Macrofossil Analyses Research Articles

Molecular to macrofossils indicating last millennium sea level in Lavsa saltpans, Croatia

Intertidal salt production sites existed continuously around the Mediterranean since classical antiquity, and their remains are present in large numbers along the Dalmatian (east Adriatic) coast. Most of them are preserved and dated to medieval times. This study aims to develop complementary proxies identifying the salt production layer in submerged ancient saltpans of Lavsa, a remote island on the central Dalmatian coast, to date the saltwork units by optically stimulated luminescence (OSL) and use them to infer changes in sea level. The significance of the study is in the application of molecular fossil analyses identifying the hypersaline layer in the sediments from a core drilled in the saltpan's site. The molecular fossil analyses correlate with the results of micro and macrofossil analyses and geochemical findings, all representing the saltwork unit. The depth of the hypersaline layers and the OSL dates provide relative sea level (RSL) lower limiting points of −145 ± 5 cm at 1309 ± 33 CE, probably the time when salt production started in Lavsa, and −115 ± 5 cm at 1364 ± 52 CE when saltwork activities ended. These limiting points extend the known RSL index point in Lavsa Island of −92 ± 8 cm, with an updated average age of 1337 ± 62 CE, correlating with the historical records. Medieval lower sea levels were also observed in the northern and southern parts of the east Adriatic coast as well as in other parts of the Mediterranean, probably driven by climate-related events, generating centennial-scale fluctuations in past sea levels that cannot be predicted by glacial isostatic adjustment (GIA) models.

Lateglacial and Holocene palaeoenvironmental evolution of alkaline peatlands in the Somme valley (France): between climate and anthropogenic forcing

As in most chalk river valleys in NW Europe, the sedimentary fill of the Somme valley is mainly composed of fluviogenic alkaline peat. The site of Morcourt exhibits a thick and well‐preserved fluvial sequence (10 m, including 6 m of peat). This sequence provides the framework for reconstructing fluvial and palaeoenvironmental dynamics from the end of the Upper Weichselian Pleniglacial (~20 000 cal. a BP) to the High Middle Ages (~700 cal. a BP). The palaeoenvironmental reconstruction is based on a high‐resolution stratigraphic study of 60 transect cores, 36 radiocarbon dates and sedimentological, geochemical, pollen and plant macrofossil analyses. There are three main phases in the development of the valley floor: (i) after the incision of the abandoned Pleniglacial braided river channels, a first generation of localized peat developed during the Bølling and the Allerød interstadial (<1 m thick); (ii) at the beginning of the Holocene, a peat formation phase began in the deepest parts of the valley and then spread over the valley floor by the end of the Middle Holocene (~4700 cal. a BP), with the limited runoff shifting to a small lateral channel; and (iii) at the transition to the Late Holocene, environmental changes, driven by the intensification of human activities and perhaps accentuated by climatic modifications, caused the incision of the peat system as a result of the formation of a channel. This channel drained the valley, and then mixed a detrital load into the peat. By the Low Middle Ages, the system had been altered to such an extent that the peat was completely covered by organic silty alluvium. The water table was lower, which definitively inhibited peat formation. The Morcourt sedimentary record (thickness and continuity) and the resumption of turfigenesis during the Late Holocene are remarkable in NW Europe, making this site a model of continuous morpho‐fluvial evolution since the Lateglacial.

Holocene vegetation and flora dynamics of the west Cork/Kerry region, south-western Ireland

