Torbjørn Alm

Glacial Survival of Boreal Trees in Northern Scandinavia

Tree Refugia Ideas of how and when boreal plants spread to the formerly glaciated parts of the world following the retreat of the glaciers 9000 years ago are long debated. Models of the postglacial spread of boreal plants argue for dispersal from southern refugia; however, Parducci et al. (p. 1083) have shown that both spruce and pine were present in small ice-free regions of Scandinavia much earlier than thought. DNA haplotyping confirmed that a remnant mitochondrial type of spruce, once unique to Scandinavia, now lives alongside the more common spruce originating from Eastern Europe. Evidence from lake cores collected from central and northern Norway indicated the survival of conifers as early as 22,000 years before the present, when apart from ice-free pockets, most of Scandinavia was covered by ice. DNA from modern and ancient spruce and pine indicate that both survived in ice-free areas during the last glaciations. It is commonly believed that trees were absent in Scandinavia during the last glaciation and first recolonized the Scandinavian Peninsula with the retreat of its ice sheet some 9000 years ago. Here, we show the presence of a rare mitochondrial DNA haplotype of spruce that appears unique to Scandinavia and with its highest frequency to the west—an area believed to sustain ice-free refugia during most of the last ice age. We further show the survival of DNA from this haplotype in lake sediments and pollen of Trøndelag in central Norway dating back ~10,300 years and chloroplast DNA of pine and spruce in lake sediments adjacent to the ice-free Andøya refugium in northwestern Norway as early as ~22,000 and 17,700 years ago, respectively. Our findings imply that conifer trees survived in ice-free refugia of Scandinavia during the last glaciation, challenging current views on survival and spread of trees as a response to climate changes.

The Witch Trials of Finnmark, Northern Norway, during the 17th Century: Evidence for Ergotism as a Contributing Factor

During the 17th century, Finnmark suffered the worst witch trials on record in Norway; at least 137 persons were tried, and about two-thirds were executed. A late 17th century manuscript by district govenor H. H. Lilienskiold provides details of 83 trials based on contemporaneous sources. More than half of these provide evidence of a potentially important role of ergotism in triggering persecutions. In 42 trials, it is explicitly stated that witchcraft was “learned” by consuming it, usually in the form of bread or other flour products (17 cases), in milk or beer (23 cases), or a combination (two cases). In the cases involving milk, several witches testifed that some kind of black, grain-like objects were found in the drink. Medical symptoms compatible with ergotism were recorded in numerous trials, including gangrene, convulsions, and hallucinations; the latter often explicitly stated to occur after consumption of foodstuffs or drink. The majority of the convicted witches were females of Norwegian ethnic origin, living in coastal communities where imported flour formed part of the diet. The few, largely self-supporting Sámi affected by the witchcraft trials were mainly men, convicted, for example, carrying out traditional shamanic rituals. All flour available in Finnmark during the late 17th century was imported. Rye (Secale cereale), which is especially prone to ergot infection, formed a major part of the imported grain.

Late weichselian chironomidae (diptera) stratigraphy of Lake Nedre Æråsvatn, Andøya, Northern Norway

A 5.6 m long sediment column from Lake Nedre Æråsvatn, Andøya, Northern Norway, spanning ca 20 000 to 11000 14C yr B.P. (Before Present) has been analysed with respect to chironomid remains. Head capsules are absent or rare in the lower, marine part of the sequence (ca 20 000 to 15 500 14C yr B.P.). From ca 15 500 14C yr B.P. onwards, a continuous representation of hygropetric or rheophilous taxa indicate the existence of stream habitats. The lake itself seemingly had no significant chironomid fauna until ca 12 800 14C yr B.P.The main taxa recorded in pre-12000 14C yr B.P. samples are Micropsectra and Metriocnemus. Increases of Micropsectra are positively correlated with climatic improvements, especially the Bølling amelioration (ca 12800 to 12000 14C yr B.P.). This may be due to a denser vegetation cover, and an increased influx of organic detritus.Chironomid concentration and influx values increased markedly from ca 12 500 14C yr B.P. onwards, attaining a maximum of 450 head capsules cm-3 in late Bølling. At ca 12000 14C yr B.P., dominance shifted to Tanytarsus lugens Kieffer. Increases of T. lugens, Psectrocladius, Procladius sp. and Heterotrissocladius subpilosus Kieffer at ca 11400 14C yr B.P. may point to slightly more mature lacustrine conditions.

