Southernmost Sweden Research Articles

The fossil alga Chaetocladus gracilis revisited: new material from the Silurian of Sweden

ABSTRACT In 2006, a new species of non-calcified dasycladalean alga, Chaetocladus gracilis, from the upper Silurian of Skåne (Scania), southernmost Sweden, was erected. The original description was based on a single incomplete fossil recovered from the abandoned limestone quarry at Bjärsjölagård, a classic geologic locality in Scania. Here we present four additional and, importantly, more complete specimens from this same site and type stratum. This new material largely corroborates the general anatomical features of C. gracilis, but also adds some intricate details, most notably with regards to the external sheet-like phytoleim and organisation of the laterals. Elemental mapping confirmed an expected carbonaceous composition of the fossils, which are embedded in a calcareous mudstone. These additional fossils show that the originally described specimen was not a singular occurrence at this locality. Based on the state of preservation of our algal fossils, we note that the mudstone facies of the Ludlow Bjärsjölagård Limestone Member of the Klinta Formation (Öved-Ramsåsa Group), from which all C. gracilis have been recovered, share characteristics with deposits typically referred to as “algal-Lagerstätten”.

Occurrence of Batrachochytrium dendrobatidis in Sweden: higher infection prevalence in southern species.

The chytrid fungus Batrachochytrium dendrobatidis (Bd) has caused worldwide declines in amphibian populations. While Bd is widespread in southern and central Europe, its occurrence and distribution in northernmost Europe is mostly unknown. We surveyed for Bd in breeding anurans in Sweden by sampling 1917 amphibians from 101 localities and 3 regions in Sweden (southern, northern and central). We found that Bd was widespread in southern and central Sweden, occurring in all 9 investigated species and in 45.5% of the 101 localities with an overall prevalence of 13.8%. No infected individuals were found in the 4 northern sites sampled. The records from central Sweden represent the northernmost records of Bd in Europe. While the proportion of sites positive for Bd was similar between the southern and central regions, prevalence was much higher in the southern region. This was because southern species with a distribution mainly restricted to southernmost Sweden had a higher prevalence than widespread generalist species. The nationally red-listed green toad Bufotes variabilis and the fire-bellied toad Bombina bombina had the highest prevalence (61.4 and 48.9%, respectively). Across species, Bd prevalence was strongly positively, correlated with water temperature at the start of egg laying. However, no individuals showing visual signs of chytridiomycosis were found in the field. These results indicate that Bd is widespread and common in southern and central Sweden with southern species, breeding in higher temperatures and with longer breeding periods, having higher prevalence. However, the impact of Bd on amphibian populations in northernmost Europe remains unknown.

Changes in numbers and distribution of wintering waterbirds at the south coast of Scania, Sweden, during 55 winters, 1964–2018

The south coast of Scania, southernmost Sweden, has long been an important wintering and staging area for waterbirds. A large part of the coast was surveyed annually as a part of the international midwinter counts for 55 years (1964–2018). The total number of wintering waterbirds showed an increasing trend but there was much variation between years. Common Goldeneye Bucephala clangula, followed by Mallard Anas platyrhynchos, Tufted Duck Aythya fuligula and—during the early years—Long-tailed Duck Clangula hyemalis, dominated the community. Great Cormorant Phalacrocorax carbo, Mallard, Common Goldeneye and Eurasian Coot Fulica atra increased in numbers, reflecting the national and international trends related to milder winters and a northward shift of the winter distribution. Eurasian Wigeon Mareca penelope and Great Crested Grebe Podiceps cristatus established wintering traditions in the area during the study period. Tufted Duck and Common Merganser Mergus merganser decreased locally due to a northward shift of the wintering distribution northwards within the country. The Long-tailed Duck was an important winter guest in the first years but was only seen in very small numbers in later years, reflecting the general and large-scale decrease of the Baltic wintering population.

