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Lacustrine fossil pollen records have been widely used to reconstruct palaeovegetation and palaeoclimate changes on the Tibetan Plateau (TP). However, little is known about the vegetation representation of modern lacustrine pollen assemblages there. This paper presents the results of modern pollen investigation on 63 surface sediments from the lake basin and 37 topsoil samples from the drainage area of a large lake, Nam Co, located in the central TP. It aims to assess quantitatively the influences on lacustrine pollen assemblages of the pollen sources and sedimentary processes, and to establish vegetation representations for modern lacustrine pollen assemblages. Modern pollen assemblages from topsoils of different vegetation had diagnostic features in terms of their composition and pollen percentage. The spatial variabilities and results of principal component analysis suggested that lacustrine pollen assemblages were influenced by both the regional/local source vegetation and sedimentary processes. The lacustrine pollen assemblages were mainly homogeneous due to in-lake sedimentary processes (mixing and redistribution). An accumulation zone for lacustrine pollen assemblages was found in the deep lake basin (depth > 60 m) due to sediment focusing. The results of boosted regression tree analysis further confirmed that source vegetation was the predominant factor (85.8%) responsible for the vegetation representation of lacustrine pollen assemblages, while sedimentary processes accounted for only 14.2%. The results of discriminant analysis indicated that most lacustrine pollen assemblages (90.5%) were representative for the regional vegetation of alpine steppe in the Nam Co catchment and central TP, while only 9.5% were representative for the local meadow vegetation. Therefore, it is recommended that lacustrine pollen assemblages from deep lake basin of accumulation zone in large lakes of the TP can be used to retrieve efficiently the signals from regional vegetation and climate changes. [ABSTRACT FROM AUTHOR]

This paper describes the analyses of pollen, non-pollen palynomorphs, macroremains and geochemistry in sediments from archaeological excavations at Wyspa Spichrzów ('Granary Island') in Gdańsk, northern Poland. The aim of this study was to reconstruct the environmental conditions in this part of the town in the period preceding its occupation and during its transformation with the establishment of a trade centre and an increasing number of granaries, warehouses and workshops. The results show that this area was originally covered by wetlands typical of river oxbows, with a landscape formed by alder woods, shallow pools of water, fens and patches of wet meadows. Around the 9th-10th centuries, a distinct lowering of the groundwater table reduced the pools, and the alder stands also reduced. These changes coincided with the Medieval Climatic Anomaly. Drying of the ground could have been an important factor enabling expansion of settlement in the Gdańsk area. Between the 10th and 13th-14th centuries, the area around the investigated sites was probably used as pasture, as shown by high frequencies of coprophilous fungal spores. A large representation of cereal pollen and pollen and macroremains of field weeds reflects crop transport and storage on the island from ca. the 13th/14th centuries in the northern part of the area and the 15th/16th centuries in its southern part. The increasing human impact caused development of a rich flora associated with human activities, habitat enrichment by nitrogen and phosphorus, and heavy metal pollution from the beginning of the 13th century. [ABSTRACT FROM AUTHOR]

The main drivers of fire regimes in southern Europe are climate, vegetation and land-use changes that interact at different spatio-temporal scales. These complex interplays between 'natural' and anthropogenic forcings hinder the identification of fire-climate linkages on the long time scale. In this paper, we focused on the Last Glacial-Holocene transition, which is the last time Europe experienced rapid warming of similar magnitude and rate of change as predicted for the future, and with minimal human impact (no agricultural activities). We derived fire activity from two neighbouring lacustrine macrocharcoal records, Ech paleolake and Lake Lourdes, located 3 km apart. To understand the effect of external forcings, we reconstructed summer T° changes and vegetation dynamics from two independent proxies. We then compared both paleofire records with chironomid-inferred summer air temperature reconstruction from Ech paleolake. We discuss the role of vegetation type, structure and biomass availability using pollen analysis from Ech paleolake and Lourdes. Fire activity is strongly modulated by summer T° oscillations as shown by the highly contrasted responses between the Oldest Dryas/Interstadial and Younger Dryas/Holocene transitions. However, vegetation type and biomass availability act as limiting factors: the slight increase in fire activity at the onset of the Interstadial is triggered by a 7 °C summer T° increase but remains limited by low availability of woody biomass in a steppe environment. On the contrary, the onset of the Holocene is characterised by a 2 °C summer T° increase and an unprecedented increase in fire activity, conditioned by the establishment of dense deciduous forests. [ABSTRACT FROM AUTHOR]

This paper discusses changing patterns of resource utilisation over time in the locality of Chibuene, Vilankulos, situated on the coastal plain of southern Mozambique. The macroscopic charcoal, bone and shell assemblages from archaeological excavations are presented and discussed against the off-site palaeoecological records from pollen, fungal spores and microscopic charcoal. The Chibuene landscape has experienced four phases of land use and resource utilisation that have interacted with changes in the environment. Phase 1 ( a.d. 400-900), forest savanna mosaic, low intensity cattle herding and cultivation, trade of resources for domestic use. Phase 2 ( a.d. 900-1400), forest savanna mosaic, high intensity/extensive cultivation and cattle herding. Phase 3 ( a.d. 1400-1800), savanna woodland and progressive decrease in forests owing to droughts. Decline of agricultural activities and higher reliance on marine resources. Possible trade of resources with the interior. Phase 4 ( a.d. 1800-1900), open savanna with few forest patches. Warfare and social unrest. Collapse of trade with the interior. Decline in marine resources and wildlife. Loss of cattle herds. Expansion of agriculture locally and introduction of New World crops and clearing of Brachystegia trees. The study shows the importance of combining different environmental resources for elucidating how land use and natural variability have changed over time. [ABSTRACT FROM AUTHOR]

Integration of pollen data from both marine and terrestrial cores contributes to the understanding of the timing of the climatic and human forces that shaped the cultural landscapes in the Italian peninsula. This paper focuses on the relation between natural and human landscapes, and the development of the cultural landscape from the Bronze Age to the medieval period and modern times. Two records were studied within independent projects, first the marine core RF93-30, from the central Adriatic, with a sediment source area including the Po valley and which spans the last 7,000 years, and secondly, material from the site of Terramara di Montale, a Bronze Age settlement on the Po plain, which was occupied from approximately 3550-3200 cal. b. p. The original chronology of the marine core was developed by using the magnetic inclination of the secular variation record and two C dates carried out on benthic and planktic foraminifera at depths of 527 and 599 cm. Its pollen record shows a gradual irreversible trend towards increasing aridity since 5700 cal. b. p. and, just after around 5100 cal. b. p., a Picea decline and a Quercus ilex type increase indicate less cool conditions. Human impact introduces rapid changes, such as the decrease of Abies alba, thinned by the reduction of precipitation and further cleared before or during the Early Bronze Age, followed by the fall of oaks. The latter started after around 3900 cal. b. p., and became evident at around 3600 cal. b. p. The gradual increase in signs of open landscape and woodland clearance correspond to the onset of Middle Bronze Age settlements in the Po valley, and to the development of the cultural landscape in the region. The impact of the terramare people includes woodland management by coppicing, and division of the territory into a patchwork of pastures and fields. Dry environments are indicated mainly by Cichorioideae, resulting from the continued human pressure, and these spread since the Recent Bronze Age. Of the possible causes for the decline of the terramare, we suggest that climate would have been less important in the decline than in the onset phases. The later cultural landscapes are mainly indicated by the trends of the Olea, Juglans and Castanea (OJC) records, besides those of cereals. At around 700 cal. b. p., the 'chestnut landscape' spread while modern times are shown by the finds of Zea mays. [ABSTRACT FROM AUTHOR]

