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Tantau I.,Babes - Bolyai University | Feurdean A.,Senckenberg Institute | Feurdean A.,Romanian Academy Emil Racovita Institute of Speleology | De Beaulieu J.-L.,Aix - Marseille University | And 2 more authors.
Journal of Quaternary Science

Although few compared with Western Europe, continental records from Central-Eastern Europe are increasingly confirming that rapid climate fluctuations of the past 15 000 years are also present in records situated far from the North Atlantic region. In the present study a new pollen record supported by 11 AMS 14C dates, from Luci (Eastern Romanian Carpathians), was used to reconstruct the Lateglacial and Holocene vegetation history of the region, and the sensitivity to past climate change and human impact. The results showed that vegetation composition reacted particularly sensitively to the climatic oscillations that occurred during the Allerød (13 800 cal a BP), the Younger Dryas (YD) and at the transition from the YD to the Holocene (11 700 cal a BP), although smaller amplitude vegetation changes also occurred at ca. 14 700 cal a BP (Greenland Interstadial (GI)-1e; Bølling), 13 900 cal a BP (GI1-d; Older Dryas) and 13 200 cal a BP (GI-1b; intra-Allerød cooling). However, the amplitude of vegetation response in the continental part of Europe was smaller as compared with the records from Greenland and the North Atlantic region. The Holocene began with the expansion of Betula, Ulmus and Picea abies, followed by Fraxinus, Quercus, Tilia and Corylus avellana from about 10 000 cal a BP when the climate became warmer and drier. Picea abies has been the dominant tree species for almost the entire Holocene period. The spread of Carpinus betulus occurred at ca. 5800 cal a BP, with maximum values between 5100 and 3100 cal a BP, while Fagus sylvatica spread at ca. 3100 cal a BP and attained maximum values between 2800 and 200 cal a BP. However, during the last 200 years, Fagus sylvatica and Picea abies forests have largely been replaced by Pinus. Human impact in the area is noted from ca. 4200 cal a BP onwards but it is expressed rather weakly until 1200 cal a BP, and primarily relates to forest clearance and grazing. © 2014 John Wiley & Sons, Ltd. Source

Galka M.,University of Latvia | Galka M.,Adam Mickiewicz University | Aunina L.,University of Latvia | Tobolski K.,Adam Mickiewicz University | And 2 more authors.

We present the paleoecological development of a rich fen located in the dune area on the SE Baltic coast, during the last 7500 years. The Apšuciems Mire hosts rare and endangered plant communities in Europe, such as Schoenus ferrugineus and Cladium mariscus. Analysis at high-resolution of plant macroremains in two peat cores was carried out to reconstruct local vegetation succession and fluctuations in moisture availability on the peatland, while a pollen record was developed to reconstruct plant succession, moisture variability and human activity at the regional scale. Based on the presence or the absence of macroremains of plants that occur in wet habitat e.g. Cladium mariscus, Schoenoplectus tabernaemontani, Alisma plantago-aquatica and Botrycoccocus we distinguished four wet periods ca. 6000, 2000, 1750–1550, 1200–150 cal yr. BP and four dry periods (ca. 7000, 4600–4200, 1800–1750, 1550–1200 cal yr. BP) in the peatland’s development. A water level increase at 1200 cal yr. BP triggered the development of plant communities containing Chara sp., Schoenoplectus tabernaemontani, then Cladium mariscus. Our study shows a link between climate change at the regional scale and vegetation development in Apšuciems Mire. We showed that changes in vegetation structure during last 150 years was caused by drainage and human activity. © 2016 The Author(s) Source

Feurdean A.,Senckenberg Institute | Feurdean A.,Romanian Academy Emil Racovita Institute of Speleology | Bhagwat S.A.,Open University Milton Keynes | Bhagwat S.A.,University of Oxford | And 8 more authors.