AbstractSediments from a small lake, Loch Beag, in Barrees, Beara peninsula, south-western Ireland, provide a record of vegetation history that spans most of the Lateglacial and Holocene (14–0.43 ka). The detailed part of the record relates to the Holocene, which is the focus of this paper. The investigations carried out include pollen and macrofossil analyses, loss-on-ignition measurements and 14C dating. As well as providing records for tree and shrub taxa, and especially Pinus, Quercus, Ulmus, Fraxinus and Taxus, other taxa mainly with Atlantic and/or Lusitanian distributions are also considered. These include Arbutus unedo (strawberry tree) and fern species such as Osmunda regalis, and the filmy ferns Hymenophyllum tunbrigense, H. wilsonii and Trichomanes speciosum (Killarney fern). Detailed records for a suite of bog/heath taxa, including ericoid species (Erica tetralix and E. cinerea), Narthecium ossifragum, Hypericum elodes and Myrica gale, are presented. The results of 14C dating of bog-pines from western Ireland are summarised. Results of other investigations, including key Holocene pollen diagrams, and charcoal and fossil-wood records from archaeological excavations that relate mainly to the Bronze Age in the wider west Cork/Kerry region, are reviewed. Vegetation dynamics, human impact and plant biogeography are discussed in the light of the considerable data now available for the region.

Natural and anthropogenic factors affecting intense slope processes in Eastern Europe during the Modern Period: Serteyka river valley, Russia

Detailed palaeogeographical studies of the accumulative fan in the Serteyka River valley in W Russia and underlying biogenic deposits were carried out. The base of a representative core of biogenic sediments in the distal zone is dated to 1291 BC, while its top to 1631 AD. In this paper, palynological, plant macrofossils, Chironomide and Cladocera, geochemical, geochronological and sedimentological analysis were performed. Four phases of biogenic deposition were distinguished by pollen and geochemical analyses. Two of them coincide with the climatic fluctuation during Medieval Climate Anomaly and Little Ice Age. During the formation of the fan, overbank deposits were accumulated also, indicating numerous and intense floods, which are in line with the trend observed for other sites in this region. The accumulative fan is formed by lower, middle and upper deluvia and agricultural diamicton in its top. All units have specific sedimentological and geochemical features as well as low admixture of plant macrofossils. The beginning of the formation of this relief form dates back to the second half of the 17th century AD, and the end of the accumulation falls on the second half of the 18th century AD. Our work suggests that natural conditions had an impact on the formation and development of studied accumulative fan, however, the decisive factor causing the intensification of the slope processes were related with deforestation resulted from strong human impact, which was marked in palynological and macrofossils analyses (e.g. increase in the contribution of plants macrofossils related to agriculture).

Development and carbon accumulation dynamics of a minerotrophic fen during the last millennium, northeast China

Peatlands are terrestrial ecosystems with high carbon sequestration efficiency, providing critical feedback on climate change. It is crucial to understand how peatland development and carbon accumulation respond to various factors to reveal the future direction of carbon reservoirs under changing climatic conditions. To assess the impact of climate and hydrological conditions on the development and carbon accumulation of peatlands, 15 peat core samples were analyzed to examine the processes of lateral expansion in the Dongfanghong (DFH) peatland, a minerotrophic fen located in the Changbai Mountains of northeast China. Accelerator Mass Spectrometry 14C, total organic carbon, dry bulk density, testate amoebae, δ13C of α-cellulose in Carex spp. and plant macrofossil analyses were conducted on a high-resolution peat core. The proxies were used to calculate carbon accumulation rate (CAR) and reconstruct water table depth as well as surface moisture and vegetation development of the DFH peatland. Our findings indicated that the DFH peatland was initiated at 1011 cal. CE and experienced paludification during the last millennium. The expansion of the DFH peatland was primarily determined by hydrological conditions rather than climatic factors such as total solar irradiance and regional temperature. The rapid expansion between 1500 and 1700 cal. CE was likely resulted from relatively low precipitation and a decrease in water table/surface moisture. CAR generally correlated with total solar irradiance, regional temperature, and precipitation, suggesting that climate may be crucial for CAR in DFH peatlands over multi-centennial timescales. However, the increased CAR under relatively dry conditions suggested that the CAR were regulated by hydrological conditions over a centennial timescale. This study highlighted the important roles of climate and hydrological conditions in the lateral expansion and CAR of the peatland in minerotrophic fen and that there may be a threshold for hydrology during the process of peatland development and carbon accumulation.

