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A comprehensive paleoecological study of permafrost peat deposits from three locations in the middle reaches of the Yuribei River in the subzone of modern subarctic shrub tundra of the Yamal Peninsula has been performed. Based on the results of palynological and carpological methods and of radiocarbon dating, the changes in regional and local vegetation and climatic conditions of Central Yamal in the Late Glacial and the Postglacial periods are reconstructed. It is found that shrubby tundra with Betula nana was widespread in this area under climatic conditions close to modern ones in the Younger Dryas about 12.6–11.7 cal ka BP. The penetration of tree species (Betula sect. Betula, Picea obovata, and Larix sibirica) and accompanying boreal herbaceous plants began due to more favorable climatic conditions during the Early Holocene warming about 10.2–9.7 cal ka BP. The most favorable conditions for the growth of birch tree, larch, and spruce existed in Central Yamal in the Early and the Middle Holocene in the range of 10.2–4.4 cal ka BP. At that time, open woodlands or even closed forests were common, and the climate was much warmer than the modern one. Forest vegetation degraded and open landscapes with tundra communities were formed at the end of the Middle Holocene (4.5–4.4 cal ka BP). The climatic conditions became similar to modern ones. [ABSTRACT FROM AUTHOR]

Pollen, plant macrofossils and charcoal analyses were used to study tree diversity, fire history and forest disturbance over the past c. 3500 years at three forest remnant sites in Vendsyssel, northern Denmark. All locations had a more diverse tree composition in the past including abundant Alnus, Betula, Corylus, Pinus, Quercus, Salix, Tilia and Ulmus. The changes in tree diversity through time can be attributed to a combination of factors including climate change, burning linked to shifting cultivation, grazing and felling. The balance between arboreal and non-arboreal pollen was already being influenced by human activities in the late Bronze Age c. 3000 years ago. The high pollen abundance values recorded for Tilia pre-2000 years ago are exceptional as compared to later periods at these sites. At one location, the transition from Tilia to Fagus indicated that Tilia prevailed until c. 1300 years ago. Subsequent periods of forest clearance, with charcoal and cereal cultivation, initially including Hordeum and subsequently also Secale, were recorded. There was pollen evidence for grazing followed by shrub regeneration including Calluna, Erica, Juniperus and herbaceous taxa, and following that, a forest recovery of mainly Fagus, Picea and Pinus. This recovery is also recorded in historical forest records from 1880 CE onwards, emphasising the dominant role of plantation schemes. Results are placed in a wider framework of other sites in Denmark and southern Scandinavia, which have also documented a reduction of tree diversity and forest cover over the same period. The evidence from the long-term record is used to draw conclusions to assist forest restoration programmes. [ABSTRACT FROM AUTHOR]

The paper presents a new high-resolution (up to decadal) palaeoecological evidence based on detailed AMS radiocarbon dating, plant macrofossils, testate amoebae, loss on ignition, peat humification, elemental and stable isotopic records, obtained from a palsa peatland located in vicinities of Igarka town. This gave us a unique possibility to examine the mid-to late Holocene environmental changes in a poorly investigated area in Yenisei Siberia. The obtained data show that the peatland initiation occurred at about 6350 cal yr BP by paludification of a larch forest in the conditions of climate warming and high surface wetness, possibly, due to permafrost thaw. The first sign of palsa formation occurred about 5360 cal yr BP and coincided with the temperature decrease, wetter and anoxic conditions in peatland. After several phases of uplifts (and relatively dryer conditions) and partial thawing and subsidence of its surface (wetter conditions) between 5360 and 2250 cal yr BP, the continuous rise of the perennial frost mound (up to the height of 5 m) accomplished by drying its surface and colonization by drought-resistant plant species, evidently, encouraged by the climate cooling and permafrost aggradation during the last two millennia. The high-resolution analyses of elemental (C and N) and stable isotope content (δ13C and δ15N) of the peat sequence revealed the strong linkages between the plant composition and mineralization/humification processes. Our multi-proxy study revealed detailed features of peat accumulation patterns driven by multiple interrelated allogenic and autogenic forcings, influencing changes in peat macroelement content and stable isotope composition. [ABSTRACT FROM AUTHOR]

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 , P lantago 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.

Increased permafrost temperatures have been reported in the circum-Arctic, and widespread degradation of permafrost peatlands has occurred in recent decades. The timing of permafrost aggradation in these ecosystems could have implications for the soil carbon lability upon thawing, and an increased understanding of the permafrost history is therefore needed to better project future carbon feedbacks. In this study, we have conducted high-resolution plant macrofossil and geochemical analyses and accelerator mass spectrometry radiocarbon dating of active layer cores from four permafrost peatlands in northern Sweden and Norway. In the mid-Holocene, all four sites were wet fens, and at least three of them remained permafrost-free until a shift in vegetation toward bog species was recorded around 800 to 400 cal. BP, suggesting permafrost aggradation during the Little Ice Age. At one site, Karlebotn, the plant macrofossil record also indicated a period of dry bog conditions between 3300 and 2900 cal. BP, followed by a rapid shift toward species growing in waterlogged fens or open pools, suggesting that permafrost possibly was present around 3000 cal. BP but thawed and was replaced by thermokarst.

The Middle Pleistocene environmental history of the north of West Siberia is very incomplete. Only a few poorly preserved paleoarchives are known so far in this huge part of Eurasia encompassing up to one million square kilometers. Here we present new data (micromammals, insects, plant macrofossils and luminescence dating) from the lower reaches of the Ob' and Irtysh Rivers. We reconstruct the circumstances of the formation of the fossil-bearing sites Bolshaya Ob 440 km – Khashgort (BOB440) and Gornopravdinsk 2 (GP2) and compare the results with the current state of knowledge of the environmental change in this area. The combined evidence suggests that the fossil-bearing unit known as the Khashgort diagonal sands at BOB440 yields 1) a late Middle Pleistocene complex of fauna and flora of a cold terrestrial environment with tundra-like vegetation, 2) a Middle Pleistocene flora of interglacial environment with temperate vegetation, and 3) reworked fossils form the Late Cretaceous – Oligocene. Geochronometric data suggest that the Khashgort sand unit at BOB440 might have been formed during the Middle/Late Pleistocene transition. However, because of a high variation in results obtained on repeated samples from the same strata, some uncertainty of the luminescence dating remains, which requires further verification. The fossil-bearing fluvial sequence at GP2 represents the lower part of the Chembakchino Formation and encompasses the lower part of the Tobolian Horizon (correlated with Holsteinian). The micromammal complex comprises Dicrostonyx simplicior (intermediate morphological stage S2 sensu Smirnov et al., 1997), Lasiopodomys gregalis , Microtus nivaloides lidiae and other taxa, which are characteristic of the early evolutionary stage of late Middle Pleistocene faunas in the north of West Siberia. The paleoecological analysis of plant and animal remains at GP2 suggests an environmental change from cold, tundra-like landscapes at the Shaitanian/Tobolian transition (MIS 12 – MIS 11) to non-analogous open patchy landscapes with highly productive moss and herbaceous vegetation during the early Tobolian time. [ABSTRACT FROM AUTHOR]

