Ein paläoökologischer Beitrag zum besseren Verständnis der natürlichen Vegetation der Schweiz

Zusammenfassung: Wie natürlich oder naturnah ist eine Pflanzengemeinschaft oder eine Landschaft? Diese Frage ist von Interesse, wenn wir verstehen wollen, wie unsere heutigen Landschaften entstanden sind. Noch wichtiger ist sie aber, wenn abgeschätzt werden muss, welche Massnahmen zum Schutz und zur Bewahrung der Funktionen eines bestimmten Vegetations-, Umwelt- oder Landschaftstyps notwendig sind. Wir fassen hier die Erkenntnisse aus über 30 paläoökologischen Untersuchen zur postglazialen Vegetationsgeschichte in der Schweiz zusammen. Die Kombination von Pollen- und Makrorestauswertungen sowie die Untersuchung von mikro- und makroskopischen Holzkohle-Partikeln und der Vergleich mit Klimaindikatoren ermöglicht es, die Vegetationsentwicklung mit hoher zeitlicher und räumlicher Auflösung zu rekonstruieren. Gemeinsame Trends bei der Vegetationsentwicklung gehen vorwiegend auf die Klimadynamik zurück, es gibt aber nennenswerte Unterschiede in Abhängigkeit vom Bodentyp, der menschlichen Aktivität (besonders unter Einsatz des Feuers) oder der Höhenlage. Verschiedene Waldtypen, die bis anhin unter den jeweiligen Klimabedingungen als natürlich betrachtet wurden, sind das Resultat menschlicher Landnutzung über die Jahrtausende, insbesondere ist die Dominanz einzelner weniger Baumarten in den Wäldern der Schweiz anthropogen bedingt. Umgekehrt wurden lokale, isolierte Bestände nicht als Relikte natürlicher Wälder betrachtet. Die Vielfalt der Waldvegetation hat also stark abgenommen, während dem die gesamte Biodiversität stark zugenommen hat, vorwiegend als Folge der Ausbreitung von Offenlandarten durch landwirtschaftliche Tätigkeiten. Die Paläoökologie hat also dazu beigetragen, die Natürlichkeit von Pflanzengesellschaften neu einzuschätzen und die Reaktionsweisen auf Störungen besser zu verstehen. In diesem Sinne stellen wir neue Projekte vor, in denen die Paläoökologie eingesetzt wird, um Kenntnisse zu gewinnen, die für Naturschutz, Waldbau und die Planung von Nationalparks unentbehrlich sin

A new Late-glacial and Holocene record of vegetation and fire history from Lago del Greppo, northern Apennines, Italy

Detailed Late-glacial and Holocene palaeoenvironmental records from the northern Apennines with a robust chronology are still rare, though the region has been regarded as a main area of potential refugia of important trees such as Picea abies and Abies alba. We present a new high-resolution pollen and stomata record from Lago del Greppo (1,442m a.s.l., Pistoia, northern Apennines) that has been dated relying on 12 terrestrial plant macrofossils. Late-glacial woodlands became established before 13000cal b.p. and were dominated by Pinus and Betula, although more thermophilous taxa such as Quercus, Tilia and Ulmus were already present in the Greppo area, probably at lower altitudes. Abies and Picea expanded locally at the onset of the Holocene at ca. 11500cal b.p. Fagus sylvatica was the last important tree to expand at ca. 6500cal b.p., following the decline of Abies. Human impact was generally low throughout the Holocene, and the local woods remained rather closed until the most recent time, ca. a.d. 1700-1800. The vegetational history of Lago del Greppo appears consistent with that of previous investigations in the study region. Late-glacial and Holocene vegetation dynamics in the northern Apennines are very similar to those in the Insubrian southern Alps bordering Switzerland and Italy, across the Po Plain. Similarities between the two areas include the Late-glacial presence of Abies alba, its strong dominance during the Holocene across different vegetation belts from the lowlands to high elevations, as well as its final fire and human-triggered reduction during the mid Holocene. Our new data suggest that isolated and minor Picea abies populations survived the Late-glacial in the foothills of the northern Apennines and that at the onset of the Holocene they moved upwards, reaching the site of Lago del Greppo. Today stands of Picea abies occur only in two small areas in the highest part of the northern Apennines, and they have become extinct elsewhere. Given the forecast global warming, these relict Picea abies stands of the northern Apennines, which have a history of at least 13,000years, appear severely endangere

Ein neues EEM-zeitliches Umweltarchiv am Spiezberg (Schweizer Alpen) im Kontext der mittel- und spätpleistozänen Landschaftsentwicklung