Peat deposits for studying the Holocene fire regime in the example of Kansk forest-steppe mires

The results of Holocene fires history reconstruction in the Kansk forest-steppe Kranoyarsk Territory are presented using the example the Kuskun mire (Esaulovka river basin) and Rybnoye mire (Rybnaya river basin). The complex of paleoecological methods (analysis of macrofossils in peat and charcoal analysis) are using. The stages of increased fire activity were established at 4000-3000 and 1500-500 cal yr BP. These time intervals coincide with a decrease in moisture during the subboreal xerothermic maximum and a short dry period 1400-1300 cal. yr BP subsequently replaced by the Medieval Warm Period. When comparing the results obtained, a coincidence of long fire episodes with a change in local vegetation was revealed.

The Holocene evolution of floodplain mire geosystems in the southeastern part of the Meshchera lowlands

The results of paleoecological studies of peat deposits in the area of the southeastern part of the Meshchera lowlands (Mostovoye mire) based on the analyses of peat properties, plant macrofossils, charcoal, pollen and radiocarbon dating are presented. The mire was formed in the oxbow depression on the floodplain of the Goose River around 9480 cal. yr. BP and was eutrophic throughout most of the Holocene. Drastic changes in the dynamics of the mire, namely its transition to the mesotrophic stage, characterized by a decrease in the degree of peat decomposition, occurred about 70 years ago. The results of the pollen analysis show the existence of birch-pine forests in combination with shrub thickets formed by Betula nana in the period 9480-8750 cal. yr. BP. In the subsequent stages, the vegetation cover turned to a combination of broad-leaved, birch-pine forests and riverine forests with alder. Frequent fires, both natural and anthropogenic, have favored the development of birch and pine forests over the last millennium.

Holocene vegetation dynamics of the Yamal Peninsula based on palaeobotanical data from relict peat bog deposits

We have performed a comprehensive paleoecological study of the peat bog deposits from six localities of the Seyakha, Yuribey and Khadytayakha rivers in the subarctic tundra zone on the Yamal Peninsula. Radiocarbon dating, as well as pollen and plant macrofossil analyses were used to track the chronological changes of the plant communities on the peninsula along the North-South transect in the Late Glacial and Postglacial periods. It was found that open woodland with tree birch and spruce existed in the Yuribey river valley during the Bölling-Allerød interstadial (between 14.7 and 12.7 cal. ka BP). Shrub tundra with Betula nana was widespread in this area during the Younger Dryas, between 12.6 and 11.7 cal. ka BP, under climatic conditions similar to modern ones. The spread of arboreal species (Betula sect. Betula, Picea obovata, Larix sibirica) and associated boreal herbaceous plants began later (between 10.2 and 9.7 cal. ka BP) as climatic conditions improved. The most favorable conditions for tree birch and larch existed in the Seyakha river valley between 10.2 and 8.7 cal. ka BP, whereas the best conditions for the same species and spruce in the Yuribey river valley were observed between 10.2 and 4.4 cal. ka BP. It was much warmer than it is today, and open woodland or even closed forests were widespread. Forest degradation and spread of open landscapes with tundra communities occurred in the Seyakha river valley after 8.7–8.5 cal. ka BP and in the Yuribey river valley after 4.7–4.3 cal. ka BP. Climatic conditions became similar to modern ones. Today, arboreal species grow in the Khadytayakha river valley, forming extrazonal forest communities in the subarctic tundra zones.

Late Quaternary Dynamics of Landscape and Climate in the North of the West Siberian Plain Revealed by Paleoecological Studies of Peat and Lake Sediments