The investigation of a hillside at Gilson (Lat. 52.510341, Long. ‐1.718313), southwest of Coleshill, Warwickshire (within the High Speed Two railway 'Delta Junction' compound), England, has yielded evidence of sedimentation during a temperate stage. The site's stratigraphy starts with the aggregation of cold‐climate sand and gravels deposited during the Anglian Stage within the proto‐Tame and proto‐Blythe palaeovalleys. A warm‐climate period is recorded by the infill of organic material representing the second half of the Hoxnian interglacial Stage. Picea, Abies and Pinus dominate vegetation within a swamp‐like environment, before a Pinus forest develops in the upper part of the organic sequence. The following cold‐climate period saw incision and aggregation of the surrounding region throughout much of the Wolstonian and Devensian Stages, where much of the overlying silt, sand and gravel were reworked under intense periglacial conditions. Presented here is a geophysical examination of the shallow basin by ground‐penetrating radar undertaken to understand the spatial distribution and stratigraphical history of the basin. The deposits at Gilson provide a valuable stratigraphic marker in the glacial sequence of the English West Midlands and are correlated to similar deposits at neighbouring Quinton and Nechells. At these regional sites organic accumulation occurred for most of the temperate stage, infilling lake basins. These sequences indicate an environment dominated by pollen of Abies, Quercus, Ulmus and Corylus woodland vegetation. These assemblages differ markedly from those typically found in the last interglacial and confirm correlation to the Middle Pleistocene Hoxnian interglacial Stage (c. MIS 11c). [ABSTRACT FROM AUTHOR]

Coeval changes in the reconstructed bog surface wetness and the pollen record of a peat sequence extracted from an ombrothropic bog (Calul de Piatră, 1630 m, Apuseni Mountains) allowed the natural and anthropogenic environmental changes over the past 1500 years to be assessed. The assessment of the social and economic context was also possible due to the exceptionally detailed documentary evidence of the investigated region. Four major deforestation periods in the past 1500 years were identified. Significant phases of deforestation coincided with particular social and political changes: (1) between AD 810 and 850, with the collapse of the Avar Khaganate and the expansion of the Bulgarian Empire in the southern areas of the Carpathian Basin; (2) between AD 1060 and 1170, with the establishment of the Kingdom of Hungary (AD 1000) and the foundation of royal, territorial administrative (county) and ecclesiastical centres of the feudal state; (3) in the sixteenth century (AD 1500–1570); and (4) after AD 1700, with population growth and economic development. Our results suggest that the observed deforestation and the consequent spread of subalpine farming were not necessarily related to the warmer or drier climatic periods, but to socioeconomic changes in nearby communities. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Climate warming is leading to permafrost thaw in northern peatlands, and current predictions suggest that thawing will drive greater surface wetness and an increase in methane emissions. Hydrology largely drives peatland vegetation composition, which is a key element in peatland functioning and thus in carbon dynamics. These processes are expected to change. Peatland carbon accumulation is determined by the balance between plant production and peat decomposition. But both processes are expected to accelerate in northern peatlands due to warming, leading to uncertainty in future peatland carbon budgets. Here, we compile a dataset of vegetation changes and apparent carbon accumulation data reconstructed from 33 peat cores collected from 16 sub‐arctic peatlands in Fennoscandia and European Russia. The data cover the past two millennia that has undergone prominent changes in climate and a notable increase in annual temperatures toward present times. We show a pattern where European sub‐Arctic peatland microhabitats have undergone a habitat change where currently drier habitats dominated by Sphagnum mosses replaced wetter sedge‐dominated vegetation and these new habitats have remained relatively stable over the recent decades. Our results suggest an alternative future pathway where sub‐arctic peatlands may at least partly sustain dry vegetation and enhance the carbon sink capacity of northern peatlands. [ABSTRACT FROM AUTHOR]

Peatlands play an important role in the global carbon cycle but have been exploited over many centuries, which reduces their carbon storage capacity. To investigate peatland development during the late Holocene and their restoration after peat extraction, we applied a multi-proxy paleoecological (pollen, plant macrofossils, testate amoebae, loss on ignition, peat humification, etc.) approach to undisturbed and floating vegetation mat deposits of the Gorenki peatland (Meshchera Lowlands, East European Plain). Peatland development started around 2550 before the common era (BCE) as a waterlogged eutrophic birch forest (terrestrial paludification) surrounded by a broadleaf forest. Around 2400 BCE, the peatland turned into an open mire with Sphagnum mosses, sedges, and willows. During 900–800 BCE, the mire transformed into a wet mesotrophic peatland surrounded by a spruce forest. The first human settlements and deforestation around 300–400 CE coincided with oligotrophization of the mire. The growth of the Slavic population in the region in 14th century CE caused transformation of indigenous spruce–broadleaf forests into croplands, and the mire became drier and forested. Since peat extraction was abandoned in the beginning of 20th century CE, the mire has undergone self-restoration starting with the formation of a Sphagnum cuspidatum/obtusum quagmire on the floating peat remains. The Sphagnum mat stabilized during 1960–2000 CE. During the last twenty years, agricultural activity decreased and pine forests were restored in the adjacent area; the floating mat became drier and more oligotrophic, which can lead to the formation of a bog in the absence of considerable anthropogenic impact. [ABSTRACT FROM AUTHOR]

Increased permafrost temperatures have been reported in the circum-Arctic, and widespread degradation of permafrost peatlands has occurred in recent decades. The timing of permafrost aggradation in these ecosystems could have implications for the soil carbon lability upon thawing, and an increased understanding of the permafrost history is therefore needed to better project future carbon feedbacks. In this study, we have conducted high-resolution plant macrofossil and geochemical analyses and accelerator mass spectrometry radiocarbon dating of active layer cores from four permafrost peatlands in northern Sweden and Norway. In the mid-Holocene, all four sites were wet fens, and at least three of them remained permafrost-free until a shift in vegetation toward bog species was recorded around 800 to 400 cal. BP, suggesting permafrost aggradation during the Little Ice Age. At one site, Karlebotn, the plant macrofossil record also indicated a period of dry bog conditions between 3300 and 2900 cal. BP, followed by a rapid shift toward species growing in waterlogged fens or open pools, suggesting that permafrost possibly was present around 3000 cal. BP but thawed and was replaced by thermokarst. [ABSTRACT FROM AUTHOR]

Aim: Pinewood decline and scrubland expansion are major features of Late Holocene vegetation history in the Cantabrian Range. However, the drivers of this remarkable vegetation shift remain to be investigated. Here, we aim at disentangling the role of past land use and climate in shaping the high‐elevation Cantabrian landscape during the past two millennia. Location: Cantabrian Range (northern Iberia). Taxa: Pinus sylvestris, Betula, Ericaceae, Juniperus, Poaceae. Methods: We conducted high‐resolution multiproxy palaeoecological analyses (pollen, plant macrofossils, microscopic charcoal and dung fungi) on lake sediments from Lago del Ausente to reconstruct vegetation, fire occurrence and grazing through time. The chronology is based on 14C (terrestrial plant macrofossils) and 210Pb dating, and Bayesian age‐depth modelling ('rbacon'). We carried out cross‐correlation analysis to quantify vegetation responses to fire. Results: Between 250 and 900 CE, the vegetation above 1700 m a.s.l. consisted of subalpine scrubland and scattered P. sylvestris trees/stands. Pinewoods with Betula were widespread at slightly lower elevation. This vegetation was resilient to moderate fire disturbance associated with limited pastoral activities. In contrast, enhanced fire occurrence alongside heavier pastoralism led to the demise of pinewoods and their replacement with Betula stands, subalpine scrublands, and meadows between 900 and 1100 CE. Later, the subalpine scrubland‐birch tree line did not respond to Little Ice Age cooling. However, further intensification of transhumant herding between 1300 and 1860 CE ('La Mesta') triggered birch decline and the establishment of the modern treeless landscape. Main conclusions The extant high‐elevation vegetation of the Cantabrian Range is largely the legacy of intensive land use starting more than one millennium ago. Recurrent and severe fires to promote pasturelands led to the regional extirpation of the previously widespread Pinus sylvestris. Future management should aim at preserving the valuable cultural open landscape of mountain scrubland and meadows and also at restoring patches of ancient pine‐birch woodlands. [ABSTRACT FROM AUTHOR]

