Boreal forest dynamics in north-eastern Sweden during the last 10,000 years based on pollen analysis

A pollen record obtained from a 2.2-m sediment succession deposited in a small lake in the province of Västerbotten, north-eastern Sweden, reveals the presence of continuous forest cover since 8,500 calendar years before present (cal b.p.). Forest with abundant Pinus (pine) and Betula (birch) initially colonized the area, followed by a dominance of deciduous trees, primarily Betula, from ca. 8,000 to ca. 3,200 cal b.p. Pollen accumulation rates of Quercus (oak), Ulmus (elm) and Tilia (linden) suggest the possible local presence of these thermophilous tree species during this period. The climate gradually became colder and moister around 3,500 cal b.p. and an increased abundance of Sphagnum spores indicates paludification. Picea (spruce) became established around 3,200 cal b.p. and less than 500 years later this was the dominant tree species around the lake. The fire frequency as inferred from charcoal particles exhibits a general increase from ca. 3,000 cal b.p. with subsequent charcoal accumulation maxima at around 2,800 cal b.p., 1,700 cal b.p. and in recent time. The human influence on vegetation was significant during the last 200–300 years. Soil erosion increased substantially and fern spores amount to ca. 55% of the total pollen assemblage in the uppermost samples. These results suggest an extensive anthropogenic impact on the local forest ecosystem, with abundant logging, burning and ditching in the vicinity of the lake. Independent evidence of sub-recent human-induced environmental change is provided by historical accounts. Complementary information on catchment soil development and aquatic nutrient status was provided by records of magnetic susceptibility and elemental carbon, and nitrogen contents obtained from the same sediment core.     

Stand-scale reconstruction of late Holocene forest succession on the Gdańsk Upland (N. Poland) based on integrated palynological and macrofossil data from paired sites

This study concerns the stand-scale palaeoecological reconstruction of the subsequent stages of late Holocene vegetation development on habitats recently covered by beech-dominated woodland in the southern Baltic region. The data, based on pollen, non-pollen palynomorphs, macrofossil and charcoal analyses from two close-lying sites, demonstrated that each of the subsequent late Holocene shifts in dominating forest communities took place because of human impact coupled with climatic events or episodic human-made disturbances. Shifts from the Tilia dominated forest to the Quercus-Corylus plant community at around 3300 bc was most probably driven by the coupled effect of climate change and human activity. Human impact was the primary driver of the final Corylus decline and concurrent major Carpinus expansion at c. 460 bc, and the Carpinus decline followed by Fagus expansion at c. ad 900. Carpinus had been lingering on the edge of a major expansion in the local forest for at least 2,500 years while Fagus had persisted in a small admixture for no fewer than 1,500 years before becoming important forest constituents. Our data illustrate the role of episodic disturbances as turning points that initiate long-term vegetation changes.     

Landscape use and fruit cultivation in Petra (Jordan) from Early Nabataean to Byzantine times (2nd century <Emphasis Type="SmallCaps">bc</Emphasis>–5th century <Emphasis Type="SmallCaps">ad</Emphasis>)

Archaeobotanical analyses of charred seeds, fruit and wood charcoal from the residential part of the ez-Zantur area at Petra, Jordan, provide new data on the agricultural economy and use of the landscape in this famous merchant Nabataean city from the middle of the 2nd century bc to the beginning of the 5th century ad. The study is based on analyses of 7,640 whole and fragmented seeds, pips and fruit stones and 624 charcoal fragments sampled from household deposits. The results show that the food supply was based on common Mediterranean cultivated taxa such as cereals (Hordeum vulgare, Triticum aestivum/durum), pulses (Lens culinaris) and fruit (Olea europaea, Ficus carica, Vitis vinifera), which were probably cultivated both in the city and its hinterland. The by-products from the processing of cereals and fruit trees played a significant role in fuel supply, supplementing woody wild plants obtained from rocky slopes and the desert valley. The variety of fuel resources shows a major capacity to manage complex supply networks and perhaps the rarity of natural woodland cover. The existence of orchards within the city centre and notably olive groves is indicated in the Early Nabataean period (mid 2nd century to mid 1st century bc) but they expanded during the Classical Nabataean period (mid 1st century bc to 1st century ad), probably reflecting specialised fruit growing. Unusual plant remains such as Prunus armeniaca (apricot), P. persica (peach) and Juglans regia (walnut) are considered to be social indicators of prosperity. These archaeobotanical results fit with others from this region and match with the urbanization and social dynamics of the city of Petra.     

