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Aim: How the ability of plants to move towards newly favourable habitats (dispersal limitation) impacts the change of biome distribution and transition under fast climate warming is still debated. Analysing vegetation change in the past may help to clarify the relative importance of underlying ecological processes such as climate, biotic interactions, and dispersal. In this study, we investigated how dispersal limitation affected the distribution of European forests in the last 18,000 years. Location: Southern and Central Europe. Taxon: Spermatophyta. Methods: Using the LPJ‐GM 2.0 model (an extension of LPJ‐GUESS), we simulated European vegetation from the end of the Last Glacial Maximum (18.5 ka) to the current time (0 ka). Using biome reconstructions from pollen data as reference, we compared the performance of two dispersal modes: with no migration constraints or seed limitation (free dispersal mode), and with plant establishment depending on seed dynamics and dispersal (dispersal limitation mode). Results: The model run, including migration processes, was better at capturing the post‐glacial expansion of European temperate forests (and the longer persistence of boreal forests) than the setting assuming free dispersal, especially during periods of rapid warming. This suggests that a number of (temperate) tree taxa experienced delayed occupancy of climatically suitable habitats due to a limited dispersal capacity, i.e., post‐glacial migration lags. Main Conclusions: Our results show that including migration processes in model simulations allows for more realistic reconstructions of forest patterns under rapid climate change, with consequences for future projections of carbon sequestration and climate reconstructions with vegetation feedback, assisted migration and forest conservation. [ABSTRACT FROM AUTHOR]

Quaternary palynology plays a pivotal role in investigating global climate change and various other research fields, serving as an essential tool for the quantitative analysis of paleoenvironment changes. However, due to the vast diversity of terrestrial ecosystems and intricate interactions between vegetation, climate, and human activities, further advancements are required in the following aspects within this discipline. (1) The accuracy of classification in pollen morphology and fossil pollen identification needs improvement, particularly at the species level. This represents a significant challenge in present Quaternary palynology. Computer-aided intelligent recognition holds promise as a solution for species identification based on more detail pollen morphology. (2) Most pollen-based vegetation and climate reconstructions overlook the significance of bare ground. Neglecting bare ground can lead to substantial inaccuracies when quantitatively reconstructing past vegetation and climate. (3) While pollen records provide reliable information on paleoclimate changes, current quantitative climate reconstruction models heavily rely on modern pollen datasets derived from present-day vegetation disturbed more or less by human activities. This introduces bias and uncertainties into paleoclimate reconstruction. (4) Although pollen can serve as an indicator of human activities, accurately quantifying the intensity of human influence remains challenging. Improving accurate identification of crop pollen, reconstructing reliable land cover/use data, and integrating multidisciplinary data may enhance the identification and quantification of signals related to human activity in pollen records. [ABSTRACT FROM AUTHOR]

The paleovegetation and paleoclimate characteristics are studied in the Palaeogene strata of Hetao Basin, Subei Basin and Qaidam Basin in China, and the Cretaceous Guyang Formation (K1g) in the Hetao Basin. These three basins receive high attention, different distribution areas, representative. Pollen evidence shows that: (1) The sporopollen assemblage of Palaeogene Linhe Formation (E3l) in Hetao Basin is characterised by Pinaceae-Ephedripites-Ulmipollenites-Chenopodipollis. It reflects that the ancient vegetation types were mainly coniferous and evergreen woody plants, and the climate was cold temperature. The sporopollen assemblage characteristics of the upper member of the Palaeogene Xiaganchaigou Formation (E32) in the Qaidam Basin are similar to it. (2) The sporopollen characteristics of the K1g in the Hetao Basin reflect that its ancient vegetation was dominated by evergreen woody plants and belongs to a warm and humid subtropical climate. (3) The assemblage of Palaeocene Funing Formation (E1f) in Subei Basin was Pterisisporites undulatus-Ulmipollenites minor-Taxodiaceaepollenites hiatus. The climate type was humid north temperate climate, vegetation was mainly deciduous trees and evergreen woody plants. (4) Leiosphaeridia/Granodiscus, Pediastrum and Botryococcus were also detected in the E1f of Subei Basin. The appearance of these algae indicates the special saline water environment and good hydrocarbon potential. [ABSTRACT FROM AUTHOR]

Mining operations in the Enmynveem valley, northeastern Siberia, exposed a well-preserved right hind leg of Mammuthus primigenius (woolly mammoth), dated to ca. 37,500 cal yr BP. The leg had a fracture that crosscut the midsections of the tibia and fibula. Additional skeletal and soft tissue remains, including two mummified adults (Berezovka, ca. 47,200 cal yr BP; Bolshoi Lyakhovsky, ca. 37,000 cal yr BP), document the presence of mammoths in interior mountain valleys and across both northern and southern coasts of far northeastern Siberia during Marine Isotope Stage (MIS) 3. A mosaic of herb-dominated tundra communities characterized the vegetation of the Enmynveem site during late to middle MIS 3 and MIS 2 (ca. 37,000–17,000 cal yr BP). Shrubs were limited to Salix during the late Pleistocene, whereas Betula also may have been present in sheltered sites during MIS 3. Herb communities remained dominant during the late Pleistocene–Early Holocene transition, although shrub Betula increased during this interval. By ca. 10,200 cal yr BP, the vegetation was Betula–Alnus shrub tundra. Larix and Pinus pumila were established in the valley by ca. 8700 cal yr BP and ca. 5700 cal yr BP, respectively. [ABSTRACT FROM AUTHOR]

Lake sediment records are of great importance for understanding the evolution of watershed environments. Various studies have been carried out to determine the depositional ages of lake sediments and to examine their physical, chemical, and biological characteristics. The aim is to construct the historical vegetation, environment, and climate patterns in Chinese lake watersheds. In this review, we obtained relevant studies on lake sediment records by searching the key word 'age-depth' from the following databases: Web of Science and the China National Knowledge Infrastructure (CNKI, the largest Chinese academic database). We analyzed the literature based on its type (published in a Chinese/English journal or as a Master's/PhD thesis), period of publication, journal (if published in a journal), key authors, study area, dating scale, and main aims. The results suggest that the lakes in the plateau regions are the most popular research topic, typically covering 100–200 years (short-term) and 500–30,000 years (long-term). The literature focuses on a wide range of topics, from past environmental evolution in watersheds to lake ecology, and it provides a solid foundation for a better understanding of the regional climate change and the preservation of lake environments and ecosystems. In the future, the resulting data obtained from environmental reconstructions with lake sediments will need to be integrated with emerging information processing technologies (e.g., artificial intelligence and meta-analysis) to disentangle the complex interplay between the Earth's surface processes and global climate change; furthermore, strengthening interdisciplinary collaboration will deepen our comprehension of the man-land relationship and promote the sustainable management of lake ecosystems in the context of global climate change. [ABSTRACT FROM AUTHOR]

Previous multi-proxy records have revealed the advantages of well-preserved and long-scale geological archives from the lake sediments of Barkol Lake, which is located at northeast Xinjiang in northwest China. However, the exact organic matter (OM) sources in the sediments and their response to climatic variability still remain unclear in this area. In this study, we present an 8.8 kyr n-alkane record extracted from the sediments in Barkol Lake to explore the OM sources and the relationship between n-alkanes and climatic changes. The results indicate that the n-alkane composition was dominated by long-chain n-alkanes(C27–C31), implying a dominant origination of OM from the terrestrial higher plants and emergent aquatic plants. The n-alkane data further revealed that changes in OM sources were related to the surface erosion-transportation-deposition processes controlled by climatic changes. Lake level changes, which are also regulated by climate conditions, played an important role in impacting OM accumulation. Relatively wetter conditions would result in a rising lake level that favored more aquatic OM and less terrestrial OM input, and vice versa. The regional climate patterns have been generally dominated by alternations of cold-wet and warm-dry episodes over the past ~8.8 kyr. We preliminarily concluded the dynamic changes of OM input and the hydrological changes in Barkol Lake was mainly controlled by SSTs in the North Atlantic region and melting water supply modulated by Eurasian ice sheet. [ABSTRACT FROM AUTHOR]