This paper deals with the Mesozoic seed ferns from the Shemshak Group from two localities in the Western Alborz Mountains, Northern Iran (i.e., the Abyek area in Qazvin Province and the Jirande area in Gilan Province). The materials were obtained from two coal-bearing horizons in the Shemshak Group, Late Triassic-Middle Jurassic in age. Five species from the Abyek and two species from the Jirande area, belonging to the phylum Pteridospermophyta, were identified. Vegetative and reproductive organs of Caytoniales (i.e., Sagenopteris sp. A and Sagenopteris sp. B leaves, Caytonia sp. ovuliferous organ, and Caytonanthus arberi Thomas (Harris) emend. Harris, 1964 microsporangiate organ, as well as two form-species of incertae sedis seed ferns, Pachypteris lanceolata Brongniart, 1828 and Ptilozamites tenuis Ôishi 1932 emend. Ôishi and Huzioka, 1938) are described in the present paper. This paper discusses the morphological characters of these species, together with discussions on their previous palaeobotanical descriptions, as well as the stratigraphic and palaeogeographical distribution of these taxa. This is the first record of Caytonanthus arberi in Asia and Ptilozamites tenuis from Iran. Pachypteris lanceolata is described for the first time in the Western Alborz. [ABSTRACT FROM AUTHOR]

In this study, we present the full sequence of Eemian succession from the Kozłów palaeolake – one of the key sites for Eemian Interglacial in this part of Poland. In the paper, previous palynological and diatom assessments were supplemented by further pollen, Cladocera and macrofossil analysis. This enabled detailed reconstruction of a palaeolake functioning under changes of climate and other environmental conditions during MIS 5e. All identified alterations of trophy, depth and aquatic vegetation within the reservoir point to dynamic changes in early stages of lake functioning, relatively stable conditions in mid-Eemian and gradual lake shallowing starting from Caprinus phase. Thus, Kozlów palaeolake joins the noble group of sites with exceptionally well-recognized multi-proxy records of the Eemian Interglacial environment, and has the potential to become a benchmark for this part of Europe. [ABSTRACT FROM AUTHOR]

Here, we present a palaeoecological study from the Valdai Hills to examine the Holocene dynamics of forest and lake ecosystems as apparent from the isolated Lake Chernoye, which developed on an island within the greater Lake Seliger middle of the East European Plain, Russia. Palaeobotanical (plant macrofossils and pollen), geochemical and quartz grains analyses, complemented with radiocarbon dating, were carried out on a 370-cm-long sediment core. Our study involves a period between ca. 11,000 and 2100 cal. yr BP, with four main results: (1) The development of Lake Chernoye began in ca. 11,000 cal. yr BP, after the melting of buried dead-ice blocks intensified by the Early Holocene warming. As pioneer plants, Chara sp., Isöetes and C. demersum, appeared in the water with a high Ca and Mg content. High values of Pinus, Artemisia, Betula nana and Chenopodiaceae pollen may indicate the remains of cold flora that have occurred in the Younger Drays in this region. (2) Between 8000 and 6500 cal. yr BP, water level decreased as apparent from a sediment hiatus. This may be connected with the Holocene thermal maximum and final melting of the buried dead-ice block. Lower water level at that time is documented by the spreading of Najas marina, N. flexilis and Potamogeton pusillus, which are all submerged plants growing in eutrophic shallow water. Significant changes in the forest ecosystem also took place in this time frame: an increase of Quercus, Corylus and Alnus was accompanied by a decrease of Pinus. (3) A decrease in deciduous tree pollen (Ulmus, Quercus, Tilia) and an increase in coniferous tree pollen (Picea and Pinus) at ca. 4200 cal. yr BP and ca. 2700 cal. yr BP are associated with the climate cooling documented by multiproxy records in many sites in Europe. (4) Location of the lake on the isolated island did not lead to different vegetation pattern development, since this latter is similar to the other sites in the East European Plain. [ABSTRACT FROM AUTHOR]

During the last decades, fluvial sediment cores have been used to reconstruct and model pollution trends, especially for the post-1945 period. Ecological changes have been rarely studied in such recent sediment archives due to low organic levels and high hydro-sedimentary dynamics. Here, we address the challenge of reconstructing ecosystem changes along highly anthropized rivers by analysing plant macrofossils (e.g. seeds, wood fragments, mosses), animal and abiotic remains (mainly iron slags) accumulated in side channels. The main objective is to determine whether this approach - inspired from palaeoecology - is reliable. Interestingly, macrofossil records offer a coherent history of the species habitats and biodiversity on different sites on either side of a bypassed section of the Rhône River (France). Three main hydro-ecological phases are identified, linked to river developments. (1) A lotic phase, before damming, is marked by various local riparian forest taxa: black alder and willow macrofossils were regularly found in the cores, while black poplar is not recorded, despite its historical presence. (2) A synchronous terrestrialization phase (transition from an aquatic to a terrestrial ecosystem) is highlighted on both side channels in the late 1970s, due to the bypassing of the river and the subsequent lowering of the water level. During this phase, nitrophilous plants (nettles) expanded on both sites. (3) Finally, the effects of restoration also appeared in fluvial sediment cores, marked by new aquatic flora and fauna macrofossil taxa since 2000. Overall, this research demonstrated the potential of studying macrofossils in side channel deposits to understand the post-1945 history of riparian habitats and biodiversity, and their evolution after developments and/or restoration actions. This macrofossil approach could be considered as a tool to supplement monitoring data and to better interpret wetland changes with regard to hydromorphological adjustments along a river system over decades or centuries., (Copyright © 2024. Published by Elsevier B.V.)

Anticosti Island, located in the Gulf of St. Lawrence (GSL; Quebec, Canada) is covered by ~25% peatland ecosystems, and conditions supporting their development remain poorly documented. We present the first reconstructions of the ecohydrological conditions (vegetation successions and water table variations) and related carbon accumulation of two maritime peatlands (Pluvier; PLU and Pointe de l'Est; PTE) located on the eastern part of Anticosti Island. These ombrotrophic peatlands developed under the influence of the GSL sea-surface conditions in interaction with atmospheric circulation during the Holocene. Long-term apparent Rate of Carbon Accumulation (LORCA, g C m−2 a−1) at PLU (13.3) and PTE (16.8) are lower than the mean global value for northern peatlands (22.9), likely due to high wind exposure. Results show that despite the earlier peat inception at PLU (9440 cal a BP) before PTE (6250 cal a BP), the fen-bog transition of both peatlands occurred almost synchronously (4540 and 5070 cal a BP respectively), suggesting favourable hydroclimatic conditions for peat growth. A slowdown in peat accumulation combined with dry and variable hydrological conditions after ca. 3300 cal a BP in the two studied peatlands coincided with the transition from the mid-Holocene to the Neoglacial cooling. At ca. 800 cal a BP, the shift from wet Sphagnum to dry ligneous peat corresponds to the transition from the Medieval Climate Anomaly to the Little Ice Age. Cooling periods, characterized by a decrease in incident solar radiation and the incursion of cold and dry Arctic air masses into the GSL, are marked by a decrease in peat accumulation, especially at PLU, due to its higher wind exposure, which influenced reduced snow cover thickness as well as frost penetration and duration through the peat. [ABSTRACT FROM AUTHOR]

Long-term ecological studies can provide useful information on forest ecosystem resilience against past climatic change and human caused disturbances. Here, we present a high-resolution 2200-year-long record of forest development in north-eastern Poland, Suwalki region, using paleobotanical proxies (pollen, plant macrofossils, and charcoal). We show that the pollen abundance of deciduous trees was higher than that of coniferous trees, indicating a near pristine state until 900 AD and a semi-natural forest state until 1500 AD. After 1500 AD, the proportion of coniferous tree taxa surpassed that of deciduous trees and have since remained the dominant forest component. The 17th century experienced massive deforestation coupled with a new phase of human colonization in the area that led to the continued and significant decline of deciduous tree cover, for example, Carpinus, Quercus, and Tilia. Cooling associated with the Little Ice Age may have played a role in Picea's expansion in this area after 1450 AD. Despite significant climatic shifts associated with the warmer Roman Period or Medieval Climate Anomaly and colder Migration Period, as well as a more sustained human impact, Quercus remained a stable forest component until 1500 AD. The stability of Quercus is an important aspect for forest management strategies as future projections suggest warmer conditions and increased frequency of climate extremes will impact forest composition and structure. Our long-term data suggest that forests in the Suwałki region should contain more abundant deciduous tree species, that is, Quercu s, whereas conifer cover should be reduced. We also show clear regional differences in the forest development in the Suwałki region, highlighting the importance of local hydrology, geomorphology, and degrees of human activity on the forest composition. [ABSTRACT FROM AUTHOR]

