Northernmost Europe Research Articles

Baetis bundyae(Ephemeroptera: Baetidae), described from Arctic Canada is found in northernmost Europe

AbstractThe taxonomy and identification of mayflies of theBaetis vernusgroup (Ephemeroptera: Baetidae) represents a major challenge in both Europe and North America. The recent description ofB. jaerviiSavolainen from Finland, a species taxonomically close to the Palaearctic taxonBaetis macaniKimmins and the NearcticB. bundyaeLehmkuhl, called for clarification of the status and distribution of these species in northernmost Europe. We generated mtDNA COI sequences for establishing the identity of the collected samples. Based on these data we conclude thatB. bundyaedoes occur in northeastern Finland in sympatry withB. macani. Accordingly, this taxon shows a highly interesting distributional pattern across the Nearctic and western Palaearctic regions.

Lithic raw material diversification as an adaptive strategy—Technology, mobility, and site structure in Late Mesolithic northernmost Europe

Formal technologies and intensified reduction are often seen as responses to increased mobility and low abundance of lithic raw material of good flakeability and controllability. Although patterns of lithic raw material availability and occurrence are in many ways analogous to those of subsistence resources, resource diversification, an adaptive strategy commonly discussed in relation to food procurement, is rarely discussed in connection to changes in lithic resource availability and technology. We present a case from northernmost Europe in which pronounced differences in raw material availability caused by a distinct geological setting existed within a relatively small area. We conclude that restricted availability of high-quality raw material due, for instance, to increased mobility or changes in the size or location of the foraging range does not necessarily lead to formalization and intensification and can, in certain situations, as in the studied case, lead to the application of an adaptive strategy that can be called raw material diversification. This strategy entails a widening of the raw material base to include raw materials of lower workability and a consequent alteration of existing technological concepts, often in the form of simplification and informalization.

Common montane birds are declining in northern Europe

Large‐scale multi‐species data on population changes of alpine or arctic species are largely lacking. At the same time, climate change has been argued to cause poleward and uphill range shifts and the concomitant predicted loss of habitat may have drastic effects on alpine and arctic species. Here we present a multi‐national bird indicator for the Fennoscandian mountain range in northern Europe (Finland, Sweden and Norway), based on 14 common species of montane tundra and subalpine birch forest. The data were collected at 262 alpine survey plots, mainly as a part of geographically representative national breeding bird monitoring schemes. The area sampled covers around 1/4 million km2, spanning 10 degrees of latitude and 1600 km in a northeast–southwest direction. During 2002–2012, nine of the 14 bird species declined significantly in numbers, in parallel to higher summer temperatures and precipitation during this period compared to the preceding 40 yr. The population trends were largely parallel in the three countries and similar among montane tundra and subalpine birch forest species. Long‐distance migrants declined less on average than residents and short‐distance migrants. Some potential causes of the current decline of alpine birds are discussed, but since montane bird population sizes may show strong natural annual variation due to several factors, longer time series are needed to verify the observed population trends. The present Fennoscandian monitoring systems, which from 2010 onwards include more than 400 montane survey plots, have the capacity to deliver a robust bird indicator in the climate‐sensitive mountainous regions of northernmost Europe for conservation purposes.

Spatio-temporal patterns in Lateglacial and Holocene vegetation and climate of Finnmark, northernmost Europe

Precisely-dated records of palaeovegetation and reconstructed palaeoclimate are presented from three lakes in northernmost Finnmark. The lakes lie adjacent to the southern shore of the Barents Sea and are located along a west–east transect. The three records are used to reconstruct spatial patterns in regional vegetation and climatic history since 13,900 cal yr BP. Longer-term shifts in treeline position and in the position of the Pinus–Betula ecotone are recorded. In addition, especially during the regional Holocene thermal maximum, the latter exhibited strong periodic fluctuations. The number and strength of these fluctuations that were recorded at each of the three sites differed systematically, with fewer and weaker fluctuations seen at the easternmost site, in particular. The patterns revealed are used to test the hypothesis that variations in the strength of the North Cape Current have been of primary importance as the proximal driver of climatic variability in the region since deglaciation. The results provide strong support for this hypothesis during the Holocene, the strong periodic fluctuations during the regional Holocene thermal maximum in particular being consistent with the proposed mechanism. During the Lateglacial and earliest Holocene the patterns are less clear, but nonetheless also consistent with the proposed mechanism. Further work on precisely-dated marine sediment cores will be necessary to understand the factors leading to the periodic and longer-term variations in strength of the North Cape Current.