The recognition of Mesolithic impacts in mid Holocene pollen diagrams of the British Isles has led to the development of models describing sophisticated woodland management, particularly through the use of fire, by Mesolithic populations. However, the significance of human agency in creating mid Holocene woodland disturbances is unclear, with natural and human-induced clearings arguably indistinguishable in the pollen record. Analysis of non-pollen palynomorphs (NPPs) should aid the identification of events and processes occurring within these woodland disturbances and provide more precise palaeoecological data. In this paper we present pollen, charcoal and NPP analyses from a potentially critical location in the Mesolithic impacts debate. NPP types aid significantly in the reconstructions, suggesting periods of dead wood, grazing, local burning and wetter ground conditions. The results indicate that between 7700 and 6800 cal b.p., a predominantly wooded environment periodically gave way to phases of more open woodland, with inconsistent evidence for animal grazing. From 6800 cal b.p., a phase of open woodland associated with high charcoal concentrations and indicators of grazing was observed. This probably represents the deliberate firing of vegetation to improve grazing and browse resources, although it remains unclear whether fire was responsible for initially creating the woodland opening, or if it was part of an opportunistic use of naturally occurring woodland clearings. [ABSTRACT FROM AUTHOR]

This paper explores the spatial and temporal land-cover variability within the main cultural landscape units in Denmark during the last 3,000 years. Quantitative estimates of the cover of trees, grasses, Cerealia and Calluna around nine Danish lakes were obtained using the recently developed Landscape Reconstruction Algorithm (LRA) (Sugita , ). The performance of the approach was evaluated by comparing reconstructed vegetation based on a.d. 1800 pollen spectra to land cover from historical maps of the same period. Although the model tended to overestimate grassland cover by 10–20%, the reconstructed vegetation was much more similar to the observed than the uncorrected pollen proportions. The LRA was then applied to 3,000 year long pollen records to reconstruct the vegetation development around each of the nine sites. The results support earlier conclusions regarding the relative stability of woodland, agrarian and heathland dominated landscapes in Denmark (Odgaard and Rasmussen ), with the distribution of the main landscape types determined by topography and soil characteristics. The present study indicates that the transition zones between agricultural and forest dominated landscapes were the most dynamic, acting as buffer zones where most of the expansions and contractions of agricultural activities took place. The quantitative vegetation reconstructions underline the importance of farming and especially pastoral activities in shaping the Danish landscapes throughout the study period. [ABSTRACT FROM AUTHOR]

Abstract  Understanding the interplay between climatic and anthropogenic factors is a major challenge in palaeo-ecology. In particular, it is often difficult to distinguish anthropogenic and “natural” fire in the charcoal record. In this paper, analysis of fossil pollen, charcoal, diatoms and isotopic evidence from Mapimbi, a small lake in the Kruger National Park, South Africa, suggests that for most of the past ca. 700 years, the riverine gallery forests surrounding Mapimbi were primarily influenced by climate, and benefited during warmer, wetter periods. The transitions between four, statistically different phases in the time-series data coincide with regional climate records previously constructed from speleothem data, and are consistent with the transition from the medieval warm period ending in the 14th century a.d. to the cooler, drier conditions prevailing during the little ice age of ca. a.d. 1400–1800. The data also suggest a period of significant, anthropogenic influence after a.d. 1800, when maize was grown and the incidence of localised fires increased. An increase in woody cover in recent decades may be associated with the management of the area by Kruger National Park. A decline in cultivation occurred in the end of the 20th century linked with changes in socio-political organisation. [ABSTRACT FROM AUTHOR]

Abstract  Information on past land cover in terms of absolute areas of different landscape units (forest, open land, pasture land, cultivated land, etc.) at local to regional scales is needed to test hypotheses and answer questions related to climate change (e.g. feedbacks effects of land-cover change), archaeological research, and nature conservancy (e.g. management strategy). The palaeoecological technique best suited to achieve quantitative reconstruction of past vegetation is pollen analysis. A simulation approach developed by Sugita (the computer model POLLSCAPE) which uses models based on the theory of pollen analysis is presented together with examples of application. POLLSCAPE has been adopted as the central tool for POLLANDCAL (POLlen/LANdscape CALibration), an international research network focusing on this topic. The theory behind models of the pollen–vegetation relationship and POLLSCAPE is reviewed. The two model outputs which receive greatest attention in this paper are the relevant source area of pollen (RSAP) and pollen loading in mires and lakes. Six examples of application of POLLSCAPE are presented, each of which explores a possible use of the POLLANDCAL tools and a means of validating or evaluating the models with empirical data. The landscape and vegetation factors influencing the size of the RSAP, the importance of pollen productivity estimates (PPEs) for the model outputs, the detection of small and rare patches of plant taxa in pollen records, and quantitative reconstructions of past vegetation and landscapes are discussed on the basis of these examples. The simulation approach is seen to be useful both for exploring different vegetation/landscape scenarios and for refuting hypotheses. [ABSTRACT FROM AUTHOR]

Abstract  Information on the spatial distribution of past vegetation on local, regional and global scales is increasingly used within climate modelling, nature conservancy and archaeology. It is possible to obtain such information from fossil pollen records in lakes and bogs using the landscape reconstruction algorithm (LRA) and its two models, REVEALS and LOVE. These models assume that reliable pollen productivity estimates (PPEs) are available for the plant taxa involved in the quantitative reconstructions of past vegetation, and that PPEs are constant through time. This paper presents and discusses the PPEs for 15 tree and 18 herb taxa obtained in nine study areas of Europe. Observed differences in PPEs between regions may be explained by methodological issues and environmental variables, of which climate and related factors such as reproduction strategies and growth forms appear to be the most important. An evaluation of the PPEs at hand so far suggests that they can be used in modelling applications and quantitative reconstructions of past vegetation, provided that consideration of past environmental variability within the region is used to inform selection of PPEs, and bearing in mind that PPEs might have changed through time as a response to climate change. Application of a range of possible PPEs will allow a better evaluation of the results. [ABSTRACT FROM AUTHOR]

Abstract  The need for quantification of land cover from pollen data has led to the development of a Landscape Reconstruction Algorithm (LRA). The LRA includes several models of which the REVEALS model estimates regional vegetation abundance using pollen assemblages from large sites (lakes or bogs). In this paper we explore the effects of selection and number of pollen samples, and choice of pollen productivity estimates on the REVEALS results. The effect of the size of vegetation surveys is also tested. The results suggest that the differences between two sizes of vegetation surveys have little effect on the model validation. The “characteristic radius” of regional vegetation in southern Sweden was estimated as 200 km. However, the vegetation composition in a 100 × 100 km2 square matches well with that estimated by REVEALS. Whether 25, 20 (outliers excluded) or 4 pollen samples are used does not change the REVEALS reconstructions much although the error estimates are larger when outliers are included, and very large when only four samples are used. Therefore validation of the REVEALS model and REVEALS reconstructions of past vegetation can be performed using a limited number of pollen samples, although with caution. The use of many pollen samples from multiple sites is always better whenever possible. REVEALS reconstructions are closer to the actual vegetation when the Danish Pollen Productivity Estimates (PPEs) are used instead of the Swedish PPEs for Cereals, Rumex acetosa/acetosella, Plantago lanceolata and Calluna, indicating that the Danish PPEs are more reliable than the Swedish ones for those taxa. It is recommended to test more than one set of PPEs in validation and applications of the REVEALS model for a better evaluation of the results. [ABSTRACT FROM AUTHOR]

Abstract  In this paper we present and discuss palynological results based on a composite profile from Birkat Ram crater lake (Northern Golan, Near East) in order to reconstruct the environmental history, including human impact, of the last 6500 years. Furthermore we apply a newly-developed botanical climatological transfer function to reconstruct climate variations in the northern Golan Heights based on this pollen data-set. The Birkat Ram record is strongly influenced by anthropogenic indicators in the pollen diagram with high quantities during the Chalcolithic period/Early Bronze Age, during the Hellenistic-Roman-Byzantine periods, during the Crusader period and finally during modern times. The palaeoclimate reconstruction method used is based on a Bayesian approach and is robust in avoiding the influence of these strong anthropogenic signals on the reconstruction results. The area has always had Mediterranean climate conditions and no distinctive climate changes can be identified during the past 6500 years. Because of the orography of the Mt. Hermon region the particular geographical position of the northern Golan Heights is obviously capable of buffering large-scale fluctuations in precipitation, which have otherwise been documented for several regions in the Near East. [ABSTRACT FROM AUTHOR]