The Early Devonian plant fossil record provides evidence of large vegetation turnover events in addition to rapid morphological and anatomical changes among vascular plants. The Ardenno-Rhenish Massif has historically yielded a vast number of these plant fossils allowing us to obtain a nearly unparalleled snapshot of Early Devonian vegetation. Nonetheless, the interest for describing or redescribing fossil floras from this region has waned in recent years despite their inherent value to understand Early Devonian plant diversity dynamics. Here, we describe a newly collected macrofossil flora from the middle Emsian Schuttbourg Formation at Consthum Quarry (Luxembourg). Six different plant macrofossil taxa were identified, including Drepanophycus spinaeformis and Psilophyton cf. princeps , in addition to putative macroalgal and fungal remains. The flora also includes other equivocal specimens resembling Sawdonia , Huvenia and Zosterophyllum. The composition of the assemblage is extremely similar, at generic level, to older Pragian–early Emsian and coeval floras from nearby localities, which indicates that there was no major floral turnover until the latter part of the Emsian in this region. Taxonomic descriptions also highlight many of the underlying issues in identifying Early Devonian sterile specimens. Inconsistencies in plant fossil identifications from this region call for a thorough revision of Belgian and German floras that together could provide a high-resolution picture of plant diversity changes in the Early Devonian. • A new collection of Emsian plant macrofossils from Luxembourg is investigated. • Six different plant macrofossil taxa were identified. • All remains are sterile except those of Psilophyton. • The floral composition is typical for the middle Emsian interval. • Taxonomic revisions of plants from the Ardenno-Rhenish region are necessary. [ABSTRACT FROM AUTHOR]

In the current situation of climate instability, research on the natural trends of vegetation development against global climate change is of high relevance, especially in areas once covered by the latest glaciation (Weichselian), and not altered substantially by human activities afterwards. The Kostomuksha State Nature Reserve, which is part of the Russian-Finnish Nature Reserve and the Green Belt of Fennoscandia, is a model area of well-preserved natural north-taiga pine (Pinus sylvestris) forest. To re-construct the history of its formation in post-glacial time, stratigraphic, radiocarbon, and palaeobotanical (determination of pollen, spores, plant macrofossils, Pediastrum algae) studies of lacustrine-paludal deposits were carried out in two sections of the mire Mezhselgovoe. The general trends and local features of vegetation development on dry land, and of the paludification process in the study area were investigated by comparing data derived by the author anew or previously from the cores taken from the Härkösuo and Isosuo mires, situated in the Finnish part of the Russian-Finnish Nature Reserve with published palaeogeographic material from nearby areas. The vegetation reconstructions cover the period from ice retreat from the study area in Preboreal time until present. Concurrent changes in the natural environment (including palaeoclimate) are specified, and the geomorphology and human impact in the territory are taken into account. The reconstructions are based on 25 radiocarbon datings. Deglaciation of the Russian-Finnish Nature Reserve area started around 9700 radiocarbon-dated years before present (14С BP) / 11 160 calibrated years before present (cal BP) and ended not later than 9500 ± 70 14C BP (10 830 ± 160 cal BP). As ice was retreating, the area got occupied by Artemisia-Chenopodium-forbs-dominated periglacial steppe, tundra (dwarf birch and dwarf shrub-true moss, willow and sedge-grass types), and birch-dominated forest-tundra communities. The first category occupied a relatively minor proportion of the study area. By the end of the Boreal period, spaces occupied by tundra vegetation also shrank. The most widespread by then were open birch woodlands. They were replaced by sparse birch and pine-birch forests, which remained widely represented through most of the Boreal period near the mires of Mezhselgovoe, Härkösuo (9110 ± 80 14C BP / 10 300 ± 100 cal BP), and Isosuo (8370 ± 60 14C BP / 9370 ± 80 cal BP). A notable increase in the proportion of Pinus in the forests was observed from 8750 ± 50 14C BP (9750 ± 120 cal BP) to a maximum in Late Boreal time, as evidenced by the dates 8240 ± 60 14C BP (9220 ± 100 cal BP) and 8090 ± 200 14C BP (9000 ± 260 cal BP). Pine and birch-pine forests prevailed throughout the Atlantic period. In the warmer and more humid climate of that time, forests acquired a middle-taiga appearance, and the environment was favourable for the expansion of Alnus and, possibly, Ulmus. Picea started spreading in the study area not later than 5700 14C BP (6500 cal BP), and since 5440 ± 40 14C BP (6240 ± 50 cal BP) its role in the plant cover has been substantial. The expansion of spruce forests reached its maximum in Subboreal time, especially after 3290 ± 70 14C BP (3520 ± 80 cal BP), when they co-dominated together with pine forests. Global cooling early in Subatlantic time caused the plant cover of the study area and its southerner neighbours to lose nemoral species, and sparsed out pine and spruce forests so that they acquired north-taiga features. The proportion of Picea in the forests decreased, especially in the last 800 (700) years. At present, pine forests dominate there. Alongside the dominant vegetation, birch and alder-birch post-fire communities have occurred there since Boreal time, while alder communities since Atlantic time. The forests affected by wild (lightning-ignited) fires have almost fully recovered by now. They mostly remained pristine in the absence of significant anthropogenic impacts. Data indicate that mire formation in some wet depressions started in Preboreal time (9500 ± 70 14C BP / 10 830 ± 160 cal BP). More thorough warming of shallowed palaeolakes in Boreal and Atlantic times promoted sapropel formation, overgrowing with wetland vegetation, and a shift to the telmatic development pathway. The detailed reconstruction of the formation history of contemporary north-taiga pine forests in the context of palaeoclimatic changes in the Holocene provided in this article bears information on how they may change in the future under different climate scenarios. Of particular interest are data on the time of spruce migration to the Russian-Finnish Nature Reserve area, which update and add detail to existing cartographic models of spruce distribution in northwest Russia and the eastern Baltic Shield. The resultant set of palynological and radiocarbon (20 dates) data can be used for correlations with palaeogeographical material from other regions in the efforts to reconstruct vegetation dynamics over time and space.