West Siberian mires covering more than 50% of area in the subarctic are still poorly investigated despite their thick peat sediments suitable for paleogeographic research of past long-term landscape and climatic changes. In this research, a combination of paleoecological methods were used, including the analysis of pollen, spores, diatoms, NPPs, and macrofossils, the measurement of peat humification, and quantitative paleoclimate reconstruction. This multi-proxy approach was applied to study a palsa bog (frost peat heave mound) located in the north of western Siberia on the border of the northern taiga and forest–tundra (65°18′56″ N, 72°52′27″ E). Chronology is based on 21 radiocarbon dates, which were calibrated in CLAM. Studies have shown that sediments of palsa bog Nadym of a 1050 cm thickness were formed both in the Holocene and earlier periods of the Quaternary. Radiocarbon dating worked well for peat sequences (610 cm thick), but failed for underlying lacustrine and mineral sediments (440 cm thick). Numerous remains of salt-water diatoms and exotic Neogene pollen were found in the lacustrine sediments (650–850 cm). The oldest sediments (850–1050 cm) have signs of secondary epicryogenic diagenesis in the form of cryogenic iron-enriched granules. Both lacustrine and bottom sediments contain abundant coniferous pollen. At the same time, spore–pollen complexes dated to the Last Glacial Age were not found in low sediments because of failed dates. To explain this, the authors turn to the hypothesis of glyacioisostatic compensation, according to which the study area was uplifted during the Last Glacial Age and the ancient deposits underwent secondary diagenesis in subaerial conditions. Holocene lacustrine sedimentation began to form about 9800 cal. a BP. These lacustrine sediments turned out to be enriched in redeposited Neogene pollen and diatoms. It was interpreted as an influence of excess humid climate in combination with geological subsidence of landscape in the study area during the Early Holocene. This caused lake formation and introduction of exotic microfossils via surface run-off from higher-relief areas in the catchment. Syngenetic sedimentation in the Nadym section is associated only with peat-mire deposits covering the last 8400 cal. a BP. For this time, the dynamic of vegetation cover and quantitative changes in paleoclimate were reconstructed using spore–pollen, macrofossil, humus, and NPP data as well as the information–statistical method of V.A. Klimanov. The spore–pollen analysis revealed four main phases in the development of vegetation cover: 1. Spruce–birch forests with open meadows and lakes (8400–7600 cal. a BP); 2. Dominance of spruce forests and thawed eutrophic (minerotrophic) mires (7600 to 6500 cal. a BP); 3. Coniferous–birch forests and thawed mesotrophic mires (6500 to 4500 cal. a BP); 4. Birch–pine forests and oligotrophic (ombrotrophic) bogs with permafrost mounds—palsa bogs (approx. the last 4500 years). Quantitative reconstructions of paleoclimate based on pollen data show that in most cases the periods of a sharp decrease in mean January and mean July temperatures coincided with episodes of low solar activity. The assumption was made about the determining influence of solar activity on the formation of permafrost in the soils and mires of the study area. Sun minima caused permafrost formation in the mire periodically since 8400 cal. a BP in study peatland, but complete freezing of the peat mire and formation of the palsa bog occurred at c. 2800 cal. a BP.

Comparison of paleobotanical and biomarker records of mountain peatland and forest ecosystem dynamics over the last 2600 years in central Germany

Abstract. As peatlands are a major terrestrial sink in the global carbon cycle, gaining an understanding of their development and changes throughout time is essential in order to predict their future carbon budget and potentially mitigate the adverse outcomes of climate change. With this aim to understand peat development, many studies have investigated the paleoecological dynamics by analyzing various proxies, including pollen, macrofossil, elemental, and biomarker analyses. However, as each of these proxies is known to have its own benefits and limitations, examining them in parallel allows for a deeper understanding of these paleoecological dynamics at the peatland and a systematic comparison of the power of these individual proxies. In this study, we therefore analyzed peat cores from a peatland in Germany (Beerberg, Thuringia) to (a) characterize the vegetation dynamics over the course of the peatland development during the late Holocene and (b) evaluate to what extent the inclusion of multiple proxies, specifically pollen, plant macrofossils, and biomarkers, contributes to a deeper understanding of those dynamics and interaction among factors. We found that, despite a major shift in the regional forest composition from primarily beech to spruce as well as many indicators of human impact in the region, the local plant population in the Beerberg area remained stable over time following the initial phase of peatland development up until the last couple of centuries. Therefore, little variation could be derived from the paleobotanical data alone. The combination of pollen and macrofossil analyses with the elemental and biomarker analyses enabled further understanding of the site development as these proxies added valuable additional information, including the occurrence of climatic variations, such as the Little Ice Age, and more recent disturbances, such as drainage.