[Objective] Since the Paleogene, with the uplift of the Qinghai-Tibetan Plateau and the large-scale thrust and strike-slip of the strata, many inland basins were formed in the northern part of the Qinghai-Tibetan Plateau. Be-cause of their particular location, the evolution of paleoclimate and paleo-vegetation in the basins is very significant for clarifying the climatic evolution in the Paleogene in Eurasia. [Methods] In this study, the evolution history of paleoclimate and paleo-vegetation in the Nangqian Basin in central and eastern Qinghai-Tibetan Plateau (51.8-37.5 Ma) was reconstructed from biomarkers and total organic carbon (TOC). [Results and Conclusions] The evolution history of Paleogene climate index in Nangqian Basin is in three stages, each with different changes of sedimentary facies. Stage I (51.8-46.4 Ma) : The sedimentary facies are mainly fluvial and short-term lacustrine, with lower CPI and TOC values and higher Paq values. ACL and nC27/nC3, show an obvious change trend in this period, which may have been affected by the mixing of terrestrial sediments brought by rivers. Most of the main peak carbon was nC22 and nC23; the vegetation type was predominantly woody plants, and the climate was relatively humid. Stage II (46.4-42.7 Ma): The Paq value and nC27/nC3, ratio gradually decreased, ACL gradually increased, the carbon number of the main peak gradually changed from low to medium or high, the vegetation gradually changed from woody to herbaceous plants, and the climate gradually became drought alternating with wet conditions. Stage III (42.7-37.5 Ma) : Paq, nC27/nC3, and ACL changed little, the carbon number of the main peak increased significantly, n-alkanes with high carbon numbers increased significantly, and drought conditions increased. TOC also significantly increased, reflecting increasing total vegetation productivity, which may have been a response to the warm Middle Eocene Climatic Optimum (MECO). In addition, from comparisons with previous reports of climate change in the study area and adjacent basins, it is considered that the climate change in the Nangqian Basin during 51.8-37.5 Ma was mainly affected by global climate change and the retreat of the Tethys Sea. The uplift of the Qinghai-Tibetan Plateau and its higher elevation greatly influenced water vapor in the Nangqian Basin, whereas monsoons have little influence on water vapor. [ABSTRACT FROM AUTHOR]

Palynological analyzes of sediments from glacial lakes in Northern Priokhot'ye provide the first continuous records of regional vegetation responses to climate change at the end of the Pleistocene and during the Holocene. The pollen stratigraphy from these coastal sites is like that described for more northern regions of Western Beringia. Herb dominated tundra with Poaceae-forb meadows characterized the Late Pleistocene and was replaced c. 12,100 cal BP by Betula shrub tundra and then by shrub Betula-Alnus tundra. In the Middle Holocene (c. 8900-4700 cal BP), Larix-Betula platyphylla forests with an undergrowth of Pinus pumila , shrub Betula, and Alnus became widespread. Pinus pumila also formed a high shrub tundra zone above altitudinal treeline. Finds of Betula platyphylla macrofossils suggest that summer temperatures were 2–4 °C warmer than today between c. 7700 and 6700 cal BP. Variations in Pinus pollen percentages during the Middle and Late Holocene suggest changes in altitudinal treeline related to intervals of relatively cooler or warmer climates. The timing of the postglacial thermal maximum and possible shifts in altitudinal treeline suggest paleoclimatic patterns that are more like southern areas of the Russian Far East than northern regions of Western Beringia. A Late Holocene tephra was found for the first time in the lake sediments and peat exposures of Northern Priokhotye. The most likely source of this important chronostratigraphic horizon is the Shiveluch volcanic eruption (Kamchatka Peninsula) dated to 2500–2600 BP (2580–2730 cal BP). [ABSTRACT FROM AUTHOR]

Desertification and drought in inland Asia are closely related to human habitation and social sustainability in western China. The climate in western China has experienced multiple shifts in temperature and aridity since the Late Pleistocene. Investigating this region's Late Pleistocene paleoclimatic changes contributes to predicting future climate trends. This study analyzes the pollen records from the Qingshuihe Basin in southern Ningxia during the middle to late Late Pleistocene, revealing four distinct pollen assemblage zones from bottom to top. These zones reflect paleovegetation and paleoclimate changes during the middle to late Late Pleistocene. The results indicate that during the middle Late Pleistocene (75-50 ka B.P.), the region featured a predominantly Artemisia-dominated steppe landscape with a cool and relatively dry climate. In the late Late Pleistocene (25-15 ka B.P.), the area experienced alternations between desert-steppe or steppe and forest-steppe, transitioning gradually to desert-steppe. During this period, the winter monsoon strengthened, leading to progressively cooler and drier conditions, with the climate shifting from cool and slightly moist to cold and arid. The further study of the palynological records during the middle and late Late Pleistocene in the Qingshuihe Basin of southern Ningxia holds significant implications for a proper understanding of the natural environmental history of the Loess Plateau and informs decision-making for its management.

Introduction: The ability of species to colonize newly suitable habitats under rapid climate change can be constrained by migration processes, resulting in a shift of the leading edge lagging behind the ameliorating climate, i.e. migration lag. The importance and extent of such migration lags during the forest expansion after the Last Glacial Maximum (LGM) are still debated. Similarly, the relative importance of the main drivers of post-glacial vegetation dynamics (temperature, dispersal limitation, and competition) is still discussed in the literature. Methods: We used the dynamic global vegetation model LPJ-GM 2.0 to reconstruct the range shifts of 16 competing major European tree species after the LGM (18.5 ka BP) until recent times (0 ka BP). We simulated two dispersal modes by allowing free establishment whenever the climatic conditions suited the species (free dispersal), or by accounting for migration processes in the simulated vegetation dynamics (dispersal limitation). We then calculated thermal and range shift velocities, competition at establishment, thermal and dispersal lags for each species and dispersal mode. Finally, we compared our simulated range shift velocities with pollen-derived migration rates. Results: The simulation assuming limited dispersal resulted in more accurate migration rates as compared to pollen-derived migration rates and spreading patterns. We found no marked migration lags in the post-glacial establishment of pioneer species (Pinus sylvestris and Betula pubescens). Under the free dispersal mode, the remaining temperate species expanded rapidly and almost synchronously across central Europe upon climate warming (Bolling-Allerod interstadial). Differently, the northward spread of temperate species simulated under dispersal limitation happened mainly during the Holocene and in successive waves, with late spreaders (e.g. Fraxinus excelsior) experiencing multi-millennial dispersal lags and higher competition. Discussion: Our simulation under dispersal constraints suggests that the postglacial tree expansion in Europe was mainly driven by species-specific thermal requirements and dispersal capacity, which in turn affected the order of taxa establishment and thus the degree of competition. Namely, taxa with less cold-tolerance and relatively low dispersal ability experienced the highest migration lags, whereas the establishment of pioneer species was mostly in equilibrium with the climate. [ABSTRACT FROM AUTHOR]

