Reidar Elven

• Eidesen, Pernille Bronken; Elven, Reidar; Arnesen, Geir; Alsos, Inger Greve; Brysting, Anne Krag & Christensen, Maj Sofie [Show all 7 contributors for this article] (2025). Lavarktiske planter i en høyarktisk oase – tre nye arter for Svalbard registrert i Indre Wijdefjord nasjonalpark. Blyttia : Norsk botanisk forenings tidsskrift. ISSN 0006-5269. 83(3), p. 169–175. doi: https:/nhm2.uio.no/botanisk/nbf/blyttia/blyttia_pdf/Blyttia%20202503_OMSLAG%2020250910_01%20SCREEN%204.pdf. Full text in Research Archive Show summary

  Indre Wijdefjorden National Park in Northern Spitsbergen is housing several regionally rare vascular plant species. In later years we have found three plant species new to Svalbard in the rich and thermic favourable scree slopes in the Ringhorndalen – Flatøyrdalen valleys: Erigeron uniflorus, Festuca ovina, and Luzula spicata. In all three cases, these sites are by far the northernmost registered locations for these species in the world, separated from their nearest known sites to the south by 800–1000 km or more. The highly isolated occurrence of these three species, and several others with similar gaps to their nearest sites in the south, most likely represent remnants from larger populations thriving during the Holocene climatic optimum.

• Nygård, Malene Østreng; Kemppainen, Petri; Speed, James D. M.; Elven, Reidar; Flatberg, Kjell Ivar & Galten, Leif Persen [Show all 9 contributors for this article] (2021). Combining population genomics and ecological niche modeling to assess taxon limits between Carex jemtlandica and C. lepidocarpa. Journal of Systematics and Evolution. ISSN 1674-4918. 59(4), p. 627–641. doi: 10.1111/jse.12743. Full text in Research Archive Show summary

  Carex section Ceratocystis (Cyperaceae) is a group of recently evolved plant species, in which hybridization is frequent, introgression is documented, taxonomy is complex, and morphological boundaries are vague. Within this section, a unified taxonomic treatment of the Carex jemtlandica–Carex lepidocarpa species complex does not exist, and Norway may currently be the sole country accepting species rank for both. Carex jemtlandica is mainly confined to Fennoscandia and is thus a Fennoscandian conservation responsibility. This motivated us to test the principal hypothesis that both C. jemtlandica and C. lepidocarpa represent evolutionary significant units, and that both deserve their current recognition at species level. We investigated their evolutionary distinctiveness in Norway, using restriction site-associated DNA sequencing and ecological niche modeling. Our genomic results reveal two genetic clusters, largely corresponding to C. jemtlandica and C. lepidocarpa that also remain distinct in sympatry, despite clear indications of ongoing hybridization and introgression. The ecological niche modeling suggests that they occupy different environmental niches. Jointly, our results clearly show that C. jemtlandica and C. lepidocarpa represent separately evolving entities that should qualify recognition as evolutionary significant units. Given the high level of introgression compared to other hybridizing species pairs in Carex we recommend treating C. jemtlandica as a subspecies of C. lepidocarpa.

• Sandvik, Hanno; Hilmo, Olga; Henriksen, Snorre; Elven, Reidar; Åsen, Per Arvid & Hegre, Hanne [Show all 51 contributors for this article] (2020). Alien species in Norway: Results from quantitative ecological impact assessments. Ecological Solutions and Evidence. 1(1). doi: 10.1002/2688-8319.12006. Full text in Research Archive Show summary

  1. Due to globalisation, trade and transport, the spread of alien species is increasing dramatically. Some alien species become ecologically harmful by threatening native biota. This can lead to irreversible changes in local biodiversity and ecosystem functioning, and, ultimately, to biotic homogenisation. 2. We risk-assessed all alien plants, animals, fungi and algae, within certain delimitations, that are known to reproduce in Norway. Mainland Norway and the Arctic archipelago of Svalbard plus Jan Mayen were treated as separate assessment areas. Assessments followed the Generic Ecological Impact Assessment of Alien Species (GEIAA) protocol, which uses a fully quantitative set of criteria. 3. A total of 1519 species were risk-assessed, of which 1183 were species reproducing in mainland Norway. Among these, 9% were assessed to have a severe impact, 7% high impact, 7% potentially high impact, and 49% low impact, whereas 29% had no known impact. In Svalbard, 16 alien species were reproducing, one of which with a severe impact. 4. The impact assessments also covered 319 so-called door-knockers, i.e. species that are likely to establish in Norway within 50 years, and 12 regionally alien species. Of the door-knockers, 8% and 10% were assessed to have a severe and high impact, respectively. 5. The impact category of most species was driven by negative interactions with native species, transformation of threatened ecosystems, or genetic contamination. The proportion of alien species with high or severe impact varied significantly across the different pathways of introduction, taxonomic groups, time of introduction, and the environments colonised, but not across continents of origin. 6. Given the large number of alien species reproducing in Norway and the preponderance of species with low impact, it is neither realistic nor necessary to eradicate all of them. Our results can guide management authorities in two ways. First, the use of quantitative assessment criteria facilitates the prioritisation of management resources across species. Second, the background information collected for each species, such as introduction pathways, area of occupancy and ecosystems affected, helps designing appropriate management measures.

• Nowak, Michael; Pedersen, Anne Tiril Myhre; Brysting, Anne Krag; Schrøder-Nielsen, Audun; Elven, Reidar & Bjorå, Charlotte Sletten (2020). Testing hypotheses of hybrid origins for two seashore species of Carex section Phacocystis (Cyperaceae). Botanical journal of the Linnean Society. ISSN 0024-4074. 194(1), p. 110–117. doi: 10.1093/botlinnean/boaa030. Full text in Research Archive Show summary

  Abstract Taxonomists have proposed numerous hybrid species in plants, but to gain a better understanding of the role that hybridization may play in plant diversification, such taxonomic hypotheses must be tested using genomic data. In this study, we employ ddRAD sequence data to test taxonomic hypotheses of hybrid origins in Carex salina and C. ramenskii (Carex section Phacocystis). Sequence data from multiple Norwegian and Icelandic populations of the putative hybrid and parental species were generated for hundreds of ddRAD loci. These data were used to estimate geographical structuring of genetic diversity and admixture and to explicitly test for hybrid origins using several analytical approaches. Our results indicate recurrent hybrid origins for the populations of C. salina and C. ramenskii sampled in our study and show that these populations are characterized by high interspecific heterozygosity. Our results support the idea that hybridization may indeed play an important role in the diversification of lineages of Carex and highlight the important role that clonal propagation might play in maintaining hybrid populations. Future studies focusing on a broader geographical sampling would be needed to assess if the genetic structuring in these Nordic populations reflects range-wide patterns in these hybrid lineages.