Early Farming in the Northern Boreal Zone: Reassessing the History of Land Use in Southeastern Finland through High‐Resolution Pollen Analysis

The early stages of agriculture in the Boreal forests of Northern Europe remain poorly understood. Although pottery appeared during the 6th millennium B.C., this has not been seen as an indication of a true Neolithic in the north. In later prehistory, vast parts of the region are thought to have remained a wilderness. In order to test these assumptions, a high‐resolution pollen analysis and an archaeological survey were carried out at Lake Huhdasjärvi, SE Finland. The results indicate signs of cultivation already by the early Neolithic, 5260–4260 B.C., and slash‐and‐burn cultivation concentrated on deciduous forests is recorded from ca. A.D. 600 onwards. By A.D. 930, an intensive form of swidden cultivation began in the coniferous forests, indicating a well‐established agricultural settlement. The discovery of Neolithic (late 6th millennium B.C.) buckwheat pollen suggests that the roots of agriculture in northernmost Europe may have to be searched for in China rather than the Near East.

Do moss samples, pollen traps and modern lake sediments all collect pollen in the same way? A comparison from the forest limit area of northernmost Europe

Moss polsters, pollen traps and lake surface sediment samples are commonly used as climate calibration data or as modern analogues for reconstructing vegetation from fossil profiles, but the differences in pollen content between these media have received little attention. This study aims to analyse how the three media differ in reflecting individual vegetation types and spatial differences in vegetation. 119 modern samples (64 moss polsters, 37 lake surface sediment samples and 18 pollen traps from which a collection was made annually) were taken from northern Fennoscandia and the Kola Peninsula as a broad transect crossing the northernmost forest limits of Betula pubescens ssp. czerepanovii (mountain birch), Pinus sylvestris (Scots pine) and Picea abies (Norway spruce). The pollen assemblages from these samples were compared with the surrounding vegetation visually and via PCA (principle components analysis) and cluster analysis. Both comparisons allow a correct distinction between pollen assemblages of arctic/alpine heath, mountain birch dominated areas, and boreal coniferous forests. The differences between the vegetation zones are stronger than the differences between the sampling media. Nevertheless, lake sediment samples from the mountain birch woodland zone tend to overestimate pine and underestimate birch. Pollen traps are biased towards lower tree pollen percentages and higher values of shrubs, herbs and Cyperaceae. This bias is especially strong in traps that have missing years in the data. Irrespective of the vegetation zone, pollen traps tend to have lower Pinus pollen percentages than in the adjacent moss polsters.

Precursors of Urban Processes in Finnish Sápmi in the 1960s

This article presents a single case of a Sámi–Finnish settlement in the 1960s to discuss the impact of expanding distribution and higher density of people, both aboriginal and immigrant, as precursors of urban processes that have occurred quite rapidly in Sápmi on the Finnish side in northernmost Europe. First, the historical emergence of Ohcejohka/Utsjoki as a central location resulting from national policies is explained; second, the socio-economic and political expansion of the local central settlement physically and socio-culturally is presented; and third, the environmental, economic, cultural and socio-political conditions and their significance are discussed in the broader context of developments throughout the circumpolar north leading to an increased urbanization of the arctic.

Reindeer corrals 4700–4200 BC: Myth or reality?

Reindeer have always been one of the important subsistence resources in northernmost Europe. Driving domestic animals into corrals to separate, distribute, and slaughter them according to ownership, is a continuation of a prehistoric practise that was linked to hunting and possibly, to acquire reindeer as decoys and for transportation. The only evidence of such prehistoric constructions and practice in northernmost Europe is nine figures of corrals and drive lanes in the rock art in Alta, Arctic Norway. These figures are a part of communication between humans, and humans and non-humans, within an understanding of what was needed for procuring reindeer that probably was somewhat different from today. Some of the figures associated with the corrals are not connected with driving and killing reindeer seen from a modern context, but their association indicates connections once existed, if not in driving and killing, then in narratives, myths and rituals.