Recent changes in the frequency of plant species and vegetation types in Scania, S Sweden, compared to changes during the twentieth century

Based on data from three surveys of the vascular flora of the province of Scania, southernmost Sweden, conducted 1938–1971, 1987–2006 and 2008–2015, we analyse the change in frequency of individual species and groups of species associated with particular vegetation types. A majority of all species have experienced a change in frequency since 1938, and this turnover has continued in recent decades. The species showing the most dramatic declines since 1987 represent a mixture of arable weeds, grassland species and ruderals, but excludes forest species. In contrast, a majority of the most increasing species are escapes from cultivation that thrive under shaded conditions. The vegetation types showing the largest decreases since 1987 are all open seminatural grasslands and wetlands, while the vegetation types performing best are wooded. All vegetation types increasing since 1987 also increased during the 1900s; however, species of wooded types performed relatively better in recent decades, as opposed to the minimal increase observed for species of vegetation strongly influenced by human activities. Among decreasing vegetation types, those that have received much attention from conservationists, e.g. sand-steppe and calcareous fens tend to perform relatively better now than during the 1900s, while those that have received less attention, e.g. poor fens, oligotrophic waters and heaths, now comprise the most rapidly declining vegetation types. A majority of the species that decreased 1938–1996 also decreased 1987–2015, but, in general, species shown to have increased during the 1900s have not continued to increase.

ETS and plastid sequence data indicate a spontaneous origin of Scandinavian betony, Betonica officinalis L.

Betony (Betonica officinalis L.) is one of the rarest and most spectacular plants in the Scandinavian flora. A long-term question has been whether it is spontaneous or introduced, or whether it comprises both spontaneous and introduced populations. This study aimed to answer this question by analyzing sequence data from the nuclear external transcribed spacer (ETS) region and three regions of the plastid genome, the trnT-trnL intergenic spacer (IGS) region, tRNA-Leu (trnL) intron, and the trnS-trnG IGS. Altogether 41 samples from 11 European countries were analyzed. A unique duplication in the trnT-trnL IGS was detected in material from Skåne (southern Sweden), the "Skåne-duplication." Populations with this duplication are united on a moderately supported branch in the phylogeny based on plastid sequences. A distinct heath genotype from Yorkshire was discovered in the phylogeny based on plastid sequences and in a comparative cultivation. Phylogeny based on ETS sequences does not support any Scandinavian group, whereas a principal coordinates analysis ordination based on variable ETS positions indicated a spontaneous origin for all Scandinavian populations, which comprise a genetically well-defined subgroup of the species, most closely related to other spontaneous populations from adjacent parts of continental parts of northern Europe. Seven possible naturally occurring localities remain in Scandinavia, five in central Skåne, southernmost Sweden, and two on the southwestern part of the Danish island of Lolland.

Effects of host species and environmental factors on the prevalence of Batrachochytrium dendrobatidis in northern Europe.

The fungal pathogen Batrachochytrium dendrobatidis (Bd) poses a major threat to amphibian populations. To assist efforts to address such threats, we examined differences in Bd host infection prevalence among amphibian species and its relations to both local environmental factors in breeding habitats and landscape variables measured at three scales (500, 2000 and 5000 m radii) around breeding sites in southernmost Sweden. We sampled 947 anurans of six species in 31 ponds and assessed their infection status. We then examined correlations of infection prevalence with canopy cover, pond perimeter and pH (treated as local-scale pond characteristics), and the number of ponds, area of arable land, area of mature forest, number of resident people and presence of sea within the three radii (treated as landscape variables). The Bd infection prevalence was very low, 0.5–1.0%, in two of the six anuran species (Bufo bufo and Rana temporaria), and substantially higher (13–64%) in the other four (Bombina bombina, Bufotes variabilis, Epidalea calamita, Rana arvalis). In the latter four species Bd infection prevalence was positively associated with ponds’ pH (site range: 5.3–8.1), and negatively associated with areas of mature forest and/or wetlands in the surroundings. Our results show that the infection dynamics of Bd are complex and associated with host species, local pond characteristics and several landscape variables at larger spatial scales. Knowledge of environmental factors associated with Bd infections and differences in species’ susceptibility may help to counter further spread of the disease and guide conservation action plans, especially for the most threatened species.

The Laacher See Tephra discovered in southernmost Sweden

ABSTRACTWe present the first geochemically confirmed finding of the Laacher See Tephra (LST) on the Swedish mainland, now the northernmost extension of the LST. Sediments were sampled at the Körslättamossen fen, southernmost Sweden, and a high‐concentration cryptotephra occurrence (>65 000 shards cm−3) of the LST was found in a sequence of calcareous gyttja. Tephra identification was confirmed by geochemical analysis using field‐emission electron probe microanalysis and through comparison of the results with published LST data from proximal sites and distal sites north‐east of Laacher See. The LST has previously been divided into eruption phases suggested to have spread in several dispersal fans, but it was not possible to confidently determine the phase of the tephra here closer than to the MLST or ULST. The finding of the LST presented here further strengthens the potential of tephrochronological studies in the south Scandinavian region.