Past vegetation, fire, and climate dynamics, as well as human impact, have been reconstructed for the first time in the highlands of the Gilan province in the Alborz mountains (above the Hyrcanian forest) for the last 4,300 cal yrs bp. Multi-proxy analysis, including pollen, spores, non-pollen palynomorphs, charcoal, and geochemical analysis, has been applied to investigate the environmental changes at 2,280 m a.s.l., above the Hyrcanian forest. Dominant steppe vegetation occurred in the study area throughout the recorded period. The formation of the studied mire deposits, as well as vegetation composition, suggest a change to wetter climatic conditions after 4,300 until 1,700 cal yrs bp. Fires were frequent, which may imply long-lasting anthropogenic activities in the area. Less vegetation cover with a marked decrease of the Moisture Index (MI) suggests drier conditions between 1,700 and 1,000 cal yrs bp. A high proportion of Cichorioideae and Amaranthaceae, as well as the reduction of trees, in particular Fagus and Quercus, at lower elevations, indicate human activities such as intense livestock grazing and deforestation. Soil erosion as the result of less vegetation due to dry conditions and/or human activities can be reconstructed from a marked increase of Glomus spores and high values of K and Ti. Since 1,000 cal yrs bp, the increasing MI, as well as the rise of Poaceae and Cyperaceae together with forest recovery, suggest a change to wetter conditions. The occurrence of still frequent Cichorioideae and Plantago lanceolata along with Sordaria reflect continued intense grazing of livestock by humans. [ABSTRACT FROM AUTHOR]

The present study aims to reconstruct vegetation development, climate changes and human impact using an ombrotrophic peat core from the Coltrondo bog in the eastern Italian Alps. Evidence from pollen, micro-charcoal, major and trace elements, and lead isotopes from this 7,900 years old peat deposit has been combined, and several climatic oscillations and phases of human impact detected. In particular, human presence was recorded in this area of the Alps from about 650 cal bc, with periods of increased activity at the end of the Middle Ages and also at the end of the 19th century, as evidenced by both human-related pollen and the increase in micro-charcoal particles. The enrichment factor of lead (EFPb) increased since the Roman period and the Middle Ages, suggesting mainly mining activities, whereas the advent of industrialization in the 20th century is marked by the highest EFPb values in the whole core. The EFPb data are strongly supported by the 206Pb/207Pb values and these are in general agreement with the historical information available. Therefore, the multi-proxy approach used here has allowed detection of climatic events and human impact patterns in the Comelico area starting from the Iron Age, giving new insights into the palaeoecology as well as the course of the interaction among humans, climate and ecosystems in this part of the eastern Italian Alps. [ABSTRACT FROM AUTHOR]

Thirty-eight samples recovered from a latrine in the rural market town of Hadersdorf am Kamp (Lower Austria) and filled during the early 17th century were analysed and compared to the current bryophyte vegetation there and in its surroundings. Twenty-eight moss species from the latrine could be identified, and four taxa could be determined only to genus level because of missing sporophytes. The resulting data set is a valuable contribution to the state of knowledge of the bryophyte flora of that historic period, as none of the traditional methods such as herbaria date back to this early era. The most frequent species in the pit, Leucodon sciuroides, Antitrichia curtipendula and Neckera complanata, could hardly be found or not at all in the current bryophyte flora of the investigated area. A comparison of Ellenberg's indicator values of the historic and current moss taxa revealed significant differences for temperature, humidity and continentality. Temperature values were much lower for the taxa found in the latrine. Furthermore, the historic mosses reflect a more humid and less continental climate than the ones growing nowadays. Many of the mosses found in the latrine are epiphytic or epilithic and could not be found in the investigated area today. These results indicate a different climate during the time of the Little Ice Age in the investigated area. According to the low total biomass of mosses in the pit (1–2 g per 10 l) we suggest that those found in the latrine arrived there mainly by chance, as in sweepings. [ABSTRACT FROM AUTHOR]

Biodiversity has attracted much attention recently due to its important relationships with ecosystem function under various global warming scenarios. However, an understanding of biodiversity mechanisms requires study over long time scales. Three high-resolution pollen records of Zoige Basin in the eastern Tibetan Plateau are used to reconstruct changes in vegetation diversity during the Holocene, allowing the mechanisms that drove the dynamic to be quantitatively explored. Rarefaction and Hill's indices are used to estimate the diversity richness and evenness based on pollen data. The results show that changes in palynological richness can be divided into five stages: an abnormal change from 10,500 to 9,000 cal bp, an obvious increase from 9,000 to 6,500 cal bp, a decreasing trend from 6,500 to 4,000 cal bp, an increasing trend after 4,000 cal bp until 1,500 cal bp, and a highly fluctuating stage from 1,500 cal bp to the present. Palynological evenness is relatively stable throughout the Holocene except for during a briefly elevated period from ca. 4,000 to 1,500 cal bp. The result of Boosted Regression Tree analysis indicates that climate is the main driving factor and the effect of temperature is stronger than that of precipitation in the study region. However, during ca. 4,000–1,500 cal bp, palynological diversity is primarily affected by vegetation structure, as shown by an increase in palynological evenness, which can in turn be explained by the climate threshold theory. This research provides a long-term, high-resolution reconstruction of palynological diversity which could be used to infer vegetation diversity change in the ecologically sensitive Tibetan Plateau. The results imply that vegetation diversity in the region may increase under global warming if human impacts are not considered. [ABSTRACT FROM AUTHOR]

In this study, late Holocene vegetation, climate and human impacts were investigated using multiproxy data-pollen percentages, pollen accumulation rates (PAR), humification and loss-on-ignition (LOI)-measured from peat sediments from Daiyun Mountain, southeast China. A stratigraphic chronology was established on the basis of four radiocarbon dates. The 4,350 year sequence of vegetation history and climate change exhibits three distinctive stages: (1) 4,350-1,000 cal bp, during which the vegetation was dominated by evergreen forests mainly composed of broad-leaf trees, indicating a warm and wet climate; (2) 1,000-550 cal bp, during which the climate was thought to be cool and dry, based on a decrease in pollen percentages and the PARs of trees, shrubs and wetland herbs, and an increase in the pollen percentage and PAR of dry land herbs, as well as high overall LOI values; and (3) 550 cal bp to modern times, during which higher pollen percentages of dry land and wetland herbs, along with low pollen percentage and PAR of trees and shrubs, as well as low absorbance and LOI values, suggest relatively cooler but wetter climate conditions. In addition, major climatic events, such as the warm period from ad 670-960, the Medieval Warm Period ( ad 1050-1520) and the Little Ice Age ( ad 1580-1850), could be identified within the peat sediments in this study, with climatic conditions at these times being characteristically warm and wet, warm and dry, and cold and wet, respectively. Pollen signals indicate significant human impact since 1,000 cal bp, which may be linked to the development of the local porcelain industry and a rapid increase in the population in the study region. [ABSTRACT FROM AUTHOR]

Based on a dataset of 434 radiocarbon dates and charcoal data from burnt abandoned ant nests which were formerly interpreted as Mesolithic hearth-pits, the correlation between short periods of abrupt climatic cooling and increased forest fires during the early and middle Holocene is studied. Despite dating calibration limits, the results indicate a clear synchronicity between the 9.3 ka event and widespread and repeated forest fires which occurred in a coniferous woodland environment dominated by Pinus sylvestris (pine). It is argued that the cold and dry climatic conditions resulted in an overall desiccation of pines, which became prone to wildfires. A similar correlation is tentatively suggested for the 8.2 ka event, though changing climate first affected vegetation by reintroducing pines followed by increased wildfires. Indications of forest fires possibly caused by humans only appear around 6,400/6,200 uncal bp, corresponding to the final stage of hunter-gatherers along the southern North Sea basin. [ABSTRACT FROM AUTHOR]

