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The Lateglacial (14,700–11,700 cal BP) is a key climate period marked by rapid but contrasted changes in the Northern Hemisphere. Indeed, regional climate differences have been evidenced during the Lateglacial in Europe and the Northern Mediterranean areas. However, past climate patterns are still debated since temperature and precipitation changes are poorly investigated towards the lower European latitudes. Lake Matese in Southern Italy is a key site in the Central Mediterranean to investigate climate patterns during the Lateglacial. This study uses a multi-proxy approach including magnetic susceptibility, geochemistry (XRF core scanning), pollen data and molecular biomarkers like branched Glycerol Dialkyl Glycerol Tetraethers (brGDGTs) to reconstruct climate changes and their impacts at Matese. Palaeotemperatures and -precipitation patterns are quantitatively inferred from pollen assemblages (multi-method approach: Modern Analogue Technique, Weighted Averaging Partial Least Squares regression, Random Forest, and Boosted Regression Trees) and brGDGTs calibrations. The results are compared to a latitudinal selection of regional climate reconstructions in Italy to better understand climate processes in Europe and in the circum-Mediterranean region. A warm Bølling–Allerød and a marked cold Younger Dryas are revealed in all climate reconstructions inferred from various proxies (chironomids, ostracods, speleothems, pollen, brGDGTs), showing no latitudinal differences in terms of temperatures across Italy. During the Bølling–Allerød, no significant changes in terms of precipitation are recorded, however, a contrasted pattern is visible during the Younger Dryas. Slightly wet conditions are recorded south of latitude 42° N whereas dry conditions are recorded north of latitude 42° N. During the Younger Dryas, cold conditions can be attributed to the southward position of North Atlantic sea-ice and of the Polar Frontal JetStream whereas the increase of precipitation is Southern Italy seems to be linked to relocation of Atlantic storm tracks into the Mediterranean, induced by the Fennoscandian ice sheet and the North European Plain. On the contrary, during the Bølling–Allerød warm conditions can be linked to the northward position of North Atlantic sea-ice and of the Polar Frontal JetStream.

International audience; The Gorgan Plain (NE Iran) is largely treeless today but it possibly was not in the past. We use palaeobotanical data from radiocarbon-dated sediments and archaeological excavations to investigate the extent and use of woodland under the Sasanian Empire (224–651 CE). Palynology, anatomical studies of charred and uncharred wood, insects and botanical macroremains have shed new light on this question. Palynological research points to natural origins of the open steppe vegetation in the Gorgan Plain contrasting to carpological and wood anatomy studies indicating wide use of trees and shrubs during the Sasanian period. As it shown by charcoal data, local sources provided enough firewood for kilns in short-term use, but were insufficient for supplying fortification garrisons which required additional supplies from the Hyrcanian forests. These forests provided the main source of firewood for sites located close to the Alborz Mountains. Cultivation of trees was widespread during the Sasanian era for fruits, shadow and possibly moriculture for silk production. Palaeobotanical records are stillvery rare in the Gorgan Plain. New data are a desideratum to gain further insights into woodland use before, during and after the Sasanian Empire.

The Late Glacial (14 700–11 700 cal BP) is a key climate period marked by rapid but contrasted changes in the Northern Hemisphere. Indeed, regional climate differences have been evidenced during the Late Glacial in Europe and the northern Mediterranean. However, past climate patterns are still debated since temperature and precipitation changes are poorly investigated towards the lower European latitudes. Lake Matese in southern Italy is a key site in the central Mediterranean to investigate climate patterns during the Late Glacial. This study aims to reconstruct climate changes and their impacts at Matese using a multi-proxy approach including magnetic susceptibility, geochemistry (XRF core scanning), pollen data and molecular biomarkers like branched glycerol dialkyl glycerol tetraethers (brGDGTs). Paleotemperatures and paleo-precipitation patterns are quantitatively inferred from pollen assemblages (multi-method approach: modern analogue technique, weighted averaging partial least-squares regression, random forest and boosted regression trees) and brGDGT calibrations. The results are compared to a latitudinal selection of regional climate reconstructions in Italy to better understand climate processes in Europe and in the circum-Mediterranean region. A warm Bølling–Allerød and a marked cold Younger Dryas are revealed in all climate reconstructions inferred from various proxies (chironomids, ostracods, speleothems, pollen, brGDGTs), showing no latitudinal differences in terms of temperatures across Italy. During the Bølling–Allerød, no significant changes in terms of precipitation are recorded; however, a contrasted pattern is visible during the Younger Dryas. Slightly wetter conditions are recorded south of 42∘ N, whereas dry conditions are recorded north of 42∘ N. During the Younger Dryas, cold conditions can be attributed to the southward position of North Atlantic sea ice and of the polar frontal jet stream, whereas the increase in precipitation in southern Italy seems to be linked to relocation of Atlantic storm tracks into the Mediterranean, induced by the Fennoscandian ice sheet and the North European Plain. By contrast, warm conditions during the Bølling–Allerød can be linked to the northward position of North Atlantic sea ice and of the polar frontal jet stream.

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International audience; New investigations performed with a multi-proxy approach provide a robust climate reconstruction for the Late-Glacial in the Massif Central, France. The temperature reconstruction from Coleoptera is obtained from the Mutual Climatic Range Method, or “MCR” method, based on the range of climates corresponding to the area occupied today by the species identified in fossil assemblages. The Weighthed Averaging Partial Least Squared (WA-PLS) method is used to produce mean July temperature estimates from Chironomid assemblages. Climate reconstruction from pollen data is performed using an assemblage approach, the Modern Analogue Technique. During the Late-Glacial the July temperature (Tmax) reconstructed from beetles (Coleoptera) was lower than the current Tmax of 18.9 ◦C. Summer conditions were close to the present at the beginning of the Oldest Dryas (17400–14600 cal. BP), and during most of the Allerød (13900–12800 cal. BP). During the Younger Dryas(12800–11700 cal. BP) Tmax estimates ranged from 12 to 13 ◦C, much lower than today. The Tmax increased at the onset of the Holocene (11700 cal. BP), reaching values close to the modern conditions from the beginning of the period. Tmax reconstructed from chironomids shows an initial warming around 15000 cal. BP, with a Tmax rise from 7 ◦C to 11 ◦C. A maximum (13.5 ◦C) was reached around 13800 cal. BP. A second optimum of 16 ◦C occurred after 10800 cal. BP. The Late-Glacial Interstadial (LGI) is marked by temperature decreases (from 13 to 12 to 10–9 ◦C) around 13200–12900 cal. BP. A second climate minimum was reached around 12600 cal. BP, during the Younger Dryas (Tmax about 10 ◦C). The end of the Younger Dryas seems to have been warmer, with a Tmax of about 13 ◦C, just before the early Holocene climate improvement. Pollen-inferred results showed that the Late-Glacial climate at Rousti`eres was characterized by colder and drier winter and summer seasons than today, and by conditions close to the modern ones around 11700 cal. BP, at the onset of the Holocene. Climate conditions comparable to the modern ones were also evidenced at the end of the Allerød, with colder than today conditions evidenced from both Tmax and Tmin (January temperature). During the Oldest and Younger Dryas the coldest month showed a temperature of - 13 ◦C, while summers appeared more moderate (warmest month around 16 ◦C). Cold conditions were also reconstructed during the Bølling, while temperatures comparable to present-day values were reached during the Allerød. A cold oscillation occurred around 13400 cal. BP. Particularly dry conditions were reconstructed during the Oldest Dryas (17000–15800 cal. BP). From 15800 to the end of the Younger Dryas, the precipitation oscillated around 750 mm, but increased during the Allerød and the Holocene periods. These climatic trends reconstructed by the three proxies allowed identifying the temperateperiods (LGI and the Holocene) and the cold events (Younger Dryas) of the Late-Glacial period. However, difficulties due to different sampling resolutions emerged, and several discrepancies linked to the proxy or the methods used are discussed

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The peat bog Mlaca Tatarilor (45° 43ʹ 00” N, 24° 39ʹ 07” E, 540 m a.s.l.) is located in the southern part of the Transylvanian Depression, near Arpasu de Sus village, on a higher terrace of the Arp...