Constant and shifting photoperiods as seasonal cues during larval development of the univoltine damselflyLestes sponsa(Odonata: Lestidae)

Larvae were reared at 21.5°C from eggs from southernmost Sweden, and fed ad libitum to emergence in four different photoperiodic treatments, intended to represent increasing levels of time stress: ...

Differences in unmet healthcare needs between public and private primary care providers: A population-based study.

To investigate if any differences in unmet healthcare needs between persons registered at public and private primary care providers exist in Skåne (southernmost Sweden). The 2012 public health survey in Skåne was conducted with a postal questionnaire and included 28,029 respondents aged between 18 and 80 years. The study was cross-sectional. If the responder in the last three months had perceived oneself to be in need of medical care by a physician but did not seek it, this was used as a measure of unmet healthcare needs. Differences in unmet healthcare needs in relation to the primary care provider were investigated while adjusting for socioeconomic status and self-rated health in a logistic regression. Differences in unmet healthcare needs were small and non-significant when comparing public and private healthcare providers. Non-manual workers were to a somewhat higher extent using private providers while manual workers showed a reverse pattern. Unmet healthcare needs had decreased slightly since 2008, but so had the response rate. With the current primary care system, no significant differences in unmet healthcare needs seem to exist when comparing public and private providers. It is likely that the providers are similar in their organizational setup, accessibility and doctor-patient continuity. Still more studies need to be done, preferably in a way so that uncertainty about what type of primary care provider the respondent is listed at can be avoided and perhaps using a longer time interval for unmet needs so that more subjects could be included.

Stratigraphy and geochemical composition of the Cambrian Alum Shale Formation in the Porsgrunn core, Skien–Langesund district, southern Norway.

The fully cored BHD-03-99 borehole (hereafter referred to as the Porsgrunn borehole and core) penetrated Ordovician and Cambrian strata in the Skien–Langesund district, southern part of the Oslo region in Norway. Hand-held X-ray fluorescence (HH-XRF) measurements combined with spectral gamma ray and density core scanning of the Middle Cambrian – Furongian Alum Shale Formation have been made and compared with similar measurements obtained on Alum Shale cores from Scania (southernmost Sweden) and Bornholm (Denmark). The Porsgrunn drill site is located in an area that was only mildly overprinted by Caledonian tectonics and represents one of the few sites in the Oslo area where a nearly untectonised sedimentary succession can be studied in terms of thickness and geochemistry. The Alum Shale Formation is 28.8 m thick in the Porsgrunn core, excluding the thickness of five 0.9–5.5 m thick dolerite sills of assumed Permian age. In the Alum Shale Formation the bulk densities are around 2.7 g/cm3 with a slightly decreasing trend up through the formation. The shale has total organic carbon (TOC) values up to 14 wt%, which is comparable to the TOC levels for the Alum Shale elsewhere in the Oslo area and for dry gas matured Alum Shale in Scania and Bornholm. The basal Furongian is characterised by a gamma ray low and an increase in Mo interpreted to reflect the Steptoean Positive Carbon Isotope Excursion (SPICE) event. The Porsgrunn core data suggest that the Mo concentration remained high also after the SPICE event. Characteristic, readily identified features in the gamma log motif are named the Andrarum gamma low (AGL), base Furongian gamma low (BFGL), Olenus triple gamma spike (OTGS) and the Peltura gamma spike (PGS). No Lower Ordovician Alum Shale is present. The 14.8 m thick Furongian part of the Alum Shale represents the Olenus, Parabolina, Leptoplastus, Protopeltura and Peltura trilobite superzones judging from log-stratigraphic correlations to Scania and Bornholm. The Middle Cambrian interval is 14.0 m thick and includes the Exsulans Limestone Bed and 1.4 m of quartz sandstone. A 0.3 m thick primary limestone bed may be an equivalent to the Andrarum Limestone Bed. The succession represents the Paradoxides paradoxissimus and P. forchhammeri superzones. The Alum Shale Formation rests atop the 13.0 m thick Lower Cambrian Stokkevannet sandstone (new informal name) that in turn directly overlies the basement. Overall, the stratigraphic development of the comparatively thin Alum Shale Formation resembles the condensed sequence seen on Bornholm.