Late Bronze Age agriculture and the early westward transmission of rice at Luanzagangzi, Northern Xinjiang, China

The Dzungar Basin of northern Xinjiang has previously been considered a marginal environment with little evidence for the development of prehistoric agriculture. Recent archaeobotanical studies have indicated the region as being a route for the transmission of domesticated plants, technologies and ideas between East and West Eurasia during prehistory, as early as 5000 BP. These interactions are still poorly understood and most evidence for early plant food production and consumption in the region comes from limited mortuary contexts. In this study we present plant macrofossil analysis from the settlement site of Luanzagangzi on the southern side of the Dzungar Basin. From ca. 3130 BP an agricultural package of east and west Asian cereals and chaff is present, comprising wheat, barley, foxtail millet, broomcorn millet, and significantly a single grain of japonica type rice. AMS dating indicates this is the oldest directly dated rice in Xinjiang and the broader region, ranging 3069–2881 cal. BP. Cereal morphometrics and material culture from the site further indicate a connection with the Gansu region to the east. The spread of agriculture into the site environment may be linked to the onset of wetter conditions relating to strengthened westerly systems across arid Central Asia in the Late-Holocene. A declining abundance of West Asian cultivars over the period of the site’s occupation possibly reflect a shift away from intensive agriculture to low-level management of millets.

Lire le passé forestier dans un bourbier : histoire écologique et dynamique contemporaine d’une population marginale nordique d’érable rouge (Acer rubrum)

ABSTRACT Populations at the edge of a species range are vulnerable to climate change. Studying their ecological history helps understanding resilience processes acting at the limit of the species’ tolerance envelope. In the mixedwood forest ecotone, several thermophilic species, such as white pine and red maple, reach the northern limit of their geographical range. Here we rely on macrofossil analysis of charcoal particles and plant macroremains of a forest hollow to reconstruct the local history of thermophilic species in a marginal red maple stand isolated within the mixedwood forest ecotone. Taxonomic identification and radiocarbon dating of charred particles and wood remains extracted along the peat accumulation profile indicated dominance of white pine during the Holocene Climate Optimum (6200 to 4300 cal yr BP). The fossil assemblage suggests the transition of a black spruce - feathermoss (>9500 to 6200 cal yr BP) to a balsam fir forest that developed after the decline of white pine (since 4300 cal yr BP). Red maple is not detected in the fossil assemblage suggesting a late arrival and/or expansion on the site, likely favored by anthropogenic activities and the climate warming ongoing since the end of the Little Ice Age.

Palaeoecological multiproxy reconstruction captures long-term climatic and anthropogenic impacts on vegetation dynamics in the Rhaetian Alps

Alpine ecosystems are particularly affected by climate change due to their high sensitivity to temperature variations. Understanding the response of vegetation to rapid temperature increase and human impact is necessary to produce accurate and reliable predictions of future mountain vegetation and mitigate climate change impacts. Our multiproxy study reconstructs climate, fire, and vegetation dynamics over the last 14,200 cal. BP at Lai da Vons (1991 m a.s.l.), a subalpine lake situated in the treeline ecotone in Eastern Switzerland. Our results based on geochemical analysis (XRF), pollen and charcoal analysis, and high-resolution macrofossil analysis reveal that early afforestation started already at the onset of the Holocene, dominated by Pinus cembra and Larix decidua. Larch and stone pine formed closed forests at the site at 10,300 cal. BP. From 9500 cal. BP onwards, when summer temperatures were warmer than today, Picea abies expanded simultaneously with Abies alba. In the past 6500 years, increasing human impact, culminating during two main phases of landscape opening and intensification of fire regime, led to a progressive increase of species richness. Considering future climate change, an upward shift of treeline and timberline is expected in the absence of domesticated herbivores. We advocate that low-intensity pastoralism in such a cultural landscape is essential to preserve the plant diversity of species-rich mountain meadows.