The plants' geographic distribution is affected by natural or human‐induced climate change. Numerous studies at both the global and regional levels currently focus on the potential changes in plant distribution areas. Ecological niche modeling can help predict the likely distribution of species according to environmental variables under different climate scenarios. In this study, we predicted the potential geographic distributions of Quercus ilex L. (holm oak), a keystone species of the Mediterranean ecosystem, for the Last Interglacial period (LIG: ~130 Ka), the Last Glacial Maximum (LGM: ~22 Ka), mid‐Holocene (MH: ~6 Ka), and future climate scenarios (Representative Concentration Pathway (RCP) 4.5 and 8.5 scenarios) for 2050–2070 obtained from CCSM4 and MIROC‐ESM global climate scenarios respectively. The models were produced with algorithms from the R‐package "biomod2" and assessed by AUC of the receiver operating characteristic plot and true skill statistics. Aside from BIOCLIM (SRE), all model algorithms performed similarly and produced projections that are supported by good evaluation scores, although random forest (RF) slightly outperformed all the others. Additionally, distribution maps generated for the past period were validated through a comparison with pollen data acquired from the Neotoma Pollen Database. The results revealed that southern areas of the Mediterranean Basin, particularly coastal regions, served as long‐term refugia for Q. ilex, which was supported by fossil pollen data. Furthermore, the models suggest long‐term refugia role for Anatolia and we argue that Anatolia may have served as a founding population for the species. Future climate scenarios indicated that Q. ilex distribution varied by region, with some areas experiencing range contractions and others range expands. This study provides significant insights into the vulnerability of the Q. ilex to future climate change in the Mediterranean ecosystem and highlights the crucial role of Anatolia in the species' historical distribution. [ABSTRACT FROM AUTHOR]

Lake sediment records are of great importance for understanding the evolution of watershed environments. Various studies have been carried out to determine the depositional ages of lake sediments and to examine their physical, chemical, and biological characteristics. The aim is to construct the historical vegetation, environment, and climate patterns in Chinese lake watersheds. In this review, we obtained relevant studies on lake sediment records by searching the key word ‘age-depth’ from the following databases: Web of Science and the China National Knowledge Infrastructure (CNKI, the largest Chinese academic database). We analyzed the literature based on its type (published in a Chinese/English journal or as a Master’s/PhD thesis), period of publication, journal (if published in a journal), key authors, study area, dating scale, and main aims. The results suggest that the lakes in the plateau regions are the most popular research topic, typically covering 100–200 years (short-term) and 500–30,000 years (long-term). The literature focuses on a wide range of topics, from past environmental evolution in watersheds to lake ecology, and it provides a solid foundation for a better understanding of the regional climate change and the preservation of lake environments and ecosystems. In the future, the resulting data obtained from environmental reconstructions with lake sediments will need to be integrated with emerging information processing technologies (e.g., artificial intelligence and meta-analysis) to disentangle the complex interplay between the Earth’s surface processes and global climate change; furthermore, strengthening interdisciplinary collaboration will deepen our comprehension of the man-land relationship and promote the sustainable management of lake ecosystems in the context of global climate change.

Abstract An integrated approach considering facies, isotopic, and palynological analyses of lake sediments from the Serra Norte de Carajás, southeastern Amazonia, is presented in this work to refine paleoclimate and paleohydrological changes based on upland lake sediments during the late Quaternary. The sediments have a fining-upward deposition cycle typical of upland swamps/lakes. The origin of organic matter is autochthonous mainly related to C3 terrestrial plants, macrophytes and algae. The pollen records of Hedyosmum during the Early Pleistocene suggest lower temperatures than those observed along Holocene. In the transitional period between the Pleistocene and the Holocene, rainfall decreased, causing the retraction of the flooded area, favoring the development of marshy conditions. The Late and Middle Holocene were marked by higher temperatures and lower humidity. Afterward, the increased pollen concentration from canga and forest vegetation, macrophytes, palms, and algae suggested increased humidity in the Early Holocene. The relative contribution of forest pollen along the records indicated that drier conditions were not strong enough for an extensive expansion of canga over forested areas.

IntroductionThe ability of species to colonize newly suitable habitats under rapid climate change can be constrained by migration processes, resulting in a shift of the leading edge lagging behind the ameliorating climate, i.e. migration lag. The importance and extent of such migration lags during the forest expansion after the Last Glacial Maximum (LGM) are still debated. Similarly, the relative importance of the main drivers of post-glacial vegetation dynamics (temperature, dispersal limitation, and competition) is still discussed in the literature.MethodsWe used the dynamic global vegetation model LPJ-GM 2.0 to reconstruct the range shifts of 16 competing major European tree species after the LGM (18.5 ka BP) until recent times (0 ka BP). We simulated two dispersal modes by allowing free establishment whenever the climatic conditions suited the species (free dispersal), or by accounting for migration processes in the simulated vegetation dynamics (dispersal limitation). We then calculated thermal and range shift velocities, competition at establishment, thermal and dispersal lags for each species and dispersal mode. Finally, we compared our simulated range shift velocities with pollen-derived migration rates.ResultsThe simulation assuming limited dispersal resulted in more accurate migration rates as compared to pollen-derived migration rates and spreading patterns. We found no marked migration lags in the post-glacial establishment of pioneer species (Pinus sylvestris and Betula pubescens). Under the free dispersal mode, the remaining temperate species expanded rapidly and almost synchronously across central Europe upon climate warming (Bølling-Allerød interstadial). Differently, the northward spread of temperate species simulated under dispersal limitation happened mainly during the Holocene and in successive waves, with late spreaders (e.g. Fraxinus excelsior) experiencing multi-millennial dispersal lags and higher competition.DiscussionOur simulation under dispersal constraints suggests that the post-glacial tree expansion in Europe was mainly driven by species-specific thermal requirements and dispersal capacity, which in turn affected the order of taxa establishment and thus the degree of competition. Namely, taxa with less cold-tolerance and relatively low dispersal ability experienced the highest migration lags, whereas the establishment of pioneer species was mostly in equilibrium with the climate.

Abstract The plants' geographic distribution is affected by natural or human‐induced climate change. Numerous studies at both the global and regional levels currently focus on the potential changes in plant distribution areas. Ecological niche modeling can help predict the likely distribution of species according to environmental variables under different climate scenarios. In this study, we predicted the potential geographic distributions of Quercus ilex L. (holm oak), a keystone species of the Mediterranean ecosystem, for the Last Interglacial period (LIG: ~130 Ka), the Last Glacial Maximum (LGM: ~22 Ka), mid‐Holocene (MH: ~6 Ka), and future climate scenarios (Representative Concentration Pathway (RCP) 4.5 and 8.5 scenarios) for 2050–2070 obtained from CCSM4 and MIROC‐ESM global climate scenarios respectively. The models were produced with algorithms from the R‐package “biomod2” and assessed by AUC of the receiver operating characteristic plot and true skill statistics. Aside from BIOCLIM (SRE), all model algorithms performed similarly and produced projections that are supported by good evaluation scores, although random forest (RF) slightly outperformed all the others. Additionally, distribution maps generated for the past period were validated through a comparison with pollen data acquired from the Neotoma Pollen Database. The results revealed that southern areas of the Mediterranean Basin, particularly coastal regions, served as long‐term refugia for Q. ilex, which was supported by fossil pollen data. Furthermore, the models suggest long‐term refugia role for Anatolia and we argue that Anatolia may have served as a founding population for the species. Future climate scenarios indicated that Q. ilex distribution varied by region, with some areas experiencing range contractions and others range expands. This study provides significant insights into the vulnerability of the Q. ilex to future climate change in the Mediterranean ecosystem and highlights the crucial role of Anatolia in the species' historical distribution.