Tree recovery during the aftermath of an outbreak episode of the Hungarian spruce scale in southern Sweden

ABSTRACTIn 2010, the first, and so far only, infestation of the Hungarian spruce scale (Physokermes inopinatus) and accompanying sooty mould occurred in Scania, southernmost Sweden. About 1000 ha of Norway spruce (Picea abies) were affected, and the trees suffered from the sucking of the insects as well as from the dense sooty mould that covered the needles. Salvage cuttings were carried out in many of the massively attacked forest stands, both in response to the fear that the trees otherwise would die, e.g. from secondary bark beetle attacks and to prevent spreading of the infestation. The aim of this study was to provide basic, quantitative knowledge on the aftermath response of trees that were heavily infested, but not exposed to salvage cutting. Growth characteristics, in terms of needle weight, shoot length and tree-ring size were measured on infested and uninfested trees to compare and contrast the spruce growth before, during and after the scale outbreak. The infestation resulted in dwarf annual shoots, stunted needles and thin tree rings. The needle weight returned to normal the following year, whereas shoot length and tree rings required one growing season before full recovery.

Climate warming and land-use changes drive broad-scale floristic changes in Southern Sweden.

Land-use changes, pollution and climate warming during the 20th century have caused changes in biodiversity across the world. However, in many cases, the environmental drivers are poorly understood. To identify and rank the drivers currently causing broad-scale floristic changes in N Europe, we analysed data from two vascular plant surveys of 200 randomly selected 2.5×2.5km grid-squares in Scania, southernmost Sweden, conducted 1989-2006 and 2008-2015, respectively, and related the change in frequency (performance) of the species to a wide range of species-specific plant traits. We chose traits representing all plausible drivers of recent floristic changes: climatic change (northern distribution limit, flowering time), land-use change (light requirement, response to grazing/mowing, response to soil disturbance), drainage (water requirement), acidification (pH optimum), nitrogen deposition and eutrophication (N requirement, N fixation ability, carnivory, parasitism, mycorrhizal associations), pollinator decline (mode of reproduction) and changes in CO2 levels (photosynthetic pathway). Our results suggest that climate warming and changes in land-use were the main drivers of changes in the flora during the last decades. Climate warming appeared as the most influential driver, with northern distribution limit explaining 30%-60% of the variance in the GLMM models. However, the relative importance of the drivers differed among habitat types, with grassland species being affected the most by cessation of grazing/mowing and species of ruderal habitats by on-going concentration of both agriculture and human population to the most productive soils. For wetland species, only pH optimum was significantly related to species performance, possibly an effect of the increasing humification of acidic water bodies. An observed relative decline of mycorrhizal species may possibly be explained by decreasing nitrogen deposition resulting in less competition for phosphorus. We found no effect of shortage or decline of pollinating lepidopterans and bees.

Changes in migration and wintering patterns of Greylag Geese Anser anser from southernmost Sweden during three decades

The recent increase of the Greylag Goose Anser anser population has caused complaints about crop damage. In response to this, the Nordic Collegium for Wildlife Research started a neck-banding program to elucidate the migration and movement patterns. During 1984–2009, 2,639 Greylag Geese were marked in a breeding area in SW Scania, southernmost Sweden. Up to and including 2012, 15,296 re-sightings were reported from outside the breeding area (in addition to more than 100 000 from the breeding area). In the early years of the study, the majority of the geese migrated to winter in southernmost Spain, staging in The Netherlands. In later years, hardly any individuals migrated to Spain, the majority staying in The Netherlands with an increasing proportion wintering in southern Sweden. From 1986 to 2017, the mean latitude for re-sightings changed ten degrees to the north. About 13% of the geese changed winter quarters between two consecutive winters. Moreover, the southward migration occurred much later in the autumn and the geese returned to the breeding areas about one month earlier in spring.