Bryozoan statoblasts from lake sediments in Madagascar, including two new species

Madagascar is a freshwater biodiversity hotspot, yet the current understanding of freshwater bryozoan diversity is limited. Using a dissecting microscope, bryozoan statoblasts were collected during macrofossil analysis of a sediment core, which was taken from Lake Sofia, Madagascar, in 2019. There was a peak in the abundance of statoblasts prior to 1900, with 67 statoblast valves found at 45.5 cm and a decline in more recent sediments. A subsample of 14 specimens was examined under a scanning electron microscope to determine species identification. One of the species found was Plumatella kinesis. Two new species, Plumatella tsimiheta sp. nov. and Plumatella sofiae sp. nov. were also found and described. These results show the potential of lake sedimentary bryozoan remains for categorising species presence and distribution. Although poor preservation was a limitation for identification, there is still value in having a historical record of past biodiversity, especially when species may no longer be extant. This study highlights the need for further research to better understand the status of these species and other potential new species of bryozoan in Madagascar.

The importance of wild plant resources in the Neolithic: a case study of the Late Neolithic lakeshore settlement of Grandson-Corcelettes, Les Pins (Switzerland)

The site of Grandson-Corcelettes, Les Pins is located at Lake Neuchâtel, Switzerland and was occupied during several phases of the Late Neolithic (between roughly 3000 and 2500 bc). Archaeobotanical analyses of the cultural layers revealed that, besides the cultivation of food plants, the inhabitants of Grandson used wild plant resources for many purposes. An estimation of the proportion of a selection of collected wild plants within the plant diet – based on calories – showed that they accounted for more than half of the calorific intake. This is in line with similar calculations performed for other Neolithic circum-Alpine settlements. The wild food plant spectrum indicates that most of them were gathered in the woodlands and semi-open habitats close to the village, whereas the riparian forest only seemed to play a marginal role. The analysis of macrofossils and pollen from dung pellets of goat and/or sheep showed that wild plants were also important as food for domestic animals, and that grazing took place in a variety of places, including forests, fallow fields and grassland-like habitats outside the village and throughout the year. Besides, there are indications that the nearby Jura mountains (reaching 1,600 m a.s.l. near the lakeshore villages) were exploited.

Holocene landscape evolution, palaeoclimate and human impact in the Fotsch Valley, Stubai Alps, Austria: Interrogating biomarkers, stable isotopes, macrofossils and palynological indicators from a subalpine mire archive

Peatlands are receiving increasing attention in palaeoenvironmental research and represent very useful terrestrial archives for reconstructing vegetation, climate and human history. Previous palaeoenvironmental studies in the Fotsch Valley, Stubai Alps, Austria, focused on geoarchaeological investigations on the Ullafelsen representing a very important prehistorical encampment site used by Mesolithic hunter-gatherers (10.9–9.5 cal. kyr BP). In order to contribute to a better understanding of the landscape evolution of the Fotsch Valley, we here studied the close-by subalpine ‘Potsdamer Hütte Mire’ by applying radiocarbon dating as well as elemental, biomarker, compound-specific stable isotope, palynological and macrofossil analyses on bulk peat samples. The calculated age-depth model using R Bacon indicates the beginning of peat formation during the Early Holocene and shows a strongly reduced peat accumulation rate (PAR) from 170 to 121 cm depth (8.5–2.1 cal. kyr BP) and/or a striking hiatus. Results of leaf wax-derived n-alkane biomarkers as well as macrofossils and palynological indicators reflect the local presence of coniferous trees and the synchronous expansion of deciduous trees during the Early Holocene. The above-mentioned strongly reduced PAR and/or hiatus coincides with the Neolithic, the Bronze and the Iron Age, and goes hand in hand with strong changes in vegetation and an increase of micro-charcoal and black carbon. Despite age uncertainties, these changes can be explained with strongly increasing human and livestock activities in form of deforestation, domestic fires and the beginning of Alpine pastoralism. The latter is confirmed by the finding of pasture and cultural indicator pollen (Cerealia-type, Rumex, Plantago lanceolata, Poaceae) occurring since the Middle to Late Bronze Age. The oxygen isotope composition of sugar biomarkers (δ18Osugars) likely reflects the dry versus humid climatic variability associated with the Holocene climatic optimum during the Mesolithic, the Roman Age, the Late Antique Little Ice Age, the Middle Ages and the Little Ice Age.

