, Norway, terrestrial ecosystem monitoring, documentation, sites, methods, data, forest, mountains, vegetation, epiphytes, birch defoliating moths, small rodents, birds

• Bratli, Harald; Halvorsen, Rune; Bryn, Anders; Arnesen, Geir; Bendiksen, Egil & Jordal, Jon Bjarne [Vis alle 11 forfattere av denne artikkelen] (2019). Beskrivelse av kartleggingsenheter i målestokk 1:5000 etter NiN (2.2.0). Utgave 1, kartleggingsveileder nr 4. Artsdatabanken. ISSN 978-82-92838-50-1.
• Halvorsen, Rune; Eriksen, Eva Lieungh; Wollan, Anders Kvalvåg; Ullerud, Heidrun Asgeirsdatter; Bryn, Anders & Bratli, Harald [Vis alle 7 forfattere av denne artikkelen] (2018). Forarbeid til standard for kontroll av kvalitet i naturtypekart etter NiN. FoU rapport 1. Artsdatabanken. ISSN 978-82-92838-51-8.
• Framstad, Erik; Halvorsen, Rune; Storaunet, Ken Olaf & Sverdrup-Thygeson, Anne (2018). Kriterier for naturverdi i skog. Norsk institutt for naturforskning. ISSN 978-82-426-3178-7. 1447(1447). Vis sammendrag

  I denne rapporten redegjør vi for et forslag til kriteriebasert fastsetting av naturverdi for skog-områder som vurderes for vern. Målsettingen er å komme fram til et system som er operativt og mest mulig objektivt, der kriteriene er spesifisert ved variabler i naturtype- og beskrivelses-systemet Natur i Norge (NiN). Vi foreslår 12 kriterier knyttet til henholdsvis naturgitt mangfold (variasjon i naturtyper, landformer, treslag), naturskogsnærhet (død ved mengde og variasjon, gamle/store trær, trær med spesielt livsmedium) og områdets skogareal (størrelse). Vi har foreløpig ikke funnet å kunne anbefale et kriterium for faktiske eller potensielle artsforekomster, siden dette krever ytterligere utviklingsarbeid for å sikre tilstrekkelig objektiv bruk av et slikt kriterium. Også NiNs variabler for skogbestandsdynamikk, spesielt for naturskog, trenger mer utviklingsarbeid før disse kan brukes som kriterier for naturverdi i skogvernarbeidet. I tillegg til kriterier for naturverdi forslår vi også at svak arrondering av området og ev. påvirkning fra nye-re hogster, teknisk infrastruktur eller fremmede arter skal kunne gi et fratrekk i samlet verdi. Systemet angir både en verdirangering for de enkelte kriteriene og en sammenstilling av disse til en samlet verdiangivelse for området. For de enkelte kriteriene viderefører vi den firedelte verdiskalaen (0-3) som er brukt tidligere i skogvernarbeidet. For hvert trinn på denne skalaen spesifiseres en grenseverdi for hvert kriterium. Der det finnes et egnet datagrunnlag for kriteriene, foreslår vi at disse grenseverdiene legges til prosentilene 50, 80 og 95 i fordelingen av mulige kriterieverdier i norsk skog. Alternativt bør man skjønnsmessig tilstrebe en tilsvarende prioritering av forholdsvis høye grenseverdier for å skille ut de beste områdene fra de mer ordinære. For samlet verdi for område basert på kvantitativ bruk av kriteriene, foreslår vi også en firedelt skala (0-3), men her åpner vi for at en mer subjektiv tilleggsvurdering kan gi ett trinn høyere verdi for områder av særlig høy nasjonal eller internasjonal naturverdi. Vi foreslår at samlet verdi beregnes som et veid gjennomsnitt av verdiskårene for de enkelte kriteriene, først som samlet verdi for kriteriene for henholdsvis naturgitt mangfold og naturskogsnærhet, der-nest ved et veid gjennomsnitt av verdiene for naturgitt mangfold, naturskogsnærhet og størrelse. Denne samlete verdien er skalert til verdier mellom 0 og 3. Deretter vurderes om områdets arrondering eller ulike negative påvirkninger bør tilsi et fratrekk i verdien på inntil 1 verdienhet. Systemet er laget for å angi samlet naturverdi for enkeltområder, basert på kriterier med felles verditrinn for hele landet. Det innebærer at ev. regionale forskjeller i forutsetninger for å til-fredsstille de ulike kriteriene, ikke er tatt hensyn til. Vi anser at vurdering ev. gitte skogområder i en regional sammenheng er en oppgave for forvaltningen. Det er behov for nærmere vurdering av hvordan samlet verdi for et område avhenger av grenseverdiene for de ulike kriteriene og av vektene som ev. både kan differensieres mellom enkeltkriterier og mellom hovedgrupper av kriterier (naturgitt mangfold, naturskogsnærhet, størrelse). Dessuten bør systemet testes mot allerede vurderte områder for å se hvordan grense-verdier og vekter bør fastlegges for å få resultater som er tilstrekkelig konsistente med tidligere vurderinger. NØKKELORD : naturverdi, kriterier, skog, skogvern, Norge KEY WORDS : conservation value, criteria, forest, forest protection, Norway

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