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A transition from widespread humid to more drought tolerant floras characterized tropical terrestrial ecosystems during the Permian (Cisuralian). Tregiovo (Southern Alps, N-Italy) is one of the very few well dated Kungurian (late Cisuralian) plant localities in Euramerica. It was located in eastern palaeoequatorial Pangea. Two units bearing fossil plant assemblages occur in finely laminated sediments deposited in a playa-lake environment. In this paper, the sedimentology of the Tregiovo Basin is reviewed, and new palaeobotanical, palynological and stable isotopic data are presented, in order to reconstruct the palaeoclimatic and palaeoenvironmental conditions of the Kungurian in the Southern Alps. Both fossil plant assemblages are dominated by conifers ( Hermitia , Feysia , Quadrocladus , Dolomitia ), together with sphenophytes ( Annularia ), ginkgophytes ( Sphenobaiera ), pteridosperms ( Peltaspermum ), taeniopterids and sphenopterids. These taxa, which occur with different abundances in the two plant assemblages, both indicate semi-arid conditions. Associated palynoflora, dominated by bisaccate pollen, and extremely rare spore occurrences, is consistent with the xerophytic character of the macroflora, and suggests that the fossil plant record was not affected by collection or preservation bias. Stable isotopic analyses of two stratigraphic sections reveal an upward trend of increasingly negative δ 13 C org (VPDB), which may correlate with roughly coeval records from marine and continental successions such as in North China and South Africa. This isotopic shift may be attributed to a global perturbation of atmospheric δ 13 C, although the influence of local environmental factors cannot be excluded. [ABSTRACT FROM AUTHOR]

Abstract This paper presents the results of palinological studies of the sediments from the site of Szklarka (Silesian Lowland, SW Poland). The pollen sequence from Szklarka records the longest continuous succession of vegetation covering the Late Saalian, Eemian Interglacial and Early Weichselian in SW Poland. The results of pollen analysis show phases with forest and open vegetation communities in response to climate changes. The pollen zones distinquished represent cool phases of the Late Saalian, a complete Eemian interglacial succession (E1-E7 R PAZ) and two cool intervals (Herning and Redestall) and one warm one (Brörup) from the Early Weichselian. Two main phases have been distinguished in the Brørup Interstadial, an older birch phase and a younger pine phase. During the Brørup Interstadial, towards the end of the birch phase, a cooling event has been recorded. [ABSTRACT FROM AUTHOR]

The Amur Basin, on the border of Russia and China, has accumulated substantial quantities of peat that have allowed the reconstruction of past vegetation and environments, especially during the Holocene. In this paper, a detailed pollen record from the Basin has been constructed for the last 3800 years and interpreted with the assistance of 40 surface pollen samples taken from vegetation types representative of a broader region. In addition, fossil microcharcoal counts were undertaken to explore variation in fire frequency and the role of fire in peat development and landscape disturbance. The record can be divided into four periods. (1) A period of deciduous broadleaved forest dominated by Betula and Quercus accompanied by thriving sedge-dominated wetlands indicating relatively warm and wet conditions between about 3800 and 2000 cal BP. (2) Coniferous and broad-leaved mixed forest domination between about 2000 and 680 cal BP indicating a shift to a cooler climate. (3) Betula-dominant deciduous forest, reduced sedge-dominated wetlands and increased burning between about 680 and 250 cal BP indicating further drying and cooling during the Little Ice Age. (4) Secondary pine forest combined with a large increase in fire activity as well as a further reduction in the swamp environment signaling substantial human impact in the last 250 years. [ABSTRACT FROM AUTHOR]

The present paper reports a complete palynological study of the Upper Turolian sediments outcropping at the Venta del Moro site (eastern Iberian Peninsula). The pollen assemblages observed mainly reflect the local and regional vegetation, which must have formed part of a wetland ecosystem within a general setting of open steppe, as indicated by the great abundance and diversity of herbaceous pollen. This reflects the persistence of open vegetation in the Iberian Peninsula after the Middle Miocene when it became extensive. We here report the most recent record of Disanthus for the Iberian Peninsula. This shrub played an important role in an unusual, edaphically-mediated vegetation linked to lacustrine–palustrine or riparian shore conditions. A shift in the water level led to a flooding episode, extending wetland and causing a drastic reduction in Disanthus and Amaranthaceae. The results of quantitative (multivariate and coexistence) and semi-quantitative (integrated plant record) analyses of the pollen dataset support these interpretations of the palaeovegetation and provide insight into the regional palaeoclimate. Stable climatic conditions would appear to have reigned before the onset of the Messinian salinity crisis. The palynoflora of Venta del Moro is compared with counterparts in other areas of the Mediterranean Basin. [ABSTRACT FROM AUTHOR]