International audience; This article presents a synthesis of mire initiation since the last 15,000 years (Late Glacial and Holocene) in theEastern Massif central (France). This work proposes an analysis of the chronological distribution of newly formedmires based on a dataset of 112 radiocarbon ages (14C). The results are compared with long-term land coverchanges described by regional palaeoenvironmental (palynology and macrofossils), used to evaluate the degree oflandscape openness and anthropization (Anthropogenic Impact Factor = FIA), and by archaeological studies. Variouscases of mire initiation were highlighted during the studied period. Some peat accumulation examples occurredearly (from 15,000 to 12,700 years before present), then a major generation of mires established during the postglacialwarming. This generation (10,000 to 7,000 years before present) is represented by fens (minerogenous)derived from terrestrialized lakes and by bogs (ombrogenous) formed by paludifi cation. A second major generationis well documented during the last 4,200 years, and still increases in the last 2,800 years. During this phase, humanactivities favoured more or less directly the establishment of small bogs (behind low stone walls, raised causeways,in abandoned drainage systems) and fens (often on former ponds). All these cases are especially highlighted in theMézenc Massif (Southern Massif central) which could be considered as a conservatory for the history of ecosystems,biodiversity and landscape evolutions.; Cet article propose un bilan du développement des tourbières depuis 15 000 avant le présent (Tardiglaciaire et Holocène) à l'échelle de l'Est du Massif central (France). Ce travail se base sur une analyse des dates d'apparition des tourbières grâce à une base de données comprenant 112 sites datés par le radiocarbone (14 C). Les résultats obtenus sont comparés aux évolutions de la couverture végétale documentées par les études paléoenvironnementales (pollen et macro-restes végétaux), grâce au calcul de facteurs d'ouverture et d'anthropisation du paysage (Facteurs d'Impact Anthropique = FIA), et avec les données archéologiques régionales disponibles. Une diversité de modalités de mise en place des tourbières apparaît au cours de la période considérée. Quelques sites présentent des accumulations de tourbe précoces (de 15 000 à 12 700 avant le présent), puis une nouvelle phase de formation de tourbières se développe durant le réchauffement climatique post-glaciaire. Cette génération (10 000 à 7 000 avant le présent) présente des tourbières planes (minérogènes) issues de l'atterrissement d'anciens lacs et des tourbières bombées (ombrogènes) formées par paludifi cation. Une seconde phase majeure de formation de tourbières est documentée depuis 4 200 ans, avec un nombre croissant de nouvelles tourbières durant les 2 800 dernières années. Durant cette phase, les activités humaines ont directement ou indirectement favorisé l'apparition de petites tourbières bombées (à l'arrière de murets, de chaussées surélevées, dans des zones drainées puis abandonnées) ou de tourbières planes (souvent installées sur d'anciens étangs). Tous ces cas sont particulièrement bien représentés dans le massif du Mézenc (Sud du Massif central) qui constitue un véritable conservatoire pour l'histoire des écosystèmes, de la biodiversité et de l'évolution des paysages.

Here we present the first Holocene-long continuous chronology of volcanic eruptions on Kerguelen archipelago, where no evidence of Holocene volcanic activity has been published so far. Our chronicle is based upon sedimentological, chronological and geochemical data form two sediment cores, taken in two different depocenters of a large lake, Lake Armor, located ca. 70 km away from the archipelago’s potentially active volcanic area. This allowed us to confidently attribute the origin of pumice-rich or ash-rich layers to contemporaneous volcanic eruptions. Altogther eight main eruptions, as well as three secondary ones, were here documented and dated, among which the youngest occurred during the Middle Age, between 890 and 980 AD. The oldest eruption is also by far the strongest one and deposited more than 1.2m of up-to 3cm large pumices, 70 km away from the volcanic edifice. It occurred at the very beginnning of the Holocene (11 ka cal. BP), suggesting a climatic control after glacial retreat upon volcanic activity. Additionnal evidences from lake sediment and geological outcrops, both close to Lake Armor and in remote areas over Kerguelen mainland, open the future possibility of a better reconstruction of major eruptions deposit spreading and thus an assessment of their intensity. This established chronostratigraphy will be useful to synchronise paleoenvironment record at least at the scale of the archipelago as well as in surrounding marine areas where Holocene climate reconstructions are particularly sparse.

International audience; The European Pollen Database (EPD) is a community effort to archive and make available pollen sequences from across the European continent. Pollen sequences provide records that may be used to infer past vegetation and vegetation change. We present here maps based on 828 sites from the EPD giving an overview of changes in postglacial pollen assemblages in Europe over the past 15,000 years. The maps show the distribution and abundance of 54 different pollen taxa at 500 year intervals, supported by new age-depth models and associated chronological uncertainty analysis. Results show the individualistic patterns of spread of different pollen taxa, and provide a standardized dataset for further analysis, defining a spatial context for the study of past plant and vegetation changes and other aspects of environmental history in Europe.

International audience; The Eemian interglacial represents a natural experiment on how past vegetation with negligible human impact responded to amplified temperature changes compared to the Holocene. Here, we assemble 47 carefully selected Eemian pollen sequences from Europe to explore geographical patterns of (1) total compositional turnover and total variation for each sequence and (2) stratigraphical turnover between samples within each sequence using detrended canonical correspondence analysis, multivariate regression trees, and principal curves. Our synthesis shows that turnover and variation are highest in central Europe (47-55°N), low in southern Europe (south of 45°N), and lowest in the north (above 60°N). These results provide a basis for developing hypotheses about causes of vegetation change during the Eemian and their possible drivers.

Biogeography developed by pioneers such as Pierre Quézel has been illuminated by the progress in palaeoecology which sets the present populations in their temporal framework and in genetic which identify infra-specific structures within populations. Here we recall the efficient junction between these two fields, illustrated by common projects linking paleaoecologists from IMEP/ IMBE (Aix-Marseille) and forest geneticists from INRA Pierroton (Bordeaux). Their collaboration led to precise the Mediterranean glacial refuge zones of different haplotypes of the main forest tree species and their migration routes toward Northern Europe. Researches on ancient DNA from fossil trees were also initiated., L’approche biogéographique de pionniers tels que Pierre Quézel a été renouvelée d’une part, par le développement de la paléoécologie, qui définit l’origine temporelle des peuplements, et, d’autre part, par celui de la génétique, qui en pénètre l’intimité infraspécifique. Est relatée ici l’histoire de la fructueuse rencontre entre ces deux champs disciplinaires à travers deux équipes de recherche, celle des palynologues de l’IMEP/ IMBE (Aix-Marseille) et celle des généticiens forestiers de l’INRA de Pierroton (Bordeaux). Cette collaboration a abouti à l’identification des zones refuges méditerranéennes de diverses lignées d’essences forestières et des routes migratoires postglaciaires de ces dernières vers les latitudes nord. Les premières recherches sur l’ADN ancien d’arbres fossiles ont aussi été conduites., Beaulieu Jacques-Louis de. L’association de la paléoécologie et de la phylogéographie : une autre approche de la biogéographie / Associating paleoecology and phylogeography: another approach of biogeography. In: Ecologia mediterranea, tome 44 n°2, 2018. Hommage scientifique au professeur Pierre Quézel (1926-2015) pp. 95-100.

Pollen data obtained from radiocarbon-dated sediments of several peat bogs and lakes located in different parts of Iran and surrounding areas have recently provided invaluable new information on agricultural practices during the Persian empires, from the Achaemenids to the Sasanians. A review of the published and unpublished data has revealed distinct phases of intensified tree cultivation and pastoral activities during this era.