Tracing a bog-iron bloomery furnace in an adjacent lake-sediment record in Ängersjö, central Sweden,using pollen and geochemical signals

Recent studies of bloomery sites in Sweden indicate the amount of iron produced with this early low-technology smelter was greater than previously thought, which implies greater economic importance. Little is known about the history of bloomery technology, not least the timeframe over which individual bloomeries were operated, as well as their impact on the landscape because of resource consumption and pollution. In this study we performed pollen and geochemical analyses of the lake-sediment record from Rörtjärnen, which is 120 m from the remains of a documented bloomery [one radiocarbon date: ad 1300–1435 (1 σ)], in Ängersjö, Hälsingland. A surface-soil transect shows a limited geochemical signal only within 20 m of the bloomery, and the sediment pollen record provides little direct evidence of an active bloomery and is consistent with other studied sites in the area linked to forest grazing or cultivation. Instead, we find major changes in sediment geochemistry during ad 800–1200, centered on a unique peak in Pb at ad 1030–1060. These changes include, e.g., Si (biogenic) and P, together with changes in pollen (e.g., Betula, Picea, Cyperaceae), which together indicate disturbance in the forest and especially the adjoining fen. We attribute these changes to a period of bloomery-related activities predating the radiocarbon date of the charcoal from the bloomery, and suggest that date represents a late phase for the site.     

Late Pleistocene and Holocene palaeoenvironmental changes in central Tierra del Fuego (~54°S) inferred from pollen analysis

A pollen record was obtained from a coring site at La Correntina mire (54°33′S, 66°59′W, 206 m a.s.l.) to the east of Lago Fagnano, centre of Tierra del Fuego. The results indicate that the valley bottom was free of ice shortly before 15,400 cal bp. Pioneer vegetation included dwarf shrub heaths, grasses and herbs with sparsely distributed Nothofagus trees, indicative of dry conditions. Nothofagus expanded by 10,000 cal bp and the forest-steppe ecotone was established by 9,400 cal bp, implying warm conditions and an increase in available moisture. After ca. 5,000 cal bp, the development of a closed-canopy forest is interpreted as the result of wetter and colder conditions. After 3,000 cal bp, Nothofagus forest became more open, and by about 400 cal bp there was a further decline of the forest. A closed-canopy Nothofagus forest re-established after 400 cal bp.     

Studies in the taxonomy of the Polypores II

The following genera are redefined:Albatrellus S. F. Gray,Heterobasidion Bref.,Haploporus Bond. et Sing. ex Sing.,Fomitopsis P. Karst. andRigidoporus Murrill two new subgenera are described:Polyporus subgen.Dendropolyporus Pouz. (type:Polyporus umbellatus) andRigidoporus subgen.Neooxyporus Pouz. (type:Polyporus latemarginatus); the genusOxyporus (Bourd. etGalz.)Donk is classified as a subgenus of the genusRigidoporus,Murrill and the generaBjerkandera P. Karst. andLeptoporus quél. are classified as subgenera of the genusTyromyces P. Karst. The new subfamilyAlbatrelloideae Pouz. (genera:Albatrellus andGrifola) is described and 14 new specific combinations are made. The new genusIrpicodon Pouz. (type:Irpex pendulus) is proposed.     

Determining the responses of vegetation to natural processes and human impacts in north-eastern Poland during the last millennium: combined pollen,geochemical and historical data