• Sandvik, Hanno; Dolmen, Dag; Elven, Reidar; Falkenhaug, Tone; Forsgren, Elisabet & Hansen, Haakon [Show all 51 contributors for this article] (2019). Alien plants, animals, fungi and algae in Norway: an inventory of neobiota. Biological Invasions. ISSN 1387-3547. 21(10), p. 2997–3012. doi: 10.1007/s10530-019-02058-x. Full text in Research Archive Show summary

  We present the results of an inventory and status assessment of alien species in Norway. The inventory covered all known multicellular neobiota, 2496 in total, 1039 of which were classified as naturalised. The latter constitute c. 3% of all species known to be stably reproducing in Norway. These figures are higher than expected from Norway’s latitude, which may be due a combination of climatic and historical factors, as well as sampling effort. Most of the naturalised neobiota were plants (71%),followed by animals (21%) and fungi (8%). The main habitat types colonised were open lowlands (79%), urban environments (52%) and woodlands (42%). The main areas of origin were Europe (67%), North America (15%) and Asia (13%). For most taxa, the rate of novel introductions seems to have been increasing during recent decades. Within Norway, the number of alien species recorded per county was negatively correlated with latitude and positively correlated with human population density. In the high-Arctic territories under Norwegian sovereignty, i.e. Svalbard and Jan Mayen, 104 alien species were recorded, of which 5 were naturalised.

• Sandvik, Hanno; Hilmo, Olga; Finstad, Anders Gravbrøt; Hegre, Hanne; Moen, Toril Loennechen & Rafoss, Trond [Show all 10 contributors for this article] (2019). Generic ecological impact assessment of alien species (GEIAA): the third generation of assessments in Norway. Biological Invasions. ISSN 1387-3547. 21(9), p. 2803–2810. doi: 10.1007/s10530-019-02033-6. Full text in Research Archive Show summary

  The Generic Ecological Impact Assessment of Alien Species (GEIAA) is described. It comprises a set of criteria and an assessment procedure. The set of criteria consists of three criteria that quantify invasion potential, and six criteria that capture the ecological effects of alien species. The threshold values for all criteria are numerically defined, rendering the set of criteria fully quantitative. Genericity is ensured by using criteria that are applicable to all taxonomic groups and in all habitats. In being generic, quantitative, ecological and normatively neutral, the criteria were inspired by the international Red List criteria. Capturing both invasion potential and effect, GEIAA can be regarded as a full ecological impact assessment. The assessment procedure contains guidelines on documentation, the collection of background information, the handling of uncertainty, and quality assurance. GEIAA represents the second revision, and thus the third generation, of assessment methodology in Norway. It has recently been used to carry out more than 2500 impact assessments of alien species in Norway and Sweden.

• Birkeland, Siri; Skjetne, Idunn Elisabeth Borgen; Brysting, Anne Krag; Elven, Reidar & Alsos, Inger Greve (2017). Living on the edge: conservation genetics of seven thermophilous plant species in a high Arctic archipelago. AoB Plants. 9(1). doi: 10.1093/aobpla/plx001. Full text in Research Archive Show summary

  Small, isolated and/or peripheral populations are expected to harbour low levels of genetic variation and may therefore have reduced adaptability to environmental change, including climate warming. In the Arctic, global warming has already caused vegetation change across the region and is acting as a significant stressor on Arctic biodiversity. Many of the rare plants in the Arctic are relicts from early Holocene warm periods, but their ability to benefit from the current warming is dependent on the viability of their populations. We therefore examined Amplified Fragment Length Polymorphism (AFLP) data from regional red listed vascular plant species in the High Arctic archipelago of Svalbard and reference populations from the main distribution area of: (1) Botrychium lunaria, (2) Carex capillaris ssp. fuscidula, (3) Comastoma tenellum, (4) Kobresia simpliciuscula ssp. subholarctica, (5) Ranunculus wilanderi, (6) Sibbaldia procumbens and (7) Tofieldia pusilla. In addition, we gathered population size data in Svalbard. The Svalbard populations had low genetic diversity and distinctiveness and few or no private markers compared to populations outside the archipelago. This is similar to observations in other rare species in Svalbard and the genetic depletion may be due to an initial founder effect and/or a genetic bottleneck caused by late Holocene cooling. There seems to be limited gene flow from other areas and the Svalbard populations should therefore be considered as demographically independent management units. Overall, these management units have small and/or few populations and are therefore prone to stochastic events which may further increase vulnerability to inbreeding depression, loss of genetic variation, and reduced evolutionary potential. Our results support theory predicting lower levels of genetic diversity in small, isolated and/or peripheral populations and may be of importance for management of other rare plant species in the Arctic.

• Elven, Reidar; Pedersen, Anne Tiril Myhre & Bjorå, Charlotte Sletten (2017). The nomenclature of two hybrid taxa in Carex sect. Vesicariae (Cyperaceae) currently assigned as Carex rostrata var. borealis and Carex stenolepis. Phytotaxa. ISSN 1179-3155. 324(1), p. 63–72. doi: 10.11646/phytotaxa.324.1.4. Full text in Research Archive Show summary

  In a recent study of Carex sect. Vesicariae in northern Europe, two hybrid species were identified using microsatellite markers. Whereas both taxa already have names associated with them, we find that these names are not appropriate for use. In this study, the taxon previously described as C. rostrata var. borealis is raised to species level as the hybrid taxon Carex ×saamica (from C. rostrata × C. rotundata). We furthermore show that the name C. stenolepis, after designation of a lectotype, becomes a synonym of C. rostrata, and hence accept C. ×grahamii as the priority name for the hybrid taxon (from C. saxatilis × C. vesicaria) previously denoted as C. stenolepis. Arguments for these choices are given. Four other species names that have been assigned to the two hybrid taxa are discussed. Types are identified or designated for the names C. rostrata var. borealis, C. stenolepis, and C. ×grahamii. A key to the hybrid taxa and their parents is given.