International audience; Retrospective science such as palaeoecology deeply depends on the preservation of archives in sensitive places. As an example, mountains of medium altitude from Mediterranean peninsulas have long been identified by biogeographers as refuges zones allowing the survival of European temperate taxa during the ice ages, but archives to validate this hypothesis are scarce, especially in Southern Italy. Here we present a new sequence from Lago Trifoglietti (1048 m a.s.l.) in the Calabrian Mountains, which covers the Late Glacial Interstadial (LGI, corresponding to the Bolling€-Allerod€ period in northern-central Europe) and the transition to the Holocene. The independent chronology based on seven radiocarbon dates is supported by the evidence of three tephra layers already identified in other regional sequences. During the LGI, besides the high diversity of non arboreal pollen grains, a great number of pollens of temperate forest trees are present or abundant (mostly deciduous oaks and fir). These assemblages suggest that the site was above but not far from the upper limit of diversified woodland stands. They confirm a local survival during the last glacial. The Younger Dryas is not marked by major changes, and oak percentages are even higher, suggesting a resilient expansion at lower altitude. Surprisingly the site remains above the timberline until an aridity crisis centered at 11,100 cal 14 C yr PB, which is correlated with the Pre-boreal Oscillation (PBO). This event is immediately followed by the local settlement of a dense fir and beech forest around the lake. A comparison with other Italian key sequences aims at explaining the climate forcing factors that governed this original vegetation dynamic. Further investigations using additional proxies are needed for a more robust climate reconstruction. (O. Peyron), l.bernardo@unical.it (L. Bernardo), Julien.Didier@ univ-fcomte.fr (J. Didier), agnes.stock@univ-fcomte.fr (A. Stock), Damien.Rius@ univ-fcomte.fr (D. Rius), Michel.Magny@univ-fcomte.fr (M. Magny).

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

International audience; The aim of this study is to describe the environmental and climate changes that occurred in the mountains of Aubrac at the transition between the Lateglacial and the Holocene, from a comparative analysis of fossil Coleoptera and pollen, and a series of 23 C-14 dates. The changes affecting the ecological categories of Coleoptera lead to a division of the sequence into 5 beetle assemblage zones (BAZ): the lowermost BAZ A is characterized by extremely poor assemblages (periglacial environment); BAZ B (Oldest Dryas and Lateglacial Interstadial) is marked by regular occurrences of taxa associated with open environments, aquatic taxa associated with running and highly oxygenated water, and cold adapted taxa with relatively low numbers; BAZ C (Younger Dryas) corresponds to two important events: a particular abundance of cold adapted taxa and a marked decrease of running water taxa, beetles associated with herbaceous vegetation and open environments are also well represented; BAZ D (Early Holocene) corresponds to the total disappearance of cold adapted taxa; the transition BAZ C/BAZ D is marked also by a dramatic peak of running water taxa; the uppermost BAZ E (Early/Mid Holocene) is marked by a total absence of running water taxa which are replaced by standing water or taxa tolerant of a range of water conditions, a particular abundance of wetland taxa, and taxa associated with herbaceous vegetation and open environments. Beetle and pollen data suggest that the harsh climatic conditions prevailing in the Aubrac mountains did not allow warm dependent fauna and trees to establish during the Lateglacial Interstadial, at least in the Roustieres region, and that wide open landscapes occupied the plateau at that time. The Older Dryas, a cold spell previously recorded at La Taphanel (Cantal), is not visible in the Roustieres record, probably because of the higher altitude at Roustieres, whereas the Younger Dryas is strongly expressed. During the Holocene, concordant beetles and pollen data enable to reconstruct the rapid recolonization of the plateau by mesophilous trees (Ulmus, Quercus), suggesting the possible presence of refugia to the southern slopes of the Aubrac plateau. Insect/pollen comparisons provide evidence for hydrological changes in the former lake of Roustieres and suggest that lacustrine water level changes often used as indicator of precipitation regime changes should be taken with caution. (C) 2016 Elsevier B.V. All rights reserved.

The Gorgan Plain (NE Iran) is characterized by fertile soils formed on a loess plateau and is at present primarily exploited for intensive agriculture. However, the timing and intensity of the human impact on the landscape in the past are still unclear. A sediment core, taken from the centre of the eastern Gorgan Plain in the Kongor Lake covering the major part of the Holocene from 6.1 to 0.8 ka (all ages are calibrated before present), has been studied for pollen, non-pollen palynomorphs, botanical macroremains, insects, charcoal, geochemistry, biomarkers and magnetism in order to provide new insights into the evolution of the landscape and to estimate the intensity of human activities. The data obtained suggest a dry period between 5.9 and 3.9 ka and an increase in regional humidity afterwards with a maximum between 2.7 and 0.7 ka, during the period of the Persian empires (Achaemenid through Sasanian) and the Islamic era. The eastern part of the Gorgan Plain was characterized by open steppe landscapes during the last 6 ka, which most likely were used for pasture and at least since 2.7 ka for agriculture including arboriculture. The strongest anthropogenic impact on the environment around the Kongor site is documented during the Parthian and Sasanian Empires (200 BC–651 AD) and the Islamic era up to the eve of the Mongol invasion.

Lac d'Armor (49°27′S, 69°42′E) is a medium-sized, fjord-type lake located on the ‘Grande Terre’ island of the Kerguelen archipelago. A dense grid of high-resolution reflection seismic profiles was collected from this lake basin. The seismic stratigraphic facies reveal a last deglaciation to Holocene infill comparable to the seismic facies found in other glacigenic lakes all over the world. Remarkable features in the seismic stratigraphy are mounded structures found at the southern edge of both sub-basins. The sediment mounds can be interpreted as sediment drifts created by wind-induced bottom currents. The onset of the build-up of these drifts initiated at some point in the Holocene and indicates a strengthening of the southern Westerlies, which are currently the dominant winds on this island.

A coarse-resolution, absolutely dated isotope record spanning the last 180 ka was constructed from aragonite-rich fecal pellets in a sediment core from Lake Urmia, Iran. The isotope record is not continuous as a consequence of detrital calcite that contaminates the pellets at certain depths. An isotopic correction was applied to samples > 50% aragonite, using the δ18O values of calcite-only pellets. Absolute dates were derived from U-Th analyses on pellets > 80% aragonite. The resultant δ18O record and sediment lithofacies confirm that the Penultimate Glacial was cold and dry, with pronounced interstadials at ca. 150 and >175 ka. Deglaciation began at ca. 130 ka, but climate was unstable and supported a probable no-analog vegetation assemblage. The onset of true interglacial conditions occurred at ca. 126 ka. Peak moisture conditions lasted for 5–6 ka before the climate became drier, with the loss of some tree taxa towards the end of the Last Interglacial. A period of greater moisture occurred between 116 and 108 ka, overlapping in timing with interstadial conditions recorded in the Soreq Cave speleothem record. In general, stadial to interstadial transitions (OIS 5d-5c, 5b-5a) are marked by decreasing δ18O values and rising lake levels. The nature of the OIS 5 to OIS 4 transition cannot be resolved in this study because of the loss of 5 m of core and imprecise dates. According to the present chronology, δ18O values, and inferred lake levels, arid conditions began at 60 ka and persisted until Termination I. Episodic increases in moisture, characterized by layers of aragonite-rich pellets, ostracodes, and the pollen of trees and/or aquatic plants, occurred during the Last Glacial. Deglaciation associated with the Late-glacial Interstadial began at 14 ka but was interrupted by a marked Younger Dryas event that resulted in renewed aridity. The Holocene began at approximately 10 ka. Despite large errors in the chronology, the overall timing and pattern of effective moisture matches the record from Soreq Cave, Israel, suggesting that the two regions were climatically in-phase.