Pollen, charcoal and geochemical investigations were carried out on annually laminated sediments of Lake ?abińskie (54°07′54.5″N; 21°59′01.1″E) and the results were combined with historical and climate data to better understand the mechanism behind plant cover transformations. A millennium-long record of environmental history at 6-years time resolution permitted an assessment of vegetation responses to past human impact and climate fluctuations. Our results show that the history of the region with repeated periods of warfare, epidemics, famine and crop failures is well reflected by environmental proxies. Before the Teutonic Order crusade (ad 1230–1283), agricultural activities of the Prussian tribes were conducted at a distance from the studied lake and caused slight disturbances of local forests. A stronger human impact was registered after ca ad 1460. We confirm that co-domination of pine forests with spruce and oak-hornbeam forests on drier habitats as well as the presence of birch and alder woods on wet surfaces near the lake lasted until ad 1610. We identified a transition period of 20 years between ad 1590 and 1610, when forest cover was significantly reduced and the area was partly transformed into open land used for farming activities. The comparison of our data with other pollen datasets from the region confirms significant spatio-temporal differences in the initiation of large-scale woodland clearings in the Great Masurian Lake District. A strong increase in local cultivation was noted after ad 1750 and became even stronger in the period ad 1810–1940. The last 60 years experienced a succession from arable fields and open grasslands to more tree-covered habitats overgrown by birch and alder.     

Karyo-taxonomic study of the genus<Emphasis Type="Italic">Pseudolysimachion</Emphasis> (<Emphasis Type="Italic">Scrophulariaceae</Emphasis>) in the Czech Republic and Slovakia

Flow cytometry was used to determine ploidy levels in the Czech and Slovak taxa of the genusPseudolysimachion (W.D.J. Koch)Opiz (=Veronica auct. p.p.,Scrophulariaceae). In total, 123 populations from the Czech Republic, Slovakia, Ukraine (one locality), Austria (one locality) and Hungary (one locality) were analyzed. InP. maritimum (L.)Á. Löve etD. Löve andP. spicatum (L.)Opiz, two cytotypes were found: diploid (2n=2x=34) and tetraploid (2n=4x=68). In both species the tetraploid cytotype predominated (P. maritimum: 41 tetraploid populations out of 45;P. spicatum: 57 tetraploid populations out of 58). The two cytotypes ofP. maritimum have no taxonomic significance because ploidy level is not obviously correlated with morphology, distribution pattern or ecology. Tetraploid populations ofP. spicatum belong to two morphologically different subspecies, subsp.spicatum and subsp.fischeri Trávní?ek. The diploid cytotype (one population only) should be provisionally classified as a third subspecies ofP. spicatum, which is morphologically similar to the Asian subsp.porphyrianum (Pavlov)Trávní?ek. Only diploid plants (2n=2x=34) ofP. orchideum (Crantz)Wraber were found; all 13 populations that were analyzed belong toP. orchideum s.str. One diploid population sample ofP. spurium subsp.foliosum (Waldst. etKit.)Holub (2n=2x=34) and one tetraploid sample ofP. incanum subsp.pallens (Host)Trávní?ek (2n=4x=68) were also analyzed. In addition, three tetraploid populations of hybrid origin were investigated:P. maritimum ×P. spicatum subsp.spicatum (one population) andP. maritimum ×P. spurium subsp.foliosum (two populations). While hybrid plants ofP. maritimum ×P. spicatum arose from tetraploid parental species, plants ofP. maritimum ×P. spurium probably resulted from a cross between tetraploidP. maritimum and diploidP. spurium. The putative origin and evolutionary importance of polyploids in thePseudolysimachion are discussed.     

Vegetation and fire history of coastal north-eastern Sardinia (Italy) under changing Holocene climates and land use

Little is known about the vegetation and fire history of Sardinia, and especially the long-term history of the thermo-Mediterranean belt that encompasses its entire coastal lowlands. A new sedimentary record from a coastal lake based on pollen, spores, macrofossils and microscopic charcoal analysis is used to reconstruct the vegetation and fire history in north-eastern Sardinia. During the mid-Holocene (c. 8,100–5,300 cal bp), the vegetation around Stagno di Sa Curcurica was characterised by dense Erica scoparia and E. arborea stands, which were favoured by high fire activity. Fire incidence declined and evergreen broadleaved forests of Quercus ilex expanded at the beginning of the late Holocene. We relate the observed vegetation and fire dynamics to climatic change, specifically moister and cooler summers and drier and milder winters after 5,300 cal bp. Agricultural activities occurred since the Neolithic and intensified after c. 7,000 cal bp. Around 2,750 cal bp, a further decline of fire incidence and Erica communities occurred, while Quercus ilex expanded and open-land communities became more abundant. This vegetation shift coincided with the historically documented beginning of Phoenician period, which was followed by Punic and Roman civilizations in Sardinia. The vegetational change at around 2,750 cal bp was possibly advantaged by a further shift to moister and cooler summers and drier and milder winters. Triggers for climate changes at 5,300 and 2,750 cal bp may have been gradual, orbitally-induced changes in summer and winter insolation, as well as centennial-scale atmospheric reorganizations. Open evergreen broadleaved forests persisted until the twentieth century, when they were partly substituted by widespread artificial pine plantations. Our results imply that highly flammable Erica vegetation, as reconstructed for the mid-Holocene, could re-emerge as a dominant vegetation type due to increasing drought and fire, as anticipated under global change conditions.     