• Pedersen, Anne Tiril Myhre; Nowak, Michael; Brysting, Anne Krag; Elven, Reidar & Bjorå, Charlotte Sletten (2016). Hybrid Origins of Carex rostrata var. borealis and C. stenolepis, Two Problematic Taxa in Carex section Vesicariae (Cyperaceae). PLOS ONE. 11(10), p. 1–18. doi: 10.1371/journal.pone.0165430. Full text in Research Archive Show summary

  Hybridization is frequent in the large and ecologically significant genus Carex (Cyperaceae). In four important sections of the northern regions (Ceratocystis, Glareosae, Phacocystis and Vesicariae), the frequent occurrence of hybrids often renders the identification of “pure” species and hybrids difficult. In this study we address the origins and taxonomic rank of two taxa of section Vesicariae: Carex rostrata var. borealis and C. stenolepis. The origin and taxonomic status of C. stenolepis has been the subject of substantial debate over the years, whereas C. rostrata var. borealis has received very little attention in the years since its first description in the 19th century. By performing an extensive sampling of relevant taxa from a broad distribution range, and analyzing data from fifteen microsatellite loci developed specifically for our study together with pollen stainability measures, we resolve the hybrid origins of C. rostrata var. borealis and C. stenolepis and provide new insights into this taxonomically challenging group of sedges. Our results are in accordance with previous findings suggesting that C. stenolepis is a hybrid between C. vesicaria and C. saxatilis. They are also in accordance with a previous proposition that C. rostrata var. borealis is a hybrid between C. rostrata and C. rotundata, and furthermore suggest that both hybrids are the result of multiple, recent (i.e., postglacial) hybridization events. We found little evidence for successful sexual reproduction within C. rostrata var. borealis and C. stenolepis, but conclude that the common and recurrent, largely predictable occurrence of these taxa justifies accepting both hybrids as hybrid species with binomial names. There are, however, complications as to types and priority names, and we therefore choose to address these problems in a separate paper.

• Vandvik, Vigdis; Elven, Reidar & Töpper, Joachim Paul (2016). Seedling recruitment in subalpine grassland forbs: Predicting field regeneration behaviour from lab germination responses. Botany. ISSN 1916-2790. 95(1), p. 73–88. doi: 10.1139/cjb-2016-0022. Full text in Research Archive
• Alsos, Inger Greve; Ehrich, Dorothee; Eidesen, Pernille Bronken; Solstad, Heidi Merethe; Westergaard, Kristine Bakke & Schonswetter, Peter [Show all 10 contributors for this article] (2015). Long-distance plant dispersal to North Atlantic islands: colonization routes and founder effect. AoB Plants. 7(1), p. 1–19. doi: 10.1093/aobpla/plv036. Full text in Research Archive Show summary

  Long-distance dispersal (LDD) processes influence the founder effect on islands.We use genetic data for 25 Atlantic species and similarities among regional floras to analyse colonization, and test whether the genetic founder effect on five islands is associated with dispersal distance, island size and species traits. Most species colonized postglacially via multiple dispersal events from several source regions situated 280 to .3000 km away, and often not from the closest ones. A strong founder effect was observed for insect-pollinated mixed maters, and it increased with dispersal distance and decreased with island size in accordance with the theory of island biogeography. Only a minor founder effect was observed for wind-pollinated outcrossing species. Colonization patterns were largely congruent, indicating that despite the importance of stochasticity, LDD is mainly determined by common factors, probably dispersal vectors. Our findings caution against a priori assuming a single, close source region in biogeographic analyses. Amplified fragment length polymorphism (AFLP); dispersal vector; founder effect; genetic diversity; islands; long-distance dispersal (LDD); postglacial; species traits.

• Alsos, Inger Greve; Ware, Christopher & Elven, Reidar (2015). Past Arctic aliens have passed away, current ones may stay. Biological Invasions. ISSN 1387-3547. 17(11), p. 3113–3123. doi: 10.1007/s10530-015-0937-9. Full text in Research Archive Show summary

  Increased human activity and climate change are expected to increase the numbers and impact of alien species in the Arctic, but knowledge of alien species is poor in most Arctic regions. Through field investigations over the last 10 years, and review of alien vascular plant records for the high Arctic Archipelago Svalbard over the past 130 years, we explored long term trends in persistence and phenology. In total, 448 observations of 105 taxa have been recorded from 28 sites. Recent surveys at 18 of these sites revealed that alien species had disappeared at half of them. Investigations at a further 49 sites characterised by former human activity and/or current tourist landing sites did not reveal any alien species. Patterns of alien species distribution suggest that greater alien species richness is more likely to be aligned with ongoing human inhabitation than sites of transient use. The probability of an alien species being in a more advanced phenological stage increased with higher mean July temperatures. As higher mean July temperatures are positively correlated with more recent year, the latter finding suggests a clear warming effect on the increased reproductive potential of alien plants, and thus an increased potential for spread in Svalbard. Given that both human activity and temperatures are expected to increase in the future, there is need to respond in policy and action to reduce the potential for further alien species introduction and spread in the Arctic.

• Willerslev, E; Davison, J; Moora, M; Zobel, M; Coissac, E & Edwards, ME [Show all 50 contributors for this article] (2014). Fifty thousand years of Arctic vegetation and megafaunal diet. Nature. ISSN 0028-0836. 506(7486), p. 47–51. doi: 10.1038/nature12921. Full text in Research Archive
• Solstad, Heidi; Eidesen, Pernille Bronken; Little, Lorna & Elven, Reidar (2014). To valmue-arter på Svalbard, og litt om fjell- og polarvalmuer. Blyttia : Norsk botanisk forenings tidsskrift. ISSN 0006-5269. 72(3), p. 187–196. Full text in Research Archive Show summary