At the turn of the second to the third millennium bc, fortified and systematically organized settlements along with a developed metallurgy emerged in the Trans-Ural steppe. In order to reconstruct the related vegetation and climatic changes in the area and to detect effects of human impact during the respective Bronze-Age Sintashta-Petrovka and Srubnaya-Alakul cultures (2100-1650 cal bc), palynological and sedimentological investigations accompanying archaeological excavations were carried out. Statistical analyses of pollen spectra from two sediment cores in the immediate vicinity of the settlement Kamennyi Ambar demonstrate substantial similarities in Bronze Age and present vegetation covers. Higher percentages of arboreal pollen, especially in respect of deciduous trees, and consistently high values of Artemisia within the regional spectra suggest that Bronze Age cultures developed in a relatively humid environment. Simultaneously, higher values of Chenopodiaceae, Plantago and Cichorioideae point to steppe degradation at local scales, whereas regional vegetation appears to have been relatively unaffected by human activities. Although more than 30 localities in the micro-region of Karagaily Ayat were analyzed, none of these sediment cores accounts for a continuous sedimentation during the last 9,000 years. Our results reveal that climatic fluctuations are not always directly reflected by sediment formation, with many non-climatic factors, such as post-sedimentary processes, local morphology and erosion believed to be crucial. Only the use of high resolution AMS radiocarbon dating is suitable to detect hiatuses, hence providing a valuable clue to the interpretation of palaeoenvironmental conditions. [ABSTRACT FROM AUTHOR]

In Near Eastern archaeology, studies on crop management during the early stages of civilisation have been based on cuneiform texts and only recently have geoarchaeological surveys and archaeobotanical studies tried to identify agricultural practices. Nevertheless, direct evidence for irrigation and water management is very rare and difficult to interpret. New possibilities for analysing these ways of management have been provided by stable carbon isotope analysis of ancient crops. In this study carbon isotope discrimination (ΔC) was performed to assess the growing conditions of fossil cereal grains. Charred grains of emmer and barley recovered from the same site, Arslantepe in eastern Anatolia, over a 1,000 years long continuous sequence during the third millennium b. c. have been analysed and compared. The variation in water availability during grain filling, estimated by ΔC, can be attributed to climate change and/or human practices. Distinguishing exactly which is to blame is complex but essential in reconstructing specific management practices. Variations in the C/C ratio suggest that barley and emmer grew under different water regimes. In particular, a different management system was adopted between 3000 and 2800 cal. b. c. when emmer was sustained by human-induced water supply, whereas the more resistant barley was rain-fed and possibly assigned to more marginal terrains. Our results are compared with the stable carbon isotope data available for other Near Eastern sites. Emmer and barley records are also compared with deciduous oak ΔC from Arslantepe in order to better understand the influence of environmental factors, climate and human impact. [ABSTRACT FROM AUTHOR]

The dynamics of mangrove forest on the island of Marajó (Ilha de Marajó) at the mouth of the river Amazon during the past ~7,500 cal. b.p. were studied using multiple proxies, including sedimentary facies, pollen, δC, δN and C/N ratio, related to 15 sediment samples by C dating. The results allow us to propose a scheme of palaeogeographical development, with changes in vegetation, hydrology and organic matter dynamics. Today, the interior of the island is occupied by várzea freshwater herbaceous vegetation, but during the early to middle Holocene, mangroves with accumulations of estuarine organic matter colonized the tidal mud flats. This spread of mangroves was caused by post-glacial sea-level rise, which combined with tectonic subsidence, produced a marine transgression. It is likely that the relatively greater marine influence at the studied area was favoured by reduced discharge from the river Amazon, which was itself caused by a dry period that occurred during the early and mid Holocene. During the late Holocene, there was a reduction of mangrove vegetation and the contribution of freshwater organic matter to the area was higher than during the early and mid Holocene. This suggests a decrease in marine influence during the late Holocene which led to a gradual migration of mangrove vegetation from the central region to the northeastern littoral zone of the island, and, consequently, its isolation since at least ~1,150 cal. b.p. This was probably a result of lower tidal water salinity caused by a wet period that resulted in greater river discharge during the late Holocene. This work details the contraction of mangrove forest from the northeastern part of the island of Marajó under the influence of Amazon climatic changes, chronologically and spatially. This allows us to propose a model of successive phases of sediment accumulation and vegetation change, according to the marine-freshwater influence gradient. As demonstrated by this work, the use of a combination of proxies is efficient for establishing a relationship between the changes in estuarine salinity gradient and depositional environment/vegetation. [ABSTRACT FROM AUTHOR]

To estimate whether or not a plant taxon found in the fossil record was locally present may be difficult if only pollen is analyzed. Plant macrofossils, in contrast, provide a clear indication of a taxon's local presence, although in some lake sediments or peats, macrofossils may be rare or degraded. For conifers, the stomata found on pollen slides are derived from needles and thus provide a valuable proxy for local presence and they can be identified to genus level. From previously published studies, a transect across the Alps based on 13 sites is presented. For basal samples in sandy silt above the till with high pollen values of Pinus, for example, we may distinguish pine pollen from distant sources (samples with no stomata), from reworked pollen (samples with stomata present). The first apparent local presence of most conifer genera based on stomata often but not always occurs together with the phase of rapid pollen increase (rational limit). An exception is Larix, with its annual deposition of needles and heavy poorly dispersed pollen, for it often shows the first stomata earlier, at the empirical pollen limit. The decline and potential local extinction of a conifer can sometimes be shown in the stomata record. The decline may have been caused by climatic change, competition, or human impact. In situations where conifers form the timberline, the stomata record may indicate timberline fluctuations. In the discussion of immigration or migration of taxa we advocate the use of the cautious term 'apparent local presence' to include some uncertainties. Absence of a taxon is impossible to prove. [ABSTRACT FROM AUTHOR]

The eastern Baltic region is situated in the southeastern part of the area which was covered by the last Scandinavian glaciation. Four well-dated sediment profiles from sites distributed along a ~330-km north-south transect were analysed for their macrofossil contents. The immigration of tree taxa during the Late-glacial (LG) period, which was the time of environmental change from tundra to woodland in previously glaciated areas, can be determined from these data. The pioneer vegetation in the study area was treeless dwarf shrub tundra with various dominant taxa. The so-called Allerød hemispheric warming permitted the Post-glacial immigration of trees into the southern part of the eastern Baltic region; however, these most probably disappeared during the following cold period, the Younger Dryas/GS-1. The local presence of Betula sect. Albae, Pinus sylvestris, Populus tremula and Picea abies during the LG period in the southern part of the region was confirmed. The northern part of the area presumably remained treeless for the entire LG period. Therefore, until the beginning of the Holocene, the tree line in the eastern Baltic region did not reach beyond 58°N. [ABSTRACT FROM AUTHOR]

This study integrates analysis of wood charcoal assemblages with climate proxies, palaeoenvironmental and archaeological data sets in hyper-arid Wadi Sana, Yemen, to address the availability and use of wood fuels by South Arabian hunter-herder groups from the Early Holocene (8000-7700 cal. b.p.) to Middle Holocene (6900-4800 cal. b.p.) periods. The Early Holocene environment, regulated by a stronger Southwest Asian monsoon, was moister than the present, providing a marshy winter grazing area for cattle herders, whose construction of hearths and food preparation strategies changed over time. This study provides an insight into long term stability of land cover and use as well as the dynamics of human contributions to landscape change. We suggest that complex environmental and cultural processes affect species availability, fuel choice and land use management. Despite environmental and economic changes in Wadi Sana, our dataset does not show changes in fuel choice from the Early to Middle Holocene. [ABSTRACT FROM AUTHOR]