Plant remains from the early modern garden of the manor of Kumpula,Helsinki, Finland: an alternative sampling method for macrofossil analysis

Garden history can be investigated through archaeobotanical research. This paper discusses the plant remains which were obtained from the soil of the historical garden of the manor of Kumpula in Helsinki, Finland. This study was an experiment to enable macrofossil analysis without archaeological excavations. The aim was to develop an alternative method for sampling for macrofossils also including radiocarbon dates, and to evaluate the usability, cost and functionality of this method. The character of the garden was also considered. The soil samples for macrofossil analysis were collected from the garden from three to eight different levels using an end-filling open-ended sampler. A total of 38 one litre soil samples from eight different pits yielded 2,036 identified macrofossils, mostly seeds. These comprised 63 different taxa, of which 26 were identified to species level with certainty. Taxa with more than 25 seeds found were Chelidonium majus, Chenopodium spp., Juncus spp., Rubus idaeus, Sambucus racemosa and Urtica dioica. Important species were Secale cereale and Hordeum vulgare. Nine AMS radiocarbon dates were obtained from macrofossil material from four different pits, giving results ranging from 1120–920 cal bc to cal ad 1680–1930 for charred wood, and from cal ad 1450–1640 to 1640–1930 for charred grains of Secale cereale and seeds of Chenopodium album. The sampling method proved to work reasonably well, considering the limitations of the sample size.     

Characterization of aspartate kinase and homoserine dehydrogenase from <Emphasis Type="Italic">Corynebacterium glutamicum</Emphasis> IWJ001 and systematic investigation of <Emphasis Type="SmallCaps">l</Emphasis>-isoleucine biosynthesis

Previously we have characterized a threonine dehydratase mutant TD^F383V (encoded by ilvA1) and an acetohydroxy acid synthase mutant AHAS^{P176S, D426E, L575W} (encoded by ilvBN1) in Corynebacterium glutamicum IWJ001, one of the best l-isoleucine producing strains. Here, we further characterized an aspartate kinase mutant AK^A279T (encoded by lysC1) and a homoserine dehydrogenase mutant HD^G378S (encoded by hom1) in IWJ001, and analyzed the consequences of all these mutant enzymes on amino acids production in the wild type background. In vitro enzyme tests confirmed that AK^A279T is completely resistant to feed-back inhibition by l-threonine and l-lysine, and that HD^G378S is partially resistant to l-threonine with the half maximal inhibitory concentration between 12 and 14 mM. In C. glutamicum ATCC13869, expressing lysC1 alone led to exclusive l-lysine accumulation, co-expressing hom1 and thrB1 with lysC1 shifted partial carbon flux from l-lysine (decreased by 50.1 %) to l-threonine (4.85 g/L) with minor l-isoleucine and no l-homoserine accumulation, further co-expressing ilvA1 completely depleted l-threonine and strongly shifted carbon flux from l-lysine (decreased by 83.0 %) to l-isoleucine (3.53 g/L). The results demonstrated the strongly feed-back resistant TD^F383V might be the main driving force for l-isoleucine over-synthesis in this case, and the partially feed-back resistant HD^G378S might prevent the accumulation of toxic intermediates. Information exploited from such mutation-bred production strain would be useful for metabolic engineering.     