New Find of Six-Spoke Sun Wheels from the Bronze Age in Scandinavia

Six-spoke Sun wheels have previously been described by us from Mesopotamia, rock-carvings in Sweden and a golden sky dome from Sweden. The division of the Sun wheel into six segments refers to the six double-months of 60 days, and a full annual cycle of 360 days. In this paper we report the findings of a stone carving with 9 six-spoke Sun wheels and two solar eclipses found and depicted in 1840 in Denmark. The spokes in the nine Sun wheels are in N-S, E-W and NW-SE direction. The NW-SE line co-insides with the sunset at summer solstice and sunrise at winter solstice, which is in full agreement with the alignment of the famous stone-ship of Ales Stones in southernmost Sweden. The new stone carving in Denmark provides a confirmation of the deep knowledge in astronomy existing among the Bronze Age people, all from Mesopotamia up the Scandinavia.

Heat flow, seismic cut-off depth and thermal modeling of the Fennoscandian Shield

SummaryBeing far from plate boundaries but covered with seismograph networks, the Fennoscandian Shield features an ideal test laboratory for studies of intraplate seismicity. For this purpose, this study applies 4190 earthquake events from years 2000–2015 with magnitudes ranging from 0.10 to 5.22 in Finnish and Swedish national catalogues. In addition, 223 heat flow determinations from both countries and their immediate vicinity were used to analyse the potential correlation of earthquake focal depths and the spatially interpolated heat flow field. Separate subset analyses were performed for five areas of notable seismic activity: the southern Gulf of Bothnia coast of Sweden (area 1), the northern Gulf of Bothnia coast of Sweden (area 2), the Swedish Norrbotten and western Finnish Lapland (area 3), the Kuusamo region of Finland (area 4) and the southernmost Sweden (area 5). In total, our subsets incorporated 3619 earthquake events. No obvious relation of heat flow and focal depth exists, implying that variations of heat flow are primarily caused by shallow lying heat producing units instead of deeper sources. This allows for construction of generic geotherms for the range of representative palaeoclimatically corrected (steady-state) surface heat flow values (40–60 mW m−2). The 1-D geotherms constructed for a three-layer crust and lithospheric upper mantle are based on mantle heat flow constrained with the aid of mantle xenolith thermobarometry (9–15 mW m−2), upper crustal heat production values (3.3–1.1 μWm−3) and the brittle-ductile transition temperature (350 °C) assigned to the cut-off depth of seismicity (28 ± 4 km). For the middle and lower crust heat production values of 0.6 and 0.2 μWm−3 were assigned, respectively. The models suggest a Moho temperature range of 460–500 °C.

Can δD and δ18O stable isotopes be used to detect long-range dispersal among carabid beetles?

We studied if hydrogen (δD) and oxygen (δ18O) stable isotope values in three common carabid species in intensively managed agricultural landscapes in southernmost Sweden indicate long-range dispersal. We matched “emerging” (emergence tents) and “colonizing” (pitfall traps) individuals of three carabid species (Trechus quadristriatus, Harpalus rufipes, Pterostichus melanarius) to account for spatial and seasonal variability. There was higher dispersion of δD values among H. rufipes individuals as compared to values of the other two species, which suggests that H. rufipes individuals had the most variable spatial natal origin. The δD values were significantly lower among colonizing compared to emerging individuals in the flight capable and carnivorous species T. quadristriatus. This result suggests long-range migration of T. quadristriatus individuals from remote locations with deuterium depleted (lower δD) meteoric water. Our study provides a first effort towards understanding the δD and δ18O dynamics in epigean carabids in northern European agroecosystems. Additional research on larger (preferably continental) spatial scales and experimental trials that attempt to disentangle major unaccounted sources of variation and decoupling of δD and δ18O among carabids and other invertebrate natural enemies is urgently needed to allow a more frequent use of δD and δ18O dynamics as indicators of long-range dispersal.

Generation and origin of natural gas in Lower Palaeozoic shales from southern Sweden

The Lower Palaeozoic succession in Scandinavia includes several excellent marine source rocks notably the Alum Shale, the Dicellograptus shale and the Rastrites Shale that have been targets for shale gas exploration since 2008. We here report on samples of these source rocks from cored shallow scientific wells in southern Sweden. The samples contain both free and sorbed hydrocarbon gases with concentrations significantly above the background gas level. The gases consist of a mixture of thermogenic and bacterially derived gas. The latter likely derives from both carbonate reduction and methyl fermentation processes. The presence of both thermogenic and biogenic gas in the Lower Palaeozoic shales is in agreement with results from past and present exploration activities; thermogenic gas is a target in deeply buried, gas-mature shales in southernmost Sweden, Denmark and northern Poland, whereas biogenic gas is a target in shallow, immature-marginally mature shales in south central Sweden. We here document that biogenic gas signatures are present also in gas-mature shallow buried shales in Skåne in southernmost Sweden.