The number of well-dated pollen diagrams in Europe has increased considerably over the last 30 years and many of them have been submitted to the European Pollen Database (EPD). This allows for the construction of increasingly precise maps of Holocene vegetation change across the continent. Chronological information in the EPD has been expressed in uncalibrated radiocarbon years, and most chronologies to date are based on this time scale. Here we present new chronologies for most of the datasets stored in the EPD based on calibrated radiocarbon years. Age information associated with pollen diagrams is often derived from the pollen stratigraphy itself or from other sedimentological information. We reviewed these chronological tie points and assigned uncertainties to them. The steps taken to generate the new chronologies are described and the rationale for a new classification system for age uncertainties is introduced. The resulting chronologies are fit for most continental-scale questions. They may not provide the best age model for particular sites, but may be viewed as general purpose chronologies. Taxonomic particularities of the data stored in the EPD are explained. An example is given of how the database can be queried to select samples with appropriate age control as well as the suitable taxonomic level to answer a specific research question. [ABSTRACT FROM AUTHOR]

We used fossil pollen to investigate the response of the eastern Chiquitano seasonally-dry tropical forest (SDTF), lowland Bolivia, to high-amplitude climate change associated with glacial-interglacial cycles. Changes in the structure, composition and diversity of the past vegetation are compared with palaeoclimate data previously reconstructed from the same record, and these results shed light on the biogeographic history of today's highly disjunct blocks of SDTF across South America. We demonstrate that lower glacial temperatures limited tropical forest in the Chiquitanía region, and suggest that SDTF was absent or restricted at latitudes below 17°S, the proposed location of the majority of the hypothesized 'Pleistocene dry forest arc' (PDFA). At 19500 yrs b.p., warming supported the establishment of a floristically-distinct SDTF, which showed little change throughout the glacial-Holocene transition, despite a shift to significantly wetter conditions beginning ca. 12500-12200 yrs b.p. Anadenanthera colubrina, a key SDTF taxon, arrived at 10000 yrs b.p., which coincides with the onset of drought associated with an extended dry season. Lasting until 3000 yrs b.p., Holocene drought caused a floristic shift to more drought-tolerant taxa and a reduction in α-diversity (shown by declining palynological richness), but closed-canopy forest was maintained throughout. In contrast to the PDFA, the modern distribution of SDTF most likely represents the greatest spatial coverage of these forests in southern South America since glacial times. We find that temperature is a key climatic control upon the distribution of lowland South American SDTF over glacial-interglacial timescales, and seasonality of rainfall exerts a strong control on their floristic composition. [ABSTRACT FROM AUTHOR]

Modern pollen samples provide an invaluable research tool for helping to interpret the quaternary fossil pollen record, allowing investigation of the relationship between pollen as the proxy and the environmental parameters such as vegetation, land-use, and climate that the pollen proxy represents. The European Modern Pollen Database (EMPD) is a new initiative within the European Pollen Database (EPD) to establish a publicly accessible repository of modern (surface sample) pollen data. This new database will complement the EPD, which at present holds only fossil sedimentary pollen data. The EMPD is freely available online to the scientific community and currently has information on almost 5,000 pollen samples from throughout the Euro-Siberian and Mediterranean regions, contributed by over 40 individuals and research groups. Here we describe how the EMPD was constructed, the various tables and their fields, problems and errors, quality controls, and continuing efforts to improve the available data. [ABSTRACT FROM AUTHOR]

The radiocarbon-dated palaeoecological study of Lago Riane (Ligurian Apennines, NW Italy) presented here forms part of a wider investigation into the relationships between Holocene vegetation succession, climate change and human activities in the northern Apennines. The record of vegetation history from Lago Riane indicates that, since the end of the last glaciation, climate change and prehistoric human activities, combined with several local factors, have strongly influenced the pattern and timing of natural vegetation succession. The pollen record indicates an important change in vegetation cover at Lago Riane at ~8500-8200 cal. years b.p., coincident with a well-known period of rapid climate change. At ~6100 cal. years b.p., Fagus woodland colonised Lago Riane during a period of climate change and expansion of Late Neolithic human activities in the upland zone of Liguria. A marked decline in Abies woodland, and the expansion of Fagus woodland, at ~4700 cal. years b.p., coincided with further archaeological evidence for pastoralism in the mountains of Liguria during the Copper Age. At ~3900-3600 cal. years b.p. (Early to Middle Bronze Age transition), a temporary expansion of woodland at Lago Riane has been provisionally attributed to a decline in human pressure on the environment during a period of short-term climate change. [ABSTRACT FROM AUTHOR]

The mid-continent of North America has experienced dramatic and abrupt climate change during the Holocene, but the response of grassland vegetation to past climate change has been difficult to quantify. To improve interpretation of tallgrass prairie vegetation from pollen assemblages, we acquired and analysed a surface sample set collected from 25 small ponds (less than 10 ha surface area) in the largest contiguous remnant of tallgrass prairie in the USA. We compared these tallgrass prairie assemblages to 476 modern pollen samples classified as 'prairie' in the North American Surface Sample database. We then compared the surface pollen assemblages with fossil pollen assemblages from sediment cores at two sites in Kansas-Cheyenne Bottoms and Muscotah Marsh-using the modern analog technique. Pollen assemblages in the Flint Hills surface samples were very similar to each other, with an average squared chord distance of 0.19. They were different than other modern grassland pollen assemblages mainly due to higher percentages of pollen from six woody taxa: Carya, Cornus, Juniperus, Juglans, Maclura, and Platanus. Arboreal pollen percentages ranged from 17 to 62 % and did not correlate with woody cover among sites. Cheyenne Bottoms was open grassland for the past 25,000 years, but it did not have many tallgrass prairie analogs. Muscotah Marsh did not have many grassland analogs over the past 30,000 years, possibly due to its position on the prairie-forest border or its surrounding wetland vegetation. [ABSTRACT FROM AUTHOR]

A detailed, AMS C-dated, pollen record from Cooney Lough, a small lake in Co. Sligo, western Ireland, is presented. Fluctuations in the pollen curves, indicative of changes in pollen productivity and shifts in woodland composition, suggest that the period spanned by the record (9.4-6 ka) was characterised by considerable climate instability. In all, five climate anomalies are recognised (CA-1 to CA-5). The most pronounced anomaly, CA-3, is dated to 8.45-8.2 ka, with the high point of that anomaly (CA-3b) centred on 8.2 ka and lasting about a century. On the basis of age, and also intensity and structure, CA-3b is equated with the 8.2 ka event as recorded in many proxies and especially the Greenland ice-core δO records. Key features of the event as recorded in the lake sediments include increased representation of Betula and Pinus (birch and pine; both widely recognised as cold tolerant trees) and a decline in Corylus and also Quercus (hazel and oak; both thermophilous). The anomalies CA-1 and CA-2 precede the 8.2 ka event, the former corresponding probably to the 9.2 ka event and the latter more pronounced, centred on ca. 8.8 ka and with a duration of approximately 100 years. The CA-4 event, at ca. 7.5 ka, is relatively minor as regards intensity while CA-5, which began at ca. 7.1 ka, initiated what seems to be a more long-lasting shift towards cooler conditions. The relationship of these developments to the arrival and expansion of alder ( Alnus), a key feature of the Boreal/Atlantic transition in European, including Irish pollen records is also discussed. [ABSTRACT FROM AUTHOR]

Late-glacial vegetation changes were studied at Rieme, NW Belgium. Human occupation of this cover sand area occurred from the Final Palaeolithic onwards. The research area is situated on the northern side of a large cover sand ridge in an undulating landscape with small ridges and depressions. The past landscape was reconstructed using a multi-disciplinary approach, including geomorphological, sedimentological, loss-on-ignition, botanical (micro- and macrofossil) and zoological analyses. AMS C dating provided an accurate chronology for the sediments. Analyses were performed on three sequences located ~200-300 m apart. Our study shows that during the Bølling (GI-1e) wet meadows developed on the sandy soils and groundwater levels increased probably as result of permafrost melting. Shallow pools formed in depressions. During the Older Dryas (GI-1d) shrubs with juniper, sea-buckthorn and willow developed. Many shallow depressions were overblown with sand and deposition of organic material almost ceased. In the early Allerød (GI-1c) open birch woodlands developed. Due to the final melting of permafrost, groundwater levels rose further and ponds with floating-leaved open water vegetation developed. Large water level fluctuations occurred in one of the ponds. Accumulation of organic deposits ceased during the mid-Allerød. Indirect evidence for human occupation during the Allerød (GI-1c) was found in indications of burning of the reed-swamps in combination with the presence of large herbivores. Final Palaeolithic people probably used the northern side of the cover sand ridge as hunting area, while they settled their temporary (base) camps on the steep southern side along the extensive and deeper Moervaart lake. [ABSTRACT FROM AUTHOR]