The recent advancements of new quantitative tools compatible with plant macrofossil proxy data have revived its potential for paleoclimate research. Plant macrofossils are commonly used in so-called indicator-species approaches, using methodologies that are typically built on known observations linking modern plant distributions with climate. This allows complementary paleoclimate reconstructions using an approach that is not limited by the spatial availability of calibration samples obtained from surface sediments (e.g., pollen or chironomids). We aim to evaluate the impact that various methodological choices have on the plant-macrofossil based reconstructions of January and July temperature patterns for the Lateglacial (14–11 ka BP) period. We use a variety of classic and novel quantitative climate reconstruction algorithms with plant macrofossil assemblages from 13 sites of the Baltic States. We use unfiltered plant data to evaluate the ability of each method to also handle the presence of plants that might have a weak sensitivity to temperature. Additionally, we test the influence of another methodological choice – the choice of modern calibration region – on the reconstructed climate. Our findings indicate that, with no prior filtering of summer and winter-sensitive plants, temporal temperature variations can be reconstructed with methods that implement probability density functions. Although some disparities in reconstructions are seen between the tested algorithms, we note that the choice of calibration region bears a greater influence on the results. A calibration region that best represents the past environment should be chosen rather than one representing the same spatial extent as the fossil site(s). Moreover, for long-term reconstructions, a "dynamic calibration set" approach should be considered in future studies by using a range of calibration regions and mirroring the continuously changing broadscale environmental regime of the past. • Seasonal temperature reconstructions vary across climate reconstruction algorithms. • Calibration region impact is greater in January temperature reconstructions than July. • Proper calibration region evaluation is crucial before reconstructions. • Calibration regions should be based on environmental instead of geographical fit. [ABSTRACT FROM AUTHOR]

Peatlands play an important role in the global carbon cycle but have been exploited over many centuries, which reduces their carbon storage capacity. To investigate peatland development during the late Holocene and their restoration after peat extraction, we applied a multi-proxy paleoecological (pollen, plant macrofossils, testate amoebae, loss on ignition, peat humification, etc.) approach to undisturbed and floating vegetation mat deposits of the Gorenki peatland (Meshchera Lowlands, East European Plain). Peatland development started around 2550 before the common era (BCE) as a waterlogged eutrophic birch forest (terrestrial paludification) surrounded by a broadleaf forest. Around 2400 BCE, the peatland turned into an open mire with Sphagnum mosses, sedges, and willows. During 900–800 BCE, the mire transformed into a wet mesotrophic peatland surrounded by a spruce forest. The first human settlements and deforestation around 300–400 CE coincided with oligotrophization of the mire. The growth of the Slavic population in the region in 14th century CE caused transformation of indigenous spruce–broadleaf forests into croplands, and the mire became drier and forested. Since peat extraction was abandoned in the beginning of 20th century CE, the mire has undergone self-restoration starting with the formation of a Sphagnum cuspidatum/obtusum quagmire on the floating peat remains. The Sphagnum mat stabilized during 1960–2000 CE. During the last twenty years, agricultural activity decreased and pine forests were restored in the adjacent area; the floating mat became drier and more oligotrophic, which can lead to the formation of a bog in the absence of considerable anthropogenic impact.

We present results from a palaeoecological analysis conducted on deposits accumulated in an oxbow lake of the Prosna River (Poland), next to the Grodzisko fortified settlement. Palaeobotanical and geochemical analyses—supported by radiocarbon dating—were performed to (i) reconstruct palaeoenvironmental conditions of the oxbow lake and its surrounding area; (ii) determine the beginning of the human activity in the fortified settlement vicinity; and (iii) assess the impact of human pressure on the environment. The Grodzisko fortified settlement was originally located on a river island, encircled by a wetland, improving its defensive value. Increases in the water level (1800–1300 BC and 700–200 BC) created a small lake/moat around the fortified settlement. Indicators for human activity from pollen records suggest the presence of human populations from the late Neolithic, ca. 2800 BC, with a clear intensification ca. 1700 BC. From ca. 1600 BC, a decrease in some decidous trees suggests forest clearance. Low levels of human activity indicator pollen ca. 2000 BC suggest a reduction of human pressure (possible depopulation). The regular presence of macrocharcoal pieces and an increase in human activity indicator pollen from ca. 1300 to 200 BC provide evidence for renewed human habitation around the sampling site. [ABSTRACT FROM AUTHOR]

Abstract This study led to identify 30 species and 16 genera of eight different plant macrofossils orders including Equisetales, Cycadales, Bennettitales, Coniferales, Peltaspermales, Ginkgoales, Corystospermales, and Filicales at the Deh-Shiykh section, north of Kerman. According to stratigraphic ranges of the index taxa such as Otozamites furoni, Nilssoniopteris mosafolia, Nilssonia tenuicaulis, Anomozamites major, Coniopteris hymenophylloides, Nilssonia bozorga and Elatides thomasii the age of early Middle Jurassic (Bajocian–Bathonian) is assigned to the Deh-Shiykh section. Middle Jurassic ichno fossils of the Hojedk Formation in the Deh-Sheikh section have been studied for the first time. The study also led to the determination of terrestrial ichno fossils including eight ichno species, belonging to four ichnogenera such as Planolithes, Rhizoliths, Taenidium and Thalassinoides. They have been found alongside the stems of Equisetals. Combination of the results of ichno fossil studies with plant fossils help us to identify the palaeoenvironment. These plant fossils are generally indicator of humid conditions. Moreover, the identified ichnofossils in accordance with the sedimentological studies, represent deltaic environments influenced by the river systems and channels. This is the first study of the combination of three studies of paleontology (Plant macrofossils), sedimentology and ichnology in east central Iran. The results have contributed to the accurate understanding of the paleoenvironment of fossiliferous horizons of the Hojedk Formation. Keywords: Plant macrofossils, Tracefossils, Middle Jurassic, Delta, Kerman. Introduction The northern region of Kerman is one of the richest areas of Iran for the study of plant fossils and so far more than 80 taxa have been reported (Khalilizadeh 2010). The first studies on coal deposits in the Kerman region have been carried out by Houtum-Schindler (1881), Stur (1886) and Stahl (1897). In recent years, Mirzaei-Ataabadi (2002) has studied the plant macrofossils of the Hojedk Formation in the Pabdana, Bab-Nizu and Hashuni areas. Vaez-Javadi and Mirzaei-Ataabadi (2006) studied the plant macrofossils of the Hojedk Formation. Ameri et al. (2014a, b) have also studied the biostratigraphy of the Hojedk Formation deposits in the Bab-Hutk section. Studies on these plant macrofossils have been more focused on coal areas and mines, non-coal areas in this respect has been received less attention. In addition, there are no reports of ichnofossil studies of the Jurassic layers of the Kerman region, especially in association with plant fossils. Trace fossils are very useful for understanding the paleoclimates and generally interpreting paleosedimentary environments (Buatois and Mangano 2004). In the present study, which focuses on the study of plantmacrofossils of the Hojdak Formation in Deh-Sheikh section north of Kerman, trace fossils have also been studied along with this macrofossils and the general sedimentology of these layers is also considered. Material & Methods Important factors in the identification of plant macrofossils include the characteristics of veins and pinnules, rachis, the grooves on the stem as well as the nodes and inter nodes in sphenophyte. In this study, about 100 plant macrofossil specimens were studied and they were photographed using a Nikon 90D digital camera. The images were processed using Adobe Photoshop CS5. All these specimens are kept in the Museum of Ferdowsi University of Mashhad. Trace fossil studies are usually carried out in the field on a centimeter scale and samples are taken to the lab for further and more detailed examination. In this study, about 20 trace fossil samples were collected. The lithofacies described in the field are divided mainly on the sedimentary texture (especially grain size) and structures; according to the Miall (1985) classification. The identified petrofacies are based on Folk (1980) classification scheme with polarizing microscope. Also, identification of sedimentary environment and subenvironments were interpreted based on the facies characterizes. Discussion of Results & Conclusions Based on the plant macrofossils, especially Coniopteris hymenophylloides, Elatides thomasii and Nilssonia friziensis, Middle Jurassic age (Bajocian–Batonian) is confirmed for the studied section. The studied plant macrofossils, especially filicales and horsetails, grow in humid environments. The in situ Equisetal stems have paleoecological significance. Horsetails, are hygrophytes, and adapted to humid conditions (Brea et al. 2009). Osmundaceae have been to warm and humid conditions along the rivers or marshes (Gordenko 2008). Due to the abundance of cycadophyta and ferns in the study area, tropical to subtropical paleoclimate have been reported (Salyukova et al. 2013). The ichno fossil diversity of the deltaic regions is very low (Hobday and Tavener-Smith 1975). Salinity changes, water turbulence, mud influx and etc. are the most important stress in the delta area. The study of 8 ichnospecies in the Deh-Sheikh section shows these traces, are simple. They are similar to those of deltaic systems (Buatois and Mangano 2011). These trace fossils resemble specimens of deltaic systems and are related to the heteropod invertebrates of Scoyenia ichnofacie. According to sedimentological studies, the sedimentary environment of the Hojedk Formation in the Deh-Sheikh section is often interpreted as a deltaic environment (coarsening upward cycles) under the influence of the river (fining upward cycles) which indicate of channel filling and energy depletion periods. From this study, the combination of paleontological, sedimentological and lithological studies with the study of ichnofossils will be very useful and effective in better understanding the palaeoenvironment and with proper interpretation, it will helpful to recognition details and create a clear picture of the environment.