  Morphological investigations confirm that there are two species of Papaver in Svalbard: P. dahlianum and P. cornwallisense. The two most distinctive diagnostic characters are the number of stamens and the length of papillae on the stigmatic rays. Papaver cornwallisense has few stamens, usually 16 but sometimes as few as 4 or 8 or as many as 24, and short papillae (0.15–0.4 mm). Papaver dahlianum usually has 25–35 stamens and conspicuously long papillae (0.5–0.9 mm). In addition, P. cornwallisense has smaller flowers than P. dahlianum and these are mostly white. The fruit of P. cornwallisense is subglobular and narrow beneath the stigmatic disc, whereas that of P. dahlianum is urn-shaped and broadest immediately beneath the disc. There are also some smaller differences in leaf lobes, which are more obtuse in P. cornwallisense than in P. dahlia-num,and leaf pubescence, which is sparse and white in P. cornwallisense, denser and more yellowish in P. dahlianum. In Svalbard, P. dahlianum is the most common of the two, occurring throughout the archipelago, but P. cornwallisense is also common, particularly in western Spitsbergen (where most people visit), where it constitutes almost exactly 50 % of the collected plants in the herbaria. The two species often grow intermixed, both in Svalbard as well as in Greenland and Canada (where they are about equally common). No hybrids or transitional forms are known. A molecular investigation supports the presence of two species.