Past vegetation change and the influence of climate change and anthropogenic pressure during the Holocene is constructed from a series of palynological records sampled from three locations within the territory of the antique site of Sagalassos. The disappearance of the original deciduous oak woodlands and increases in anthropogenic indicator species around 5300 and 4300 b.c. correspond with an increase in settlements in the region. A period of drought following the deforestation may have hampered the recovery of deciduous oak. The timing of the onset of the Beyşehir Occupation Phase (BO-Phase) in the territory differs between locations, estimates ranging from ca. 1000-800 b.c. to the start of the Hellenistic period (334 b.c.). The most intense period of arboriculture coincides with the Roman and late-Roman periods. Increases in human pressure on the landscape as reflected in the pollen record correspond with an increased rate of sedimentation and fire activity. The timing of the end of the BO-Phase again differs between locations. Estimates range from the 4th century a.d. to the mid 7th century a.d., when a region-wide shift to dry environmental conditions is observed. Numerical analyses show that post BO-Phase vegetation change is largely driven by climate and displays a succession of dry and wet periods that coincided with well-defined European climate shifts, including the Medieval Climate Anomaly and the Little Ice Age. Current agricultural activities in the region are of a very recent (20th century) origin. [ABSTRACT FROM AUTHOR]

We reconstructed the palaeoenvironmental conditions of the last ca. 8,000 years in the Tres Lagunas region of the Quimsacocha volcanic basin (ca. 3,800 m a.s.l.) in the southwestern Ecuadorian Andes. By means of a pollen and charcoal record, we analysed vegetation, fire, and climate history of this area, which is sensitive to climatic changes of both the Pacific as well as of the eastern Andes and Amazon region. Sediment deposits, pronounced increases of pollen and charcoal concentrations, and pollen taxa reflect warmer and drier conditions in the early to mid-Holocene (~8000 to 3900 cal. b.p.). During the late Holocene (2250 to −57 cal. b.p.), five warm and cold phases occurred at Quimsacocha. The most prominent cold phase possibly corresponds to the globally recognized Little Ice Age (LIA; ~600 to 100 cal. b.p.). The cold phase signal at Quimsacocha was characterized by a higher abundance of Poaceae, Isoëtes and Gentianella, which are favoured by cold and moist conditions. Frequent charcoal particles can be recorded since the early to mid-Holocene (~7600 b.p.). The high Andean tree species Polylepis underwent several phases of degradation and re-establishment in the basin, which could indicate the use of fire by pre-Columbian settlers to enhance the growth of preferred herb species. The Tres Lagunas record suggests that human populations have been influencing the environment around Quimsacocha since the last ca. 8,000 years. [ABSTRACT FROM AUTHOR]

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 correlations between pollen data and climate. Pollen data are PAR summarized per region (4–7 traps selected per region) for each pollen type (9–14 per region) using log-transformed, detrended medians. Climate data are monthly temperature and precipitation measured at nearby stations, and their averages over all possible 2- to 6-month windows falling within the 20-month window ending with August, just prior to the yearly pollen-trap collection. Most PAR/climate relationships were found to differ both among pollen types and among regions, the latter probably due to differences among the study regions in the habitats of plant populations. Results shared by a number of regions can be summarized as follows. Summer warmth was found to enhance the following year’s PAR of Picea, Pinus non- cembra, Larix and Fagus. Cool summers, in contrast, increase the PAR of Abies, Alnus viridis and Gramineae in the following year, while wet summers promote PAR of Quercus and Gramineae. Wetness and warmth in general were found to enhance PAR of Salix. Precipitation was found to be more important for PAR of Alnus glutinosa-type than temperature. Weather did not have an impact on the PAR of Gramineae, and possibly of Cyperaceae in the same year. Care is advised when extrapolating our results to PAR in pollen sequences, because there are large errors associated with PAR from sediments, due to the effects of taphonomy and sedimentation and high uncertainty in dating. In addition, in pollen sequences that have decadal to centennial rather than near-annual resolution, plant-interaction effects may easily out-weigh the weather signal. [ABSTRACT FROM AUTHOR]

In the DOORMAT (Direct Observation of Recent Macrofossils Across Treeline) project, the modern representation of local vegetation by pollen and plant remains (plant macrofossils) across a west Norwegian tree line, composed of Betula pubescens and Pinus sylvestris, has been studied over 2 years. The aim was to discover if the modern tree line could be detected and therefore how precisely past tree-line movements could be reconstructed and related to Holocene climate changes by using one proxy or a combination of both. Traps were placed in the vegetation from 663 to 1,120 m a.s.l., spanning the pine altitudinal species limit, the birch tree-line ecotone, and the vegetation zones up to the mid-alpine zone. Three traps were also set in the small lake Trettetjørn close to the modern tree line at 800 m a.s.l. Traps were emptied twice a year to sample both summer and winter seasons. Macrofossils represent their local vegetation well. However, tree Betula remains were trapped above the tree line and Pinus and Picea remains were recorded 1.0–1.5 km away from their sources, demonstrating considerable dispersal capacity. This shows that rare macrofossil remains do not necessarily represent the local presence of these trees. Aerial tree pollen deposition in traps at the upper limit of pine woodland and in the subalpine birch woodland was unexpectedly low, whereas pollen accumulation rates (PAR) were orders of magnitude higher in the lake traps. We hypothesise that the lake receives regional pollen rain washed in from its catchment by snow meltwater and that high values in traps are due to continuous suspension of pollen in the lake water during summer. The interpretation of tree-line changes from existing Holocene pollen and plant macrofossil data from Trettetjørn was supported and refined by the DOORMAT macrofossil data, but the modern pollen data were anomalous. [ABSTRACT FROM AUTHOR]

Abstract  Here we argue that, based on evolutionary, ecological and agronomic considerations, climate change could not have been a suitable background nor a probable cause of plant domestication in the Near East. This thesis is developed based on the year-to-year yield dynamics in traditional rainfed grain farming in semi-arid environments, on the genetic basis that underlies temporal yield dynamics in natural wild cereal populations as well as in traditional farming systems, and upon the recognition that prior to elaborate high capacity and long-range trade networks, yield stability was more important than yield maximization. We also briefly discuss the likely social and cultural responses to subtle and real climatic changes vs. responses to rapid directional environmental trends. Taking into account the agronomic, ecological and genetic aspects discussed, it is suggested that the Near Eastern founder crop assemblage was chosen to function within the normal east Mediterranean precipitation regime, in which good rainy years create the ‘normal surplus’ that sustains farming communities during drought years, and the different crop types provide the system with its compensating ability. A slow (but real) climatic change is unlikely to induce major (revolutionary) cultural changes. Nor would a prominent environmental change provide the proper background for the origins of agriculture because it would abolish the buffering capacity of the system. Therefore, farming cannot function as a sustainable ‘buffering mechanism’ to counterbalance climatic instability causing natural resource depletion. [ABSTRACT FROM AUTHOR]