In this paper we present a review of the available Holocene pollen records from the Spanish Central System (113 sites and 150 14 C dates). Palynological data obtained from pollen analyses of peat-bogs, lakes and archaeological sites, as well as radiocarbon dating, were used to infer the human impact on vegetation and landscape during the last 9 millennia. The Neolithic contribution to the configuration of landscape is scarce, limited to the valleys, while Chalcolithic settlements and their related activities (agriculture and grazing) represent the first evidence of significant human impact on the high-mountains. The pollen record has allowed us to relate two cultural periods of changing, the Copper Age–Early Bronze Age and Late Bronze Age–Early Iron Age transitions, to abrupt climate disruptions, the so-called 4.2 and 2.8 ka cal BP events respectively. From the Iron Age to the Early Middle Ages, anthropic activities were still sporadic, mainly located in the lowlands, but from the Feudal Period onwards, when La Mesta transhumance system takes place, high-mountain landscapes changed dramatically. Late Modern Period brings a further intensification of human pressure, especially related to forestry, with widespread pinewood afforestation. [ABSTRACT FROM AUTHOR]

Abstract: This paper shows a Holocene paleoecological reconstruction based on a peat bog sequence (El Paují, 4°28′N–61°35′W, 865m elevation) located in the transition zone between the Gran Sabana (SE Venezuela) savannas and the Amazon rainforests. Paleoecological trends are based on the analysis of pollen and pteridophyte spores, algal and animal remains, fungal spores, and charcoal particles. The whole record embraces the last ca. 8000calyr BP, and was subdivided into five pollen zones, representing the following vegetation succession: savanna/rainforest mosaic (8250–7715yr BP), dense rainforests (7715–5040yr BP), savanna/rainforest mosaic (5040–2690yr BP), secondary dry forests (2690–1440yr BP), and peat bog in an open savanna landscape (1440yr BP–present). These vegetation changes have been attributed to the action of climate and/or land use changes, as well as the corresponding synergies between them. Fire has been determinant in the landscape evolution. Based on the reconstructed fire and vegetation shifts, a changing land use pattern could have been recognized. Between the early and the mid Holocene (ca. 8.3–5.0kyr BP), land use practices seem to have been more linked to shifting agriculture in a rainforest landscape – as is usual in Amazon cultures – with medium fire incidence affecting only local forest spots or surrounding savannas. More extensive forest burning was recorded between ca. 5.0 and 2.7kyr BP, followed by land abandonment and the dominance of drier climates between 2.7 and 1.4yr BP. The modern indigenous culture, which prefers open environments and makes extensive use of fire thus preventing forest re-expansion, seem to have established during the last 1500yr. Therefore, a significant cultural replacement has been proposed for the region, leading to the present-day situation. Changing human activities have been instrumental for ecological evolution in this savanna–rainforest transitional region, as well as for the shaping of modern landscapes. [Copyright &y& Elsevier]

Abstract: The question of whether Pliocene climate was warm enough to support a substantial vegetation cover on Antarctica is of great significance to the ongoing and controversial debate on the stability or dynamism of Antarctic ice sheets during warm periods with high atmospheric greenhouse gas concentrations. Here we present a systematic palynological comparison of pollen and dinoflagellate cyst assemblages from Early Pliocene diamictites and underlying late Cretaceous sediments collected from James Ross Island, northern Antarctic Peninsula. The diamictites are dated using a combination of 40Ar/39Ar and 87Sr/86Sr isotope ages on interbedded lavas and pristine bivalves. Well preserved pectinid shells and cheilostome bryozoans suggest that the palynomorph-bearing sediments were probably deposited during warmer Pliocene interglacials and later amalgamated into a diamictite formed by a major ice advance during cold glacial cycle. The palynological analyses presented herein do not identify any in-situ pollen and spores which indicate the presence of a substantial vegetation cover. Our study suggests a local (i.e. James Ross Island) provenance for most of the diamictites, whilst sediments from the western coast might have been delivered by ice sheets from the Antarctic Peninsula. Whilst the acritarch Leiosphaeridia might imply the presence of sea-ice and near-modern climate conditions during the Late Neogene, the presence of the dinoflagellate cyst Bitectatodinium tepikiense at one location suggests that sea surface temperatures might have been substantially warmer during some interglacials. The absence of in-situ pollen and spores in the James Ross Island diamictites cannot be taken as proof of non-existence of vegetation. However, the combined palynological and geological evidence presented in this paper makes the presence of a substantial Pliocene vegetation cover on James Ross Island unlikely and supports previous reconstructions of a permanent ice sheet on the Antarctic Peninsula throughout the Late Neogene. [Copyright &y& Elsevier]