Karten- und Profilkonstruktionen in der Region Thunersee (Berner Oberland, Schweiz) haben in vergangenen Untersuchungen zu Spekulationen über unterschiedliche, mehrphasige eiszeitliche Erosionsvorgänge und Sedimentakkumulationen geführt. Wissenschaftshistorisch nachweisbar sind bereits im 19. Jahrhundert Erklärungsmodelle mit mehreren quartären Eiszeiten. Bereits zu Beginn des barocken 18. Jahrhunderts besuchte und beschrieb Johann Jakob Scheuchzer die «sintflutlich» überschotterten Schieferkohlen entlang des damaligen Kanderlaufes und den im Bau befindlichen Kanderdurchstich durch die Strättligmoräne. Bei diesen Schieferkohlen handelt es sich um organische Sedimente aus Seen, Teichen und Mooren, die im Verlauf des 20. Jahrhunderts quartären Interglazialen und/oder Interstadialen zugeordnet wurden. Am Spiezberg über dem linken Thunerseeufer wurde 2005 zur geotechnischen Baugrunderkundung eine Sondierbohrung abgeteuft. Unerwartet erschloss diese 7 m mächtige intramoräne Stillwassersedimente (laminierte Silte und Tone mit eingelagerter Gyttja und fossilen Holzresten), welche sich ausgezeichnet für stratigraphische Studien eigneten. Die vorliegenden Analysen (Sedimentologie, Palynologie, 14C-Datierung, Paläogeographie) führen zu folgenden Erkenntnissen: Bei den See- oder Teichsedimenten handelt es sich um warmzeitliche Ablagerungen, die wir als Arbeitshypothese vorerst dem Eem-Interglazial zugeordnet haben. Die Stillwasserablagerungen sind in kaltzeitliche Flussschotter und Moränen eingebettet. Paläogeographische Korrelationen mit bereits bekannten mittel- bis spätpleistozänen glazigenen Sedimenten aus der Region Thunersee – Aaretal erlauben eine räumliche Rekonstruktion einerseits der Eem-Gewässer und andererseits der nachfolgenden Frühwürm Vorstossschotter.Map and profile constructions in the region Lake Thun (Bernese Oberland, Switzerland) lead to speculations of different glacial erosions (extensive gravel during glacial advance, dynamic erosion during ablation) in early studies. Historically explanatory models operating with several ice ages are proven back to the 19th century. At the beginning of the baroque 18th century, Johann Jakob Scheuchzer mislead himself to «diluvial» speculations based on his precise observations about «schist coals» covered by gravel layers studied during the construction work for the Kander river deviation. This «shist coals» consist of organic sediments from lakes and mires and were attributed to Quaternary interglacials or interstadials during the 20th century. In 2005, at Spiezberg, above the left shoreline of Lake Thun, an exploration drilling was conducted for an excavation pit. As a result, 7 m thick intermoraine still water sediments (laminated silt and clay with gyttja and fossil wood residues) were unexpectedly found. This sediment profile has been ideally suited for stratigraphical studies. The presented analyses (sedimentology, palynology, radiocarbon dating, paleogeography) lead to the following results: The lake or pond sediments, respectively, are interglacial deposits, which, geo- and biostratigraphically, we assign to the Eemian interglacial. These still water deposits are intercalated between coarse river deposits and glacial till. Paleogeographical correlations with pre-identified sediments from the middle to upper Pleistocene of the region Lake Thun – Aare Valley allow a spatial reconstruction of the Eemian-water bodies and the following early Würm glacial advance gravels

Mid- and late-Holocene vegetation and fire history at Biviere di Gela, a coastal lake in southern Sicily, Italy

The vegetation and fire history of few coastal sites has been investigated in the Mediterranean region so far. We present the first paleoecological reconstruction from coastal Sicily, the largest island in the Mediterranean Sea. We analysed pollen and charcoal in the sediments of Biviere di Gela, a lake (lagoon) on the south coast of Sicily. Our data suggest that the area became afforested after a marine transgression at ca. 7200 cal b.p. (5250 b.c.). Build-up of forest and shrublands took ca. 200-300years, mainly with the deciduous trees Quercus, Ostrya and Fraxinus. Juniperus expanded ca. 6900 cal b.p. (4950 b.c.), but declined again 6600 cal b.p. (4650 b.c.). Afterwards, evergreen trees (Q. ilex-type and Olea) became dominant in the forest and Pistacia shrublands were established. Forest and shrubland reached a maximum ca. 7000-5000 cal b.p. (5050-3050 b.c.); subsequently forest declined in response to human impact, which was probably exacerbated by a general trend towards a more arid climate. During the Neolithic, fire was used to open the landscape, significantly reducing several arboreal taxa (Q. ilex, Fraxinus, Juniperus) and promoting herbs and shrubs (Achillea, Cichorioideae, Brassicaceae, Ephedra). Final forest disruption occurred around 2600 cal b.p. (650 b.c.) with the onset of the historically documented Greek colonization. We conclude that the open maquis and garrigue vegetation of today is primarily the consequence of intensive land-use over millennia. Under natural or near-natural conditions arboreal taxa such as Q. ilex, Olea and Pistacia would be far more important than they are today, even under the hot and rather dry coastal conditions of southern Sicil