Wetland conservation and management are generally only based on present-day studies, without integrating historical considerations. However, wetlands contain palaeoecological archives that can provide accurate records of their own history. Our study aims at reconciling this paradox in the central French Alps, by reconstructing the past wetland diversity/richness and the controls of Holocene hydroseral dynamics, and by discussing on this historical basis their conservation, management and restoration. Previously published data, complemented by the palaeoecological study of a sedge mire, reveal three main stages in the regional hydroseral succession: initial aquatic plant communities (Nymphaea alba, Nuphar cf. lutea, Menyanthes trifoliata), carrs (Alnus glutinosa/incana, Salix spp., Thelypteris palustris), then sedge meadows (Cyperaceae, Poaceae, Lythrum salicaria…). This dynamic comprises (1) a classical evolution from open water bodies to treed wet communities, controlled by the relationships between sedimentation processes and climate, and (2) an unexpected return to herbaceous wet habitats mainly triggered by Subatlantic human-induced managements. Such recent changes induced in the studied region the decline of Alnus cf. glutinosa, the disappearance of Thelypteris palustris, and the extinction of the carr communities they constituted. The historically-based assessment of community naturalness and resilience appears critical for defining conservation priorities, refining management actions, and identifying baseline conditions for restoration initiatives. The main implications of our results are to reinforce conservation measures on the less impacted habitats and to increase the diversity/richness of isolated lowland mires, notably by restoring alder communities in some of them.

Coprolite pollen analysis is increasingly used by palynologists to reconstruct the palaeovegetation especially in the arid to semi-arid regions where lakes and peat bogs are scarce. This study is the first palynological analysis of coprolites in Iran to examine their potential in palaeoenvironmental reconstructions. Four pollen-rich coprolite samples were studied from the Wezmeh Cave in western Iran with a recently discovered late Quaternary (70 ka to sub-recent) faunal assemblage dominated by carnivore remains. Pollen analysis of coprolites shows that a mountain steppe dominated the glacial landscapes of the area. Only one sub-recent sample indicates the presence of dispersed tree stands. One sample was rich in Tulipa pollen suggesting that tulips were relatively abundant during the glacial periods. Cousinia (Asteraceae) pollen was found in all samples with considerable values in one sample indicating its importance in the glacial landscapes of the Zagros Mountains. This study revealed that coprolite pollen analysis can provide an invaluable source of information to understand the floristic composition of palaeolandscapes of the Irano-Turanian region.

Pollen analysis supported by nine AMS 14 C dates from the Poiana Stiol peat sequence (1540 m), in the Rodnei Mountains, Eastern Romanian Carpathians (Romania) is used to reconstruct the Holocene vegetation history in this mountain region. The results are then compared with other sequences from Romania and Eastern Europe in order to better understand the past dynamics of the main forest constituents. The vegetation record at Poiana Stiol starts at ca. 11,000 cal yr BP, with the occurrence of rather closed woodlands composed of Betula , Pinus , Picea abies , Alnus , A. viridis , and Ulmus . Picea abies was the dominant tree species for almost the entire period. However, during the last 3000 years, P. abies forests were largely replaced by Pinus in the area. Temperate tree taxa ( Fraxinus , Quercus , Acer , Tilia , and Corylus avellana ) were also common but likely at lower elevation. C. avellana expanded around 10,300 cal yr BP and reached maximum values after 9000 cal yr BP. Pollen of Carpinus betulus and Fagus sylvatica was already recorded around 7000 cal yr BP. However, the spread of C. betulus occurred at ca. 6000 cal yr BP, with maximum values between 4800 cal yr BP and 3000 cal yr BP, while F. sylvatica spread from ca. 3200 cal yr BP and attained maximum values between 2000 and 200 cal yr BP. The first indications of human activities appeared around 3200 cal yr BP and intensified within the last 200 years. Comparison with other sequences from Romania and surrounding countries reveals both similarity and great differences related to the location of glacial refugia, climate change and human impact.

This study presents pollen-based climate reconstructions of Holocene temperature and precipitation seasonality for two high-resolution pollen sequences from the central (Lake Accesa, central Italy) and eastern Mediterranean (Tenaghi Philippon, Greece) regions. The quantitative climate reconstruction uses multiple methods to provide an improved assessment of the uncertainties involved in palaeoclimate reconstructions. The multimethod approach comprises Partial Least Squares regression, Weighted Average Partial Least Squares regression, the Modern Analogues Technique, and the Non-Metric-Multidimensional Scaling/Generalized Additive Model method. We find two distinct climate intervals during the Holocene. The first is a moist period from 9500 to 7800 cal. BP characterised by wet winters and dry summers, resulting in a strongly seasonal hydrological contrast (stronger than today) that is interrupted by a short-lived event around 8200 cal. BP. This event is characterised by wet winters and summers at Accesa whereas at Tenaghi Philippon the signal is stronger, reversing the established seasonal pattern, with dry winters and wet summers. The second interval represents a later aridification phase, with a reduced seasonal contrast and lower overall precipitation, lasting from 7800 to 5000 cal. BP. Present-day Mediterranean conditions were established between 2500 and 2000 cal. BP. Many studies show the Holocene to have a complex pattern of climatic change across the Mediterranean regions. Our results confirm the traditional understanding of an evolution from wetter (early Holocene) to drier climatic conditions (late Holocene), but highlight the role of changing seasonality during this time. Our data yield new insights into the aspect of seasonality changes, and explain the apparent discrepancies between the previously available climate information based on pollen, lake-levels and isotopes by invoking changes in precipitation seasonality.

Resume Deux sequences polliniques provenant des marais littoraux d’El-Kala ont ete etudiees en vue de retracer l’histoire de la vegetation regionale. Les assemblages polliniques etayes par huit datations 14 C ont revele, dans le marais de Bourdim une histoire recente dominee localement par une aulnaie-saulaie ; l’abondance d’ Erica arborea indique que la vegetation regionale est constituee par une suberaie tres degradee. La sequence de Garaat El-Ouez presente deux periodes distinctes : les assemblages superieurs sont comparables a ceux de Bourdim ; par contre, ceux de la base sont domines par Pinus , des Poaceae et diverses herbacees heliophiles, avec presence de Cedrus . Ils temoignent d’une vegetation forestiere ouverte attribuee par trois datations a la fin de la derniere glaciation et demontrent l’existence de refuges regionaux de Cedrus sous un climat relativement clement.

International audience; Despite the high potential of pollen records for climate reconstruction, pollen-climate relationships may be biased due to past and present human activities on the landscape. We use (i) transfer functions based on modern pollen-climate relationships to infer seasonal temperature and summer precipitation for the period 11 500-4500 cal. a BP and (ii) lake-level change records based on different sedimentary proxies in multiple cores that are mainly indicative for summer hydrology at Lago dell'Accesa (central Italy). Quantitative reconstructions indicate lowest summer precipitation during two phases (8500-7700 cal. a BP and after 6000 cal. a BP) and a gradual winter temperature increase from 11 500 to ca. 8000 cal. a BP. Lowest summer precipitation was reconstructed during these phases characterised by vegetation shifts from open forests dominated by summergreen oaks (Quercus) to forests dominated by evergreen oaks (Quercus ilex), which are at present most abundant where summer drought is stronger. Similarly, the lake-level record indicates two long-lasting low summer precipitation phases (8800-7700 and 6400-4400 cal. a BP) that were interrupted by short-term high summer precipitation events. Based on the broad agreement between the pollen-inferred summer precipitation and the low-frequency lake-level changes, we suggest that the duration of the high summer precipitation events may have been too short to maintain drought-sensitive trees, which may have been affected by high mortality rates when summer dry conditions returned. Although past and modern pollen-climate relationships may very likely have been affected by human activities since the Neolithic (i.e. when exploitation of the landscape started), we reject the hypothesis of a significant anthropogenic bias in the pollen-based climate reconstruction. In addition, we suggest that pollen-based and lake-level reconstructions may have different inherent abilities of capturing high- and low-frequency precipitation signals