Holocene tree‐line fluctuations and climate in central troms, Northern Norway

Based mainly on pollen influx data, an attempt is made at reconstructing Holocene tree‐line fluctuations and palaeotemperatures in central Troms, North Norway. Both past and present‐day (Tauber trap) pollen influx data suggest that influx rates exceeding 250–300 pollen/cm2/year for each of the major arboreal taxa (Betula pubescens and Pinus sylvestris) are only found at sites with corresponding forest types in the immediate surroundings. High influx rates, raised tree‐lines and favourable climatic periods are recorded at 7500–4500 and 3000–2600 B.P. Betula and Pinus woodlands may have reached more than 200 m above their present altitude limits, suggesting a July mean temperature 2°C higher than at present during the Holocene optimum.

Ethnobotany of Heracleum persicum Desf. ex Fisch., an invasive species in Norway, or how plant names, uses, and other traditions evolve

BackgroundHeracleum persicum was introduced to Norway as an ornamental in the 1830′s. Towards the end of the 19th century, it started spreading outside gardens, later to become a frequent sight in the major towns and settlements of North Norway – and a veritable pest plant. During the last 100 years or so, a substantial ethnobotanical tradition related to the species has evolved, demonstrating that folk knowledge is not only forgotten and lost, but also charting new terrain.MethodsThis survey is based on data extracted from all relevant publications, including botanical literature, travel accounts, newspaper notes, etc., as far as they have come to my attention. In addition, information on vernacular names and various uses of the H. persicum in Norway has been extracted from my own, substantial archive of interviews, questionnaires, and correspondence related to the ethnobotany of Norway.ResultsWhere extant, H. persicum tends to be known to everyone, even by city dwellers who otherwise generally neglect plants. People tend to love or hate it, and in Tromsø, the largest town of northern Norway, the species has become more or less emblematic of the city. Both here and in other areas of northern Norway, it is referred to by a variety of vernacular names, partly borrowed from other species, partly derived from the Latin genus name, and partly coined for this species only. In the latter group, tromsøpalme (‘the palm of Tromsø’) has proved by far the most popular invention. It was seemingly first used (and coined) by German soldiers during the World War II occupation of Norway, but now largely replaces other vernacular names. The plant is still popular with children, who frequently play in and with it, whereas adults have been more prone to speculate on its origins – and how to get rid of it. Salt is the most popular “herbicide” for this purpose.ConclusionsOver the years, H. persicum has accumulated at least twenty different vernacular names in Norway, and a variety of other traditions. By necessity, all these traditions are less than 180 years old, showing that even modern and urban societies may produce a substantial body of plant lore, which certainly merits ethnobotanical attention.

Reconstructing the invasion history of Heracleum persicum (Apiaceae) into Europe.

Sparse, incomplete and inappropriate historical records of invasive species often hamper invasive species management interventions. Population genetic analyses of invaders might provide a suitable context for the identification of their source populations and possible introduction routes. Here, we describe the population genetics of Heracleum persicum Desf. ex Fisch and trace its route of introduction into Europe. Microsatellite markers revealed a significantly higher genetic diversity of H. persicum in its native range, and the loss of diversity in the introduced range may be attributed to a recent genetic bottleneck. Bayesian cluster analysis on regional levels identified three and two genetic clusters in the native and the introduced ranges, respectively. A global structure analysis revealed two worldwide distinct genetic groups: one primarily in Iran and Denmark, the other primarily in Norway. There were also varying degrees of admixture in England, Sweden, Finland and Latvia. Approximate Bayesian computation indicated two independent introductions of H. persicum from Iran to Europe: the first one in Denmark and the second one in England. Finland was subsequently colonized by English populations. In contrast to the contemporary hypothesis of English origin of Norwegian populations, we found Finland to be a more likely source for Norwegian populations, a scenario supported by higher estimated histor‐ical migration from Finland to Norway. Genetic diversity per se is not a primary determinant of invasiveness in H. persicum. Our results indicate that, due to either pre‐adaptations or rapid local adaptations, introduced populations may have acqu‐ired invasiveness after subsequent introductions, once a suitable environment was encountered.

Ergotism in Norway. Part 1: The symptoms and their interpretation from the late Iron Age to the seventeenth century.

Ergotism is a horrendous disease with grotesque symptoms caused by ingesting specific ergot alkaloids. Mass poisoning episodes are attributable to consumption of grain – usually rye – infected with the fungus Claviceps purpurea. By focusing on possible cases of ergotism, we re-examine Norwegian history from the sagas through to the end of the seventeenth century. Our review – not intended to be exhaustive, or ex post facto to assign medical or psychiatric labels – draws attention to the very real possibility that many remarkable medical cases may have been the result of the ingestion of highly poisonous and psychoactive food substances. Where possible we highlight explanations given at the time – often rooted in religion or demonology – to explain the disease.