Production and characterization of CSSI003 (2961) human induced pluripotent stem cells (iPSCs) carrying a novel puntiform mutation in RAI1 gene, Causative of Smith–Magenis syndrome

Smith-Magenis syndrome (SMS) is a complex genetic disorder characterized by developmental delay, behavioural problems and circadian rhythm dysregulation. About 90% of SMS cases are due to a 17p11.2 deletion containing retinoic acid induced1 (RAI1) gene, 10% are due to heterozygousmutations affecting RAI1 coding region. Little is known about RAI1 role

Copy number variations in healthy subjects. Case study: iPSC line CSSi005-A (3544) production from an individual with variation in 15q13.3 chromosome duplicating gene CHRNA7

CHRNA7, encoding the neuronal alpha7 nicotinic acetylcholine receptor (a7nAChR), is highly expressed in the brain, particularly in the hippocampus. It is situated in the 15q13.3 chromosome region, frequently associated with a Copy Number Variation (CNV), which causes its duplication or deletion. The clinical significance of CHRNA7 duplications is unknown so far, but there are several research data suggesting that they may be pathogenic, with reduced penetrance. We have produced an iPS cell line from a single healthy donor's fibroblasts carrying a 15q13.3 CNV, including CHRNA7 in order to study the exact role of this CNV during the neurodevelopment

Generation of an induced pluripotent stem cell line (CSS012-A (7672)) carrying the p.G376D heterozygous mutation in the TARDBP protein

Amyotrophic lateral sclerosis (ALS) is an incurable neurodegenerative condition with phenotypic and genetic heterogeneity. It is characterized by the selective vulnerability and the progressive loss of the neural population. Here, an induced pluripotent stem cell (iPSC) line was generated from dermal fibroblasts of an individual carrying the p.G376D mutation in the TDP-43 protein. Fibroblasts were reprogrammed using nonintegrating episomal plasmids. There were no karyotype abnormalities, and iPSCs successfully differentiated into all three germ layers. This cell line may prove useful in the study of the pathogenic mechanisms that underpin ALS syndrome

Palynological investigations reveal Eemian interglacial vegetation dynamics at Spiezberg, Bernese Alps, Switzerland

Interglacial pollen records are valuable archives of past vegetation dynamics and provide important information about vegetation responses to different-than-today climates. Interglacial pollen archives pre-dating the Last Glacial Maximum (LGM) are scarce on the Swiss Plateau in contrast to the many available Late Glacial and Holocene records. This is mainly due to the rapidly changing palaeo- environmental conditions throughout the Quaternary and the low preservation potential of material suitable for palynological investigations. The Spiezberg site offers a palynological record situated most proximal to the Alps in Switzerland. Previous investigations tentatively assigned this record to the Eemian interglacial (MIS 5e). We have conducted additional pollen analytical investigations to increase the quantity of pollen information. Besides biostratigraphic interpretations, we use numerical methods such as distance analysis (distantia) and ordination techniques (PCA) to evaluate the similarities and differences between the Spiezberg record and its geographically and chronostratigraphically closest physically dated (U/Th, luminescence) analogues from the Eemian (MIS 5e) and Meikirch 3 (MIS 7a) interglacials. Our palynological investigations reveal the predominance of closed temperate forests with abundant fir (Abies) and spruce (Picea) as well as evergreen broad-leaved taxa (e.g. Hedera). The attri- bution to the Eemian interglacial relies on the observation of very rare beech (Fagus) occurrences, a phase with prominent yew (Taxus) and the unimportance of hornbeam (Carpinus), all of which are typical Eemian features on the Swiss Plateau. An Eemian age is supported by the numerical comparison with the Beerenmo€sli (MIS 5e) and Meikirch 3 (MIS 7a) reference records. Furthermore, the Picea, Taxus and Fagus dynamics observed on the Swiss Plateau during the Eemian are in excellent agreement with vegetational patterns observed elsewhere in Central Europe. Surprisingly, Carpinus was almost absent on the Swiss Plateau during the Eemian, whereas it was a major component of the forest at other European sites with a similar elevation as Spiezberg. We explain this by environmental conditions and the strong competition with Abies alba. In particular, considering the European Eemian vegetation history and the results of our reconstructions from the Swiss Plateau, we find that Abies alba was a highly competitive tree under natural warmer-than-today conditions. This finding provides further evidence that Abies alba may benefit from future climate warming