Abstract  Connections between environmental and cultural changes are analysed in Estonia during the past c. 4,500 years. Records of cereal-type pollen as (agri)cultural indices are compared with high-resolution palaeohydrological and annual mean temperature reconstructions from a selection of Estonian bogs and lakes (and Lake Igelsjön in Sweden). A broad-scale comparison shows increases in the percentage of cereal-type pollen during a decreasing trend in annual mean temperatures over the past c. 4,300 years, suggesting a certain independence of agrarian activities from environmental conditions at the regional level. The first cereal-type pollen in the region is found from a period with a warm and dry climate. A slow increase in pollen of cultivated land is seen around the beginning of the late Bronze Age, a slight increase at the end of the Roman Iron Age and a significant increase at the beginning of the Middle Ages. In a few cases increases in agricultural pollen percentages occur in the periods of warming. Stagnation and regression occurs in the periods of cooling, but regression at individual sites may also be related to warmer climate episodes. The cooling at c. 400–300 cal b.p., during the ‘Little Ice Age’ coincides with declines in cereal-type and herb pollen curves. These may not, however, be directly related to the climate change, because they coincide with war activities in the region. [ABSTRACT FROM AUTHOR]

Abstract  Distribution maps of crop plants in Early to Middle Bronze Age northern Mesopotamia and the Levant show distinct changes with regard to relative plant presence in samples, proportions of various crops found and frequencies in the total number of finds, which may be interpreted as changes in agro-production reflecting human adaptation to increasing aridity from climate change after 4200 b.p. The hypothesis of a causal relationship between correlated proxy palaeoclimate and archaeobotanical data is tested with the independent evidence from stable carbon isotope analysis in plant remains. Ancient plant remains show that Δ13C is decreased for Middle Bronze Age objects, which coincides chronologically with a broad pattern of drier climate inferred from several palaeoclimate proxy records. The hypothesis of a causal relation between climate change and farming is valid, thus archaeobotanical data are suitable for investigating past relations between climate change and agro-production on a broader scale. [ABSTRACT FROM AUTHOR]

Abstract  Palaeoecological data are compared with output from climate-driven forest simulation models to separate human influence as a driver of vegetation dynamics from other drivers such as climatic change. The transition from Tilia cordata to Fagus sylvatica dominance in a small forest hollow in Denmark was not predicted by a climate-driven forest simulation model and could be ascribed to anthropogenic impact. This transition can be upscaled to a large region of north-west Europe and contributes to a data-model mismatch for the European distribution of Fagus 6,000 years ago. A data-model mismatch for Picea abies during the last few centuries in southern Scandinavia can also be attributed to anthropogenic impact. Combining pollen data and vegetation models can help with the important task of upscaling from the scale of the forest stand, where anthropogenic impact is readily detectable, to regions and continents, where it is more challenging to distinguish anthropogenic impact from the impacts of climatic change. [ABSTRACT FROM AUTHOR]

Abstract  We simulated pollen assemblages for 11 sites on the Swiss Plateau (Schweizer Mittelland) based on a low resolution land cover map and pollen productivity estimates (PPE) from this region. A comparison between observed and simulated pollen data demonstrated that the majority of the simulated pollen proportions were within a range of 5% of over- or underestimation, and that at eight of the 11 sites the dominant taxon was correctly estimated. The modelled sum of arboreal pollen was correct within ±11% at nine sites. Our results indicate that the PPE established for the Swiss Plateau can be used to simulate pollen assemblages with reasonable accuracy. Moreover, our results justify the use of the POLLSCAPE simulation using the Prentice-Sugita model and its variations of pollen dispersal and deposition in more complex topographic landscapes than those to which they have hitherto been applied. [ABSTRACT FROM AUTHOR]

Abstract  Understanding the characteristics of pollen dispersal and deposition of different plant taxa is crucial to accurately reconstructing past landscapes using fossil pollen data. Quantitative reconstruction of past landscapes from pollen data using the Prentice-Sugita approach requires estimates of fall speed and relative pollen productivity for all taxa modelled. This study presents estimates of pollen productivity and fall speeds for key southern African savanna taxa, providing a basis for the improved interpretation of fossil pollen records from this extensive and heterogeneous biome. The work was carried out in 5 steps. (1) Modern pollen assemblages from 34 surface sediment samples were analysed. (2) Vegetation around each sampling site was surveyed in concentric circles to a radius of 50 m, and data from existing park surveys were analysed to extend the survey distance to 5 km. (3) Fall speeds for the main pollen taxa were estimated using Stoke’s Law of particle settling velocity. (4) Vegetation data were weighted using three different distance-weightings, one incorporating the different particle fall speeds. (5) Extended R-Value analysis was carried out on the pollen and distance-weighted plant abundance datasets using HUMPOL software to estimate relevant source area and relative pollen productivity for the main pollen taxa present. Results showed the Relevant Source Area of Pollen surrounding the sites to be 600–900 m radius, and Poaceae/Cyperaceae were found to be twice as productive (PPE 2.03) as the arboreal taxa analysed (PPE 0.50–0.99). The problems encountered in calculating pollen productivity estimates in savanna environments are discussed and improvements for future studies are suggested. [ABSTRACT FROM AUTHOR]

Abstract  The New Forest is one of the most visited regions of Britain. It has recently been designated a National Park in recognition of its unique wood pasture ecosystems, a traditional land-use system, its magnificent scenery and recreational potential, and its biodiversity importance. The Forest’s highly prized Ancient and Ornamental (A&O) woodlands are a result of complex interactions among human activities of several kinds and the ecology of the dominant species–beech and oak—under the climate conditions of the last one to two millennia. Major changes in management practices over the 20th century, combined with the historical imprint of previous centuries of use, have set the A&O woodlands on a trajectory that means their nature and appearance will inevitably change over the coming decades. When the potential stresses that will be imposed by 21st century climate change are also considered, it will be challenging to find a management strategy to maintain A&O woodlands in their present form. Beech, which owes its current dominance largely to human disturbances of the woodland ecosystem, will be particularly stressed under future conditions. Future conservation policies, and hence management strategies, must be flexible as to the species composition and structure of future woodlands. However, the wide range of users and their different values add further complexity to forest management, and managers must also focus on issues of public perception. For example visitors idealize current landscapes, and this exerts a pressure to maintain the status quo as far as appearance is concerned that will be hard to achieve in practice. Management strategies will be greatly constrained unless conflicts about values and uses are resolved. [ABSTRACT FROM AUTHOR]

Abstract  An interdisciplinary palaeoecological study in the low-alpine and subalpine zones of Val Febbraro, upper Valle di Spluga (Italy), between 1830 and 2304 m a.s.l., suggests the temporary presence of early Neolithic groups at about 6000 uncal b.p. Evidence for local woodland clearance and charcoal dust were found. Phases of woodland and treeline disturbances, and indications of increased human presence are evident at about 5500, 5100, and 4000 b.p. A marked increase in disturbance, mainly related to pasturing, is dated to the beginning of the Bronze Age. The last major stage of human impact on the vegetation coincides with the Final Bronze phase and the beginning of the Iron Age, with a small temporary reduction during the Roman period. 14C dated archaeological sites and finds are broadly concordant with the phases of human impact on the vegetation. A summary figure is presented. No locally significant climatic changes have been traced during the last 6000 years, and if present, they are probably overshadowed by the vegetational changes caused by human activity. [ABSTRACT FROM AUTHOR]

Abstract  In 1998, an ancient shipping wharf was brought to light in Pisa, Italy. The shipwrecks found there showed human activity from the Etruscan to the late Roman Empire periods. Sandy sediments burying the ships and related materials show four main periods of catastrophic floods separated by thin muddy layers pointing to phases between flooding episodes. Pollen analyses in these fine grained deposits showed: 1) significant percentages of Abies and Fagus during the pre-Roman period; 2) elements of mixed oak woodland together with hygrophilous plants in pollen spectra dominated by herbs, in the Roman interflood deposits. On the whole, the pollen data show a vegetational change which may be attributed to different climatic conditions, supporting the hypothesis that the Roman period was warmer, even though a significant human influence cannot be excluded. Numerous fresh water genera suggest that the area was a poorly drained alluvial plain. Integration between pollen and sedimentological analyses allows some inferences on the dynamics of the warm Roman period and indicates that the warm climate was punctuated by century-scale hydro-climatic crises triggering catastrophic floods. [ABSTRACT FROM AUTHOR]

