Multiple origins of the octoploid Scandinavian endemic Draba cacu minum: electrophoretic and morphological evidence

The octoploid Draba cacuminum (Brassicaceae) is one of the few endemic species in Scandinavia and has frequently been considered an example supporting the glacial survival theory. Two subspecies, ssp. cacuminum in southern Norway and ssp. angusticarpa in northern Scandinavia, have been described and suggested to be geographically diverged remnants of a more continuously distributed ancestor. To test an alternative hypothesis of independent origins of similar octoploids in different areas, we investigated populations of D. cacuminum and its possible progenitors using enzyme electrophoresis and morphological analysis. Electrophoretic analysis of progeny of D. cacuminum revealed high levels of fixed heterozygosity, suggesting that the species is a genetic alloploid. Fixed electrophoretic differences among the populations and additivity of electrophoretic phenotypes indicate that the octoploid D. cacuminum has originated at least three times by alloploidizations involving different populations of the hexaploid D. norvegica and a diploid species, possibly D. fladnizensis. Electrophoretic and morphometric data suggest that populations of D. cacuminum with broad siliculae have originated from populations of D. norvegica that had broad siliculae, and that populations of D. cacuminum with narrow siliculae have originated from populations of D. norvegica that had narrow siliculae. However, the electrophoretic and morphometric variation within D. cacuminum did not correspond to the geographic origin of the populations, and the previously described subspecies could not be recognized. Draba cacuminum gives no relevant information on the glacial survival theory; the polyploidizations may have occurred in postglacial time as well as in pre-Weichselian periods.     

Population structure and migratory directions of Scandinavian bluethroats Luscinia svecica– a molecular, morphological and stable isotope analysis

Many species of birds show evidence of secondary contact zones and subspeciation in their Scandinavian distribution range, presumably resulting from different post-glacial recolonization routes. We investigated whether this is the case also in the Scandinavian bluethroat Luscinia svecica , a species that has been suggested to consist of two separate populations: one SW-migrating and long-winged ( L. s. gaetkei ) breeding in southern Norway, and one shorter-winged ESE-migrating ( L. s. svecica ) in northern Scandinavia. We sampled males at eleven breeding sites from southern Norway to northernmost Sweden. There were no morphological differences or latitudinal trends within the sample, neither were there any genetic differences or latitudinal trends as measured by variation in AFLP and microsatellite markers. Stable isotope ratios of throat feathers moulted on the wintering grounds showed no, or possibly marginal differences between birds from southern Norway and northern Sweden. We also re-measured old museum skins that in previous studies were classified as L. s. gaetkei , and found marginally longer wings in birds from the southern part of the Scandinavian breeding range. The difference, however, was much smaller than proposed in earlier studies. We conclude that there is no evidence of a genetic population structure among Scandinavian bluethroats that would suggest the presence of a zone of secondary contact. Finally we discuss whether the presumed subspecies gaetkei ever existed.     

Plastid DNA haplotype variation in Dactylorhiza incarnata (Orchidaceae): evidence for multiple independent colonization events into Scandinavia

The early marsh orchid, Dactylorhiza incarnata (L.) Soó s. l., grows in medium-rich to rich fens and marshes over much of Europe and parts of Asia. The species is highly polymorphic and different forms may grow together at the same site. In the present study, I tested the hypothesis that these forms represent different migrant populations that have colonized Scandinavia independently of each other, possibly from different source areas. Accessions from Scandinavia and elsewhere were screened for variation at three size-variable plastid marker loci, one polyA repeat, one polyA-polyTA-polyT repeat and one 9 bp indel. Ten haplotypes were defined on basis on the combined variation pattern. The common occurrence of several haplotypes in southern Scandinavia and adjacent areas to the south and the east of the Baltic Sea suggests that D. incarnata has been dispersed on repeated occasions across the Baltic. Also, there was some correlation between haplotype composition and morphological form on the island of Gotland, in agreement with the independent colonization hypothesis. Material from northernmost Sweden, Finland and northwest Russia was fixed for a single widespread haplotype, indicating that populations in this area are located farther away from the Pleistocene refugia. Dactylorhiza incarnata ssp. lobelii from southwest Norway was characterized by a haplotype that was not encountered elsewhere in Scandinavia. Given its proximity to British populations dominated by the same haplotype, it is suggested that D. incarnata ssp. lobelii was established independently of the other Scandinavian populations, from coastal refugia located in western Europe.     