This study was carried out in the Karakuyu Marsh (Afyonkarahisar-Dinar) located in the upper basin of the Büyük Menderes River. In the study, it was aimed to determine the *8200 year paleo vegetation history of the research area. For this purpose, 730 cm long sediment cores were taken from Karakuyu Marsh, and fossil pollen and 14C dating analyzes were performed on the cores. The data obtained within the scope of fossil pollen analyzes were diagrammed according to the aget depth model and paleo vegetation data of the study area was created. According to fossil pollen findings, Pinus sp., Juniperus sp., Quercus deciduous and Quercus evergreen were important taxa in Arboreal Pollen (AP), Amaranthaceae, Asteraceae, Poaceae and Artemisia sp. were important in Non-Arboreal Pollen (NAP). A high rate of forest presence (84.8%) were found in the study area and the forest presence were mostly composed of Pinus sp., and Juniperus sp., taxa. The changes that the species showed during the focused time period indicated that the vegetation pattern changed in a more natural process (climate and interspecies competition). The results showed that the Middle Holocene paleo vegetation changes (forest progression and regression) are consistent with the studies in Anatolia. High forest existence continued in the Late Holocene, land use was limited, and these changes were consistent with fossil pollen studies in the Lakes Region [ABSTRACT FROM AUTHOR]

Complete dinosaur footprint fossils are preserved on the surface of the fluvial and lacustrine sediments of Early Cretaceous Madongshan Formation in Liupanshan area of Ningxia, and the sporopollen is a good carrier to study the paleoclimate information of the time when dinosaurs lived. A systematic sporopollen study was carried out on the fossil occurrence profile of sauropod dinosaur footprints from Cretaceous Madongshan Formation in Qianzhuang village of Longde county, Liupanshan area. A total of 41 genera and 63 species of sporopollen were identified. It is divided into 3 sporopollen assemblages from bottom to top of the profile, including Bisaccates-Jiaohepollis assemblage, Classopollis-Jiaohepollis-Cicatricosisporites assemblage and Cicatricosisporites-Foraminisporis assemblage. The geological age reflected by the characteristics of the sporopollen assemblage is Early Cretaceous Aptian-Albian period. The established vegetation of dinosaurs footprint fossils has undergone a transition from conifers to cypresses, and then to ferns. Further research suggests that the paleoclimate in the age of dinosaurs experiences a change from subtropical subhumid climate to subtropical warm and semi-arid climate, and then to subtropical humid climate. This is consistent with previous research conclusions on sedimentary paleoclimatic environment of Cretaceous Madongshan Formation in Liupanshan area. [ABSTRACT FROM AUTHOR]

Paleoecological and modern studies at Priyatnoye Lake, which is located within an intermontane depression in the interior of northeastern Siberia, indicate a similar paleovegetation record as has been documented for nearby mountain valleys, but a history of basin stability and instability that is uncharacteristic of the valley lakes. Analyses of a 385-cm-long core from the western basin of Priyatnoye Lake shows that sediment accumulation began in late Marine Oxygen Isotope Stage 3 (MIS 3), followed by a hiatus during MIS 2, and then continuous accumulation over the past ca. 14,000 cal yr BP. The eastern basin of the lake has a sediment thickness of ∼35 cm, suggesting that it intermittently contained water and/or is younger than the western basin. A drop in lake levels between AD 2005 and AD 2009 resulted in the formation of two distinct lakes. This change was caused by the melting of underlying ice wedges and the formation of sinkholes through which the lake water drained. Although the northern coastal lowlands have been the geographic focus of permafrost global warming research, the Priyatnoye study draws attention to the intermontane depressions in northeastern Siberia. While less extensive, these depressions contain organic-rich deposits, are underlain by permafrost, and have the potential to affect future carbon budgets as global temperatures rise and permafrost melts. [ABSTRACT FROM AUTHOR]

We introduce a new method to compute plant distribution in Ethiopia under paleoclimatic conditions using fuzzy logic. Using a published map of the potential vegetation for Ethiopia we decipher the boundary conditions for the main vegetation units shown, reflecting modern climatic conditions for temperature and precipitation in this region. Fuzzy logic using these climatic values on a GIS platform then derived the computational map of the potential vegetation. Comparing it with the original map shows a general correspondence of about 90%. By changing the underlying climate parameters, we then used this model for hypothetical paleoclimatic conditions to simulate the vegetational response on these changed climate settings. Finally, vegetational response maps for Ethiopia are presented for two scenarios: (i) a colder and drier condition (such as the Last Glacial Maximum) and (ii) a warmer and wetter condition (such as the last interglacial) than today.

Palynological analysis was conducted on one hundred and twenty-four samples collected from ten sedimentary outcrops in Sangan, Tatau, Bintulu and Similajau areas of central Sarawak. These outcrops form part of the Oligocene-Miocene marginal marine successions of the Nyalau Formation. Rich palynomorph assemblages were recovered from the samples and they provide well-preserved palynological record for the Oligocene-Miocene boundary in the onshore of northwest Borneo. Three distinct palynological zones were identified based on changes in pollen assemblages. The three zones are informally named FT-I, FT-II and FT-III. The FT-I zone is characterized by high frequency of Florschuetzia trilobata with common Florschuetzia semilobata including sporadic Meyeripollis naharkotensis. High percentage of F. trilobata and sporadic occurrence of F. semilobata are typical of the FT-II zone. Another important characteristic for this zone is characterized by common to abundant Casuarina type pollen while M. naharkotensis is virtually absent. The FT-III zone is marked by the presence of Florschuetzia levipoli. The zone is also characterized by abundant F. trilobata including regular occurrence of F. semilobata with common montane elements represented by Pinus, Picea, Alnus, Ephedra and Tsuga. All the identified zones record regular occurrence of Gramineae throughout with strong variation in diversity and frequency of peat swamp taxa represented by Blumeodendron type, Calophyllum type, Stemonurus type Calamus type and Dactylocladus type. The mangrove element such as Rhizophora type exhibits gradual increased in number throughout the FT-I and FT-II zone and showing reduced abundance in FT-III zone. These three zones are correlatable to the Late Oligocene to Early Miocene palynostratigraphy of the Cycle I and Cycle II in the Sarawak Basin. The palynological successions from these areas suggest a typical wet climate with intermittent seasonally dry conditions throughout the Late Oligocene - Early Miocene. This is evident from the regular occurrence of grass pollen i.e., Gramineae/Poaceae with common rain forest and peatswamp elements. This is supported by the common to high frequency of mangrove pollen notably Rhizophora type (Zonocostites ramonae). The Early Miocene may have experienced occasional super wet climatic conditions where rain forest pollen assemblages were prevalent including intermittent acme of Casuarina type pollen. [ABSTRACT FROM AUTHOR]

Epicontinental basins are extremely prone to major paleogeographic changes, and this will directly affect any organic matter (OM) preserved in the depositional record. In this study the Middle–Late Miocene successions in the northern Pannonian Basin System were investigated via sedimentological, petrographic, and geochemical analyses of cores from the Danube Basin to reveal the interplay of factors driving the character of the OM. In the late Middle Miocene (~12.3 Ma), the Central Paratethys Sea maintained normal marine salinity, with dysoxic bottom waters in a distal basin floor environment rich in aquatic OM. The last rifting phase followed during the Late Miocene and led to formation of the deep Lake Pannon. Like seawater, the brackish lake water still also contained sulfate. These open lacustrine deposits (~11.6–10.0 Ma) reveal OM sourced from submerged/floating macrophytes and algae, and humid conditions are indicated by the preponderance of deciduous trees and shrubs on shores. The study identifies hybrid event beds (HEBs) on Lake Pannon's floor (~10.0–9.3 Ma), with currents redepositing mud and OM, resulting in similarities between the Middle Miocene and Late Miocene successions. Turbidite deposition (~9.3–9.0 Ma) from the paleo-Danube induced a shift in OM, replacing algae with terrestrial input. Complete isolation from the main water masses of Lake Pannon (~9.0–8.9 Ma) altered its sources of OM, transitioning from algae to macrophytes, and caused a drop in salinity, likely associated with a humidity peak. The subsequent deltaic dominance (~8.9–8.6 Ma) features well-developed topset lakes, swamps, and floodplain forests, reflecting warm temperate to subtropical climates. The Middle–Upper Miocene deposits studied here are source rocks with fair to very good richness and poor to fair generative potential, and contain kerogen types III and IV, while type II is rare. The rapid paleoenvironmental changes observed over the order of ~100 kyr caused the complete switching of OM type and delivery, giving an indication of the complexity of epicontinental basins. • Multi-proxy approach tracing organic matter (OM) delivery in Pannonian Basin • Sarmatian sea (~12.3 Ma): normal marine salinity, dysoxic waters rich in aquatic OM • Lake Pannon HEBs (~10.0–9.3 Ma) share Middle Miocene strata traits due to redeposition. • Turbidite deposition (~9.3–9.0 Ma) from paleo-Danube shifts OM composition. • Deltaic topset beds (~8.9–8.6 Ma) bear aquatic OM with coal layers under warm climate. [ABSTRACT FROM AUTHOR]