• Elven, Reidar (2013). Hippuris lanceolata Retz. In Elven, Reidar; Fremstad, Eli & Pedersen, Oddvar (Ed.), Distribution maps of Norwegian vascular plants. IV The eastern and northeastern elements. Akademika forlag. ISSN 9788232102464. p. 232–235. Full text in Research Archive
• Elven, Reidar (2013). Hierochloë odorata (L.) Wahlenb. In Elven, Reidar; Fremstad, Eli & Pedersen, Oddvar (Ed.), Distribution maps of Norwegian vascular plants. IV The eastern and northeastern elements. Akademika forlag. ISSN 9788232102464. p. 229–232. Full text in Research Archive
• Elven, Reidar (2013). Hippuris tetraphylla L.f. In Elven, Reidar; Fremstad, Eli & Pedersen, Oddvar (Ed.), Distribution maps of Norwegian vascular plants. IV The eastern and northeastern elements. Akademika forlag. ISSN 9788232102464. p. 235–236. Full text in Research Archive
• Elven, Reidar (2013). Juncus gerardii Loisel. subsp. atrofuscus (Rupr.) Printz. In Elven, Reidar; Fremstad, Eli & Pedersen, Oddvar (Ed.), Distribution maps of Norwegian vascular plants. IV The eastern and northeastern elements. Akademika forlag. ISSN 9788232102464. p. 240–241. Full text in Research Archive
• Elven, Reidar (2013). Poa palustris L. In Elven, Reidar; Fremstad, Eli & Pedersen, Oddvar (Ed.), Distribution maps of Norwegian vascular plants. IV The eastern and northeastern elements. Akademika forlag. ISSN 9788232102464. p. 291–293. Full text in Research Archive
• Elven, Reidar (2013). Lycopodium annotinum L. subsp. alpestre (Hartm.) Á. & D.Löve. In Elven, Reidar; Fremstad, Eli & Pedersen, Oddvar (Ed.), Distribution maps of Norwegian vascular plants. IV The eastern and northeastern elements. Akademika forlag. ISSN 9788232102464. p. 250–252. Full text in Research Archive
• Wischmann, Finn & Elven, Reidar (2013). Luzula pallescens Sw. In Elven, Reidar; Fremstad, Eli & Pedersen, Oddvar (Ed.), Distribution maps of Norwegian vascular plants. IV The eastern and northeastern elements. Akademika forlag. ISSN 9788232102464. p. 248–250. Full text in Research Archive
• Elven, Reidar (2013). Myriophyllum sibiricum Kom. In Elven, Reidar; Fremstad, Eli & Pedersen, Oddvar (Ed.), Distribution maps of Norwegian vascular plants. IV The eastern and northeastern elements. Akademika forlag. ISSN 9788232102464. p. 264–266. Full text in Research Archive
• Elven, Reidar (2013). Myriophyllum verticillatum L. In Elven, Reidar; Fremstad, Eli & Pedersen, Oddvar (Ed.), Distribution maps of Norwegian vascular plants. IV The eastern and northeastern elements. Akademika forlag. ISSN 9788232102464. p. 266–268. Full text in Research Archive
• Elven, Reidar (2013). Gentianopsis detonsa (Rottb.) Ma. In Elven, Reidar; Fremstad, Eli & Pedersen, Oddvar (Ed.), Distribution maps of Norwegian vascular plants. IV The eastern and northeastern elements. Akademika forlag. ISSN 9788232102464. p. 217–219. Full text in Research Archive
• Elven, Reidar (2013). Gentianella amarella (L.) Börner. In Elven, Reidar; Fremstad, Eli & Pedersen, Oddvar (Ed.), Distribution maps of Norwegian vascular plants. IV The eastern and northeastern elements. Akademika forlag. ISSN 9788232102464. p. 215–217. Full text in Research Archive
• Elven, Reidar (2013). Persicaria foliosa (H.Lindb.) Kitag. In Elven, Reidar; Fremstad, Eli & Pedersen, Oddvar (Ed.), Distribution maps of Norwegian vascular plants. IV The eastern and northeastern elements. Akademika forlag. ISSN 9788232102464. p. 280–282. Full text in Research Archive
• Elven, Reidar (2013). Oxytropis deflexa (Pall.) DC. In Elven, Reidar; Fremstad, Eli & Pedersen, Oddvar (Ed.), Distribution maps of Norwegian vascular plants. IV The eastern and northeastern elements. Akademika forlag. ISSN 9788232102464. p. 273–275. Full text in Research Archive
• Elven, Reidar (2013). Lathyrus palustris L. In Elven, Reidar; Fremstad, Eli & Pedersen, Oddvar (Ed.), Distribution maps of Norwegian vascular plants. IV The eastern and northeastern elements. Akademika forlag. ISSN 9788232102464. p. 245–248. Full text in Research Archive
• Wischmann, Finn & Elven, Reidar (2013). Juncus stygius L. In Elven, Reidar; Fremstad, Eli & Pedersen, Oddvar (Ed.), Distribution maps of Norwegian vascular plants. IV The eastern and northeastern elements. Akademika forlag. ISSN 9788232102464. p. 242–243. Full text in Research Archive
• Elven, Reidar (2013). Moehringia lateriflora (L.) Fenzl. In Elven, Reidar; Fremstad, Eli & Pedersen, Oddvar (Ed.), Distribution maps of Norwegian vascular plants. IV The eastern and northeastern elements. Akademika forlag. ISSN 9788232102464. p. 254–255. Full text in Research Archive
• Elven, Reidar (2013). Lycopodium clavatum L. subsp. monostachyon (Grev. & Hook.) Selander. In Elven, Reidar; Fremstad, Eli & Pedersen, Oddvar (Ed.), Distribution maps of Norwegian vascular plants. IV The eastern and northeastern elements. Akademika forlag. ISSN 9788232102464. p. 252–254. Full text in Research Archive
• Elven, Reidar (2013). Hierochloë hirta (Schrank) Borbás. In Elven, Reidar; Fremstad, Eli & Pedersen, Oddvar (Ed.), Distribution maps of Norwegian vascular plants. IV The eastern and northeastern elements. Akademika forlag. ISSN 9788232102464. p. 227–229. Full text in Research Archive
• Wischmann, Finn & Elven, Reidar (2013). Galium trifidum L. In Elven, Reidar; Fremstad, Eli & Pedersen, Oddvar (Ed.), Distribution maps of Norwegian vascular plants. IV The eastern and northeastern elements. Akademika forlag. ISSN 9788232102464. p. 212–214. Full text in Research Archive
• Elven, Reidar (2013). Gymnocarpium continentale (Petrov) Pojark. In Elven, Reidar; Fremstad, Eli & Pedersen, Oddvar (Ed.), Distribution maps of Norwegian vascular plants. IV The eastern and northeastern elements. Akademika forlag. ISSN 9788232102464. p. 223–225. Full text in Research Archive
• Elven, Reidar (2013). Eurybia sibirica (L.) G.L.Nesom. In Elven, Reidar; Fremstad, Eli & Pedersen, Oddvar (Ed.), Distribution maps of Norwegian vascular plants. IV The eastern and northeastern elements. Akademika forlag. ISSN 9788232102464. p. 210–212. Full text in Research Archive
• Elven, Reidar (2013). Myosotis decumbens Host. In Elven, Reidar; Fremstad, Eli & Pedersen, Oddvar (Ed.), Distribution maps of Norwegian vascular plants. IV The eastern and northeastern elements. Akademika forlag. ISSN 9788232102464. p. 258–261. Full text in Research Archive
• Elven, Reidar (2013). Mulgedium sibiricum (L.) Cass. ex Less. In Elven, Reidar; Fremstad, Eli & Pedersen, Oddvar (Ed.), Distribution maps of Norwegian vascular plants. IV The eastern and northeastern elements. Akademika forlag. ISSN 9788232102464. p. 257–258. Full text in Research Archive
• Elven, Reidar (2013). Carex laxa Wahlenb. In Elven, Reidar; Fremstad, Eli & Pedersen, Oddvar (Ed.), Distribution maps of Norwegian vascular plants. IV The eastern and northeastern elements. Akademika forlag. ISSN 9788232102464. p. 127–129. Full text in Research Archive
• Elven, Reidar (2013). Carex lapponica O.Lang. In Elven, Reidar; Fremstad, Eli & Pedersen, Oddvar (Ed.), Distribution maps of Norwegian vascular plants. IV The eastern and northeastern elements. Akademika forlag. ISSN 9788232102464. p. 125–127. Full text in Research Archive
• Elven, Reidar (2013). Alopecurus aequalis Sobol. In Elven, Reidar; Fremstad, Eli & Pedersen, Oddvar (Ed.), Distribution maps of Norwegian vascular plants. IV The eastern and northeastern elements. Akademika forlag. ISSN 9788232102464. p. 57–59. Full text in Research Archive
• Elven, Reidar (2013). Calamagrostis lapponica (Wahlenb.) Hartm. In Elven, Reidar; Fremstad, Eli & Pedersen, Oddvar (Ed.), Distribution maps of Norwegian vascular plants. IV The eastern and northeastern elements. Akademika forlag. ISSN 9788232102464. p. 86–90. Full text in Research Archive
• Elven, Reidar (2013). Calamagrostis chalybaea (Laest.) Fr. In Elven, Reidar; Fremstad, Eli & Pedersen, Oddvar (Ed.), Distribution maps of Norwegian vascular plants. IV The eastern and northeastern elements. Akademika forlag. ISSN 9788232102464. p. 84–86. Full text in Research Archive
• Elven, Reidar (2013). Alopecurus pratensis L. subsp. alpestris (Wahlenb.) Selander. In Elven, Reidar; Fremstad, Eli & Pedersen, Oddvar (Ed.), Distribution maps of Norwegian vascular plants. IV The eastern and northeastern elements. Akademika forlag. ISSN 9788232102464. p. 61–63. Full text in Research Archive
• Elven, Reidar (2013). Carex jemtlandica (Palmgr.) Palmgr. In Elven, Reidar; Fremstad, Eli & Pedersen, Oddvar (Ed.), Distribution maps of Norwegian vascular plants. IV The eastern and northeastern elements. Akademika forlag. ISSN 9788232102464. p. 123–125. Full text in Research Archive
• Elven, Reidar (2013). Carex cespitosa L. In Elven, Reidar; Fremstad, Eli & Pedersen, Oddvar (Ed.), Distribution maps of Norwegian vascular plants. IV The eastern and northeastern elements. Akademika forlag. ISSN 9788232102464. p. 111–115. Full text in Research Archive
• Elven, Reidar (2013). Calamagrostis neglecta (Ehrh.) P.Gaertn., B.Mey. & Scherb. In Elven, Reidar; Fremstad, Eli & Pedersen, Oddvar (Ed.), Distribution maps of Norwegian vascular plants. IV The eastern and northeastern elements. Akademika forlag. ISSN 9788232102464. p. 90–92. Full text in Research Archive
• Danielsen, Anders & Elven, Reidar (2013). Calla palustris L. In Elven, Reidar; Fremstad, Eli & Pedersen, Oddvar (Ed.), Distribution maps of Norwegian vascular plants. IV The eastern and northeastern elements. Akademika forlag. ISSN 9788232102464. p. 92-94–92-94. Full text in Research Archive
• Elven, Reidar (2013). Atriplex lapponica Pojark. In Elven, Reidar; Fremstad, Eli & Pedersen, Oddvar (Ed.), Distribution maps of Norwegian vascular plants. IV The eastern and northeastern elements. Akademika forlag. ISSN 9788232102464. p. 71–72. Full text in Research Archive
• Elven, Reidar (2013). Chamaedaphne calyculata (L.) Moench. In Elven, Reidar; Fremstad, Eli & Pedersen, Oddvar (Ed.), Distribution maps of Norwegian vascular plants. IV The eastern and northeastern elements. Akademika forlag. ISSN 9788232102464. p. 149–151. Full text in Research Archive