The taxonomy, morphology and distribution of species of Scinaia Biv.–Bern. (Nemaliales, Rhodophyta) in north–western Europe

Re–examination of herbarium material and new collections of species of Scinaia in north–western Europe shows that the distributions of Scinaia forcellata Biv.–Bern. and S. turgida Chemin have been wrongly assessed in recent literature. S. forcellata ssp. forcellata is found on southern and western coasts of the British Isles north to Co. Clare, Ireland and on Channel coasts east to Boulogne. S. turgida , on the other hand, is found on southern and western coasts of the British Isles north to Shetland and on Channel coasts east to Roscoff. A new subspecies, S. forcellata ssp. scandinavica ssp. nov., is proposed for material previously referred to S. forcellata ssp. forcellata from Denmark, Helgoland, Sweden and possibly Norway. Specimens of a small Scinaia species collected off the Aran Islands, western Ireland are provisionally referred to S. complanata (F. S. Collins) Cotton pending the collection of further material.     

A phylogeographic analysis of Viola rupestris: three post-glacial immigration routes into the Nordic area?

Morphology and isoenzyme patterns support the taxonomic delimitation of two subspecies of Viola rupestris F. W. Schmidt in the Nordic area, i.e. ssp. rupestris and ssp. relicta Jalas. Three different, geographically distinctly defined genotypes, are revealed (based on seven enzyme systems): one in north Scandinavia (= ssp. relicta , distinct in AAT-I, AMP-I and PGM-3), one in north Finland (distinct in AMP-2), and one widespread in the southern and central parts of Norden. Two of the three unique bands in ssp. relicta are also detected in British material. The data are consistent with the scenario of three post-glacial immigration routes into the Nordic area: one from the south-west, today represented by the north Scandinavian populations, one from the east, today represented by the populations in the Kuusamo area of north Finland, and one from the south-east, today represented by widespread populations south of the mentioned areas.     

Morphometric analyses of capsule and seed traits in Scandinavian Papaver radicatum (Papaveraceae) in relation to the bicentric distribution pattern

The bicentric distribution pattern of certain plant species in the southern and northern Scandinavian mountains has been explained in different ways. Either by refugial survival, by late-glacial immigration to the first deglaciated areas in southern and northern Norway or by a successive fragmentation of wide-distributed populations during post-glacial time — or by present-day ecological factors. Even if the bicentric distribution pattern is at least partly explained by present-day ecological conditions, the question about the origin of the bicentric distribution still remains. One way to tackle this problem, is to investigate the morphometric and/or the genetic differentiation between isolated populations of ‘bicentric’ species and its impact on the explanation of the disjunct pattern. The overall morphometric differentiation pattern in seeds and capsules was investigated in populations of Papaver radicatum, a perennial herb with a bicentric distribution in the Scandinavian mountain range. Canonical variates analysis of capsules separates the populations into two groups in accordance with their geographic origin, i.e. the regions of southern and northern Scandinavia. The differentiation pattern indicates a two-step development of the present-day distribution: first separation of the southern and northern Scandinavian occurences of older origin, then separation between populations within each region. The results from canonical variates analysis of seeds shows a weaker variation pattern with a tendency of overlapping inter-region populations. The most northerly situated populations from the southern region are grouped with populations from the northern region. The pattern of differentiation in capsules may be interpretated in terms of refugial survival or late-glacial immigration. However, the variation pattern in seeds rather points to a scenario where a widespread occurrence that previously ranged from southern to northern Scandinavia was successively fragmented, which makes a postglacial development of the differentiation pattern more probable.     

Genetic variation and population structure in Scandinavian wolverine (Gulo gulo) populations

Wolverine (Gulo gulo) numbers in Scandinavia were significantly reduced during the early part of the century as a result of predator removal programmes and hunting. Protective legislation in both Sweden and Norway in the 1960s and 1970s has now resulted in increased wolverine densities in Scandinavia. We report here the development of 15 polymorphic microsatellite markers in wolverine and their use to examine the population sub-structure and genetic variability in free-ranging Scandinavian wolverine populations as well as in a sample of individuals collected before 1970. Significant subdivision between extant populations was discovered, in particular for the small and isolated population of southern Norway, which represents a recent recolonization. Overall genetic variability was found to be lower than previously reported for other mustelids, with only two to five alleles per locus and observed heterozygosities (H(O)) ranging from 0.269 to 0.376 across the examined populations, being lowest in southern Norway. Analysis of the mitochondrial DNA control region revealed no variation throughout the surveyed populations. As the historical sample did not show higher levels of genetic variability, our results are consistent with a reduction in the genetic variation in Scandinavian wolverines that pre-dates the demographic bottleneck observed during the last century. The observed subdivision between populations calls for management caution when issuing harvest quotas, especially for the geographically isolated south Norwegian population.     