Faster-than-expected post-glacial migration rates of trees have puzzled ecologists for a long time. In Europe, post-glacial migration is assumed to have started from the three southern European peninsulas (southern refugia), where large areas remained free of permafrost and ice at the peak of the last glaciation. However, increasing palaeobotanical evidence for the presence of isolated tree populations in more northerly microrefugia has started to change this perception. Here we use the Northern Eurasian Plant Macrofossil Database and palaeoecological literature to show that post-glacial migration rates for trees may have been substantially lower (60-260 m yr-1) than those estimated by assuming migration from southern refugia only (115-550 m yr-1), and that early-successional trees migrated faster than mid- and late-successional trees. Post-glacial migration rates are in good agreement with those recently projected for the future with a population dynamical forest succession and dispersal model, mainly for early-successional trees and under optimal conditions. Although migration estimates presented here may be conservative because of our assumption of uniform dispersal, tree migration-rates clearly need reconsideration. We suggest that small outlier populations may be a key factor in understanding past migration rates and in predicting potential future range-shifts. The importance of outlier populations in the past may have an analogy in the future, as many tree species have been planted beyond their natural ranges, with a more beneficial microclimate than their regional surroundings. Therefore, climate-change-induced range-shifts in the future might well be influenced by such microrefugia. © 2013 Feurdean et al. Source

Feurdean A.,Senckenberg Institute | Feurdean A.,Romanian Academy Emil Racovita Institute of Speleology | Tamas T.,Romanian Academy Emil Racovita Institute of Speleology | Tamas T.,Babes - Bolyai University | And 2 more authors.
Journal of Biogeography

Aim We used fossil records to explore patterns of change in vegetation composition, turnover and diversity along an elevational gradient during the late-glacial to early Holocene, and to locate the elevations most sensitive to past climate changes. Location Romania. Methods Changes in the late-glacial vegetation communities were inferred from seven published pollen records distributed within the main vegetation belts of the Romanian Carpathians, at elevations from 275 to 1840m. Principal components analysis, detrended canonical correspondence analysis (DCCA) and rarefaction analysis were undertaken on these data. Results DCCA indicates that compositional change is strongest (SD 1.2, c.70%) at the late-glacial/Holocene transition (c.11,500cal. yr bp), but significant shifts also occur at c.14,700, c.13,800 and c.12,700cal. yr bp (SD 0.4-0.8, 25-50%). Palynological turnover is greater for mid-elevation records (730-1100m) than at low and high elevations. Intervals of greater palynological richness occur between c.13,800 and 12,500cal. yr bp and after 11,500cal. yr bp, and intervals of lower richness occur before c.14,000cal. yr bp and between c.12,900 and 11,500cal. yr bp. Main conclusions Variations in species composition during repeated climate changes of the late-glacial suggest that community composition at a given time was not only a result of the environmental conditions of that period, but also the legacy of previous cumulative recruitment and extirpation events. Turnover estimates suggest that mid-elevations have been the most sensitive to climate change during the late-glacial and early Holocene. Palynological richness estimates show a less clear elevational pattern and no evidence for a greater sensitivity of this measure of biodiversity at high elevations to past climate change. However, results may have been affected by taxa with high pollen productivity and distance dispersability. Our finding concurs with other palaeoecological and local-scale modelling studies in suggesting that small populations have survived in favourable microhabitats embedded within larger unsuitable areas during the late-glacial, features not captured by broad-scale model predictions. © 2011 Blackwell Publishing Ltd. Source

Hutchinson S.M.,University of Salford | Akinyemi F.O.,University of Salford | Mindrescu M.,Stefan Cel Mare University of Suceava | Begy R.,Babes - Bolyai University | And 2 more authors.
Regional Environmental Change

Longer-term environmental studies are increasingly used to better understand contemporary ecosystems conditions and for forecasting their future trajectories. Here, we use radiometric measurements and the characterisation of sediment properties from six mountain and a lowland lake in Central Eastern Europe with the aim to assess temporal and spatial variability in sediment accumulation rates (SARs) in relation to three socio-economic regimes: traditional (1840–1948), socialist (1948–1989) and post-socialist (post-1990). We also set out to determine reference conditions for these lakes i.e. conditions before significant human impact. Our results show a trend of increasing SARs from basal sediments (pre 1840) towards the present at only two sites. This contrasts with findings from Western and Central European lakes where SARs have predominantly increased from 1850 towards the top of cores. We highlight the differential impacts of the traditional, socialist and post-socialist periods on the SARs at these lakes. Lowland and mid-elevations lakes (n = 2) were most markedly impacted by the socialist period of land use regime; lakes from the southern Carpathians (n = 2) were more impacted in the traditional period (transhumance pastoral activities), whereas those from the north (n = 3) in the socialist and post-socialist periods (summer pastoralism). Results from our study show a continuous anthropogenic impact during the entire period considered, even in remote mountain areas. This suggests that a temporal frame of 100–150 years is too short to meaningfully register the reference conditions of these lakes. Furthermore, a predominantly natural state may not have existed for centuries in this region. © 2015, Springer-Verlag Berlin Heidelberg. Source

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