In this study, we present pollen records together with a multiproxy analysis from a sediment core collected from the Güllük Bay (Bargilya Cove, Muğla, SW Turkey), covering the last 400 years. Pistachio shrubland was occupying around the Güllük Bay between 1613 and 1741 AD. However, after 1741 AD, the vegetation canopy suddenly changed and Turkish pine (Pinus brutia) was established. This supports that the main factor affecting the expansion of Pistacia lentiscus was precipitation rather than temperature after 1741 AD. This change is also indicated by high Sr-Ca values, reflecting arid conditions. Two anthropogenic phases developed in the region. The first phase is marked by Olea europeae between 1613 and 1789 AD. The second is characterized by Plantago, Caryophyllaceae, Cerelia, Rumex, and Sanguisorba minor type suggesting pastoralism and agricultural activities between 1789 and 1964 AD. Macrofaunal communities are also indicative of environmental changes. Abra ovata, Cerastoderma glaucum, Bittium reticulatum, and Skenea catenoides were first settlers between 1572 and 1643 AD. The prominent presence of lagoonal species Abra ovata and Hydrobia ventrosa indicates a lagoonal depositional environment in 1799-1948 AD. [ABSTRACT FROM AUTHOR]

The examined peatlands were assayed for the n-alkanes С14Н44–С31Н64; their contents of in all studied soil profiles are determined by both different botanical compositions of plant residues in peatlands and different climatic conditions (temperature and humidity) during these alkanes formation. The maximum total content of n-alkanes dates back to the Holocene climatic optimum and amounts to 104–191 μg/g for the studied peatlands of the extreme northern taiga. The composition of n-alkanes (the homologs with an odd number of carbon atoms C21H44, C23H48, C25H52, C27H56, C29H60, and C31H64) and their ratios are shown to reflect the specific features of the changes in plant communities composing the peat layers and the climatic conditions of peat soils genesis. The data on n-alkanes in combination with radiocarbon and paleobotanical data are useful in identification of the initial vegetation during the peat formation in the Holocene phases and more accurate reconstruction of the peatland genesis. [ABSTRACT FROM AUTHOR]

We briefly describe selected results from our thematic project focused on the biodiversity of the Atlantic Forest ("AF BIOTA"), which was jointly funded by FAPESP's BIOTA Program, the U.S. National Science Foundation Dimensions of Biodiversity Program, and the National Aeronautics and Space Administration (NASA). As one of the five most important hotspots of biodiversity in the world, the Atlantic Forest (AF) holds less than 16% of its vegetation cover, yet, amongst the hotspots, it still harbors one of the highest numbers of species, including endemics. By gathering specialists across multiple disciplines (biology, geology, engineering), we aimed to understand how this megabiodiversity was built through time, informing biodiversity science and conservation. Among the results, we trained 18 Master's and 26 Ph.D. students, published more than 400 peer-reviewed papers that improved our knowledge about the forest's biologic and climatic diversity and dynamics through time, developed new analytical methods, produced outreach videos and articles, and provided data to help define biodiversity conservation policies. [ABSTRACT FROM AUTHOR]

Since the Cenozoic, the earth entered a period of relatively active tectonic movement, which led to significant environmental and climatic shifts, including inland drought in Asia, global cooling, and the formation of the Asian monsoon. The Asian aridification has a far-reaching impact on the human living environment, and so do the climate changes in China. The beginning, strengthening, and ending times of the inland drought in Asia have been a long-concerned issue. Therefore, it is necessary to reveal the starting time, evolution process, and underlying driving mechanisms. Because of its unique topography and geographical location, the Qinghai–Tibet Plateau is known as the “starter” and “amplifier” of global climate change. It is a key area and an ideal “laboratory” for long-time scale climate change. Located in the central-eastern part of the Qinghai–Tibet Plateau, the Nangqian Basin is not only the confluence area of major monsoons and westerly winds but also the boundary between humid and arid areas. Moreover, the Nangqian section in the basin has a long continuous sedimentary sequence, making it a good carrier for long-time scale climate change research. In this study, biomarkers and total organic carbon (TOC) in the sedimentary strata of the Nangqian Basin in the central-eastern Qinghai–Tibet Plateau were used to reconstruct the paleoclimate and paleovegetation evolution history over the time interval of 51.8–37.5 Ma. According to the climatic index of the Nangqian Basin, the climate evolution history can be divided into three stages. StageⅠ: during 51.8–46.4 Ma, the depositional environments at this stage were mainly a braided river and an ephemeral shallow pond/lake environment. Also, the value of CPI, δ13Cn-alkanes, and total organic carbon (TOC) was low; meanwhile, ACL value increased with nC27/nC31 decrease, and these obvious change trends might be affected by the mixing of terrestrial sediments brought by rivers. The main peak carbons were nC22 and nC23, the vegetation type was predominantly woody plants, and the climate was relatively humid. Stage Ⅱ: during 46.4–42.7 Ma, Paq and nC27/nC31 values decreased gradually, and ACL, δ13Cn-alkanes, and CPI values increased slowly. Also, the main peak carbon number changed from low to high, and the vegetation type varied from woody to herbaceous. All these proxies displayed that the climate became more arid. Stage Ⅲ: during 42.7–37.5 Ma, Paq, ACL, and nC27/nC31 values did not vary too much, δ13Cn-alkanes values increased slightly, and ACL values decreased slightly, while the main peak carbon number, TOC, and CPI increased significantly, indicating that the climatic conditions continued to get dryer, which may have been affected by the MECO events. In addition, through the comparative study of the climate evolution history of the Eocene in the Nangqian Basin reconstructed by the multi-index system, together with the climate change in the adjacent area, the retreat process of the Paratethys Sea, the global deep-sea oxygen isotopes, and the global atmospheric CO2 concentration, it is considered that the Eocene climate change in the Nangqian Basin is mainly affected by the global climate change and the retreat of the Paratethys Sea. The uplift of the Qinghai–Tibet Plateau and the increase of altitude have little influence on the water vapor of the Nangqian Basin, and the basin was rarely affected by the South Asian monsoon.