Viola rupestris: molecular analyses to elucidate postglacial migration in Western Europe

Aim Our aim was to elucidate the postglacial migration of Viola rupestris F.W. Schmidt, with its two subspecies, rupestris and relicta Jalas, in Europe, using molecular methods. Location Norway, Sweden, Finland, England, the Netherlands, France and Switzerland. Methods Isoenzymes were analysed from 49 populations of Viola rupestris s.lat. Based on former experience of variation in the taxon, the following were included: aspartate aminotransferase, leucine/aminopeptidase, and phosphoglucomutase, yielding a total of nine interpretable and six variable (putative) loci. Results Six multilocus phenotypes were revealed (A–F). Phenotype A (only one individual) is restricted to northern Norway, B is shared by all populations in northern Norway and an isolated population on the west coast of southern Norway (Møre). Phenotype B comes close to C, co‐occurring with D in England, the latter also occurring in southern France. Phenotypes E and F occur in the rest of Europe. Main conclusions Viola rupestris ssp. relicta Jalas, previously known only from northern Scandinavia (northern unicentric), was discovered on the west coast of southern Norway (Møre), making the taxon ‘bicentric’. Populations are connected through a putative migration route from the Grands Causses in southern France (Massif Central) via England and western Norway to northern Scandinavia. The Grands Causses might represent a glacial refugium.     

Morphology and taxonomy of the genus Cochlearia (Brassicaceae) in Northern Scandinavia

The morphological variation between populations of Cochlearia in Northern Scandinavia has been analysed. The variation is correlated to ecology, and four ecotypes are recognized. Based on the morphological differentiation of the ecotypes and the results of crossing experiments, the populations are referred to the following three taxa: C. officinalis ssp. officinalis which includes the common beach ecotype and the bird cliff ecotype; C. officinalis ssp. integrifolia stat. nov. which includes the spring ecotype growing in inland localities up to about 600 m a.s.l. in cold more or less eutrophic springs, and C. officinalis ssp. norvegica ssp. nov. which includes the estuary ecotype, growing in poor, often inundated habitats near river outlets at the fjord ends. All the differentiation has taken place at the tetraploid level (2n = 24). The subspecies are kept more or less distinct due to ecological and seasonal isolating mechanisms rather than internal, reproductive barriers. A key to the subspecies and distribution maps for ssp. integrifolia and ssp. norvegica are presented.     

Cranial variation in the European badger Meles meles (Carnivora,Mustelidae) in Scandinavia

Morphometric variation in 30 craniometric characters of 465 skulls of the European badgers (Meles meles) from across Europe was analysed. Multivariate analyses revealed that the populations from Norway, Sweden, and Finland differ from other European populations in having smaller skulls. The analyses also revealed significant differences between the ‘south‐western Norwegian’ and ‘main Fennoscandian’ forms. On average, badgers from south‐west Norway were smaller than those of the remaining Fennoscandia. Morphological differences between the ‘south‐western Norwegian’ and ‘main Fennoscandian’ populations of M. meles suggest a possible in situ semisympatric divergence since the beginning of the Holocene warming, or a complex history of two groups involving at least two colonization routes. The small‐sized Scandinavian badgers may be close to the ancestral form that used to be widespread in Denmark and throughout Europe. The animals from south‐west Norway may instead be descendants of ancestors that were the first to penetrate the southern parts of the Scandinavian Peninsula. The ‘main Fennoscandian’ badgers are likely to have been the descendants of the second wave of recolonization of Scandinavia. Specifically, they might have colonized the Scandinavian Peninsula from the east after the last glaciation.     