Editorial

Editorial

The effects of climate, natural disturbances, and human occupation on the rainforest boundary at the eastern foothills of Northern Patagonian Andes since the Late Glacial period

Available studies on the vegetation development in Patagonia cluster along the forest-steppe ecotone, whilst little information is available from within the mountains. This study investigates shifts in the eastern boundary of rainforest taxa during the Late Glacial and Holocene periods. Continuous sections of highly organic sediments with several interbedded tephra layers were obtained at El Laguito del Morro Lake (41° 32′ 24.4″ S, 71° 47’ 50.0” W), which were analyzed for pollen and macro charcoal. Additional macrofossil analysis was conducted to support the interpretations of pollen data and gain reliable material for radiocarbon dating. Fluctuations in regional precipitation were inferred from changes in the adjacent peatbog. The pollen record documents five distinct periods of forest diversity and structure. Late Glacial and early Holocene vegetation were characterized by a combination of Podocarpus and Cupressaceae pollen which has no modern analogue. Taxa in question became rare, and or gradually disappeared around 10,300 cal yr BP when Nothofagus dombeyi type pollen increases but fluctuates. With the overall decline of charcoal concentrations around 7500 cal. BP Nothofagus dombeyi-type pollen stabilizes and dominates the diagram. After the rise in charcoal concentrations around 4000 cal yr BP also the overall vegetation composition changes around 3600 cal yr BP, with the rise of Cupressaceae pollen attributed to Austrocedrus chilensis marking the establishment of the modern vegetation structure. The last stronger change in vegetation composition is characterized by the expansion of the shrub Discaria sp. 770 cal yr BP. Charcoal and pollen data show a clear link between changes in fire regime and vegetation composition, however, changes in climate were most likely the main driver for both. During the Late Glacial period, a rainforest developed under cool temperatures and high moisture. Severity of fires decreased during a cold reversal period from ca. 12,800 to 11,300 cal yr BP. During Early Holocene, increased seasonality, volcanism-derived disturbances, and low-frequency surficial fires, enhanced Nothofagus dombeyi forest establishment. The expansion of the mixed Nothofagus dombeyi - Austrocedrus chilensis forest occurred under increased precipitation variability and the increase of low severity fires related to the establishment of El Niño Southern Oscillation and the Southern Annular Mode during the Late Holocene. Scrub expansion occurred during historical times because of induced fires.

Болота северной Евразии: биосферные функции, разнообразие и управление (Петрозаводск, 25–28 сентября 2023 г.)