Quantifying Sami Settlement and Movement Patterns in Northern Sweden 1700–1900

The indigenous Sami people of northernmost Europe have developed unique adaptations that enable them to cope with harsh climate and subsist in low-productivity ecosystems. These adaptations have been shaped by both internal factors, such as demographic and traditional land-use systems, and external factors, such as colonization and national legislation. In this paper we interpret the quantitative impacts of land use by reindeer herders in a subarctic forest landscape in northern Sweden during the 18th and 19th centuries. We used archival sources (cameral and judicial documents and church records) together with environmental data to reconstruct past changes in population size and the spatial configuration of traditional Sami lands, which the Swedish state accepted and recognized as taxation units for several centuries up to the 19th century. The taxation lands encompassed several hundred square kilometres and featured distinct proportions of different vegetation types. We propose that these taxation lands were originally established so that each provided sufficient resources to support the subsistence of a Sami family, incorporating pastures for small-scale reindeer herding and opportunities for hunting and fishing within its borders. However, there were substantial differences in the resources they provided. Estimates of population density indicate that they may have been able to support 0.04–0.06 persons per km2. Unlike many other indigenous groups around the globe, the Sami interacted with the state and claimed their rights in court proceedings and were thus able to maintain strong recognition of their land tenure by the Swedish state until the late 19th century.Key words: northern Sweden, forest history, archaeology, archival sources, Sami, population changes, reindeer pastoralism, taxation lands, mountain birch, Scots pine

Pollution history from 256 BC to AD 2005 inferred from the accumulation of elements in a varve record of Lake Korttajärvi in Finland

In order to assess the importance of different pollution sources for the increase in element concentration and accumulation, historical changes in selected elements were studied in the annually laminated sediment of Lake Korttajarvi in Central Finland (62°20′N; 25°41′E). The sediment chronology based on varve counting (256 BC to AD 2005) provided a unique opportunity to explore and date signals of metal emissions, including the ancient metallurgical activities of the Roman Empire at the beginning of the Current Era. Records of this kind are mostly lacking in Finland and northernmost Europe. The stratigraphic sequence of element concentrations did not reflect any major changes in the lake, but changes in element accumulation rates provided distinct pollution signals caused by airborne fallout, catchment erosion, and to some extent municipal wastewater loading. The maximum bulk sedimentation recorded in the twentieth century was 11-fold and organic sedimentation 4-fold higher than the mean background sedimentation rate (256 BC to AD 1019). The increase in the accumulation rates of the majority of the elements, such as Cd, Sn, Pb, Si, Ni, B, Cu, Zn, Sr, Na, K, Sb, Ca, Cr, U and Mg, in descending order, was at least equal to that of bulk sedimentation or much greater, especially for Cd, Sn, and Pb. Changes in the accumulation of Co, Fe, Mn, Mo and As were small and mainly followed those of organic sedimentation. The earliest pollution signals were those of Pb recorded in AD 1055–1141. A weak signal of Pb pollution from the Roman Era was detected in metal concentrations, but this could not be confirmed by the accumulation rate data for Pb.

Challenges to Adaptation in Northernmost Europe as a Result of Global Climate Change

Global warming will continue, and the Arctic is expectedto warm at twice the global average rate (Intergovern-mental Panel on Climate Change 2007). The most pro-nounced changes will occur during winter with increasedprecipitation, more precipitation falling as rain, and ashorter snow period (Intergovernmental Panel on ClimateChange 2007; Roderfeld et al. 2008). These changes willhave far-reaching consequences for ecosystems and for thepeople dependent on their services and may serve as anindicator of environmental change and an ‘‘early warningsystem’’ for other parts of the world (Arctic Climate ImpactAssessment, Symon et al. 2005). We assessed the likelychanges in the provision of goods and services from naturaland seminatural ecosystems (i.e., excluding urban, indus-trial, and agricultural land) in the Barents region—thenorthern parts of Norway, Sweden, and Finland, andnorthwestern Russia—as a consequence of anticipatedclimate changes during the twenty-first century. Thisregion includes approximately six million people in an areathe size of France, Portugal, Spain, and Germany together,totaling 1.75 million km