Genetic evidence for different migration routes of freshwater fish into Norway revealed by analysis of current perch (Perca fluviatilis) populations in Scandinavia

To elucidate the colonization of freshwater fish into Norway following the last deglaciation of Europe 10 000 years ago, we have performed a survey using mitochondrial DNA variation (20 populations) and multilocus DNA fingerprinting (14 populations) of the widely distributed perch ( Perca fluviatilis ) from the Scandinavian peninsula and the Baltic Sea. Sequence analysis of a 378 bp segment of the perch mitochondrial control region (D-loop) revealed 12 different haplotypes. A nested clade analysis was performed with the aim of separating population structure and population history. This analysis revealed strong geographical structuring of the Scandinavian perch populations. In addition, the level of genetic diversity was shown to differ considerably among the various populations as measured by the bandsharing values ( S -values) obtained from multilocus DNA fingerprinting, with intrapopulation S -values ranging from 0.19 in Sweden to 0.84 in the central part of Norway. Analysis of the intrapopulation S -values, with S -value as a function of lake surface area and region, showed that these differences were significant. The mitochondrial and DNA fingerprinting data both suggest that the perch colonized Norway via two routes: one from the south following the retreating glacier, and the other through Swedish river systems from the Baltic Sea area. Perch utilizing the southern route colonized the area surrounding Oslofjord and the lakes which shortly after deglaciation were close to the sea. Fish migrating from the Baltic Sea seem to have reached no further than the east side of Oslofjord, where they presumably mixed with perch which had entered via the southern route. It seems likely that the migration events leading to the current distribution of perch also apply to other species of freshwater fish showing a similar distribution pattern.     

Chromosome numbers of flowering plants from northern Norway and Svalbard

Chromosome numbers of 25 taxa of flowering plants from northern Norway and Svalbard are reported. Four species and one subspecies, Carex halophila F. Nyl. (2n = ca. 78), C. stenolepis Less. (2n = ca. 80), Salicorniapojarkovae N. Sem. (2n = 36), Alnus incano (L.) Moench ssp. kolaensis (Orlova) Love (2n = 28), and Saxifraga svalbardensis D. O. Øvstedal (2n = ca. 64), have not been studied karyologically before. Chromosome numbers of four additional species are reported for the first time from Norway; those of another six species for the first time from northern Norway. The hybrid Salix herbacea L. (2x) x 5. polaris Wahlenb. (6x) is proved tetraploid and may be fertile. A possible hybrid between Saxifraga hyperborea R. Br. and S. rivularis L. was revealed.     

Morphological and pollen differentiation in Solanum cardiophyllum ssp. cardiophyllum and S. cardiophyllum ssp. ehrenbergii

A multivariate analysis to differentiate morphologically the populations of wild potatoes Solanum cardiophyllum ssp. cardiophyllum and S. cardiophyllum ssp. ehrenbergii was carried out. An analysis of the morphology and the viability of pollen of these potato populations was also made. The results of the morphometric analysis indicate that both subspecies are phenetically different. The pollen grain shape and size in ssp. cardiophyllum are different in northern and southern populations. Pollen diameter is significantly different between subspecies. Based on these results we propose that these taxa should be considered as two separate species.  © 2002 The Linnean Society of London, Botanical Journal of the Linnean Society , 2002, 140 , 415–426.     

Weak geographical structure in sperm morphology across the range of two willow warbler Phylloscopus trochilus subspecies in Scandinavia

Sperm morphology is highly diversified among species and at higher taxonomic levels. In birds, there is also increasing evidence of geographical differentiation in sperm traits within species, especially in those with strong sperm competition. Geographical divergences in sperm traits might imply the formation of a reproductive barrier in a speciation process. Here we study sperm morphology variation of willow warblers Phylloscopus trochilus in a geographical context in Scandinavia, across the range of two subspecies that are differentiated in certain genetic markers, morphology and migratory routes. We describe geographical patterns in genotypes (two previously described single‐nucleotide polymorphism (SNP) markers and four polymorphic microsatellites); in wing length, tarsus length and body mass; and in sperm traits of 330 male willow warblers sampled at 33 localities across Norway (58°N–69°N). Birds were on average larger and longer‐winged in the north (spp. acredula) than in the south (spp. trochilus), and showed a sigmoid change in the SNP allele frequencies and body morphology around 65°N. We found no evidence of genetic structuring in the microsatellites. There was no geographical variation in sperm traits across Norway, except that sperm heads were on average longer in the south. Sperm head length was also associated with the two SNP markers, with longer sperm heads for the southern alleles, and midpiece length was weakly associated with one of the SNP markers. Similar among‐male variances in total sperm length among the 33 sampling sites indicate uniform levels of sperm competition across Norway. We conclude that sperm morphology remains a rather undifferentiated trait between the two willow warbler subspecies in Scandinavia, which is consistent with a pattern of a shallow genetic divergence. This indicates that sperm morphology is not a reproductive barrier maintaining the narrow hybrid zone.     