New pollen evidence from two sites in South-Central Zagros (Lake Maharlou), Southwestern Iran, and Sahand Mountains (Lake Almalou), Northwestern Iran, provide evidence for the emergence of tree cultivation in Southwestern Iran since the 3rd and 2nd millennia BC and upland agricultural activities in Northwestern Iran since 5th to 3rd centuries BC. Juglans cf. regia could have been cultivated firstly at ~ 2500 BC and became more extensively cultivated since ~ 1200 BC. Platanus cf. orientalis was also probably cultivated very early at ~ 1900 BC during the Middle Elamite period (2800-550 BC) and became more widely cultivated from ~ 1200 BC along with Juglans. The latter arboricultural events could have resulted from the establishment of great urban civilizations in Southwestern Iran. The rise of the Persian Empires seems to have been associated with a large-scale agricultural revolution over the Iranian Plateau. During the Persian Achaemenid Empire (550-330 BC) tree cultivation expanded in the Lake Maharlou area and agricultural practices expanded into upland areas in Lake Almalou area probably due to socio-economic stability and the development of water exploitation and irrigation techniques. The Parthian (250 BC-225 AD) and Sassanian (224-642 AD) periods were also associated with tree cultivation practices in Lake Maharlou area but to a lower extent comparing to the Achaemenid period. In the Lake Almalou area, the Parthian period saw no spectacular agricultural event at least partly due to political and socio-economic instability caused by conflicts with Romans over Armenia. The socio-economic stability and further development in agricultural techniques during the Sassanian Empire could, however, favor again the large-scale tree cultivation practices in Northwestern Iran. The Post-Islamic period is characterized by reduced agricultural activities in the Iranian Plateau most probably due to political instability caused by numerous invasions by Arabs, Turks and Mongols. The last signifi cant agricultural event recorded in the Lake Almalou pollen record is the appearance of Ricinus communis cultivated since the beginning of the Safavid Empire (1501-1722 AD)., De nouvelles données polliniques provenant de deux sites dans les montagnes du Zagros (lac Maharlou, Sud-Ouest l’Iran) et de Sahand (lac Almalou, Nord-Ouest de l’Iran), apportent des indications sur l’émergence de l’arboriculture dans le Sud-Ouest iranien depuis les IIIe et IIe millénaires av. J.-C., et sur les pratiques agricoles dans les hautes terres du Nord-Ouest iranien du Ve au IIIe siècles av. J.-C. Juglans cf. regia fut probablement cultivé dès 2500 av. J.-C., puis plus extensivement à partir de 1200 av. J.-C. environ. Platanus cf. orientalis fut probablement cultivé précocement, vers 1900 av. J.-C., au cours de la période élamite moyenne (2800-550 av. J.-C.), et il devint plus largement cultivé à partir de ca. 1200 av. J.-C, parallèlement à la culture de Juglans. Ces innovations agricoles ont pu résulter du développement des grandes civilisations urbaines dans le Sud-Ouest de l’Iran. L’émergence de l’Empire perse semble être associée à une révolution agraire à grande échelle sur le plateau iranien. Sous l’Empire achéménide (550-330 av. J.-C), l’arboriculture s’est développée dans la région du lac Maharlou alors que l’agriculture atteignait les hautes terres autour du lac Almalou, probablement en raison d’une plus grande stabilité socio-économique et du développement des techniques d’irrigation. Les périodes parthe et sassanide (224-642 de notre ère) ont également vu le développement de l’arboriculture dans la région du lac Maharlou, mais dans une moindre mesure que lors de la période achéménide. Dans la région du lac Almalou, la période parthe ne témoigne pas de pratiques agricoles spectaculaires, en raison peut-être de l’instabilité politique et socio-économique consécutive aux conflits avec l’Empire romain en Arménie. Sous l’Empire sassanide, la stabilité socio-économique et le renouveau des techniques agricoles ont pu toutefois favoriser le développement à grande échelle de l’arboriculture dans le Nord-Ouest de l’Iran. La période qui suit l’arrivée de l’Islam est caractérisée par des activités agricoles moins importantes sur le plateau iranien, très probablement en raison de l’instabilité politique liée aux invasions arabes, turques et mongoles. Le dernier fait agricole significatif enregistré au lac Almalou est l’apparition de Ricinus communis, cultivé dès le début de l’Empire safavide (1501-1722 de notre ère)., Djamali Morteza, Miller Naomi F., Ramezani Elias, Andrieu-Ponel Valérie, de Beaulieu Jacques-Louis, Berberian Manuel, Guibal Frédéric, Lahijani Hamid, Lak Razieh, Ponel Philippe. Notes on Arboricultural and Agricultural Practices in Ancient Iran based on New Pollen Evidence. In: Paléorient, 2010, vol. 36, n°2. pp. 175-188.

Pollen analysis from a peat core 7.0 m in length, taken from a bog near Bisoca, in a mid-altitude area of the Buzăului Subcarpathian mountains, is used to reconstruct the postglacial vegetation history of the region. The vegetation record, which is supported by twelve 14C dates, starts at the end of the Late Glacial period. At the Late Glacial/Holocene transition, open vegetation was replaced by forest, suggesting a fast response to climatic warming. The Holocene began with the expansion of Betula, Pinus and Ulmus, followed, after 11,000 cal yr BP, by Fraxinus, Quercus, Tilia and Picea. The rapid expansion of these taxa may be due to their existence in the area during the Late Glacial period. At ca. 9200 cal yr BP, Corylus expanded, reaching a maximum after 7600 cal yr BP. The establishment of Carpinus occurred at ca. 7200 cal yr BP, with a maximum at ca. 5700 cal yr BP. Fagus pollen is regularly recorded after 7800 cal yr BP and became dominant at ca. 2000 cal yr BP. The first indications of human activities appear around 3800 cal yr BP.

Spores of the liverwort Riella are documented in a long late-Pleistocene to early Holocene pollen record from the hypersaline Lake Urmia in NW Iran. The pollen record indicates that Riella aff. cossoniana Trab. has played an important role in the aquatic vegetation in the plains around Lake Urmia, particularly in the late Pleistocene. The concentration of Riella spores was greater during the high lake stands corresponding to the middle part of the last glaciations (MIS 3) and the upper part of the penultimate glaciations (MIS 6). The presence of Riella suggests that during these periods numerous brackish ponds and marshes developed on the present salt flats around the lake, creating suitable habitat for colonization. The spores of Riella can therefore be used as a palaeoecological indicator of lake level changes in saline lake environments situated in semi-arid regions.

A pollen diagram was derived from a 150 cm core taken from the shallow hypersaline Lake Maharlou in the south-eastern part of the Zagros Mountains, SW Iran. The pollen record shows that Quercus brantii woodland and Pistacia–Amygdalus scrub dominated the area during the late Holocene. The record starts at around 5700 cal b.p. with a dry period during which both Pistacia–Amygdalus scrub and Quercus brantii woodland were at their minimum extent. This period was followed by the expansion of Pistacia–Amygdalus scrub in the area and the spread of Quercus brantii woodlands at higher altitudes. An important occupation phase, characterized by the appearance of several cultivated tree species such as Juglans, Olea, Vitis and Platanus, started at ca. 4300 cal b.p., coinciding with the onset of the Bronze Age civilization of Jiroft in Central Iran. Human activities become very clear after 3700 cal b.p. Around 2700 cal b.p., extensive stands of Pistacia–Amygdalus scrub became profoundly degraded, presumably under strong human pressure coinciding with the beginning of the Persian Empires. The maximum expansion of the Quercus brantii woodland occurred about 2100 to 1700 cal b.p. This woodland remained relatively stable until the end of the diagram at 400 cal b.p.