Distribution and biological characteristics of escaped farmed salmon in a major subarctic wild salmon river: implications for monitoring

We report the occurrence, distribution, and biological characteristics of escaped farmed salmon in the River Teno in northernmost Europe, which supports one of the largest and most versatile wild Atlantic salmon ( Salmo salar ) populations in the world. Farmed salmon were caught during the fishing season (May–August) when their proportion in the catch varied between 0.0% and 0.7%. Occasional sampling after the fishing season revealed much higher proportions of escapees, up to 47%, indicating a potential for a more severe impact of farmed fish than the in-season monitoring is able to uncover. Peak migration of the wild salmon was in June or July, but that of escaped farmed fish was in August. Up to 88% of the escaped salmon caught in August showed gonad development, and scale analysis indicated that 4.5% of them were repeat spawners. Genetic analyses using microsatellite markers revealed highly significant genetic differentiation between wild salmon and escaped farmed fish (FST = 0.05) caught in the River Teno and a Norwegian farmed strain (FST = 0.10). The heterogeneity of escapees compared with the single farmed strain indicated that escapees apparently originate from multiple sources, which will complicate their genetic identification and the assessment of the level of hybridization with wild salmon.

Folivorous larvae on flowers: do autumnal moths benefit from catkins of the mountain birch?

AbstractImmature leaves of birches and other deciduous trees and shrubs are the principal food resource for the larvae of the autumnal moth, Epirrita autumnata (Borkhausen) (Lepidoptera: Geometridae). However, the larvae of this geometrid, which displays pronounced population cycles and causes massive forest defoliations in northernmost Europe, are also frequently found on the catkins of mountain birch, Betula pubescens ssp. czerepanovii (Orlova) Hämet‐Ahti (Betulaceae). To examine whether autumnal moth larvae visit birch catkins for their high nutritional value, we conducted two growth experiments in which the larval diet was supplemented with male catkins, and a single test where female catkins were used. We found that the presence of male catkins in the larval diet had a positive effect on the larvae, in relation to their pupal mass (reflecting life span fecundity), survival probability, as well as the duration of the larval period. The presence of female catkins in the diet did not affect larval performance. Our findings suggest that young autumnal moth larvae actively move to male catkins, which provide a nutritional benefit and thus lead to a better performance compared with those feeding elsewhere. Another possible benefit for young larvae choosing the catkins instead of leaves may involve predator or parasitoid avoidance.

Signals of major histocompatibility complex overdominance in a wild salmonid population

The major histocompatibility complex (MHC) contains the most variable genes in vertebrates, but despite extensive research, the mechanisms maintaining this polymorphism are still unresolved. One hypothesis is that MHC polymorphism is a result of balancing selection operating by overdominance, but convincing evidence for overdominant selection in natural populations has been lacking. We present strong evidence consistent with MHC-specific overdominance in a free-living population of Arctic charr (Salvelinus alpinus) in northernmost Europe. In this population, where just two MHC alleles were observed, MHC heterozygous fish had a lower parasite load, were in better condition (as estimated by a fatness indicator) and had higher survival under stress than either of the homozygotes. Conversely, there was no consistent association between these fitness measures and assumedly neutral microsatellite variability, indicating an MHC-specific effect. Our results provide convincing empirical evidence consistent with the notion that overdominance can be an important evolutionary mechanism contributing to MHC polymorphism in wild animal populations. They also support a recent simulation study indicating that the number of alleles expected to be maintained at an MHC loci can be low, even under strong heterozygote advantage.

Temporally stable genetic structure and low migration in an Atlantic salmon population complex: implications for conservation and management.