International Symposium “Mires of Northern Eurasia: Biosphere functions, diversity and management”, held on September 25–28, 2023 in Petrozavodsk, continued the traditions of the previous symposums organized by Karelian specialists in 2005 and 2015. Totally 101 participants from 21 regions of Russia and Belarus attended the Symposium. They represented 42 organizations: Universities and Research Institutes of the Russian Academy of Sciences, environmental organizations, Nature reserves and industrial enterprises. 86 scientists arrived to Petrozavodsk, 9 specialists presented online reports. During the two days of the Symposium, 6 plenary and 56 sectional oral presentations and 28 posters were presented. Six plenary presentations were devoted to the history of mire research in different regions, the diversity of types of mires and mire vegetation, the history of climate and vegetation dynamics in the Holocene, the importance of mires in the exchange of greenhouse gases and the development of modern methodological approaches to the study of mire dynamics. The most extensive section called “Diversity, structure, dynamics and functioning of mire ecosystems” contained 32 oral presentations. The issues of the typology of mire massifs of different regions of Russia, diversity and originality of mire plant communities, their dynamics, geographical distribution of mires, and conservation value of mire communities were highlighted. Such classical studies continue the traditions of the Russian and Soviet geobotanical school and provide a new level of insight into mire ecosystems and form the basis for solving such current problems as assessment of climate change, carbon balance, protection of rare species. The traditional part of the mire conferences are the presentations devoted to paleoecology, based on the results of analysis of the peat deposit structure, were. Within the section “Mires and climate in the Holocene, Paleoecology” 15 oral presentations were devoted to the impact of climate change to the Holocene vegetation, the frequency of natural fires that have left traces in the peat sediments, reconstruction of vegetation successions on mires and their connections with archaeological research of the Middle Ages. Separately, a wide range of methods used by paleo ecologists was noted. Along them together with traditional spore-pollen analysis and analysis of plant macrofossils, some modern methods of analyzing arthropods and mollusks and testate amoebas were used. At the section entitled “Research methods, management of mire ecosystems and their restoration” nine reports were presented, covering such topics as the influence of cranberry pickers’ on the mire vegetation, remote sensing methods used for monitoring plant successions and typology of mire ecosystems, the growth of sphagnum mosses as an indicator of activity of ultraviolet, and thermal analysis of organic matter of peat soils. Twenty eight posters were exhibited at the poster session, their topics mostly repeated such of sectional presentations, but were more specific. The works of young scientists and students were presented there. The youngest participant of the session and the entire Symposium was a student of the Lomonosov Lyceum from Arkhangelsk, who presented a poster on the features of cranberries cultivated in the White Sea region. An important part of the symposium were field trips. During two days participants were able to visit two remarkable sites in the southern part of Karelia. Small eutrophic fens near the village of Kolatselga (150 km west of Petrozavodsk) had a specific floristic composition. In 1942–43, two Finnish botanists have described these mires. Their publication provided an excellent comparative data for the further researchers. The participants of the Symposium visited four of these fens and assessed their current state. Another object of excursion were the mires of the Kivach Nature Reserve situated 80 km north from Petrozavodsk. The Reserve is a popular tourist attraction for visiting the Kivach Waterfall on the Suna River. However, the local nature is quite rich, diverse and picturesque, so the reserve serves as a traditional place for environmental research in Karelia. Local mires are also well studied; the participants of the Symposium visited some of them. Video broadcasts of the symposium sessions are available on Youtube channel of the Karelian Scientific Center of the Russian Academy of Sciences, a collection of abstracts has been published (Mires…, 2023).

Holocene vegetation history of the Western Rhodope Mountains (South Bulgaria): the paleoecological record of peat bog Beliya Kanton

Pollen and plant macrofossil analyses supported with radiocarbon dating were conducted on a Holocene core from the peat bog Beliya Kanton (1547 m a.s.l.) located in the Western Rhodope Mountains (South Bulgaria). In the early Holocene until ~10 000 cal. BP the mountain slopes were covered by Pinus, admixed with Betula, Juniperus and shrubland of Ephedra among herb communities dominated by Poaceae, Cichorioideae, Achillea, Artemisia, Brassicaceae species. Subsequently, the afforestation continued with the expansion of broadleaved oak forests with Tilia, Ulmus and Corylus which reached their maximum distribution ~8800 cal. BP. Gradually, these forests began to retreat, replaced at many places first by Corylus and later on by Picea abies, Abies alba and Fagus. The formation of the contemporary coniferous belt with the dominance of Pinus – Picea abies and fragmented mixed coniferous-deciduous communities in the late Holocene was attributed not only to climate change but also to diverse human interference in the natural forest cover. During the last 2000 years the continuous presence of Juniperus, Juglans, Rumex, Cirsium, Plantago lanceolata and Hordeum pollen indicated intensive stock-breeding, grazing and crop cultivation. The fragments of charred wood testify to tree felling and fire clearances on flat ground to obtain new pasture land.