Abstract: The paper presents the first reconstructions of vegetation and climate of the North Pre-Baikal region covering the last 9000 years based on detailed pollen records from peatlands. Recorded major changes in pollen spectra and vegetation are demonstrated to correlate with large-scale climatic events, such as the regional climatic optimum ca. 9000–6800 BP, termination of the optimum ca. 7000–6500 BP, and Neoglacial cooling culminated ca. 3000–2000 BP. The most warm and wet climate existed about 9000–6800 BP, the interval being referred to as the regional Holocene optimum. At that time, vegetation was dominated by dark coniferous forests of Abies sibirica, Picea obovata with Pinus sibirica. Since 6800 BP, the dark coniferous forests gave way to light coniferous ones (Pinus sylvestris and Larix) in response to gradual decrease of precipitation and summer temperatures to today’s values, agreeing well with earlier obtained data. The new records suggest the cold boreal plant communities are highly sensitive to climatic changes. Detailed dating of the sequences would facilitate inter- and intra-regional correlations of the obtained records and reconstructed events. [Copyright &y& Elsevier]

Abstract: High-resolution macroscopic charcoal and pollen analyses were used to reconstruct the fire and vegetation history of the Willamette Valley for the last 1200years. Presented in this paper are three new paleoecological reconstructions from Lake Oswego, Porter Lake, and Warner Lake, Oregon, and portions of previous reconstructions from Battle Ground Lake, Washington, and Beaver Lake, Oregon. The reconstructions show that prior to Euro-American settlement vegetation and fire regimes were influenced by a combination of natural and anthropogenic factors. Battle Ground Lake shows a stronger influence from climate, while Lake Oswego, Beaver Lake, Porter Lake, and Warner Lake were more controlled by human activity. However, human-set fires were also modulated by regional climate variability during the Medieval Climate Anomaly and the Little Ice Age. Fire reconstructions from Battle Ground Lake, Lake Oswego, Beaver Lake, and Porter Lake imply that fires were infrequent in the Willamette Valley 200–300years prior to Euro-American settlement. The decline of Native American populations due to introduced disease may have led to this reduction in fire activity. The prehistoric record from Warner Lake, however, indicates that fires in the foothills of the Cascade Range were more frequent than on the valley floor, at least until ca. AD 1800. The historic portions of the reconstructions indicate that Euro-American land clearance for agriculture and logging produced the most dramatic shifts in vegetation and fire regimes. All five records indicate that few fires in the Willamette Valley have occurred since ca. AD 1930, and fires today are predominantly grass fires. [ABSTRACT FROM AUTHOR]

Abstract: Commonly applied methods such as pollen analysis, charcoal analysis, and archaeological studies make it possible to reconstruct the trend of changes in vegetation during the Holocene and determine the role of humans in its transformation. However, it is not always possible to obtain a complete picture of changes which took place in the past and the reasons for their occurrence. This paper presents the results of molecular investigations of lacustrine sediments from Lake Miłkowskie, aimed at confirming human presence in the vicinity of the lake and its correlation with the palynological and archaeological data. The molecular analyses were based on identification of ancient DNA (aDNA) of faecal bacteria, as indicators of human and cattle presence. Application of comprehensive studies comprising both palaeoenvironmental and molecular methods allowed a detailed determination of the stages of human presence in the vicinity of the lake and confirms the anthropogenic impact on the changes of local plant communities. [Copyright &y& Elsevier]