Organic carbon isotopic composition (δ13Corg) in loess deposits is an important indicator of terrestrial paleovegetation, and it has been widely used for paleoenvironmental reconstruction in aeolian sediments around the world. However, little research has been done on the variation and paleoenvironmental implication of δ13Corg from loess deposits on Shengshan Island, East China Sea, during the last glacial period (LG). In this research, we present optically stimulated luminescence (OSL) ages, total organic carbon (TOC) data and δ13Corg records of the loess section at Chenqianshan (CQS) on Shengshan Island. Additionally, to study the effectiveness of δ13Corg in documenting paleoenvironmental changes, magnetic susceptibilities and diffuse reflectance spectra were surveyed. TOC concentration for the CQS loess section ranged from 0.11% to 0.47%, and the δ13Corg composition of the CQS loess section varied between −20.80‰ and −24.56‰ during the LG. The average value of C4 abundance was 21.31%. TOC, δ13Corg, χfd, and Hm/(Hm + Gt) curves for the CQS loess section showed similar patterns. The results of our study indicated that the vegetation of the CQS loess deposit was mainly C3/C4 mixed vegetation, and C3 vegetation was the most important vegetation. The comparison between the δ13Corg curve for the CQS section and other existing δ13Corg records of the loess sections from central and northern China showed similar trends and their vegetation succession exhibited synchronous change during the LG. Based on a comparison of the δ13Corg record, C4 abundance and χfd of the CQS section and other global geological records, it was concluded that the mutual effects of precipitation and temperature caused the change of paleovegetation in loess deposits on islands in the East China Sea during the LG. [ABSTRACT FROM AUTHOR]

• Phytolith based paleoenvironmental reconstruction is reported first time from the Kashmir Himalaya. • Phytolith assemblages of the last 42 ka reveal interplay of warm and cold events preserved in LPS. • The substantial decrease in phytolith count during cold events could be linked to the Heinrich events. The temporal vegetation development provides vital information for understanding past climatic changes. In this study, we reconstruct vegetation dynamics from the last glacial period using phytoliths as a proxy from the Wanihama loess-paleosol sequence (LPS) near Srinagar in Kashmir Himalaya, India. Different phytolith assemblages and indices (Ic and Iw) revealed a series of warm and cold events documented in the LPS. The data indicate the predominance of broad-leaved and sparse conifer vegetation from ca. 42 ka to 39 ka, suggesting a comparatively warm and humid climate. After ca. 39 ka, conifers and grasses increased, indicating a transition to a cold climate. The cold climate, intervened by a short stadial, continued until ca. 31 ka with the predominance of conifers, grasses, and sedges. Subsequently, three other cold events were noted until ca. 14 ka, which resulted in vegetation disappearance and a substantial decrease in phytolith count. These cold events roughly coincide with the climatic instability in the Atlantic Ocean that caused severe cooling at high northern latitudes and likely impacted the Asian climate. Phytolith assemblages showed an overall increasing proportion of C4 grasses towards the top of the LPS, suggesting warm and dry climatic conditions. We also correlated the phytolith-based vegetation reconstruction with other paleoenvironmental proxies recorded from the same section, as well as with the last glacial climatic changes documented in different regions, to determine the reliability of phytoliths in LPSs as a proxy for past vegetation and climate reconstruction in the Kashmir Himalaya. [ABSTRACT FROM AUTHOR]

Palynological analysis of sediments from El'gygytgyn Lake document vegetation changes in the Eastern Arctic from early marine isotope stage (MIS) 74 to late MIS 80 (c.2.1–1.9 MA) and close the last remaining gap in the El'gygytgyn pollen record. Cooler climates were characterized by a mix of Larix forest-tundra, shrub Betula tundra, and herb-dominated communities. During interglaciations, Larix forests with tree Betula and Alnus, and perhaps with a minor component of Picea and tree Pinus , characterized areas that today are tundra. These forests included a rich shrub understory of Betula , Duschekia , Salix , and Pinus pumila. Although MIS 77 has been considered a "super" interglaciation, the data do not indicate that this stage was exceptionally warm. Interstadial conditions are denoted by pollen assemblages that indicate the regional vegetation was dominated by Larix forest -tundra and an absence of Pinus pumila. The palynological results from this Early Pleistocene interval demonstrate the need to: 1) modify the El'gygytgyn age model; 2) reevaluate the relationship of sediment facies to climate change; and 3) reconsider the occurrence and/or definition of "super" interglaciations. • MIS 77 "super" interglaciation is not exceptionally warm. • Larix forest dominated interglacial and interstadial periods during MIS 75-MIS 79. • Larix forest-tundra dominated glacial periods during MIS 75-MIS 79. • MIS 77 and MIS 78 are the warmest and coolest periods during MIS 75-MIS 79. [ABSTRACT FROM AUTHOR]

The Aurora Subglacial Basin (ASB) catchment contains 3–5 m of sea-level equivalent ice volume that drains to the Sabrina Coast, East Antarctica via the Totten Glacier system. Observed thinning and retreat of Totten Glacier indicate regional sensitivity to oceanographic and atmospheric warming. Paleoclimate studies of climatically sensitive catchments are required to understand the evolution of the East Antarctic Ice Sheet (EAIS) and its outlet glacier systems. Recent seismic and sediment studies from the Sabrina Coast document the evolution of the EAIS in the ASB catchment, suggesting that the region has long been sensitive to climatic changes. This study presents new palynological and biomarker data from Sabrina Coast continental shelf sediments. Detailed palynological records were obtained from four short jumbo piston cores (JPC; NBP14-02 JPC-30, -31, -54 and -55), enabling reconstructions of regional vegetation and environments prior to and during Cenozoic EAIS development. The Sabrina Flora is dominated by angiosperms, with Gambierina spp. often exceeding 40% of the assemblage, and diverse Proteaceae, Battenipollis spp., Forcipites spp., Nothofagidites spp., fern, and conifer palynomorphs indicative of an open shrubby ecosystem. Excellent preservation and frequent occurrence of Gambierina spp. clusters suggest that a majority of the Sabrina Flora assemblage is penecontemporaneous with sedimentation; however, some uncertainties remain whether this sedimentation occurred in the Late Cretaceous or the Paleogene. Despite that uncertainty, high abundances of Gambierina spp. and Battenipollis spp., in combination with relatively low (<10%) Nothofagidites spp. abundances indicate that the Sabrina Flora is unique in Antarctica. Evaluation of biomarkers finds evidence for penecontemporaneous and reworked components. The penecontemporaneous C 30 n -alkanoic acids have δ13C values of −30.2 ± 0.5‰, consistent with δ13C values in an open canopy woodland or shrubby open vegetation. Their hydrogen isotope (δD) values of −215 ± 4.5‰, indicate precipitation isotopic composition (δD precip) of −130‰, similar to coastal snow in the same region today. Together, Sabrina Flora palynomorph and plant wax data suggest a drier, more open coastal vegetation in the Aurora Basin of East Antarctica rather than the closed rainforest vegetation often described from other parts of Antarctica for the Cretaceous to Paleogene. To directly compare records from the circum-Antarctic, additional long sedimentary records with improved biostratigraphic constraints are required. Such records will enable identification of regional climate gradients or micro-climates, and allow assessment of the environmental conditions and mechanisms driving observed differences. [ABSTRACT FROM AUTHOR]