• Elven, Reidar (2013). Carex tenuiflora Wahlenb. In Elven, Reidar; Fremstad, Eli & Pedersen, Oddvar (Ed.), Distribution maps of Norwegian vascular plants. IV The eastern and northeastern elements. Akademika forlag. ISSN 9788232102464. p. 143–145. Full text in Research Archive
• Elven, Reidar (2013). Arctophila fulva (Trin.) Andersson. In Elven, Reidar; Fremstad, Eli & Pedersen, Oddvar (Ed.), Distribution maps of Norwegian vascular plants. IV The eastern and northeastern elements. Akademika forlag. ISSN 9788232102464. p. 64–66. Full text in Research Archive
• Elven, Reidar (2013). Carex bergrothii Palmgr. In Elven, Reidar; Fremstad, Eli & Pedersen, Oddvar (Ed.), Distribution maps of Norwegian vascular plants. IV The eastern and northeastern elements. Akademika forlag. ISSN 9788232102464. p. 107–109. Full text in Research Archive
• Elven, Reidar (2013). Carex aquatilis Wahlenb. In Elven, Reidar; Fremstad, Eli & Pedersen, Oddvar (Ed.), Distribution maps of Norwegian vascular plants. IV The eastern and northeastern elements. Akademika forlag. ISSN 9788232102464. p. 103–107. Full text in Research Archive
• Elven, Reidar (2013). Draba cinerea Adams. In Elven, Reidar; Fremstad, Eli & Pedersen, Oddvar (Ed.), Distribution maps of Norwegian vascular plants. IV The eastern and northeastern elements. Akademika forlag. ISSN 9788232102464. p. 180–182. Full text in Research Archive
• Elven, Reidar (2013). Diphasiastrum complanatum (L.) Holub. In Elven, Reidar; Fremstad, Eli & Pedersen, Oddvar (Ed.), Distribution maps of Norwegian vascular plants. IV The eastern and northeastern elements. Akademika forlag. ISSN 9788232102464. p. 174–178. Full text in Research Archive
• Elven, Reidar (2013). Carex buxbaumii Wahlenb. In Elven, Reidar; Fremstad, Eli & Pedersen, Oddvar (Ed.), Distribution maps of Norwegian vascular plants. IV The eastern and northeastern elements. Akademika forlag. ISSN 9788232102464. p. 109–111. Full text in Research Archive
• Elven, Reidar (2013). Carex stylosa C.A.Mey. In Elven, Reidar; Fremstad, Eli & Pedersen, Oddvar (Ed.), Distribution maps of Norwegian vascular plants. IV The eastern and northeastern elements. Akademika forlag. ISSN 9788232102464. p. 141–143. Full text in Research Archive
• Elven, Reidar (2013). Carex media R.Br. In Elven, Reidar; Fremstad, Eli & Pedersen, Oddvar (Ed.), Distribution maps of Norwegian vascular plants. IV The eastern and northeastern elements. Akademika forlag. ISSN 9788232102464. p. 132–134. Full text in Research Archive
• Elven, Reidar (2013). Carex acuta L. In Elven, Reidar; Fremstad, Eli & Pedersen, Oddvar (Ed.), Distribution maps of Norwegian vascular plants. IV The eastern and northeastern elements. Akademika forlag. ISSN 9788232102464. p. 99–101. Full text in Research Archive
• Elven, Reidar (2013). Carex rotundata Wahlenb. In Elven, Reidar; Fremstad, Eli & Pedersen, Oddvar (Ed.), Distribution maps of Norwegian vascular plants. IV The eastern and northeastern elements. Akademika forlag. ISSN 9788232102464. p. 139–141. Full text in Research Archive
• Elven, Reidar (2013). Alchemilla subglobosa C.G.Westerl. In Elven, Reidar; Fremstad, Eli & Pedersen, Oddvar (Ed.), Distribution maps of Norwegian vascular plants. IV The eastern and northeastern elements. Akademika forlag. ISSN 9788232102464. p. 47–49. Full text in Research Archive
• Elven, Reidar (2013). Alchemilla propinqua H.Lindb. ex Juz. In Elven, Reidar; Fremstad, Eli & Pedersen, Oddvar (Ed.), Distribution maps of Norwegian vascular plants. IV The eastern and northeastern elements. Akademika forlag. ISSN 9788232102464. p. 45–47. Full text in Research Archive
• Elven, Reidar (2013). Callitriche cophocarpa Sendtn. In Elven, Reidar; Fremstad, Eli & Pedersen, Oddvar (Ed.), Distribution maps of Norwegian vascular plants. IV The eastern and northeastern elements. Akademika forlag. ISSN 9788232102464. p. 95–97. Full text in Research Archive
• Elven, Reidar (2013). Epilobium laestadii Kytöv. In Elven, Reidar; Fremstad, Eli & Pedersen, Oddvar (Ed.), Distribution maps of Norwegian vascular plants. IV The eastern and northeastern elements. Akademika forlag. ISSN 9788232102464. p. 196–198. Full text in Research Archive
• Elven, Reidar (2013). Butomus umbellatus L. In Elven, Reidar; Fremstad, Eli & Pedersen, Oddvar (Ed.), Distribution maps of Norwegian vascular plants. IV The eastern and northeastern elements. Akademika forlag. ISSN 9788232102464. p. 80–81. Full text in Research Archive
• Elven, Reidar (2013). Elymus mutabilis (Drobow) Tzvelev. In Elven, Reidar; Fremstad, Eli & Pedersen, Oddvar (Ed.), Distribution maps of Norwegian vascular plants. IV The eastern and northeastern elements. Akademika forlag. ISSN 9788232102464. p. 194–196. Full text in Research Archive
• Elven, Reidar (2013). Betula pendula Roth var. lapponica (Lindq.) Hämet-Ahti. In Elven, Reidar; Fremstad, Eli & Pedersen, Oddvar (Ed.), Distribution maps of Norwegian vascular plants. IV The eastern and northeastern elements. Akademika forlag. ISSN 9788232102464. p. 75–76. Full text in Research Archive
• Elven, Reidar (2013). Elymus fibrosus (Schrenk) Tzvelev. In Elven, Reidar; Fremstad, Eli & Pedersen, Oddvar (Ed.), Distribution maps of Norwegian vascular plants. IV The eastern and northeastern elements. Akademika forlag. ISSN 9788232102464. p. 192–194. Full text in Research Archive
• Elven, Reidar (2013). Eleocharis palustris (L.) Roem. & Schult. subsp. palustris. In Elven, Reidar; Fremstad, Eli & Pedersen, Oddvar (Ed.), Distribution maps of Norwegian vascular plants. IV The eastern and northeastern elements. Akademika forlag. ISSN 9788232102464. p. 189–190. Full text in Research Archive
• Elven, Reidar (2013). Eleocharis mamillata H.Lindb. subsp. austriaca (Hayek) Strandhede. In Elven, Reidar; Fremstad, Eli & Pedersen, Oddvar (Ed.), Distribution maps of Norwegian vascular plants. IV The eastern and northeastern elements. Akademika forlag. ISSN 9788232102464. p. 187–189. Full text in Research Archive
• Elven, Reidar (2013). Eriophorum x medium Andersson. In Elven, Reidar; Fremstad, Eli & Pedersen, Oddvar (Ed.), Distribution maps of Norwegian vascular plants. IV The eastern and northeastern elements. Akademika forlag. ISSN 9788232102464. p. 203–205. Full text in Research Archive
• Elven, Reidar (2013). Eriophorum brachyantherum Trautv. & C.A.Mey. In Elven, Reidar; Fremstad, Eli & Pedersen, Oddvar (Ed.), Distribution maps of Norwegian vascular plants. IV The eastern and northeastern elements. Akademika forlag. ISSN 9788232102464. p. 200–201. Full text in Research Archive
• Elven, Reidar (2013). Deschampsia cespitosa (L.) P.Beauv. subsp. glauca (Hartm.) Hartm. In Elven, Reidar; Fremstad, Eli & Pedersen, Oddvar (Ed.), Distribution maps of Norwegian vascular plants. IV The eastern and northeastern elements. Akademika forlag. ISSN 9788232102464. p. 171–172. Full text in Research Archive
• Elven, Reidar (2013). Alchemilla taernaënsis Hyl. ex Ericsson & S.Hellq. In Elven, Reidar; Fremstad, Eli & Pedersen, Oddvar (Ed.), Distribution maps of Norwegian vascular plants. IV The eastern and northeastern elements. Akademika forlag. ISSN 9788232102464. p. 49–50. Full text in Research Archive
• Danielsen, Anders & Elven, Reidar (2013). Cicuta virosa L. In Elven, Reidar; Fremstad, Eli & Pedersen, Oddvar (Ed.), Distribution maps of Norwegian vascular plants. IV The eastern and northeastern elements. Akademika forlag. ISSN 9788232102464. p. 152–155. Full text in Research Archive
• Elven, Reidar (2013). Alnus incana (L.) Moench subsp. kolaënsis (Orlova) Á.Löve & D.Löve. In Elven, Reidar; Fremstad, Eli & Pedersen, Oddvar (Ed.), Distribution maps of Norwegian vascular plants. IV The eastern and northeastern elements. Akademika forlag. ISSN 9788232102464. p. 54–57. Full text in Research Archive
• Elven, Reidar (2013). Sorbus aucuparia L. subsp. glabrata (Wimm. & Grab.) Hayek. In Elven, Reidar; Fremstad, Eli & Pedersen, Oddvar (Ed.), Distribution maps of Norwegian vascular plants. IV The eastern and northeastern elements. Akademika forlag. ISSN 9788232102464. p. 391–393. Full text in Research Archive
• Elven, Reidar (2013). Pyrola rotundifolia L. In Elven, Reidar; Fremstad, Eli & Pedersen, Oddvar (Ed.), Distribution maps of Norwegian vascular plants. IV The eastern and northeastern elements. Akademika forlag. ISSN 9788232102464. p. 326–328. Full text in Research Archive
• Elven, Reidar (2013). Ranunculus confervoides (Fr.) Fr. In Elven, Reidar; Fremstad, Eli & Pedersen, Oddvar (Ed.), Distribution maps of Norwegian vascular plants. IV The eastern and northeastern elements. Akademika forlag. ISSN 9788232102464. p. 328–331. Full text in Research Archive
• Elven, Reidar (2013). Sparganium emersum Rehm. In Elven, Reidar; Fremstad, Eli & Pedersen, Oddvar (Ed.), Distribution maps of Norwegian vascular plants. IV The eastern and northeastern elements. Akademika forlag. ISSN 9788232102464. p. 393–395. Full text in Research Archive
• Elven, Reidar (2013). Alchemilla oxyodonta (Buser) C.G. Westerl. In Elven, Reidar; Fremstad, Eli & Pedersen, Oddvar (Ed.), Distribution maps of Norwegian vascular plants. IV The eastern and northeastern elements. Akademika forlag. ISSN 9788232102464. p. 43–45. Full text in Research Archive
• Elven, Reidar (2013). Tephroseris integrifolia (L.) Holub. In Elven, Reidar; Fremstad, Eli & Pedersen, Oddvar (Ed.), Distribution maps of Norwegian vascular plants. IV The eastern and northeastern elements. Akademika forlag. ISSN 9788232102464. p. 414–416. Full text in Research Archive
• Elven, Reidar (2013). Thalictrum kemense Fr. In Elven, Reidar; Fremstad, Eli & Pedersen, Oddvar (Ed.), Distribution maps of Norwegian vascular plants. IV The eastern and northeastern elements. Akademika forlag. ISSN 9788232102464. p. 416–418. Full text in Research Archive
• Elven, Reidar (2013). Silene involucrata (Cham. & Schltdl.) Bocquet. In Elven, Reidar; Fremstad, Eli & Pedersen, Oddvar (Ed.), Distribution maps of Norwegian vascular plants. IV The eastern and northeastern elements. Akademika forlag. ISSN 9788232102464. p. 387–389. Full text in Research Archive