Historic grazing in southern New England,USA, recorded by fungal spores in lake sediments

Decadal-scale analyses of fungal spores in a lake-sediment core from Ware Pond, located in the town of Marblehead in northeastern Massachusetts, test the potential of this approach for reconstructing past sheep and cattle grazing in southern New England, USA. The influx of spores of Sordaria and other coprophilous taxa increases at ad 1650, which corresponds with the beginning of European settlement, and subsequent peaks in these taxa at ad 1840 coincide with maximum abundances of weedy and agricultural taxa in the pollen record. Historical data from Marblehead and neighbouring towns indicate that maximum numbers of cattle and sheep occurred at this time. These findings suggest that fungal spores in New England lake sediments can be used to reconstruct changes in grazing pressure over time at the landscape scale.     

Late Holocene vegetation history and human activity shown by pollen analysis of Novienki peat bog (Kargaly region,Orenburg Oblast,Russia)

The vegetation history of the Kargaly region has been reconstructed on the basis of pollen analysis of archaeological sediments and one peat bog, the only one found during some years of surveying this area. This latter, Novienky peat bog, located in the steppe transition zone, offers an interesting cultural and natural sequence. Palynological analysis reveals several palaeoecological phases from 4300 b.p. (Bronze Age) to the 18th–19th centuries a.d. (Russian period). Metallurgical activities in Kargaly caused deforestation from the Bronze Age onwards that mainly affected the distribution of birch forests in the region. The palaeoclimatic interpretation of the Novienki pollen diagram is based on the observed changes in the pollen curves of Picea (spruce), Pinus (pine), Abies (silver fir) and Betula (birch). These arboreal taxa are regarded as main climate indicators. The chronology is established on a ¹⁴C-dated pollen profile from the lowest peat layer as well as on the regional pollen sequences and archaeological stratigraphies.     

Some chromosome numbers of the CzechoslovakLeguminosae

Chromosome numbers of the Czechoslovak species of the genusLotus, from various localities have been determined. The paper includes the speciesLotus uliginosus Schkuhr,L.tenuis Waldst. etKit. andL. borbásii Ujhelyi.     

The variability of critical species ofLotus L. in Iran and in the neighbouring countries I. the circle ofL. corniculatus L. andL. gebelia Vent.

The region of Iran, Iraq, Afghanistan and the neighbouring countries is important for some groups of the speciesLotus L., especially those of the circle ofL. corniculatus L. andL. gebelia Vent. The first group is represented by the speciesL. corniculatus L. with 4 subspecies (3 of which are important for this region), andL. tenuis Waldst. etKit. which here attains the eastern boundary of the continuous area of distribution, and by the eastern speciesL. krylovii Schischk. etSerg. andL. rechingeri Chrtková-?ertová. The second group is represented by the speciesL. gebelia Vent.,L. michauxianus Ser. in DC. andL. libanoticus Boiss. their areas of distribution covering mostly those regions. Most of the species show considerable variability within the species.     

Ectopic expression of sorbitol-6-phosphate 2-dehydrogenase gene from <Emphasis Type="Italic">Haloarcula marismortui</Emphasis> enhances salt tolerance in transgenic <Emphasis Type="Italic">Arabidopsis thaliana</Emphasis>

d-Sorbitol-6-phosphate 2-dehydrogenase (S6PDH, E.C. 1.1.1.140) catalyzes the NADH-dependent conversion of d-fructose 6-phosphate (F6P) to d-sorbitol 6-phosphate (S6P). In this work, recombination and characterization of Haloarcula marismortui d-sorbitol-6-phosphate 2-dehydrogenase are reported. Haloarcula marismortui d-sorbitol-6-phosphate 2-dehydrogenase was expressed in P. pastoris and Arabidopsis thaliana. Enzyme assay indicated that HmS6PDH catalyzes the reduction of d-fructose 6-phosphate to d-sorbitol 6-phosphate and HmS6PDH activity was enhanced by NaCl. Furthermore, transgenic A. thaliana ectopic expressing HmS6PDH accumulate more sorbitol under salt stress. These results suggest that the ectopic expression of HmS6PDH in plants can facilitate future studies regarding the engineering and breeding of salt-tolerant crops.     