In fire-prone biomes, the interpretation of paleoecological proxies is subjected to uncertainties since the plant biomarkers/molecules are thermally modified during vegetation fires, and the extent of alterations is yet to be well-constrained, particularly for oxic conditions. Towards this, we performed a series of controlled experiments where leaf samples from C 3 (tree and shrub) and C 4 (grass) plants were burned under ambient oxygen at temperatures between 200 °C and 500 °C. A topsoil sample was also heated to understand the effect of thermal degradation on organic matter (OM) already present in the soil. Our results show a reduction in the total organic carbon content and leaf wax concentrations which is consistent with the previous studies. We also observed a shift from predominantly long-chain homologues (with odd-over-even in n -alkanes or even-over-odd predominance in n -alkanoic acids; FAs) to balanced distributions with increased mid and short-chain homologues. We observed that the short, mid, and long-chain n -alkanes were mainly formed at the expense of FAs (with losses up to 100%), possibly due to oxygen-rich burning conditions. Burning of plant leaves also affected their stable isotopic compositions. In burned C 3 plant leaves (tree and shrub), the bulk carbon isotope values (δ13C OM) increased by 1.0–1.4‰, while in C 4 grasses, it was 0.4–1.6‰ lower than their unburned counterparts. The changes in the δ13C OM values are suggested to be a cumulative product of the kinetic isotope effect and source-driven isotopic fractionation. The carbon isotope values in long-chain n -alkanes (δ13C n -alk) mostly decreased (up to 4.6‰) in burned C 3 and C 4 plant leaves due to the isotopic modifications associated with the generation of secondary n -alkanes from FAs. In contrast, the hydrogen isotope values of n -alkanes (δ2H n -alk) in the burned samples were up to 86‰ higher than their initial values, mainly due to the kinetic isotope effect. Therefore, in biomes susceptible to frequent canopy and litter layer fires, unusually high δ2H n -alk values coupled with a disproportionate change between δ13C n -alk and δ2H n -alk values might indicate pyrogenic OM presence within the soil. We also observed that changes in the n -alkane characteristics due to heating of soil samples were substantially lower than those in plant leaves due to the protected lipid component within organomineral complexes. In summary, we recommend careful consideration and identification of vegetation fire history before using stable isotope-enabled organic proxies for generating paleoecological records. [ABSTRACT FROM AUTHOR]

We introduce a new method to compute plant distribution in Ethiopia under paleoclimatic conditions using fuzzy logic. Using a published map of the potential vegetation for Ethiopia we decipher the boundary conditions for the main vegetation units shown, reflecting modern climatic conditions for temperature and precipitation in this region. Fuzzy logic using these climatic values on a GIS platform then derived the computational map of the potential vegetation. Comparing it with the original map shows a general correspondence of about 90%. By changing the underlying climate parameters, we then used this model for hypothetical paleoclimatic conditions to simulate the vegetational response on these changed climate settings. Finally, vegetational response maps for Ethiopia are presented for two scenarios: (i) a colder and drier condition (such as the Last Glacial Maximum) and (ii) a warmer and wetter condition (such as the last interglacial) than today. [ABSTRACT FROM AUTHOR]

Quaternary palynology in the Tibetan Plateau (TP) was initiated in the 1960s to meet the needs of economic development in western China. Pollen analysis was conducted for the first time on a 200-m long core of Quaternary lacustrine sediments taken from the main body of the TP in order to study pollen assemblages as well as vegetation and climate changes of glacial (cold)/interglacial (warm) periods. Pollen analysis of alpine snow and ice began at the first scientific expedition to the TP in the 1970s. After the 1980s, a series of international collaborative programs were carried out under Sino-French, Sino-German, Sino-Australian, and Sino-American cooperation, marking the integration of Chinese Quaternary palynology society with the international community. New methods for Quaternary palynology were gradually promoted and applied, changing the vegetational and climatic interpretation of Quaternary palynology from qualitative to quantitative. Since the 1990s, many palynologists have carried out extensive Quaternary palynological studies on fossil pollen sites of more than 60 lakes/sections and alpine glaciers in the TP to discuss the spatiotemporal vegetation changes and climatic and environmental evolution of the TP since the Pleistocene. Over the past half-century, Quaternary palynology in the TP has contributed to the establishment of the Chinese Quaternary pollen database and the study of vegetation and climate evolution since the Last Glacial Maximum (LGM) in the TP. Currently available pollen records revealed the spatial and temporal distribution of vegetation in the TP since the LGM, exhibiting expansions and shrinkages of forest, meadow, grassland and desert in different periods such as the LGM, the last deglaciation, and Holocene optimum period. The paleomonsoon reflected by paleovegetation since the LGM has undergone the changes of weak-strengthening-strong-weakening but still active-shrinking, which is mainly affected by solar insolation. [ABSTRACT FROM AUTHOR]

A distinctive fill top terrace accompanying with thick deposits develops along the Hinokinai River which flows in hills and mountains in north of the Yokote basin, northeastern Honshu island. The authors analyzed tephra-origin materials in the tephric loess overlying on this terrace and pollen assemblages in the terrace deposits. The results are followings: 1)Pollen assemblages showed that paleovegetation was conifer-riched and deciduous broadleaved mixed forest without Fagus during the depositional period of fill top terrace. 2) Tephric loess analyses showed that this terrace emerged just before the falling of the To-Of tephra (ca. 36 cal ky BP). These indicates that the aggradation terrace had formed since the MIS 3 when it's climate had been little cooler and less precipitation than the Holocene. [ABSTRACT FROM AUTHOR]

This paper investigates the much-debated Jurassic/Cretaceous (J/K) boundary as well as the Early Cretaceous climate using palynomorphs of the Chichali Formation, Upper Indus Basin, North Pakistan. Based on the palynostratigraphy, two dinoflagellates and one spore/pollen assemblage are recorded, suggesting a Kimmeridgian to Valanginian age for the sediments of the Chichali Formation. The palynostratigraphic results further suggest that the Tithonian to Berriasian strata are truncated along the J/K boundary. The warm and humid conditions are supported by the consistent dominance of ferns corresponding to the Schizaeaceae and the intermittent appearance of herbs from Gleicheniaceae. Such climatic conditions are further supported by the consistent presence of evergreen trees with a broad leave of Cyatheaceae and Matoniaceae. The warm and humid conditions are also supported by conifers of the Araucariaceae in association with Cycadaceae. Such conditions during the Valanginian are further supported by the switch from the Bajocian–Oxfordian shallow carbonates of the Samana Suk Formation to the Kimmeridgian–Valanginain clastics of the Chichali Formation. Hence, the expansion of warm and humid tropical flora to the middle latitude (∼40°S) during the Valanginain hints strongly for global warming instead of previously suggested global cooling. Palynostratigraphic investigation shows Kimmeridgian to Valanginian age for the Chichali Formation, Upper Indus Basin, Pakistan. The J/K boundary is marked by an unconformity along which the Tithonian to Berriasian time record is missing. The reconstruction of paleovegatation indicates warm humid climate during the Valanginian instead of previously reported global cooling. [ABSTRACT FROM AUTHOR]

Pollen evidence from a 25.3-m-long section (~2.2–0.41 Ma) in the Jinyuan Cave, Liaodong Peninsula, indicates that from the Early–Middle Pleistocene, the climate showed a trend of gradual cooling and drying, with obvious fluctuations. The vegetation was represented by temperate broad-leaved forest from ca. 2.2 to 1.87 Ma, suggesting a relatively warm and humid climate. The period from 1.87 to 1.82 Ma witnessed an obviously cold and dry event, and coniferous and broadleaved mixed forests developed from 1.82 to 1.76 Ma. From 1.52 Ma to the Mid-Pleistocene Transition (MPT), the vegetation was dominated by forest steppe, and the climate became cold in the later stage. During the 0.59–0.41 Ma period, steppes developed, and the climate was cold and arid. At the same time, with climate variation, the faunal communities also changed obviously and co-evolved with vegetation types. In the early stage of the Early Pleistocene, the warm and humid climate was related to the presence of a wide range of thermophilous animals. From 1.7 to 1.5 Ma, the transition from forest to forest steppe might have promoted the emergence of certain grassland-adapted animals. During the MPT, grassland-adapted animals became dominant due to the flourishing forest steppe vegetation. The Middle Pleistocene witnessed the expansion of steppe and animals adapted to the arid grassland environment at that time. [ABSTRACT FROM AUTHOR]