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• Elven, Reidar; Bjorå, Charlotte Sletten; Fremstad, Eli; Hegre, Hanne & Solstad, Heidi (2022). Norsk Flora, 8. utgåva. Det Norske Samlaget. ISBN 9788252198621. 1255 p. Full text in Research Archive
• Elven, Reidar & Fremstad, Eli (2018). Salix - vier, selje og pil i Norge. NTNU Vitenskapsmuseet. ISBN 9788283221534. 715 p. Full text in Research Archive

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• Bjorå, Charlotte Sletten; Elven, Reidar & Hessen, Dag Olav (2023). Hva skjer med plantene i Norge? [Radio]. NRK P2 EKKO. Full text in Research Archive
• Elven, Reidar; Bjorå, Charlotte Sletten; Fremstad, Eli; Hegre, Hanne & Solstad, Heidi (2022). Bakgrunn for endringer i ‘Norsk flora’ 2022 (1). Blyttia : Norsk botanisk forenings tidsskrift. ISSN 0006-5269. 80(2), p. 118–135. Full text in Research Archive
• Bjorå, Charlotte Sletten & Elven, Reidar (2022). Nå kommer den første floraen på 17 år. [Journal]. Apollon : Forskningsmagasin for Universitetet i Oslo. Full text in Research Archive
• Båtvik, Jan Ingar Iversen; Elven, Reidar; Solstad, Heidi; Grundt, Hanne Hegre & Elven, Anne (2022). No kjem ein ny epistel av «botanikkens bibel». [Journal]. Nationen s. 21. Full text in Research Archive Show summary