The response of peatlands to climate change can be highly variable. Through understanding past changes we can better predict the response of peatlands to future climate change. We use a multi-proxy approach to reconstruct the surface wetness and carbon accumulation of the Mukhrino mire (Western Siberia), describing the development of the mire since peat formation in the early Holocene, around 9360 cal. year BP. The mire started as a rich fen which initiated after paludification of a spruce forest (probably in response to a wetter climate), while the Mukhrino mire progressed to ombrotrophic bog conditions (8760 cal. year BP). This transition coincided with the intensive development of mires in Western Siberia and was associated with active carbon accumulation (31 g m−2 year−1). The ecosystem underwent a change to a tree-covered state around 5860 cal. year BP, likely in response to warming and possible droughts and this accompanied low carbon accumulation (12 g m2 year−1). If the future climate will be warmer and wetter, then regional mires are likely to remain a carbon sink, alternatively, a reversion to the wooded state with reduced carbon sink strength is possible. [ABSTRACT FROM AUTHOR]

Examination of macrofossils from the late Neogene Pipe Creek Sinkhole in Indiana, USA, yielded 15 distinct plant taxa, one fungal taxon, and six invertebrate taxa. The plant assemblage was dominated by terrestrial taxa both in richness and abundance. Of the 12 terrestrial plant taxa, eight were trees or shrubs including two Carya spp., Corylus sp., Fraxinus sp., aff. Pinaceae, Quercus sp., aff. Rosaceae, and an unknown gymnosperm, possibly Ginkgophyta or Cycadophyta. Fossil nuts of a new species, Carya pipecreekensis Swinehart and Farlow sp. nov., are described. Other terrestrial plant macrofossils include a species of Asteraceae, Vitis sp., Xanthium sp., and Poaceae indet. Charcoalified remains of wood, Asteraceae achenes, and Poaceae crowns suggest fires were an important factor in ecosystem structure. Condition of some of the macrofossils suggests high-energy, post-depositional transport. Aquatic species include the plants Chara sp. and two Potamogeton spp. as well as the animals Helisoma sp., Physa sp., Sphaeriidae, and ostracoda. The terrestrial flora suggests a temperate woodland savanna community with a canopy that includes Carya, Fraxinus, Quercus, Corylus, and Pinaceae, a sub-canopy with Vitis, and a ground flora with a species of Asteraceae and abundant Poaceae. The assemblage shares elements and characteristics with the similarly-aged Gray Fossil Site in Tennessee. [ABSTRACT FROM AUTHOR]

The lower Kolyma region is known for rich Early Olyorian large mammal assemblages including plesiomorphic musk ox, reindeer, horse, broad-fronted moose, steppe mammoth and cave bear. Data on the vegetation in zonal habitats from the Olyorian period are, in contrast, scarce. Earlier palynological results from classical Olyorian sites indicated predominant grassland vegetation with scattered larch occurrences but are, due to limited taxonomical resolution, uncertain. Plant macrofossil data were, so far, only available from azonal, aquatic habitats. Here, we describe Olyorian palaeo-vegetation from an exposure near Cherskiy, Nizhnekolymsky District, Sakha Republic, Russia. The macrofossil-based reconstruction of palaeo-vegetation revealed the existence of an open forest steppe comprising a mosaic of sparse larch groves in a dry grassland composed of tundra steppes, degraded meadow steppes and saline meadows. In the larch groves, light demanding shrubs and dwarf shrubs such as shrub birch (Betula cf. fruticosa, B. nana ssp. exilis), raspberry (Rubus idaeus), cowberry (Vaccinium vitis-idaea), and crowberry (Empetrum nigrum) formed the understory. Ruderal pioneer plants point to open ground as result of disturbances, possibly due to the activity of large herbivores. The nitrophytic ruderal species Urtica dioica, in particular, suggests locally increased nutrient supply from animal excretions. Also, the abundant remains of Chenopodium cf. prostratum might be explained by disturbances and nutrient enrichment, but Chenopodium is also characteristic of salt accumulation in the soil owing to high evaporation under arid conditions, which are also indicated by alkali grass (Puccinellia sp.). The presence of trees and shrubs indicates interglacial-like temperature conditions but the dominance of dry grassland species and the occurrence of facultatively halophytic plants (Chenopodium prostratum, Puccinellia sp.) suggests aridity, which is more typical of cold stages. During the early Pleistocene, i.e., prior to the Early-Middle Pleistocene transition (EMPT) culminating around 900 ka ago, the duration of climate cycles was shorter and the amplitude of climate fluctuations was smaller. Ice-rich permafrost formed only after the EMPT during increasingly extreme cold stages, and, during warm stages, its thawing resulted in paludification of the active layer. Prior to the EMPT, the climate in West Beringia was constantly relatively dry, more or less moderate and more stable than thereafter. In contrast to modern tundra and northern taiga in the study region, dry habitats apparently prevailed during the time of deposition of the plant macro-remains.

The calcareous substrate of spring-fed fens makes them unique islands of biodiversity, hosting endangered, vulnerable, and protected vascular plants. Hence, spring-fed fens ecosystems require special conservation attention because many of them are destroyed (e.g. drained, forested) and it is extremely difficult or even impossible to restore the unique hydrogeological and geochemical conditions enabling their function. The long-term perspective of paleoecological studies allows indication of former wetland ecosystem states and provides understanding of their development over millennia. To examine the late Holocene dynamics of a calcareous spring-fed fen (Raganu Mire) ecosystem on the Baltic Sea coast (Latvia) in relation to environmental changes, substrate and human activity, we have undertaken high-resolution analyses of plant macrofossils, pollen, mollusc, stable carbon (δ13C) and oxygen (δ18O) isotopes combined with radiocarbon dating (AMS) in three coring locations. Our study revealed that peat deposits began accumulating ca. 7000 cal. yr BP and calcareous deposits (tufa) from 1450 cal. yr BP, coinciding with regional hydrological changes. Several fire events occurred between 4000 and 1600 cal. yr BP, which appeared to have had a limited effect on local vegetation. The most significant changes in the forest and peatland ecosystems were at 3200 cal. yr BP associated with a dry climate stage and high fire activity, and then between 1400 and 500 cal. yr BP potentially associated with temperature changes during the Medieval Climate Anomaly (MCA) and Little Ice Age. Hydrological disturbances in the peatland catchment from 1400 cal. yr BP were most likely strengthened by human activity (deforestation) in this region. The relationship between the development of this peatland and changes in its catchment area, such as land cover changes or fluctuations in groundwater levels, suggest that protection and restoration of spring-fed fen ecosystems should also include the surrounding catchment. The presence of calcareous sediments, as well as appropriate temperature and local hydrological conditions appear to be the most crucial factors controlling Cladium marisus populations in our site - currently at the eastern limit of its distribution in Europe.