Scented grasses in Norway—identity and uses

BackgroundSome grass species are richer in coumarin and thus more sweetly scented than others. These have been eagerly sought after in parts of Norway, but the tradition has been weakly documented, both in terms of the species collected, their vernacular names, and uses.MethodsBased on literature data and a substantial body of information collected during my own ethnobotanical field work, artefacts and voucher specimens, the grass species are identified, and their uses clarified.ResultsIn Norwegian literature, the tradition of collecting and using scented grasses has received little attention, and past authors largely refer it to Anthoxanthum spp. The tradition’s concentration to the Sámi strongholds of northernmost Norway, and most authors’ lacking knowledge of the Sámi language, have contributed to the weak and misleading coverage in previous publications. Coumarin-rich grass species are well known in folk tradition in northernmost Norway, as luktegress (Norwegian, “scent grass”), háissasuoidni (North Sámi, “scent grass”), hajuheinä (Finnish, “scent grass”), or similar terms. They have been (and still are) frequently collected, and used as perfume, for storing with clothes, and a number of other purposes. Despite literature records identifying the species used as Anthoxanthum odoratum coll. (including A. nipponicum), the main source utilized in North Norway is Hierochloë odorata, both ssp. arctica and ssp. odorata. Anthoxanthum nipponicum and Milium effusum are alternative, but infrequently used sources of material, depending on local tradition and availability.ConclusionBy far the most important grass species hiding behind the “scented grass” tradition in Norway is Hierochloë odorata. Anthoxanthum nipponicum is also used, but much less frequently, and only a single record confirms the use of Milium effusum. Only the foliage of Hierochloë provides suitable material for making traditional braids. The three major ethnic groups in Norway have all utilized scented grasses as perfume and for storing with clothes, but the tradition’s geographical concentration to the far north of Norway (Finnmark and NE Troms), suggests that it has originally mainly been a Sámi tradition, adopted by their neighbours.

Ergotism in Norway. Part 2: The symptoms and their interpretation from the eighteenth century onwards

Ergotism, the disease caused by consuming Claviceps purpurea, a highly poisonous, grain-infecting fungus, occurred at various places scattered throughout Norway during the eighteenth and nineteenth centuries. By focusing on these cases we chart the changing interpretations of the peculiar disease, frequently understood within a religious context or considered as a supernatural (e.g. ghostly) experience. However, there was a growing awareness of the disease ergotism, and from the late eighteenth century onwards it was often correctly interpreted as being due to a fungus consumed via bread or porridge. Also, nineteenth-century fairy-tales and regional legends reveal that people were increasingly aware and fearful of the effects of consuming infected grain.

Giant invasive Heracleum persicum: Friend or foe of plant diversity?

Abstract The impact of invasion on diversity varies widely and remains elusive. Despite the considerable attempts to understand mechanisms of biological invasion, it is largely unknown whether some communities’ characteristics promote biological invasion, or whether some inherent characteristics of invaders enable them to invade other communities. Our aims were to assess the impact of one of the massive plant invaders of Scandinavia on vascular plant species diversity, disentangle attributes of invasible and noninvasible communities, and evaluate the relationship between invasibility and genetic diversity of a dominant invader. We studied 56 pairs of Heracleum persicum Desf. ex Fisch.‐invaded and noninvaded plots from 12 locations in northern Norway. There was lower native cover, evenness, taxonomic diversity, native biomass, and species richness in the invaded plots than in the noninvaded plots. The invaded plots had nearly two native species fewer than the noninvaded plots on average. Within the invaded plots, cover of H. persicum had a strong negative effect on the native cover, evenness, and native biomass, and a positive association with the height of the native plants. Plant communities containing only native species appeared more invasible than those that included exotic species, particularly H. persicum. Genetic diversity of H. persicum was positively correlated with invasibility but not with community diversity. The invasion of a plant community by H. persicum exerts consistent negative pressure on vascular plant diversity. The lack of positive correlation between impacts and genetic diversity of H. persicum indicates that even a small founder population may cause high impact. We highlight community stability or saturation as an important determinant of invasibility. While the invasion by H. persicum may decrease susceptibility of a plant community to further invasion, it severely reduces the abundance of native species and makes them more vulnerable to competitive exclusion.