  Boka Norsk flora med ei samling av 3533 planteartar blir lansert av Samlaget 30. november. Dette er den åttande utgåva av boka og inneheld nesten dobbelt så mange artar som den første utgåva, heiter det i ei pressemelding. Boka gjev eit djupdykk i karplanter frå fastlandsnoreg og dei arktiske øyane gjennom tidene. Om lag 3220 av dei mange presenterte plantene i boka er illustrerte med både karakteristiske og instruktive teikningar. Norsk flora fungerer som eit oppslagsverk. Her finn ein mellom anna raudlista som viser kva slags planter som er sjeldne og utrydjingstruga. Boka inneheld òg framandartlista, som viser dei planteartene som ikkje er heimlege i Noreg og som fortrengjer andre vokstrar som har opphavet sitt her. Boka som er kjend som «botanikkens bibel» blir presentert av forfattarane professor Reidar Elven, Hanne Hegre, og illustratør Anne Elven i samtale med biolog Jan Ingar Båtvik i Nynorskens hus i Oslo 30. november. (©NPK) Tradisjon: Den første utgåva kom i 1944 og tradisjonen lever vidare. I november 2022 blir den åttande utgåva av Norsk Flora lansert. Foto: Det Norske Samlaget

• Elven, Reidar; Bjorå, Charlotte Sletten; Fremstad, Eli; Hegre, Hanne & Solstad, Heidi (2022). Bakgrunn for endringer i 'Norsk Flora' 2022 (3). Blyttia : Norsk botanisk forenings tidsskrift. ISSN 0006-5269. 80(4), p. 239–259. Full text in Research Archive
• Elven, Reidar; Bjorå, Charlotte Sletten; Fremstad, Eli; Grundt, Hanne Hegre & Solstad, Heidi (2022). Bakgrunn for endringer i ‘Norsk flora’ 2022 (2). Blyttia : Norsk botanisk forenings tidsskrift. ISSN 0006-5269. 80(3), p. 175–203. Full text in Research Archive
• Bjorå, Charlotte Sletten; Nordal, Inger & Elven, Reidar (2016). Tidenes første panarktiske Flora. [Journal]. Apollon. Full text in Research Archive
• Grundt, Hanne H.; Brysting, Anne Krag & Elven, Reidar (2015). Storlind Tilia platyphyllos i Østfold og Norge: Rød eller svart? Blyttia : Norsk botanisk forenings tidsskrift. ISSN 0006-5269. 73, p. 13–22. Full text in Research Archive
• Alsos, Inger Greve; Ehrich, Dorothee; Eidesen, Pernille Bronken; Tribsch, Andreas; Schonswetter, Peter & Westergaard, Kristine Bakke [Show all 13 contributors for this article] (2015). Colonization of Arctic islands revealed by modern and ancient DNA analyses. Full text in Research Archive
• Alsos, Inger Greve; Ehrich, Dorothee; Eidesen, Pernille Bronken; Schonswetter, Peter; Tribsch, Andreas & Westergaard, Kristine Bakke [Show all 14 contributors for this article] (2014). Effects of past and future climate change on plant colonization in the Arctic: insights gained from phylogeography, species distribution modelling and ancient DNA. Full text in Research Archive
• Alsos, Inger Greve; Ehrich, Dorothee; Eidesen, Pernille Bronken; Pellisier, Löic; Tribsch, Andreas & Schonswetter, Peter [Show all 14 contributors for this article] (2014). Effects of past and future climate change on plant colonization of arctic islands. Full text in Research Archive
• Alsos, Inger Greve; Ehrich, Dorothee; Eidesen, Pernille Bronken; Pellisier, Loic; Tribsch, Andreas & Schonswetter, Peter [Show all 14 contributors for this article] (2014). Effects of past and future climate change on plant colonization of arctic Islands. Full text in Research Archive
• Elven, Reidar; Fremstad, Eli & Alm, Torbjørn (2013). Introduction. In Elven, Reidar; Fremstad, Eli & Pedersen, Oddvar (Ed.), Distribution maps of Norwegian vascular plants. IV The eastern and northeastern elements. Akademika forlag. ISSN 9788232102464. p. 7–34. Full text in Research Archive
• Elven, Reidar; Økland, Karen Anna & Økland, Jan (2013). Sjøpiggknopp Sparganium gramineum funnet i Finnmark og Telemark. Blyttia : Norsk botanisk forenings tidsskrift. ISSN 0006-5269. 71(2), p. 127–131. Full text in Research Archive

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