A palynological study based on two 100-m long cores from Lake Urmia in northwestern Iran provides a vegetation record spanning 200 ka, the longest pollen record for the continental interior of the Near East. During both penultimate and last glaciations, a steppe ofArtemisiaand Poaceae dominated the upland vegetation with a high proportion of Chenopodiaceae in both upland and lowland saline ecosystems. WhileJuniperusand deciduousQuercustrees were extremely rare and restricted to some refugia,Hippophaë rhamnoidesconstituted an important phanerophyte, particularly during the late last glacial period. A pronounced expansion inEphedrashrub-steppe occurred at the end of the penultimate late-glacial period but was followed by extreme aridity that favoured anArtemisiasteppe. Very high lake levels, registered by both pollen and sedimentary markers, occurred during the middle of the last glaciation and late part of the penultimate glaciation. The late-glacial to early Holocene transition is represented by a succession ofHippophaë, Ephedra, Betula, Pistaciaand finallyJuniperusandQuercus. The last interglacial period (Eemian), slightly warmer and moister than the Holocene, was followed by two interstadial phases similar in pattern to those recorded in the marine isotope record and southern European pollen sequences.

An attempt is made to reconstruct the palaeoenvironmental Holocene history at the timberline on the basis of the analysis of various palaeoecological proxy indicators available on a marshy area and its surroundings in the Taillefer Massif (Isere. France). The multidisciplinary approach involves analyses of pollen assemblages. plant macrofossils, coleoptera remains. subfossil trunks extracted from lakes or peat-bogs. and charcoals derived from the surrounding soils. This enables definition of the respective roles of five forest taxa (Pinus uncinata Mill., Pinus cembra L., Larix decidua Mill., Abies alba Mill, and Picea abies L. Karsten) in the evolution of high altitude forests during the Holocene. Pinus uncinata was present on the plateau throughout the Holocene. Larix and Pinus cembra were present only during two periods: 7500-5000 BP and 3500-2000 BP. All trees disappeared from the plateau at about 2000 BP, while, at lower altitude. Abies was replaced by Picea. The action of both climate and early human impact can explain these changes.

Analysis of 732 samples through 39 m of sediments from the ancient lake of Les Echets, 15 km northeast of Lyon, France, resulted in a long, continuous pollen diagram covering the interval from the Late Rissian to the Holocene. Above a complete Ecmian sequence, there are two Early Wiirmian temperate cycles (the older one including two climatic optima separated by a brief deterioration) with forest successions characterized by the spread of Carpinus at the end of the early temperate phase. These episodes, whose exact equivalents are found at Grande Pile in the Vosges area, are correlated with the Early Wiirmian trilogy Amersfoort-Brorup-Odderade of northern Europe. The absolute dates proposed for the Grande Pile sequence arc accepted, whereas those for the three northern European stratotypes are rejected. The Early Wiirmian is thus placed between 115,000 and 70,000 years B.P. In the Middle Wiirm, three undated intcrstadials arc characterized by a sparse forest cover. The long Late Wiirmian section is a characteristic feature of the sediment history at Les Echets. Very cold and arid conditions prevailed during this interval, without any unequivocal indications of intcrstadial episodes. A rise in Artemisia around 15,000 B.P. marks the transition from the Pleniglacial to the Oldest Dryas.

Pollen rain-vegetation relationships were studied over a forest-steppe transect in Golestan National Park, NE Iran. The surface pollen percentages were compared to the vegetation composition of the respective vegetation types in 18 sampling points using both descriptive and numerical approaches. Hyrcanian lowland forests are characterized by pollen assemblages dominated by Quercus, Carpinus betulus and low frequencies of Zelkova carpinifolia. Both Parrotia persica and Zelkova carpinifolia show a very low pollen representation in modern surface samples, an under-representation that should be taken into account in the interpretation of past vegetation records. Transitional communities between the forest and steppe including Acer monspessulanum subsp. turcomanicum, Crataegus and Paliurus scrubs, Juniperus excelsa woodlands and shrub-steppe patches are more difficult to distinguish in pollen assemblages, however, they are characterized by higher values of the dominant shrub species. The transitional vegetation communities at the immediate vicinity of the forest show also a substantial amount of grass pollen. Many insectpollinated taxa are strongly under-represented in the pollen rain including most of the rosaceous trees and shrubs, Rhamnus, Paliurus, Acer, Les relations pluie pollinique-végétation ont été étudiées sur un transect de forêt-steppe dans le parc national du Golestan dans le nord-est de l’Iran. Les pourcentages polliniques ont été comparés à la composition des 18 relevés floristiques par des méthodes descriptives et des analyses multivariées. Les forêts hyrcaniennes de basses altitudes sont caractérisées par des assemblages polliniques dominés par Quercus, Carpinus betulus et Zelkova carpinifolia. La faible représentation pollinique de Parrotia persica et Zelkova carpinifolia dans les échantillons de surface est une information qui doit être prise en compte pour l’interprétation des diagrammes polliniques. Les communautés de transition entre la forêt et la steppe y compris les brousses à Acer monspessulanum, Crataegus et Paliurus, les junipéraies et les taches des steppes arbustives dans les zones steppiques sont plus difficiles à mettre en évidence par les assemblages polliniques de surface, mais d’une façon générale, ces communautés sont caractérisées par une meilleure représentation pollinique des arbustes dominants. Les communautés de transition à proximité immédiate de la forêt se distinguent par une importante représentation du pollen des Poaceae. De nombreux taxons entomogames sont fortement sous-représentés dans la pluie pollinique, plus particulièrement les arbres et arbustes appartenant à la famille des Rosaceae, ainsi que Rhamnus, Paliurus, Acer et Berberis. Les steppes à Artemisia sont caractérisées par la présence dominante du pollen d’Artemisia et la quasi-absence de pollen arborescent., Djamali Morteza, Beaulieu Jacques-Louis de, Campagne Pierre, Ajani Yousef, Andrieu-Ponel Valérie, Ponel Philippe, Cheikh Al Bassatneh Marwan, Leroy Suzanne A. G. Relations pluie pollinique-végétation sur un transect forêt-steppe dans le parc national du Golestan, nord-est de l’Iran. In: Ecologia mediterranea, tome 34,2008. pp. 35-52.

Les Échets mire (near Lyon, France) is one of the very few European sites showing an almost continuous record from the glaciation that preceded the Eemian up to now. The pollen diagram can easily be correlated with those from Grande Pile (Vosges). On the basis of a comparison between the two sequences, the age of three clearly temperate post-Eemian episodes (Saint-Germain Ia, Ic and Il at Grande Pile) is discussed. The authors correlate these episodes with the Early Würm Interstadials of Amersfoort, Brorup and Odderade described in Northern Europe and accept the chronology of Grande Pile that dates Saint-Germain I and Saint-Germain Il between ca 115 000 and 70 000 BP, thus making them equivalents of deep sea isotopic stages 5c and 5a. This leads to refute the 14C chronology admitted up to now that places the Early Würm between 75 000 and 55 000 BP. Considering the predominant temperate episodes during this period, the authors propose to use the term "Pre-Würm" instead of "Early Würm". During the Middle Würm, three not well-marked interstadials can be recognized. No interstadial is found during the late Pleni-Würm., Le marais des Échets (près de Lyon, France) constitue l'un des rares sites européens qui présente un remplissage à peu près continu depuis la glaciation qui a précédé l'Éémien jusqu'à nos jours. Le diagramme pollinique peut aisément être mis en corrélation avec ceux de La Grande Pile (Vosges). À partir de comparaisons entre ces deux séquences, la position chronostratigraphique des trois épisodes très nettement tempérés post-éémiens (Saint-Germain la, Ic et II à La Grande Pile) est discutée. Les auteurs mettent en corrélation ces épisodes avec les interstades du Würm ancien, Amersfoort, Brorup et Odderade, décrits en Europe du Nord et acceptent la chronologie de La Grande Pile qui situe Saint-Germain I et II entre environ 115 000 et 70 000 BP et qui en font les équivalents des étages isotopiques océaniques 5c et 5a. Ceci implique que la chronologie 14C admise jusqu'ici et plaçant le Würm ancien entre environ 75 000 et 55 000 BP est totalement erronée. Compte tenu de la prépondérance des épisodes tempérés durant cette période, les auteurs proposent le remplacement de la dénomination "Würm ancien" par celle de "Pré-Würm ". Durant le Würm moyen, trois interstades de faible amplitude ont été reconnus aux Échets, alors qu'aucune variation climatique positive n'est décelable durant le Pléni-Würm final., Das Moor von Les Échets (in der Nàhe von Lyon, Frankreich) ist eines der wenigen europàischen Gelànde, das ein fast kontinuierliches Zeugnis ablegt von der dem Eemian vorausgehenden Eiszeit bis heute. Das Pollendiagramm kann sehr leicht mit denen von Grande Pile (Vogesen) in Zusammenhang gebracht werden. Ausgehend von dem Vergleich zwischen diesen zwei Sequenzen wird das Alter von drei auf das Eemian folgenden und eindeutig gemàpigten Stadien diskutiert (Saint-Germain la, Ic und Il in Grande Pile). Die Autoren setzen dièse Episoden in Beziehung zu den Interstadialen von Amersfoort, Brerup und Odderade, die in Nord Europa beschrieben werden und akzeptieren die Chronologie von Grande Pile, die Saint-Germain I und Saint-Germain II zwischen etwa 115 000 und 70 000 v.u.Z. datiert, und sie so zu Àquivalenten der iso-topischen Tiefsee-Stadien 5c und 5a macht. Das fùhrt zu einer Ablehnung der 14C Chronologie, die bisher galt, und das frühe Würm zwischen 75 000 und 55 000 v.u.Z. ansetzte. Unter Beachtung der dominierenden gemàssigten Episoden wàhrend dieser Zeit schlagen die Autoren vor, den Terminus "Prâ-Würm" an Stelle von "Frùhes Würm" zu benutzen. Wàhrend des Mittel-Würms kônnen drei nicht gut voneinander abgegrenzte Interstadiaie erkannt werden. Während des spàteren Pleni-Würms kann kein Interstadial festgestellt werden.