The evolutionary potential of a population is closely related to two key population genetic parameters, namely the effective population size (Ne) and migration rate (m). Furthermore, knowledge of these parameters is required in order to assess potential constraints on local adaptation and for the development of biologically sound management strategies. We addressed these key issues by investigating the temporal and spatial genetic structure of over 2000 adult Atlantic salmon (Salmo salar) collected from 17 sites in the Teno and Näätämö rivers in northernmost Europe with up to five time points spanning temporal intervals up to 24 years (∼4 generations). In all cases except one, local populations were found to be temporally stable within the river system. Estimates of Ne were generally a magnitude larger for the mainstem and headwater populations (MS+HW, Ne∼340–1200) than for the tributary populations (Ne∼35–160), thus explaining the higher genetic diversity and lower divergence of the MS+HW populations compared to tributaries. The overall migration rates to tributaries were low, and in some cases, low enough for local adaptations to potentially evolve, despite their lower Ne. Signs of a population bottleneck and natural recruitment from nearby populations were detected in one local population. This highlights a fact which is relevant for the conservation and management of highly substructured population systems in general: that even when the overall census size is large, local populations can be vulnerable to perturbations. To preserve the current and to regain the historical distribution of salmon within the river system, we propose that the status of the total population complex should be evaluated at the local population level rather than from descriptive statistics at the system level.

Community viability and well-being in northernmost Europe: social change and cultural encounters, sustainable development and food security in Finland's North

Northernmost Europe is characterised by diversity. Relations between indigenous (minority) and immigrant(majority) populations concern territorial claims, resource utilisation and human rights. Indigenous Sami feel encapsulated in centralised states. Norwegians, Swedes, Finns and Russians, historic immigrants, represent these states. The collapse of the Soviet Union effected cross-border relations. New structures have emerged stressing community viability. Developments have progressed in economic performance, human security, quality of life, education and health focusing of local activities such as reindeer herding. These conditions have an impact on transnational relations and community viability.

Can Reindeer Overabundance Cause a Trophic Cascade?

The region Finnmark, in northernmost Europe, harbors dense populations of semi-domestic reindeer of which some exhibit characteristics of overabundance. Whereas overabundance is evident in terms of density-dependent reductions in reindeer body mass, population growth and abundance of forage plants, claims have been made that this reindeer overabundance also has caused a trophic cascade. These claims are based on the main premise that reindeer overgrazing negatively impacts small-sized, keystone tundra herbivores. We tested this premise by a large-scale study in which the abundance of small rodents, hares and ptarmigans was indexed across reindeer management districts with strong differences in stocking densities. We examined the scale-dependent relations between reindeer, vegetation and these small-sized herbivores by employing a spatially hierarchical sampling design within the management districts. A negative impact of reindeer on ptarmigan, probably as a result of browsing reducing tall Salix, was indicated. However, small rodents (voles and lemmings), which are usually the keystone herbivores in the plant-based tundra food web, were not negatively impacted. On the contrary, there was a strong positive relationship between small rodents and reindeer, both at the scale of landscape areas and local patches, with characteristics of snow-bed vegetation, suggesting facilitation between Norwegian lemmings and reindeer. We conclude that the recent dampening of the vole and lemming population cycle with concurrent declines of rodent predators in northernmost Europe were not caused by large herbivore overgrazing.

Holocene climate variability in northernmost Europe

The sediments of a small lake on Nordkinnhalvøya, Finnmark, Norway, were investigated in order to test the hypothesis that this region was sensitive to centennial–millennial climatic fluctuations during the Holocene related to changes in ocean circulation. Sedimentation at the site began during the Younger Dryas, although the site chronology, developed using a series of 14C age measurements, reveals an early Holocene hiatus in accumulation. Pollen analysis confirmed that the regional vegetation responded to Holocene climatic variability at centennial–millennial time scales and provided data used to make quantitative palaeoclimate reconstructions. The latter indicate that marked changes in seasonality characterised Holocene climatic fluctuations. Intervals with warmer summers, higher temperature sums and higher precipitation, but cooler winters and generally reduced moisture availability, alternated with intervals with cooler summers, lower temperature sums, lower precipitation, warmer winters and greater moisture availability. The former conditions were more prevalent between ca 8950 and 3950 cal BP, whereas the latter were predominant before ca 8950 and since ca 3950 cal BP. Sediment geochemistry indicates minerogenic material deposited in the lake was probably derived from two or more distinct sources or transport pathways that differed in their responses to palaeoclimatic conditions. A series of cryptotephras were located, although the small size of the shards rendered them unsuitable for electron microprobe analyses. Time-series analysis of pollen analytical and sediment geochemical data indicates that each exhibits statistically significant periodic behaviour (at periods of ca 190, 410, 1050, 1650 and 1810 yr). The periods detected suggest this behaviour may reflect regional expression of climate system responses to solar variability and/or of effects upon tides and ocean circulation of periodic lunar orbital variation. Comparison with records of fluctuations in ocean thermohaline circulation strength indicate some concordance with respect to timing of warmer and cooler intervals, but also some differences. The 8.2 ka event, that is evident in marine records from the Barents Sea, is clearly expressed by both the palaeovegetation and geochemical records. Distinctive temporal behaviour of the palaeovegetation and of different geochemical components indicates complexity in the underlying causes and mechanisms of regional climatic variability; ocean circulation variability alone cannot account for the complex climatic variability observed.