Abstract: Possible effects of seismic activity in the Dead Sea basin on the regional vegetation distribution are presented in this paper. The palynology was investigated in high resolution at the Holocene outcrop near the Ein Feshkha oasis. Pollen samples were collected from three intervals (A, B, D), with thicknesses of 5–15 cm, containing 1–2 seismites each, and from one undisturbed layer (interval C). All four intervals are from the same Ein Feshkha outcrop section, but from different depths. In two of the intervals (B, C) the main pollen indicators (e.g. Olea, Pinus, Asteroideae, Cichorioideae) show no significant aberrations from the typical pollen fluctuations. Interval A, deposited during the late Byzantine period, shows a decline of Olea percentages immediately after the sedimentation of a breccia layer (interpreted as a seismite). While this decrease in olive percentages predominantly reflects an aridification crisis at the end of the Byzantine period, damage to olive orchards due to earthquake (root damages, collapses of the crowns) and/or the abandonment of cultivated land as a consequence of an earthquake cannot be ruled out. Nevertheless, minor anthropogenic indicators like Vitis or Juglans, which show low abundances in the pollen diagram of Ein Feshkha, as well as other trees and herbs, are not affected by the late Byzantine earthquake. Interval D, deposited during the Hellenistic–Roman period, shows a slight decrease of Olea and an increase of Cichorioideae after the deposition of a seismite. Our hypothesis that earthquakes might have affected vegetation dynamics in intervals A and D is supported by cluster analysis. While the data of this study do not support the use of pollen as a reliable paleoseismic tool in the lacustrine environment of the Dead Sea, some small effects of earthquakes on pollen fluctuations cannot be excluded. [Copyright &y& Elsevier]

Abstract: This paper contributes to an understanding of the relationship between pollen assemblages and grain-size in north-west China. Based on the relationship, we have reconstructed the environmental and vegetation history from sediments from Zhuye Lake, located in the marginal area of the Asian monsoon. During the Late Glacial (before ~13 cal ka BP), the high content of sand is correlated with low pollen concentrations, which implies an arid environment and low vegetation cover in the drainage. The relatively high percentages of Pinus and Quercus pollen, derived from nearby high elevations, may indicate particularly low vegetation cover in the lower part of the watershed. Between 13 and 7.7 cal ka BP, increasing silt content is correlated with high percentages of Picea pollen. Fluvial flow and effective humidity at high elevations, as well as lake-level, all increase. Following this, an abrupt environmental change which is likely caused by some change in lake geomorphology persists for about 300 years. The Holocene Optimum is between 7.4 and 4.7 cal ka BP in this region. Pollen concentrations reach their highest values in the section. The abundant herb pollen reflects the high vegetation cover in the lower part of the watershed. The silt and the fine components in the sediments are high and stable indicating optimal moisture conditions. Between 4.7–1.5 cal ka BP the lake-level fell and silty peat was formed at the site. The pollen concentration decreased in contrast to the high pollen concentration in the Holocene Optimum. In the last 1500 years the lake-level fell while terrestrial sediments were deposited at the site. In this phase Chenopodiaceae, Nitraria and Ephedra reach their highest values in the section reflecting an arid environment. In Zhuye Lake and the surrounding area environmental changes are mainly controlled the combined effects of the East Asian monsoon and the Westerlies since the Late Glacial. In the last ~1.5 cal ka BP the intensive arid trend may be correlated with changes in the Westerlies. [Copyright &y& Elsevier]

Abstract: This paper contributes to the emerging picture of late Pleistocene and Holocene environmental change in the Bonneville basin, western North America, through analysis of pollen and sediments from the Blue Lake marsh system, a major wetland area located on the western margin of the Great Salt Lake desert. Analyses of data obtained from the upper 4m of the Blue Lake core suggest that during the latest Pleistocene, when Lake Bonneville covered the Blue Lake site, pine and sagebrush dominated terrestrial plant communities. These steppe-woodland taxa declined in abundance after ∼12calka BP. Wetland plant communities developed at or nearby Blue Lake by ∼11.9calka BP and bulrush-dominated marshes were established no later than 10.8calka BP. The Blue Lake wetlands largely desiccated during a dry and warm early middle Holocene ∼8.3–6.5calka BP. Climatic amelioration starting ∼6.5calka BP is marked principally by a local return of marshes at the expense of playa and grass meadow communities, and a regional increase in sagebrush relative to other dryland shrubs. Singleleaf pinyon pine migrated into the nearby Goshute Mountains after ∼8calka BP. Late Holocene fluctuations include cool intervals from ∼4.4 to 3.4 and ∼2.7 to 1.5calka BP and warmer conditions from 3.4 to 2.7cal BP and after 1.5calka BP. [Copyright &y& Elsevier]