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The paper reports on the results of the pollen, plant macrofossil and geochemical analyses and the AMS 14C-based chronology of the «Rüdersdorf» outcrop situated east of Berlin in Brandenburg (Germany). The postglacial landscape changed from an open one to generally forested by ca. 14 cal. kyr BP. Woody plants (mainly birch and pine) contributed up to 85% to the pollen assemblages ca. 13.4–12.5 cal. kyr BP. The subsequent Younger Dryas ( YD) interval is characterized by a decrease in arboreal pollen (AP) to 75% but led neither to substantial deforestation nor spread of tundra vegetation. This supports the concept that the YD cooling was mainly limited to the winter months, while summers remained comparably warm and allowed much broader (than initially believed) spread of cold-tolerant boreal trees. Further support for this theory comes from the fact that the relatively low AP values persisted until ca. 10.6 cal. kyr BP, when the «hazel phase» of the regional vegetation succession began. The postglacial hunter-gatherer occupation is archaeologically confirmed in Brandenburg since ca. 13 cal. kyr BP, i.e. much later than in the western part of Germany and ca. 1000 years after the major amelioration in the Rüdersdorf environmental record.

Trapa natans (water chestnut) is an aquatic, thermophilic plant whose decline has been observed in many localities in central Europe during the last decades. In this paper, we present a description of two new T. natans subfossil sites located outside its present northern distribution in Poland. High-resolution analysis of plant macrofossils supported by geochemical analysis were undertaken to reconstruct the palaeoecological habitat and examine the cause of the late Holocene decline of T. natans that took place ca. 4000 calibrated years before AD 1950 (cal. yr BP) in a paleolake, presently the Bagno Kusowo bog. Its disappearance was a consequence of terrestrialisation and the development of peatland. In paleolake sediments covered by the peat layer in the Mechacz Wielki bog, T. natans macrofossils were found from before ca. 3300 cal. yr BP. The decline of T. natans could have resulted from the changes and development of other plant communities where the dominant role was played by Stratiotes aloides and Nymphaea sp. In our study sites, T. natans occurred together with Potamogeton crispus, Potamogeton obtusifolius, Nymphaea alba, and Nuphar sp. in eutrophic water dominated by Ca2+, Fe3+, and Al3+ ions. Our palaeobotanical and geochemical results align with the contemporary conditions of T. natans habitat.

Peatlands are natural ecosystems that provide archives of the hydrological cycle, ecological processes and terrestrial carbon dynamics. In the north-central region of Quebec (eastern Canada), patterned peatlands developed in topographic depressions of the Precambrian Shield following the Laurentide Ice Sheet retreat. These peatlands display characteristics similar to appa mires and other peatlands that developed at the ecotone between the open (taiga) and closed boreal forest biomes of the Northern Hemisphere, and also correspond to the biogeographic limit between ombrotrophic and minerotrophic peatlands. During the Neoglacial cooling period in northeastern Canada, patterned peatlands, mainly oligotrophic fens, registered a hydrological disequilibrium expressed by an increase in surface wetness as aquatic microforms expanded to the detriment of terrestrial surfaces. Ecohydrological trajectories were reconstructed from a detailed study of two patterned peatlands in order to document their sensitivity to climate variations. To do this, plant macrofossil and testate amoeba data were combined with peat carbon accumulation rates, C:N ratios, 210Pb and 14C chronologies. Data show that peatlands initiated ca 6500 cal. y BP as ombrotrophic or minerotrophic systems depending on site-specific conditions, followed by a general increase in surface wetness during the Neoglacial cooling until the end of the Little Ice Age. A relatively synchronous ecosystem state shift from oligotrophic to more ombrotrophic conditions was registered at the beginning of the 20th century in central and lateral cores of both study sites, evoking the likely influence of recent warming on peat accumulation. These results suggest a potential northward migration of the biogeographic limit of the ombrotrophic peatland distribution during the 20th century, which could have implications for the role of these ecosystems as C sinks at the continental scale. Overall, these peatlands have stored a mean carbon mass of ca 100 kg m− 2. [ABSTRACT FROM AUTHOR]

The piggyback basin of Bezhan, southeastern Albania, was formed during the late Neogene and contains Pliocene/Pleistocene deposits. These continental deposits consist of marls, siltstones and clays separated by a thin series of lignite-seams alternating with clays (Bezhan formation). We investigated leaf fossils and dispersed pollen from marls of the upper portion of this formation. Fifty-two plant taxa comprising algae, gymnosperms, and angiosperms were recovered. Of these, at least 19% belong to extant species and less than 16% belong to taxa today extinct in western Eurasia. Tsuga is represented by three pollen taxa with affinities to modern Chinese, Japanese, and North American species. Herbaceous taxa indicative of steppe (Artemisia, Amaranthaceae) occur in low quantities (≤1%) suggesting an interglacial setting. Four vegetation units are recognised: Wet riparian and aquatic vegetation, mesic oak forest, dry sub-Mediterranean woodland, and montane conifer forest. A comparison of the Bezhan flora with well-dated Pliocene and Pleistocene floras of Italy suggests a Calabrian (late early Pleistocene) age for the upper unit. This estimate is based on the abundance of extant taxa, the absence of subtropical taxa, and threshold values of particular taxa (Tsuga, Carya). The findings are in agreement with age estimates for extant tree species from molecular studies. [ABSTRACT FROM AUTHOR]

A better understanding of past long-term environmental changes in the subarctic region is crucial for mitigation of the possible negative effects of climate warming in this vulnerable region. This study provides a new multi-proxy reconstruction of regional vegetation changes and peatland development for north-eastern Fennoscandia (Russia) during most of the Holocene. To that purpose, we performed plant macrofossil, pollen, testate amoebae, peat humification, loss on ignition and radiocarbon analyses of the peat deposits from a mire around Vodoprovodnoe Lake (the Kindo Peninsula, the Republic of Karelia). Our data indicate that the peat deposits started accumulating before 9147 ± 182 cal. yr. BP. The vegetation cover in the area was mainly typical for the northern taiga zone, except for the period ~7800–5600 cal. yr. BP, when it generally resembled the middle taiga zone. The vegetation cover and peatland were greatly affected by reoccurring fires, which can be partly related to human activity. These events were associated with an increased proportion of birch in the vegetation cover (as a pioneer species) and/or water level decreases. By 600 cal. yr. BP, the peatland and the surrounding vegetation reached its current state and only minor changes had been recorded since that time. Overall, our results suggest a considerable and unexpected role of fires in the postglacial dynamics of subarctic peatlands. [ABSTRACT FROM AUTHOR]

Palaeoecological studies can identify past trends in vegetation communities and processes over long time scales. Pollen, plant macrofossils and charcoal analyses are used to reconstruct vegetation over the last 6400 years and provide information about former human impact and disturbance regimes in Färnebofjärden National Park, Central Sweden. Three specific conservation planning topics were addressed: (1) the changing ratio of conifers to broadleaved trees; (2) the origin and history of the river meadows and the biodiverse Populus tremula meadows; (3) the role of fire in the maintenance of biological values. Early diverse mixed broadleaved forest assemblages with pine were followed by significant declines of the more thermophilic forest elements prior to the expansion of spruce in the Iron Age. The rise to dominance of spruce was a 'natural' process that has been exaggerated by anthropogenic disturbance to artificially high levels today. The initial river meadow communities were facilitated by fire and frequent flooding events, but subsequent dynamics have more definitely been supported by human activities. Rural abandonment during the last 100 years has led to woody successions. Fire has been a continual disturbance factor with an influence on conservation issues such as Picea abies dominance and the maintenance of diverse, non-forest communities. Present occurrence of fire is unusually low, but natural fire frequencies are increasing in the region. [ABSTRACT FROM AUTHOR]

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The late Miocene is marked by pronounced environmental changes and the appearance of strong temperature and precipitation seasonality. Although environmental heterogeneity is to be expected during this time, it is challenging to reconstruct palaeoenvironments using plant fossils. We investigated leaves and dispersed spores/pollen from 6.4 to 6 Ma strata in the intermontane Florina–Ptolemais–Servia Basin (FPS) of northwestern Greece. To assess how well plant fossils reflect the actual vegetation of the FPS, we assigned fossil taxa to biomes providing a measure for environmental heterogeneity. Additionally, the palynological assemblage was compared with pollen spectra from modern lake sediments to assess biases in spore/pollen representation in the pollen record. We found a close match of the Vegora assemblage with modern Fagus–Abies forests of Turkey. Using taxonomic affinities of leaf fossils, we further established close similarities of the Vegora assemblage with modern laurophyllous oak forests of Afghanistan. Finally, using information from sedimentary environment and taphonomy, we distinguished local and distantly growing vegetation types. We then subjected the plant assemblage of Vegora to different methods of climate reconstruction and discussed their potentials and limitations. Leaf and spore/pollen records allow accurate reconstructions of palaeoenvironments in the FPS, whereas extra-regional vegetation from coastal lowlands is probably not captured.

