Jacqueline F. N. van Leeuwen

Jacqueline F. N. van Leeuwen
Universität Bern | UniBe

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49
Publications
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Publications

Publications (49)
Article
Although there is a long history of palaeoecological investigation in the Massif Central, detailed reconstruction of the flora, vegetation, and environment in the Late Pleniglacial, the Würmian (Weichselian) Late-Glacial, and early Holocene in the Monts du Forez (Massif Central, France) is still largely lacking. We inferred the palaeoecology of the...
Article
Full-text available
Observing natural vegetation dynamics over the entire Holocene is difficult in Central Europe, due to pervasive and increasing human disturbance since the Neolithic. One strategy to minimize this limitation is to select a study site in an area that is marginal for agricultural activity. Here, we present a new sediment record from Lake Svityaz in no...
Article
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Knowledge about the vegetation history of Sardinia, the second largest island of the Mediterranean, is scanty. Here, we present a new sedimentary record covering the past ~ 8,000 years from Lago di Baratz, north-west Sardinia. Vegetation and fire history are reconstructed by pollen, spores, macrofossils and charcoal analyses and environmental dynam...
Article
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Understanding the significance of pollen diversity is key to reconstructing plant diversity over long timescales. Here we present quantitative pollen-plant diversity comparisons for a mountainous area of the Western Mediterranean region. Samples were collected between 430–1,865 m elevation and pollen-plant diversity assessed through richness and tu...
Article
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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...
Article
The lithology, ostracods, palynomorphs and black carbon of a sediment core from a saline wetland in the southern Tibetan highlands (29°14′33.40″N/87°13′09.10″E, 4480 m a.s.l., A.R. Xizang, China) is analyzed and climate modelling applied with respect to core questions in Quaternary research: (1) Do meso-climatic effects of regional landscape struct...
Article
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National parks are supposed to protect large-scale ecological processes, along with species and ecosystems. Detailed knowledge about past vegetation and disturbance regimes therefore forms an important basis for appropriate management. In the Bavarian Forest National Park in SE Germany, we therefore studied fossil pollen, spores and macrofossils fr...
Poster
Full-text available
We present a novel Eemian palynological record (Spiezberg) from the Swiss northern Alpine foreland and its biostratigraphical correlation to the only physically dated Eemian record (Beerenmösli) within the study area. For this purpose, the biostratigraphy of the reference record Beerenmösli has been re-interpreted with state-of-the-art statistical...
Conference Paper
Full-text available
Humans have changed European ecosystems since the beginning of agriculture in the early Neolithic. Anthropogenic activities around lakes increased soil erosion and changed terrestrial nutrient cycles in the course of agriculture and domestication of animals, causing a release of additional nutrients into lakes and consequently leading to lake eutro...
Poster
Full-text available
Abstract: Many oceanic islands have undergone dramatic ecological changes during the last few centuries. Human activities and exotic species have so greatly modifed the landscapes of these islands that the original vegetation is difficult to imagine. Areas of remnant vegetation are therefore used as baselines for restoration. But how representative...
Article
We present a geochemically confirmed finding of the Laacher See tephra (LST), directly east of the Laacher See volcano (LSV). European lake sediment (Rachelsee, Germany) contains the time period of the Laacher See volcanic explosion (LSE) ca. 12900 yr cal BP in the East Eifel volcanic field. This eruption significantly affected the local environmen...
Article
We compared simple mathematical pollen dispersal–deposition models with Gaussian plume models. The simple mathematical models proved equal or better approximations of real world pollen dispersal–deposition. We concluded that for most standard applications, such as estimating pollen productivity or quantitative vegetation reconstructions, simple mat...
Article
Full-text available
Vegetation reconstructions in the Dead Sea region based on sediment records are potentially biased, because the vast majority of them derive from the western side of the sea, and only focus on large areas and time spans, while little is known about extra-local (< 1,000 m radius) to local (< 20 m radius) changes. To fill this gap, we compared a vege...