Variation and taxonomy in Hordeum depressum and in the H. brachyantherum complex (Poaceae)

The variation pattern in the perennial Hordeum brachyantherum complex and in the annual H. depressum are described. The diploid form of H. brachyantherum s. lat., endemic to California in USA, previously recognized as a separate species is here treated as a subspecies ( H. brachyantherum ssp. californicum ). Despite its restricted distribution it shows a considerable variation and overlap in morphology with the tetraploid ssp. brachyantherum , and no unambiguous determination based on morphology between the two tax a is possible. The tetraploid cytotype has a large distribution area in western North America and easternmost Asia and a very wide morphological variation. It has also a small disjunct distribution area in easternmost Canada. A single hexaploid population from California is referred to ssp. brachyantherum .     

A taxonomic revision of Secale (Triticeae, Poaceae)

Several taxa have previously been recognized within Secale , but most of them are difficult or even impossible to distinguish morphologically. We recognize only three species: S. sylvestre, S. strictum , and S. cereale. Secale strictum has priority over S. montanum and has two subspecies, ssp. strictum and ssp. africanum , and two varieties within ssp. strictum , van strictum and var. ciliatoglume comb. nov. Secale cereale is also treated as having two subspecies. The cultivated taxa, marked by their tough rachises, are placed in ssp. cereale and the wild or weedy taxa that have more or less fragile rachis, in ssp. ancestrale. A complete synonymy is given for S. cereale , but typification has been omitted because, in many instances, type material does not exist or has been impossible to trace.     

A new subspecies of Paraphysomonas punctata (Paraphysomonadaceae, Chrysophyceae)

A new subspecies, ssp. hexagona within the species complex of Paraphysomonas punctata is described. It is particularly distinguished by its large round to oblong perforations and also deviates in other respects from known subspecies of P punctata , so that it is here described as a new subspecies, ssp. hexagona . Type material has been collected in a small Danish pool in the Copenhagen area. A previous finding of scales with similar large perforations has been considered to be an indication of weakly silicified scales. This, however, cannot be the case since the present algae have been found in silica-enriched samples. Furthermore the pool is shallow and fully mixed throughout the year.     

Taxonomy of Asaemia with notes on Stilpnophyton (Compositae–Anthemideae)

Asaemia is a genus of one species with two subspecies from southern Africa. The nomenclature and systematic position of Asaemia and the related Stilpnophyton are discussed. Both genera are related to Athanasia. Asaemia minula (L. f.) Bremer and A. minuta ssp. inermis (Phillips) Bremer are new combinations. Stilpnophyton is typified by S. longifolium (Tfiunb.) Less.     

Glacial history of Saxifraga paniculata (Saxifragaceae): molecular biogeography of a disjunct arctic-alpine species from Europe and North America

The molecular biogeography of the disjunctly distributed and morphologically highly variable species Saxifraga paniculata Mill. was analysed using amplified fragment length polymorphism (AFLP) and chloroplast microsatellites. The study comprised 77 samples from mountain regions in Europe and North America throughout the complete range of distribution. AFLP data revealed clear genetic differentiation between samples from the Arctic, the Caucasus, and the eastern European mountains. Samples from the Alps were divided into two groups. One group clustered with the samples from central Europe and the Pyrenees, whereas another group with individuals from southern Norway. AFLP diversity was lowest in the Arctic and highest in the Alps. Chloroplast microsatellite analysis revealed eight haplotypes but no unequivocal phylogeographical pattern. However, haplotype diversity was highest in the Alps and central Europe whereas, in the Arctic, only few widespread haplotypes could be found. The results indicate in situ survival of S. paniculata in the Caucasus, the eastern European mountains, and the Alps. The Arctic has presumably been colonized postglacially from North American refugia south of the ice shield. Southern Norway and the Pyrenees have most likely been colonized from two phylogeographically different groups in the Alps. The origin of the central European samples remains ambiguous. In situ survival seems to be as possible as several postglacial recolonization events from the Alps. The obtained molecular data clearly support the subdivision of S. paniculata into three subspecies: ssp. cartilaginea from the Caucasus, ssp. laestadii from northern Norway, Iceland, and North America, and ssp. paniculata from the other geographical regions.  © 2008 The Linnean Society of London, Biological Journal of the Linnean Society , 2008, 93 , 385–398.