Does immune function influence population fluctuations and level of parasitism in the cyclic geometrid moth?

AbstractPopulations of the autumnal moth, Epirrita autumnata, exhibit cycles with high amplitudes in northernmost Europe, culminating in devastating outbreak densities at favourable sites. Parasitism by hymenopteran parasitoids has been hypothesised to operate with a delayed density dependence capable of producing the observed dynamics. It has also been hypothesised that insects in crowded conditions invest greatly in their immunity as a counter‐measure to increased risk of parasitism and pathogen infections. Furthermore, inducible plant defences consequent to grazing by herbivorous insects may be linked to the performance of parasitoids and pathogens through increased immunocompetence of the herbivore feeding on the foliage, in which the defence induction has taken place. At ten sampling sites, we quantified larval abundance, outbreak status and percentage larval parasitism during an extended peak phase of a population cycle. These population level covariates, together with an individual pupal mass, were used to explain differences in the immune defence, measured as an encapsulation reaction to artificial antigen. We also conducted a field study for an investigation of the susceptibility of autumnal moth pupae to naturally occurring pupal parasitoids. We did not find obvious differences between the encapsulation rate of autumnal moths originating from the sites with different past and current larval densities and risks for parasitism. The best ranked statistical models included pupal mass and outbreak status as explanatory variables, although both showed only slight effects on the encapsulation rate. The host resistance test revealed positive relationships between the encapsulation rate, body size and percentage parasitism of the exposed pupae, indicating that pupal parasitoids chose, and/or survived better, in large host individuals irrespective of their encapsulation ability. Thus, our results do not provide support for the hypothesis that variation in the immune function drives or modulates population cycles of autumnal moths.

Growing seasons of Nordic mountain birch in northernmost Europe as indicated by long-term field studies and analyses of satellite images

The phenophases first greening (bud burst) and yellowing of Nordic mountain birch (Betula pubescens ssp.tortuosa, also called B. p. ssp. czerepanovii) were observed at three sites on the Kola Peninsula in northernmost Europe during the period 1964-2003, and at two sites in the trans-boundary Pasvik-Enare region during 1994-2003. The field observations were compared with satellite images based on the GIMMS-NDVI dataset covering 1982-2002 at the start and end of the growing season. A trend for a delay of first greening was observed at only one of the sites (Kandalaksha) over the 40 year period. This fits well with the delayed onset of the growing season for that site based on satellite images. No significant changes in time of greening at the other sites were found with either field observations or satellite analyses throughout the study period. These results differ from the earlier spring generally observed in other parts of Europe in recent decades. In the coldest regions of Europe, e.g. in northern high mountains and the northernmost continental areas, increased precipitation associated with the generally positive North Atlantic Oscillation in the last few decades has often fallen as snow. Increased snow may delay the time of onset of the growing season, although increased temperature generally causes earlier spring phenophases. Autumn yellowing of birch leaves tends towards an earlier date at all sites. Due to both later birch greening and earlier yellowing at the Kandalaksha site, the growing season there has also become significantly shorter during the years observed. The sites showing the most advanced yellowing in the field throughout the study period fit well with areas showing an earlier end of the growing season from satellite images covering 1982-2002. The earlier yellowing is highly correlated with a trend at the sites in autumn for earlier decreasing air temperature over the study period, indicating that this environmental factor is important also for autumn phenophases.