Abstract: This paper investigates changes in the vegetation and hydrology at Ljubljansko barje (Slovenia) using a multi-proxy approach (pollen, diatoms, geochemical and stable isotope analysis). During the Lateglacial Ljubljansko barje was a deep, oligotrophic lake surrounded by open woodland comprised predominantly of Pinus and Betula which in the early Holocene, when the lake became shallower and mesotrophic (Fragilaria pinnata, δ 15N~3.3‰, δ 13C~−33.7‰, C/N~7.9), was replaced by broadleaved tree taxa (Tilia, Ulmus, Quercus, Corylus) and Picea. This was followed by the spread of Fagus and after ~9200 cal yr BP Abies and planktonic and oligotrophic diatom taxa (Aulacoseira italica, Gomphonema angustum) as well as an increased allochthonous influx (silt, SiO2, Al2O3). Between ca. 6750 and 6000 cal yr BP the diatom data suggest shallower and oligotrophic conditions, whereas the stable isotope record (increased δ 13C and decreased δ 15N) indicates terrestrial input. Changes in forest composition (increase of Quercus, Alnus, Corylus) and the spread of herb taxa were probably advanced by human impact on the environment. The beginning of organic sedimentation, dated to 6000 cal yr BP, was followed by an increase of Fagus and Abies and by eutrophication and peat growth at ~5200 cal yr BP. [Copyright &y& Elsevier]

Abstract: Accurate reconstruction of late-Quaternary vegetation cover is necessary for better understanding of past vegetation dynamics, the role of vegetation feedbacks in glacial–interglacial climate variations, and for validating vegetation and climate models. In this paper over 1700 surface-pollen spectra from the former Soviet Union, Mongolia, northern China, and northern Japan together with data from the Advanced Very High Resolution Radiometer (AVHRR) were used to calibrate modern-analogue method for quantitatively reconstructing past woody cover from fossil pollen data. The AVHRR-based estimates of woody cover percentages within a 21×21 km window around pollen sampling sites were attributed to the respective modern pollen spectra. Reconstructions of modern woody cover using the pollen data and best-modern-analogues (BMA) method matched well to the original AVHRR-based estimates, for both total woody cover (r 2 =0.77) and its fractions, including broad-leaved (r 2 =0.66), needle-leaved (r 2 =0.79), deciduous (r 2 =0.60) and evergreen (r 2 =0.76) woody cover. Discrepancies in the pollen–AVHRR cross-validation may be caused by long-distance transport of arboreal pollen, patchy forest distributions, underrepresentation of Larix and Populus in pollen records, and errors in the AVHRR classification. The generally strong correlations encourage application of the modern-analogue approach for reconstructing late-Quaternary variations in vegetation cover from northern Asian fossil pollen records. At the last glacial maximum (LGM: ∼21,000 cal yr BP), areas presently occupied by boreal forest were much more open, suggesting a reduction in total woody cover to below 20% at most modern forest sites. Pollen records from northern and central Siberia suggest a rather quick spread of tree and shrub vegetation after 15,000 cal yr BP, presumably in response to increased summer insolation. Woody cover histories are spatially variable in the modern forest-steppe, where tree growth is largely controlled by the ratio of annual actual over potential evapotranspiration which serves as an index of moisture availability. In northwestern Mongolia, woody cover percentages decreased between ∼9000 and 5000 cal yr BP and again between 2000 and 1000 cal yr BP and may be linked to shifts in intensity of the Pacific monsoon. In contrast, pollen data from the Kazakhstan forest-steppe (where atmospheric precipitation is associated with the Atlantic westerly flow) suggest that woody cover density reached modern levels only during the last millennium. [Copyright &y& Elsevier]

Abstract: The composition of the glacial vegetation of southern French plains has been a matter of debate for several decades. Vegetation is considered as steppic according to French and Spanish lacustrine pollen records whereas cave deposits suggest the presence of mesothermophilous trees through the Last Glacial Maximum. In our paper, we display new palynological records from marine sediments of the Gulf of Lions. They indicate the presence of Abies, Picea and deciduous Quercus in the Gulf of Lions, certainly located in the drainage basins of the Pyreneo-Languedocian rivers. These populations that were sensitive to short climatic events during Marine Isotopic Stage 2 could have been linked to northeastern Spanish and southeastern French relicts already evidenced by phylogenetic data. These trees were absent from the Rhone drainage basin during the deglaciation and certainly also disappeared from the Pyreneo-Languedocian drainage basins from ca 17 to 15kycalBP. Finally, the Last Glacial Maximum does not appear as stable, cold and dry as previously thought. [Copyright &y& Elsevier]