There has been an upsurge of interest and research activity in trait-based approaches in ecology, biogeography, and macroecology. I discuss if this upsurge has impacted Quaternary botany (the study of plant remains preserved in sediments). I show that ecological attributes (including traits) have played and continue to play an integral part in the interpretation of Quaternary botanical data in terms of reconstructing past environments and interpreting long-term changes in plant assemblages. This use started over 120 years ago and continues to the present. It is unclear if a “new” Quaternary botany based on traits will develop because of the taxonomic limitations of much Quaternary botanical data.

The aim of the study was to propose a so called dynamic curve for identification of hydrological conditions of peatland formation. This method facilitates interpretation of accumulation processes based on sequence of biogenic sediments depending on variable hydrological conditions. Eleven types of hydrological conditions (HC) were distinguished and characterized with reference to ecohydrological interrelations governing the formation of peatlands. Each HC type was associated with specific peat type and species rendered in a classification for Central Europe. When employing a synthetic description of the identified HCs, it is possible to use the dynamic curve to provide a graphical representation of a hydration status for a geological profile and a general interpretation of the course of changes in water conditions during peatland development. The discussed method is somewhat simplified but it can be used for general interpretation of hydrological conditions of peatland development and would not require some highly specialized analyses. Such an approach may prove sufficient, particularly in engineering practice.

The middle Eocene (Lutetian) fossil plant assemblage from Tatabánya (N Hungary) comprises plant remains preserved mostly as impressions. Remains of angiosperms are represented by Lauraceae (Laurophyllum div. sp., Daphnogene Unger), Rhamnaceae (Ziziphus Miller), Malvaceae s.l. (Byttneriopsis Z.Kvaček et Wilde), Leguminosae, and Palmae, and the occurrence of other families, i.e., Dioscoreaceae, Myrtaceae, Fagaceae, Anacardiaceae, Berberidaceae, Juglandaceae, and Theaceae, is uncertain. The scarcity of gymnosperms is a character similar to the coeval floras of Csordakút (N Hungary) and Girbou in Romania. The presence of Ziziphus ziziphoides (Unger) Weyland, high number of linear shaped leaves with entire margin and coriaceous texture (Lauraceae vel Fagaceae), and small-leaved Leguminosae suggests a "subhumid" character of the vegetation, which is recognisable also in early Palaeogene floras of eastern Central and Southeastern Europe, e.g., the Tard Clay floras in Hungary and floras of Serbia/Macedonia. In contrast, the Eocene floras from Central/Western Europe are indicative of a generally non-xerophytic character, e.g., Staré Sedlo in Bohemia, Messel, Geiseltal, and the Weisselster Basin floras in Germany. A frost-free climate with high mean annual temperatures similar to that estimated for coeval European floras may also be inferred for the Tatabánya flora. [ABSTRACT FROM AUTHOR]

Mesotrophic rich fens, that is, groundwater-fed mires, may be long-lasting, as well as transient ecosystems, displaced in time by poor fens, bogs, forests or eutrophic reeds. We hypothesized that fen stability is controlled by plant stress caused by waterlogging with calcium-rich and nutrient-poor groundwater, which limits expansion of hummock mosses, tussock sedges and trees. We analysed 32 European Holocene macrofossil profiles of rich fens using plant functional traits (PFTs) which indicate the level of plant stress in the environment: canopy height, clonal spread, diaspore mass, specific leaf area, leaf dry matter content, Ellenberg moisture value, hummock-forming ability, mycorrhizal status and plant functional groups. Six PFTs, which formed long-term significant trends during mire development, were compiled as rich fen stress indicator (RFSI). We found that RFSI values at the start of fen development were correlated with the thickness of subsequently accumulated rich fen peat. RFSI declined in fens approaching change into another mire type, regardless whether it was shifting into bog, forest or eutrophic reeds. RFSI remained comparatively high and stable in three rich fens, which have not terminated naturally until present times. By applying PFT analysis to macrofossil data, we demonstrated that fens may undergo a gradual autogenic process, which lowers the ecosystem's resistance and enhances shifts to other mire types. Long-lasting rich fens, documented by deep peat deposits, are rare. Because autogenic processes tend to alleviate stress in fens, high levels of stress are needed at initial stages of rich fen development to enable its long persistence and continuous peat accumulation. [ABSTRACT FROM AUTHOR]

The hemispheric-scale climatic fluctuations during the Holocene have probably influenced the large Siberian rivers. However, detailed studies of the West Siberian Plain postglacial environmental change are scarce and the records of millennial-scale palaeohydrology are nearly absent. This paper presents the Holocene palaeoecological reconstruction based on the sedimentary record of Lake Svetlenkoye, located near the confluence of major Siberian rivers Ob and Irtysh. Postglacial history of flooding, dynamics of regional and local vegetation, sedimentation regime, geochemical changes and lake water pH were reconstructed based on multi-proxy studies. We used palaeobotanical (plant macrofossils, pollen, diatoms), geochemical (organic matter, total organic carbon and nitrogen content, carbon/nitrogen ratio) and chronological (14C dates, spheroidal fly-ash particle counts) methods. The studied sediment section started to accumulate ~11,400 cal. yr BP. The initial shallow water body was flooded by Ob River waters ~8100–8000 cal. yr BP as confirmed by a remarkable increase in the sedimentation rate and the accumulation rate of the aquatic vegetation proxies. The period of flooding coincides with the high humidity periods reconstructed from regional palaeobotanical records. About 6800–6700 cal. yr BP, the study site became isolated from the Ob River floodplain and remained a small lake until present. The diatom-based lake water pH estimates suggest fluctuations in the pH values during the Holocene, the recent decrease since 1960s being the most notable. The vegetation record revealed constant postglacial presence of tree taxa – Betula, Pinus and Picea – although in different pollen ratios and accumulation rates through time. The paludification of the surroundings occurred since ca. 8500 cal. yr BP. [ABSTRACT FROM AUTHOR]

Pollen, plant macrofossils, and sedimentary analyses from archaeological deposits at North Creek Shelter (NCS) on the Colorado Plateau provide data on vegetation and climate change during the Holocene. From 11,300–10,200 cal yr BP, NCS was embedded in a mixed conifer forest of cool-adapted species (e.g., Abies , Pseudotsuga menziesii , and Pinus ponderosa) with an Artemisia understory. During this interval, NCS pollen corresponds to modern pollen from Picea–Abies forests that reside 950 m higher in elevation. Rapid deposition rates of NCS sediments indicate that climatic conditions during the Early Holocene were more mesic than today, with increased precipitation. The onset of warmer conditions at NCS began at 10,200 cal yr BP, and pollen and plant macrofossils indicate that a semiarid woodland and scrub mosaic dominated by Pinus edulis , Juniperus osteosperma , and Amaranthaceae surrounded NCS by 9300 cal yr BP. This is corroborated by fossil pollen that is similar to modern pollen from P. edulis – J. osteosperma woodlands and Amaranthaceae scrub that currently surround NCS. Sedimentary analyses suggest that during this time, accumulation rates were very low due to low precipitation and a drier climate overall. Migration of P. edulis into southern Utah is directly dated to 8100 cal yr BP, thus confirming recently proposed patterns of northward expansion. [ABSTRACT FROM AUTHOR]