The role of pollinators, pests and different yield components for organic and conventional white clover seed yields

A high and stable seed production of both organic and conventional white clover (Trifolium repens L.) is needed to meet market requirements. Seed yields of white clover are, however, known to vary greatly, and organic yields are often considerably lower than conventional yields. Our aim in this study was to estimate the roles of pollinators, pests and different yield components for organic and conventional white clover seed yields. We surveyed pollinators (honey bees, bumble bees and solitary bees), reared the main insect pests (Protapion fulvipes Geoffroy and Hypera spp. weevils) from flowers and measured the yield components (inflorescences per area, flowers per inflorescence, seeds per flower and weight per seed) in organic, conventional untreated and conventional insecticide treated plots in 27 white clover seed fields over two years in southernmost Sweden. Unexpectedly, densities of bees other than honey bees were higher in insecticide treated plots compared to organic plots, but pollinator densities were not related to seed set. The lower pollinator visitation in organic plots might have been caused by pest damage to the flowers, as P. fulvipes and Hypera spp. weevils were more common in organic plots than in conventional insecticide treated plots. The abundances of both P. fulvipes and Hypera spp. weevils were negatively related to seed set, with P. fulvipes being most damaging for seed set. Seed yield was considerably lower (42%) in organic plots compared to conventional insecticide treated plots, and this was driven by a lower (36%) seed set. Taken together, our results indicate that pollinator densities are not limiting yields in either conventional or organic white clover seed production, whereas P. fulvipes crop damage is an important factor limiting organic yields via negative effects on seed set. Research efforts to raise white clover seed yield with minimized environmental impacts should include a focus on integrated pest management of P. fulvipes, including the development of control methods accepted in organic farming.

Sedimentary features reveal transport paths for Holocene sediments on the Kristianstad coastal plain, SE Sweden

We have investigated coastal and aeolian deposits on the Kristianstad plain in southernmost Sweden by a combination of methods that has yielded data on sedimentary features such as grain-size variations, shape and character of quartz grain surfaces (determined in light microscope and scanning electron microscope), and mineralogical composition. Such sedimentary techniques have been not applied to coastal deposits in this part of the Baltic Sea region before. The littoral, foredune and parabolic dune sands are sedimentologically similar, only a slight grain-size transformation by aeolian processes in the foredune was observed. Sand in straight-crested dunes, on the other hand, originates from immature glaciolacustrine sediments, seen e.g. through the increase in mineral maturity during active aeolian transport. Finally, a palaeosol, occuring below an aeolian cover, carries both aeolian and glaciolacustrine sedimentary signals.

Variation in laying date in relation to spring temperature in three species of tits (Paridae) and pied flycatchers Ficedula hypoleuca in southernmost Sweden

This study documents the advancement of laying dates in three species of tits (Paridae) in southernmost Sweden during recent decades, and the absence of a similar response in the pied flycatcher Ficedula hypoleuca. It is based on several different nestbox studies; the oldest one starting in 1969. During 1969 to 2012, mean spring temperatures in the study area increased by between 0.06 and 0.08°C per year, depending on the period considered. Great tits Parus major, blue tits Cyanistes caeruleus and marsh tits Poecile palustris, which generally start egg laying between the last week of April and the first week of May, all advanced laying date at a similar rate during the study period (0.25 d yr–1). This indicates that these species were similarly affected by increasing temperatures. When accounting for mean spring temperature variation, we still found an advancement of laying date over the study period, mostly due to such relationships among marsh and blue tits. This result could reflect ongoing microevolution favouring earlier laying, but could also be a result of other factors such as increased intra‐ or inter‐specific competition for early breeding. Pied flycatchers, which generally lay during the third week of May, did not significantly advance the date of egg laying despite that the long‐term trend in the increase in ambient temperature during the 30‐d period preceding the start of egg laying was similar for pied flycatchers compared to the tit species.