High-resolution diatom analysis was carried out to assess the limnological and climatic changes that took place at Ribains maar (French Massif Central) during the Late Pleistocene (∼131–∼105 ka BP), with a focus on the Eemian interglacial in particular. Numerical analyses were used to show that most of the variability in the fossil diatom assemblages was due to climate independently from the changes in the lake catchment vegetation (as represented by pollen data). Diatom-based quantitative reconstructions of the past limnological conditions, as well as a comprehensive literature review on the auto-ecological requirements for the principal diatom taxa, were used to interpret the record. An absolute time-scale for the sequence was derived by matching the major pollen shifts with the radiometrically dated changes in oxygen isotopes observed in Italian stalagmites. This study shows that at Ribains maar, the transition from the Riss (=Saalian) Glacial to the Eemian interglacial was marked by a gradual increase in the contribution of spring-blooming diatom species, indicating a longer growing season and milder winter/spring conditions at that time. A short cooling event interrupts this trend and may correspond to a stadial. At the start of the Eemian a peak in benthic taxa and the suppression of spring-blooming flora probably reflects the effects of deglaciation on the catchment. During the Eemian interglacial itself three main phases were distinguished within the diatom record. The first phase (∼8000 years in duration) was dominated by Stephanodiscus minutulus , which suggests that intense mixing in the water-column took place during spring. The pollen record was simultaneously dominated by Quercus and Corylus that typify this phase as the climatic optimum of the Eemian. The second phase, almost equal in duration to the first phase (∼7000 years), is generally dominated by Cyclotella taxa and suggests a less productive lake and much reduced period of spring mixing compared with the first phase. In the pollen diagram this corresponds to an interval dominated by Carpinus–Picea–Abies that indicates a cooler and wetter climate. The third and last phase of the Eemian, ∼2000 year long, saw the return to Stephanodiscus -dominated assemblages, indicating a warming that may correspond to the Dansgaard–Oeschger event 25 identified in the Greenland ice-core record. In the early stage of the Wurm Glacial (=Weichselian), assemblages in the Melisey I stadial (∼3000 year long) were dominated by either Aulacoseira subarctica or Asterionella formosa , which suggest colder spring conditions than during the late Eemian, but not as cold as the ones indicated by the pollen record. Stephanodiscus spp. again dominate during the Saint-Germain Ia interstadial (∼5000 year long) suggesting a return to the conditions that prevailed before the Melisey stadial, in agreement with the pollen record. The record ends with the Montaigu cold event, which is characterised by a Pinus peak in the pollen record, and corresponds to a large abundance of A. subarctica in the diatom sequence. Throughout the Eemian the abundance of Stephanodiscus spp., which is thought to be driven by winter conditions, show cyclic fluctuations that most likely match the cooling events identified in a pollen record from Germany. Variation in insolation throughout the Eemian may have been the driving factor behind the species succession observed in the diatom sequence. While this study demonstrates that diatom analysis of lake sediment can provide very detailed information on long-term climate change, a review of the few other diatom investigations published on European Eemian deposits shows that this technique has been so far seldom used to its full potential in this context in central and southern Europe.

This study focuses on the response of lacustrine littoral chironomid communities to late glacial changes in limnological, environmental and climate conditions in the Mediterranean context. Late glacial chironomid (Diptera: Chironomidae) assemblages, organic petrography and geochemistry were analysed in a sediment core from the littoral zone of Lago dell’Accesa (Tuscany, Italy), where the lake-level fluctuations and the vegetation history have been previously reconstructed. Comparison of the chironomid stratigraphy to other proxies (pollen assemblages, organic petrography and geochemistry, lake-level) and regional climate reconstruction suggested the predominant influence of lake-level changes on the littoral chironomid fauna. The main lowering events that occurred during the Oldest and the Younger Dryas were followed by higher proportions of taxa typical of littoral habitats. A complementary study of organic matter suggested the indirect impact of lake-level on the chironomids through changes in humic status and habitat characteristics, such as the type of substrate and aquatic macrophyte development. Several chironomid taxa, such as Glyptotendipes, Microtendipes and Cricotopus type patens, were identified as possible indicators of low lake-level in the late glacial records. Nevertheless, this study suggested that parallel analyses of organic matter and chironomid assemblages may be needed to circumvent misinterpretation of littoral chironomid assemblage stratigraphy. There was a weak response of the chironomid assemblages to small lake-level lowerings that corresponded to the Older Dryas and Preboreal oscillations. A higher level of determination, e.g. to the species group level, may be necessary to increase the sensibility of the indicators to lake-level changes.

Aim Previous studies have failed to reconstruct the regional post-glacial migration pattern of Abies alba in southern France. Based on the first exhaustive compilation of palaeoecological data in this region, we present the state-of-the-art and attempt to synthesize the available information concerning glacial refugia and post-glacial migration, and analyse the information with regard to climate and orography. Location South-western Alps and adjacent areas, southern France. Methods The work compiles the available palaeoecological data in the south-western Alps (52 sites, 290 radiocarbon dates). The post-glacial migration pattern of Abies alba is reconstructed based on 22 selected palynological analyses (11 well-dated reference sites and 11 supplementary ones). Results The geographical patterns of approaching area limit, immigration and expansion are reconstructed at the scale of the southern French Alps. Main conclusions Despite previous assertions, the evidence of refugia in southern France is non-existent. The late-glacial records of fir pollen, previously interpreted in French Mediterranean regions and on adjacent foot-hills as possibly reflecting regional refugia, most probably correspond to reworking phenomena or long-distance pollen transport. Fir migration, originating in the Apennine refugia and through the south-western extremity of the Alps, was extremely rapid in the southern French Alps, only spanning a few centuries between 10,100 and 9800 cal. yr BP. The subsequent spread of fir populations was controlled by local parameters, such as the aridity of the inner valleys, which resulted in a delayed expansion in comparison to other regions. Abies almost disappeared from the south-western Alps during the Roman era, around 2000 cal. yr BP.