Long-term forest composition and its drivers in taiga forest in NW Russia

Understanding the processes behind long-term boreal forest dynamics can provide information that assists in predicting future boreal vegetation under changing environmental conditions. Here, we examine Holocene stand-scale vegetation dynamics and its drivers at the western boundary of the Russian taiga forest in NW Russia. Fossil pollen and conifer stomata records from four small hollow sites and two lake sites are used to reconstruct local vegetation dynamics during the Holocene. Variation partitioning is used to assess the relative importance of the potential drivers (temperature, forest fires and growing site wetness) to the long-term stand-scale dynamics in taiga forest. All the main tree taxa, including the boreal keystone species Picea abies (Norway spruce) and Larix sibirica (Siberian larch), have been locally present since 10,000 cal yr bp. The constant Holocene presence of L. sibirica at three small hollow sites suggests a fast postglacial immigration of the species in northern Europe. Picea was present but not dominant at all study sites until its expansion between 8,000 and 7,000 cal yr bp markedly changed the forest structure through the suppression of Betula (birch), Pinus (pine) and Larix. Our results demonstrate that in general, the Holocene forest dynamics in our study region have been driven by temperature, but during short intervals the role of local factors, especially forest fires, has been prominent. The comparison between sites reveals the importance of local factors in stand-scale dynamics in taiga forests. Therefore, the future responses of taiga forest to climate change will be predominantly modulated by the local characteristics at the site.     

Differentiation of species in Gonioloboceras

The type specimen ofGonioloboceras goniolobum (Meek), rediscovered by Spath in the British Museum, is the foundation for a more accurate comparative study of this and other species ofGonioloboceras.Gonioloboceras described asG. goniolobum byElias in 1938 is differentiated asGonioloboceras schmidti, new species. Suture sets (new term) for several growth stages inG. goniolobum (Meek),G. welleriSmith,G. schmidtiElias, G.eliasiMiller &Owen, andG. asiaticumLibrovitch are assembled and used for differentiation of the species.The Kazakhstan goniatite faunule containingG. asiaticum is considered of very late Pennsylvanian age.     

Characterization of<Emphasis Type="SmallCaps"> D</Emphasis>-lactic acid,spore-forming bacteria and <Emphasis Type="Italic">Terrilactibacillus laevilacticus</Emphasis> SK5-6 as potential industrial strains

In this study, we screened and isolated D-lactic acid-producing bacteria from soil and tree barks collected in Thailand. Among the isolates obtained, Terrilactibacillus laevilacticus SK5-6 exhibited good D-lactate production in the primary screening fermentation (99.27 g/L final lactate titer with 0.90 g/g yield, 1.38 g/L?h, and 99.00% D-enantiomer equivalent). Terrilactibacillus laevilacticus SK5-6 is a Gram-positive, endospore-forming, homofermentative D-lactate producer that can ferment a wide range of sugars to produce D-lactate. Unlike the typical D-lactate producers, such as catalase-negative Sporolactobacillus sp., T. laevilacticus SK5-6 possesses catalase activity; therefore, a two-phase fermentation was employed for D-lactate production. During an aerobic preculture stage, a high-density cell mass was rapidly obtained due to aerobic respiration. When transferred to the fermentation stage at the correct physiological stage (inoculum age) and proper concentration of cell mass (inoculum size), T. laevilacticus rapidly converted glucose into D-lactate under anaerobic conditions, resulting in a high final lactate titer (102.22 g/L), high yield (0.84 g/g), and high productivity (2.13 g/L?h). When the process conditions were shifted from an aerobic to an anaerobic environment, unlike other lactate-producing bacteria, the mixed acid fermentation route was not activated in the culture of T. laevilacticus SK5-6 during the fermentation stage when some trace oxygen still remained. Our study demonstrates the excellent characteristics of this isolate for D-lactate production; in particular, a high product yield was obtained without byproduct formation. Based on these key characteristics of T. laevilacticus SK5-6, we suggest that this isolate is a novel D-lactate producer for use in industrial fermentation.     

Beiträge zur Sedimentation und fossilführung des hunsrückschiefers 14.Viriatellina fuchsi (Kutscher, 1931) im Hunsrückschiefer und im Tentaculitenknollenkalk thüringens

The new genusViriatellina Bou?ek, 1964 unites the two older species namedNovakia gemündina Runzheimer, 1932 andTentaculites fuchsi Kutscher, 1931. ThusViriatellina gemuendina (Runzheimer) is cancelled, on the other handViriatellina fuchsi (Kutscher) remains valid. RecentlyViriatellina fuchsi (Kutscher) has been found in the tentaculitiferous limestone of Thuringia.