Article
Full-text available
Microscopic charcoal particles are fire-specific tracers, which are ubiquitous in natural archives such as lake sediments or ice cores. Thus, charcoal records from lake sediments have become the primary source for reconstructing past fire activity. Microscopic charcoal particles are generated during forest and grassland fires and can be transported...
Chapter
Full-text available
Palaeoecological Analysis at the Prehistorical Site Kamyana Mohyla in the Ukrainian Steppe conducted by Swiss and Ukrainian scientists are published. Environmental shifts during the Mesolithic and Neolithic, and their Impact ofn the Neolithisation process are discussed.
Article
Full-text available
Microscopic charcoal particles are fire-specific tracers, which are ubiquitous in natural archives such as lake sediments or ice cores. Thus, charcoal records from lake sediments are nowadays the primary source for reconstructing past fire activity. Microscopic charcoal particles are generated during forest and grassland fires and can be transporte...
Article
Full-text available
In 1927, the first pollen diagram was published from the Bohemian/Bavarian Forest region of Central Europe, providing one of the first qualitative views of the long-term vegetation development in the region. Since then significant methodological advances in quantitative approaches such as pollen influx and pollen-based vegetation models (e.g., Land...
Article
Full-text available
Little is known about the timing and the vegetation dynamics shortly after the Last Glacial Maximum (LGM) on the Swiss Plateau 19,000–15,000 cal bp. Subsequent Late Glacial and Holocene vegetation changes are better known; however, it is unclear if the few available palynological and macrofossil records are able to capture the entire vegetation var...
Article
Population dynamics is a field rich in theory and poor in long-term observational data. Finding sources of long-term data is critical as ecosystems around the globe continue to change in ways that current theories and models have failed to predict. Here we show how long-term ecological data can improve our understanding about palaeo-population chan...
Book
The first part of the book contains chapters on Pollen Chironomids Botanical remains (the largest dataset on plant remains from a waterlogged settlement ever collected) Animal bones Small animal remains such as fish, molluscs, mice... Insects Human bones Parasitology Mycology Find distribution mechanisms The second part contains six syntheses on Ta...
Article
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This paper describes the present-day vegetation, stratigraphy and developmental history of the mire of Egelsee-Moor (Salzburg, Austria; 45°45′N, 13°8.5′E, 700 m a.s.l., 15 ha in area) since the early Late Glacial on the basis of 4 transects with 14 trial borings across the peatland. We present a vegetation map of the mire, a longitudinal section th...
Article
Full-text available
Knowledge about vegetation and fire history of the mountains of Northern Sicily is scanty. We analysed five sites to fill this gap and used terrestrial plant macrofossils to establish robust radiocarbon chronologies. Palynological records from Gorgo Tondo, Gorgo Lungo, Marcato Cixé, Urgo Pietra Giordano and Gorgo Pollicino show that under natural o...
Article
Full-text available
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 his...
Article
Full-text available
A deeper understanding of past vegetation dynamics is required to better assess future vegetation responses to global warming in the Alps. Lake sediments from Lac de Bretaye, a small subalpine lake in the Northern Swiss Alps (1780 m a.s.l.), were analysed to reconstruct past vegetation dynamics for the entire Holocene, using pollen, macrofossil and...
Article
Pollen-trap results from the Swiss Alps 1996–2009 were used to assess the pollen dispersal–deposition properties of Poaceae (grasses) and Cyperaceae (sedges). Dispersal parameter values were investigated for a modified version of the Prentice–Sugita pollen dispersal–deposition model. Appropriate values (i.e. realistic in the field and allowing real...
Article
Full-text available
Highlights ► The shift of δ18O coincides with the “juniper jump”. ► This is a transition from shrub-tundra to juniper–birch woodland. ► Some responses of pollen to warming occur within sampling resolution (< 10 yr). ► Responses on the population level include immigration and (local) extinction. ► Ecosystem responses include interactions e.g. nitrog...
Article
Full-text available
Oxygen-isotope variations were analyzed on bulk samples of shallow-water lake marl from Gerzensee, Switzerland, in order to evaluate major and minor climatic oscillations during the late-glacial. To highlight the overall signature of the Gerzensee δ 18 O record, δ 18 O records of four parallel sediment cores were first correlated by synchronizing m...