Despite the large body of research devoted to understanding the role of Quaternary glacial cycles in the genetic divergence of European trees, the differential contribution of geographic isolation and/or environmental adaptation in creating population genetic divergence remains unexplored. In this study, we used a long-lived tree (Taxus baccata) as a model species to investigate the impact of Quaternary climatic changes on genetic diversity via neutral (isolation-by-distance) and selective (isolation-by-adaptation) processes. We applied approximate Bayesian computation to genetic data to infer its demographic history, and combined this information with past and present climatic data to assess the role of environment and geography in the observed patterns of genetic structure. We found evidence that yew colonized Europe from the East, and that European samples diverged into two groups (Western, Eastern) at the beginning of the Quaternary glaciations, c. 2.2 Myr before present. Apart from the expected effects of geographical isolation during glacials, we discovered a significant role of environmental adaptation during interglacials at the origin of genetic divergence between both groups. This process may be common in other organisms, providing new research lines to explore the effect of Quaternary climatic factors on present-day patterns of genetic diversity. © 2015 New Phytologist Trust.

International audience; This study investigates sediment cores from the Mediterranean alpine lakes located in upvalley cirques upper than 1700 metres a.s.l. using sedimentological, palynological and geomorphological studies, in order to document environmental changes following the last phase of glacier retreat. These results are considered in the framework of the deglaciation characterized from 16 sediment cores from high-altitude lakes and mires including 104 14C ages and geomorphological studies of the Mediterranean Alps. Considering each sediment core proxy as an independent observation, i.e., comparisons between 14C ages and palynostratigraphy, between 14C ages and lithostratigraphy, between palynostratigraphy and lithostratigraphy, these data are aimed at contributing to a better understanding of the timing of postglacial environmental changes. The 14C ages combined with pollen biostratigraphy indicate that the deglaciation of cirque catchments is dated between 14,500 and 13,000 cal. BP, i.e., during the Lateglacial Interstadial (Greenland Interstadial-1e). The sixteen lacustrine and mire sediment records are systematically characterized by three units from bottom to top: organic-poor blue clay, beige to light-brown silty clay and organic rich dark brown gyttja lithotype. During the Younger Dryas, lakes located below 2300 m a.s.l. were ice-free and their pollen record indicates steppe conditions. The sedimentary facies also informs on the timing of glacial-dominated processes. The onset of organic-rich gyttja is dated at 11,000 cal. BP suggesting the last influence of cirque glaciers in these lakes at the beginning of the Holocene. The timing of the onset of this organic rich unit differs in sites (±2000 years) probably due to an altitudinal and exposure gradient of the glacial cirques. The presence of gyttja from 11,000 cal. BP to Present indicates biogenic infilling lake for all the Holocene. Even though the literature have indicated rock glacier advances occurred during the Holocene (Subboreal and LIA) in the south of the Alps, no significant sedimentological patterns related to glacier fluctuations are recorded in Lake Vens. The glacier fluctuations in the Mediterranean Alps are concomitant with those dated in the non-Mediterranean Alps, thus suggesting a main common climate forcing. However, the increase in terrigenous sediment inputs since 1800 cal. BP is mainly due to human activities.

International audience; La comparaison de six diagrammes polliniques des Alpes françaises permet de reconstituer les changements passés de la structure de la végétation à la limite supérieure de l'étage subalpin. Des peuplements denses de Pinus cembra s'y sont développés entre 6500 et 2400 cal. BP, à la fois dans les Alpes du Sud et du Nord. Les Alpes du Sud semblent toutefois caractérisées par des limites altitudinales plus élevées, comme en témoigne le développement passé de sapinières à 2080 m dans la vallée de l'Ubaye. Cette étude souligne l'importance de la prise en compte des paramètres locaux dans les synthèses régionales ou continentales.

This study aims at elucidating modern pollen spectra/environmental data relationships from both natural and human-induced vegetation types as an aid for palaeoecological reconstructions. A set of 51 surface moss polsters was sampled from different vegetation and land-use types in the Champsaur area (French Alps) and analysed to obtain modern pollen analogues of ancient cultural landscapes in mountain ecosystems. Samples were selected from grazed areas,mown meadows, cultivated fields, fallow land and deciduous and coniferous forests.Vegetation composition around the sampling points and seventeen types of environmental variables (e.g., management type, soil and topography) were collected all for these 51 sites. Patterns of modern local pollen variation in relation to the environmental variables were explored by means of canonical correspondence analysis (CCA) and associated statistical tests. This correlative model allows us to determine the major explanatory variables and to identify taxa indicative of particular anthropogenic activities, and thus may help to calibrate fossil pollen assemblages.The indicator pollen types are evaluated in the light of comparable material from lowland and mid-elevation areas of western Europe. The results of the French data-set confirm some of the conclusions drawn from the North European data-sets, but also show some site specific features.Pollen markers with a broader global significance common to other regions include Rhinanthus type, Apiaceae and Dipsacaceae for mown meadows, Urtica type, Plantago media/major, Trifolium type and Potentilla type for grazed areas, and Cerealia type, Centaurea cyanus,and Polygonum aviculare for cultivated fields. New pollen anthropogenic indicators typical of our study area are Sanguisorba officinalis, Vicia type (mowing), Lotus type, Onobrychis type, Centaurea nigra type, Serratula type (grazing), Sinapis type and Papaver rhoeas (cultivation). This study provides potentially valuable analogues for humaninduced vegetation types, and it may then become possible to interpret more objectively local pollen diagrams from Alpine mountain environments in terms of past cultural landscape development.

Pollen and plant macrofossil records from a selection of sites in Spain, France and Italy are used to explore the origin and the development of the Mediterranean vegetation. The role of evergreen and summergreen taxa is discussed. The expansion of sclerophyllous trees during the Pleistocene interglacials is well correlated with the orbital forcing. During the Holocene, the large number of data illustrates latitudinal and longitudinal differences in vegetation dynamics. Multidisciplinary studies identify short terms climatic fluctuations. The debate is still open between those who attribute an increase of sclerophyllous forests during the late Holocene to a trend toward aridity and those who consider this dynamic as human-induced.

Summary We present here a review of the recolonisation of the Atlantic oakwoods following the end of the last glacial period. The study is based on two independent data sources: palaeoecological and phylogeographical data. The spread of oak is examined at two scales: (1) continental, allowing a consideration of the location of glacial refugia and the broad outlines of the migration, (2) the Atlantic coastal region, in order to establish the specific history of the Atlantic oakwoods. Climatic and human controls on the timing, speed and pattern of spread are considered, in particular, the conditions of the early Holocene period during which the majority of the recolonisation took place.

Resume — Les activites sublimatoires debutent normalement des le plus jeune âge au travers de la cocreation d’objets transitionnels. La participation de l’Autre parental (maternel) est essentielle au developpement de ces sublimations premieres. Cela eclaire l’aptitude des sublimations ulterieures a servir de recours en cas de perte physique de cet Autre – ainsi subrepticement maintenu. Cela conduit aussi a mieux reconnaitre le role de la mere comme sujet transmetteur – bete noire des integrismes et illusions narcissiques de tout poil.

We present here the results of pollen analysis of two sequences of about 8.06 m and 11.90 m length, originating from two adjacent peat bogs in the southern part of Transylvania province, Romania (155 and 122 pollen spectra). The vegetation record, which is supported by 17 14 C dates, begins in the Late Glacial interstadial when forest recolonisation began with the development of Pinus, without a pioneer Betula phase. Picea began to expand from regional refuges. After a well-defined Younger Dryas, the Holocene opens with the expansion of Betula, Ulmus and Picea, followed, at about 10 400 cal. yr BP, by Fraxinus, Quercus and Tilia. The Corylus optimum is correlated with the Atlantic chronozone (after 8600 cal. yr BP). The local establishment of Carpinus occurred at about 6500 cal. yr BP, with a maximum at about 5700 cal. yr BP. Fagus pollen is regularly recorded after 8200 cal. yr BP. This taxon became dominant at about 3700 cal. yr BP. The first indications of human activities appear at around 7200 cal. yr BP. Copyright 2005 John Wiley & Sons, Ltd.