Abstract  A pollen and charcoal record from Gargano (southern Italy) provides new information on the vegetation history and environmental change in southern Italy during the middle to late Holocene. The chronological framework is provided by six AMS radiocarbon dates carried out on plant macroremains. Pollen diagrams record a Mediterranean vegetation along the coastland and a stable mixed oak forest at higher elevations between ca. 5900 and 4200 calb.p.A sharp and dramatic fall of tree pollen concentrations and a change in fire frequencies occurred from approximately 4200 calb.p.suggesting a climate change towards drier conditions. This event is coherent with regional and extra-regional palaeoclimatic records that suggest that a mid-Holocene dry period was experienced in southern Italy, southern Spain, and perhaps further afield. Human impact on vegetation seems to have occurred since about 2700 calb.p. [ABSTRACT FROM AUTHOR]

Abstract??Two pollen diagrams from near the Chuya Basin, Russian Altai, are presented together with results from geomorphological archives. The Kuray Range profile (2330?m?a.s.l.) is situated just above the forest line and starts with the weak cooling of the middle Atlantic period (ca. 6500?5900b.p.) that bisects the Holocene optimum, as in other parts of Siberia. Taiga (boreal coniferous forest) withPicea obovataestablished afterwards but was displaced at ca. 5300b.p.by the pronounced cooling of the early Sub-boreal. A gradual recovery of taiga stopped and it disappeared around 3400b.p.at the end of the middle Sub-boreal. Since then the climatic and vegetational conditions much resemble those of the Sub-atlantic. In the last two millennia, three climatic declines are documented in the second diagram from the Tarkhata Valley (2210?m?a.s.l.) from the dry limit ofLarix sibirica: a cold and wet one around the 5th centurya.d., a cold and dry one arounda.d.1200 and the Little Ice Age which started arounda.d.1600. In addition, several of the climatic periods and especially local human influence can be proved by the geomorphological findings. Most of the climatic changes seem to be connected with socio-ecological changes in Asia and even Europe, with movements of the Huns and Mongols, which show the possible dimensions of global climatic change. Hints of teleconnections between Siberia, the Mediterranean and the Himalayas via the North Atlantic and the Arctic Oscillation are discussed. [ABSTRACT FROM AUTHOR]

Abstract  Holocene environmental and climatic changes are reconstructed using analyses of biological proxies in lake sediments from Vuolep Njakajaure, a lake located near the altitudinal treeline in northern Sweden (68°20′ N, 18°47′ E). We analysed biological proxy indicators from both aquatic and terrestrial ecosystems, including diatoms, pollen and chironomid head capsules, in order to reconstruct regional Holocene climate and the development of the lake and its catchment. During the early Holocene and after 2500 cal b.p., Fragilaria taxa dominated the diatom assemblages, whereas planktonic Cyclotella taxa prevailed during the major part of the Holocene (7800–2300 cal b.p.), indicating the importance of the pelagic habitat for diatom assemblage composition. The planktonic diatoms appeared at the same time as Alnus became established in the catchment, probably altering nutrient availability and catchment stability. The pollen record is dominated by mountain birch (Betula pubescens ssp. tortuosa) pollen throughout the Holocene, but high percentage abundances of Scots pine (Pinus sylvestris) pollen suggest the presence of a mixed pine-birch forest during the mid-Holocene (6800–2300 cal b.p.). Head capsules of Tanytarsini and Psectrocladius dominated the chironomid assemblage composition throughout the Holocene, in combination with Corynocera ambigua after 2300 cal b.p. A quantitative, diatom-based reconstruction of mean July air temperature indicated a relatively cold temperature during the early Holocene (9000–8000 cal b.p.) and after ca. 2300 cal b.p., whereas the mid-Holocene period is characterised by stable and warm temperatures. The overall patterns of Holocene climate and environmental conditions are similarly described by all biological proxy-indicators, suggesting relatively warm conditions during the mid-Holocene (ca. 7800–2300 cal b.p.), with a subsequent colder climate after 2300 cal b.p. However, the onset and magnitude of the inferred changes differ slightly among the proxies, illustrating different responses to lake development phases, land-uplift, and climate forcing (e.g., insolation patterns) during the Holocene in northern Sweden. [ABSTRACT FROM AUTHOR]

Abstract  In the last decades, data on the economy and environment of the Neolithic period of lake dwellings (4300–2400 b.c.) in central Europe has increased considerably and also palaeoecological data on lake level fluctuations has been thoroughly elaborated. Lake shores were mainly settled during warm and rather dry climate periods which caused a fall in the lake levels. Nevertheless, there were strong and partly very short-term shifts in the economy during the lake-dwelling period. These can be recognised only because the settlement layers can be very precisely dated by dendrochronology. In this article we discuss in an interdisciplinary way the possible interrelations between climatic and economic changes. To explain the latter, we assume crop failures as the main reason, which caused intensified hunting and gathering. There are three different possibilities which might explain this: cold and wet summers, severe droughts during spring and summer, or local over-exploitation of soils in densely settled areas. [ABSTRACT FROM AUTHOR]

Two14C-dated pollen profiles from mires in the steppe belt of southern Russia are presented. On the basis of these and data from earlier investigations, the Holocene forest history of the southern part of Russia and Ukraine is reconstructed. The steppe belt is very sensitive to climatic oscillations and, in particular, to changes in evapotranspiration. The most favourable climate occurred between 6000 and 4500 B.P. (6800–5200 cal. B.P.), when forest attained its maximum extent in the steppe belt. The period 4500–3500 B.P. (5200–3800 cal. B.P.) was characterised by drier climate with the most arid phase occurring between 4200–3700 B.P. (4700–4000 cal. B.P.). During arid phases, the area under forest and also peat accumulation rates declined. Subsequently, a number of less pronounced climatic oscillations occurred such as in the period 3400/3300−2800 B.P. (3600/3500−2900 cal. B.P.) when there was a return to more humid conditions. During the last 2500 years, the vegetation cover of the steppe belt in southern Russia and Ukraine took on its present-day aspect. On the one hand, there is close correlation between the Holocene vegetation history of southern Russia and Ukraine and, on the other hand, the steppe belt of Kazakhstan and transgressions in the Caspian sea. Human impact on the natural vegetation became important from the Bronze Age onwards (after 4500 B.P.; 5200 cal. B.P.). Particular attention is given to the history of Scots pine ( Pinus sylvestris), which had a much wider distribution in the southern part of eastern Europe in the early Holocene. The reduction in range during recent millennia has come about as a result of the combined effects of both climatic deterioration and increased human impact. [ABSTRACT FROM AUTHOR]

The palynostratigraphy of two sediment cores from Soppensee, Central Switzerland (596 m asl) was correlated with nine regional pollen assemblage zones defined for the Swiss Plateau. This biostratigraphy shows that the sedimentary record of Soppensee includes the last 15 000 years, i.e. the entire Late-glacial and Holocene environmental history. The vegetation history of the Soppensee catchment was inferred by pollen and plant-macrofossil analyses on three different cores taken in the deepest part of the lake basin (27 m). On the basis of a high-resolution varve and calibrated radiocarbonchronology it was possible to estimate pollen accumulation rates, which together with the pollen percentage data, formed the basis for the interpretation of the past vegetation dynamics. The basal sediment dates back to the last glacial. After reforestation with juniper and birch at ca. 12 700 B.P., the vegetation changed at around 12 000 B.P. to a pine-birch woodland and at the onset of the Holocene to a mixed deciduous forest. At ca. 7000 B.P., fir expanded and dominated the vegetation with beech becoming predominant at ca. 50014C-years later until sometime during the Iron Age. Large-scale deforestation, especially during the Middle Ages, altered the vegetation cover drastically. During the Late-glacial period two distinct regressive phases in vegetation development are demonstrated, namely, the Aegelsee oscillation (equivalent to the Older Dryas biozone) and the Younger Dryas biozone. No unambiguous evidence for Holocene climatic change was detected at Soppensee. Human presence is indicated by early cereal pollen and distinct pulses of forest clearance as a result of human activity can be observed from the Neolithic period onwards. [ABSTRACT FROM AUTHOR]