Article
The large, rapid increase in atmospheric N2O concentrations that occurred concurrent with the abrupt warming at the end of the Last Glacial period might have been the result of a reorganization in global biogeochemical cycles. To explore the sensitivity of nitrogen cycling in terrestrial ecosystems to abrupt warming, we combined a scenario of clima...
Article
Full-text available
The giant tortoises of the Galápagos have become greatly depleted since European discovery of the islands in the 16th Century, with populations declining from an estimated 250 000 to between 8000 and 14 000 in the 1970s. Successful tortoise conservation efforts have focused on species recovery, but ecosystem conservation and restoration requires a...
Article
Full-text available
Anumber of hydrological, botanical, macro- and micro-climatological processes are involved in the formation of patterned peatlands. La Grande Tsa at 2336 m a.s.l. is probably the highest bog in the central Swiss Alps and is unique in its pattern. In two of five pools there is in the contact zone between the basal peat and the overlying gyttja an un...
Conference Paper
Background/Question/Methods The Bavarian Forest, a middle-high mountain in SE Germany, experienced after two severe windstorms in 1983/84 intense and widespread infestations by the bark beetle Ips typographus. In the area of the Bavarian Forest National Park, the beetle killed over 6000 ha of spruce stands (Picea abies). The National Park adheres...
Chapter
Full-text available
Palaeoclimatic stability is regarded as an important factor in explaining patterns of end-emism in the Azorean flora. However, modelling simulations and quantitative reconstructions for the last 6000 years suggest considerable palaeoclimatic variability. Here we explore the link between Holocene palaeoclimate and palaeovegetation on the islands of...
Article
Full-text available
Fire is currently perceived as a major threat to ecosystems and biodiversity in the mountains of the Mediterranean region. Portugal's highest mountain range, the Serra da Estrela, is one of the country's most important protected areas and also the most fire-prone. We present a similar to 14,000-year fire history based on microscopic charred particl...
Article
High-resolution pollen, macrofossil and charcoal data, combined with accelerator mass spectrometry 14C dating and multivariate analysis, were used to reconstruct Holocene vegetation and fire dynamics at Urio Quattrocchi, a small lake in the supra-mediterranean belt in the Nebrodi Mountains of Sicily (Italy). The data suggest that after 10 000 cal a...
Article
Full-text available
Atmospheric dusts are an important part of the global climate system, and play an important role in the marine and terrestrial biogeochemical cycles of major and trace nutrient elements. A peat bog record of atmospheric deposition shows considerable variation in dust deposition during the past 15 k.y., with abrupt changes in fl uxes at 12, 9.2, 8.4...
Article
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This paper compares pollen spectra derived from modified Tauber traps and moss samples from a selection of woodland types from Bulgaria, the Czech Republic, Georgia, Greece, Poland, Switzerland and Wales. The study examines the representation of individual taxa in the two sampling media and aims to ascertain the duration of pollen deposition captur...
Article
Full-text available
Annual PAR (pollen accumulation rates; grains cm−2 year−1) were studied with modified Tauber traps situated in ten regions, in Poland (Roztocze), the Czech Republic (two regions in Krkonoše, two in Šumava), Switzerland (4 regions in the Alps), and Georgia (Lagodekhi). The time-series are 10–16 years long, all ending in 2007. We calculated correlati...
Article
Climatic relationships were established in two 210Pb dated pollen sequences from small mires closely surrounded by forest just below actual forest limits (but about 300 m below potential climatic forest limits) in the northern Swiss Alps (suboceanic in climate; mainly with Picea) and the central Swiss Alps (subcontinental; mainly Pinus cembra and L...
Article
Annual pollen influx has been monitored in short transects across the altitudinal tree limit in four areas of the Swiss Alps with the use of modified Tauber traps placed at the ground surface. The study areas are Grindelwald (8 traps), Aletsch (8 traps), Simplon (5 traps), and Zermatt (5 traps). The vegetation around the traps is described. The res...

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