This study aims to determine how the distribution of Carpinus betulus L. (Linnaeus 1763) has changed from LGM to the present and the future. For this purpose, the species fossil pollen data, occurrence data, and bioclimatic variables obtained from WorldClim were used in this study. Representative Concentration Pathway (RCP) 2.6, 4.5, and 8.5 scenarios and Community Climate System Model (CCSM4) model were used for future projection. The PCA method was applied to these variables, and nine variables were determined for species distribution models (SDMs). Models were produced with MaxEnt 3.4.1, and ArcGIS 10.5. Among the nine bioclimatic variables, the BIO18 parameter had the highest contribution to the resulting prediction pattern. The accuracy of the models was measured as 0.83 with the AUC test and 0.80 with the TSS test. According to the obtained results, the most suitable distribution areas of Carpinus betulus in the Last Glacial Maximum (LGM) were the Black Sea region and Western Anatolia. In the future, distribution patterns of Carpinus betulus may shift to the north by decreasing the available present distribution areas in Anatolia and its surroundings. When the models produced according to different climate scenarios for the future are examined, it is predicted that the species will preserve most of the distribution areas in Anatolia according to the RCP 2.6, and will lose most of its distribution areas based on the RCP 4.5. The suitable distribution area will almost disappear according to the RCP 8.5. Hence, these results should be taken into account to improve conservation and management plans for Carpinus betulus and considering biodiversity, and model results will make an important contribution to the future distribution of hornbeams habitat in Anatolia and its surroundings. [ABSTRACT FROM AUTHOR]

Here we report continuous and chronologically well-constrained records of stable oxygen (δ18O) and carbon (δ13C) isotope compositions of carbonate nodules (nodular calcretes), and δ13C of sediment organic matters (δ13C SOM) in samples from two (~48 m deep) drill-sediment cores, collected from a paleo-Yamuna channel in the NW Indo-Gangetic Plain in north Haryana. The results were used to reconstruct Indian summer monsoon (ISM) precipitation variability and paleovegetation pattern during the past ~75 ka and present a longer record of ISM variability in the Indo-Gangetic Plain. The δ18O of carbonate nodules (−7.80‰ to −4.04‰, average −6.01‰) shows a good negative covariation with variability in the model-derived intensity of ISM precipitation, indicating it to be a good proxy for ISM variability. We infer intense ISM precipitation during late marine isotope stage (MIS) 5, early and late MIS 3, and early MIS 1 periods, marked by relatively lower δ18O of carbonates. These changes in the ISM intensity are in-phase with the precession-induced changes in the Northern Hemisphere summer insolation. The δ13C SOM (−27.4‰ to −22.3‰, average −25.3‰) indicates C 3 -dominated vegetation in the Himalayan catchment with a noticeable increase in δ13C SOM during late MIS 4 to early MIS 3, late MIS 3, and early MIS 1 periods, which are characterized by the intense ISM (warm and moist condition). This suggests an increased abundance of C 4 plants during the periods of intensified ISM precipitation. The δ13C of carbonate nodules varies from −3.63‰ to 1.56‰ (average −1.55‰). The enrichment in 13C of the carbonates is most likely due to the influence of dissolved inorganic carbon derived from the Himalayan source and/or atmospheric CO 2 on the carbonate nodules. Therefore, we suggest that the δ13C of carbonate nodules from the Indo-Gangetic Plain requires a careful evaluation. • δ18O and δ13C of carbonate nodule, and δ13C of organic matter records from NW India. • NH summer insolation controlled the intensity of Indian summer monsoon (ISM). • The intensity of ISM precipitation mainly controlled the C 3 :C 4 abundances. • Increased abundance of C 4 plants during the intense ISM precipitation. [ABSTRACT FROM AUTHOR]

Organic carbon isotopic composition (δ13Corg) in loess deposits is an important indicator of terrestrial paleovegetation, and it has been widely used for paleoenvironmental reconstruction in aeolian sediments around the world. However, little research has been done on the variation and paleoenvironmental implication of δ13Corg from loess deposits on Shengshan Island, East China Sea, during the last glacial period (LG). In this research, we present optically stimulated luminescence (OSL) ages, total organic carbon (TOC) data and δ13Corg records of the loess section at Chenqianshan (CQS) on Shengshan Island. Additionally, to study the effectiveness of δ13Corg in documenting paleoenvironmental changes, magnetic susceptibilities and diffuse reflectance spectra were surveyed. TOC concentration for the CQS loess section ranged from 0.11% to 0.47%, and the δ13Corg composition of the CQS loess section varied between −20.80‰ and −24.56‰ during the LG. The average value of C4 abundance was 21.31%. TOC, δ13Corg, χfd, and Hm/(Hm + Gt) curves for the CQS loess section showed similar patterns. The results of our study indicated that the vegetation of the CQS loess deposit was mainly C3/C4 mixed vegetation, and C3 vegetation was the most important vegetation. The comparison between the δ13Corg curve for the CQS section and other existing δ13Corg records of the loess sections from central and northern China showed similar trends and their vegetation succession exhibited synchronous change during the LG. Based on a comparison of the δ13Corg record, C4 abundance and χfd of the CQS section and other global geological records, it was concluded that the mutual effects of precipitation and temperature caused the change of paleovegetation in loess deposits on islands in the East China Sea during the LG.

In order to study the history of natural fires under warming scenarios and to evaluate the possible incidence of fires in the future, we analyzed the carbon concentration and carbon isotope composition of black carbon within the loess-paleosol sequence of the Chinese Loess Plateau. Notably, the interglacials in this East Asian monsoon region were abnormally warm. The results from the interval of L5-S5 of the studied Xifeng section suggest that the principal factors controlling natural fires in an interglacial period (S5) and a glacial period (L5) were fuel load and fuel moisture level, respectively. The difference between the carbon isotope composition of black carbon and soil organic carbon during S5LL1 (marine oxygen isotope stage (MIS) 14) was due to the fact that the former records the more positive carbon isotope values of C 3 plants caused by drought and low temperatures in the fire season, while the latter records the carbon isotope of plants throughout the year. The optimum temperature and humidity conditions during S5SS1 (MIS 13) were the most conducive to fires during the interglacial period of S5. However, when the temperature and humidity decreased to a specific range (mean annual temperature 2-12 °C, mean annual precipitation 200–700 mm) during the glacial period of L5, the fire occurrence reached its highest level. [ABSTRACT FROM AUTHOR]

How to distinguish and quantify past human impacts on vegetation is a significant challenge in paleoecology. Here, we propose a novel method, the error inflection point-discriminant technique. It finds out the inflection points (IPs) of the regression errors of pollen-climate transfer functions using modern pollen spectra from vegetation with different values of the Human Influence Index (HII), which represent the HII threshold values of native/secondary and secondary/artificial vegetation systems. Our results show that the HII value at the native/secondary vegetation IPs is approximately 22 and globally uniform, whereas it varies regionally for the secondary/artificial vegetation IPs. In a case study of the Liangzhu archaeological site in the lower Yangtze River, discriminant functions for pollen spectra from three vegetation types and pollen-climate transfer functions of the native vegetation were established to reconstruct paleovegetation and paleoclimate over the past 6,600 years. Our study demonstrates this method's feasibility for quantitatively distinguishing human impacts on paleovegetation and assessing quantitative paleoclimate reconstructions using pollen data., (© The Author(s) 2024. Published by Oxford University Press on behalf of National Academy of Sciences.)

Microcharcoal in soils and sediments is an ideal proxy for studying fire activity. Phytoliths in soils and sediments record the environmental conditions in which the phytoliths were formed by plants. However, our understanding of the relationships between fire activity, plant communities, and the preservation of microcharcoal and phytoliths in soils and sediments remains limited. In this study, we collected soils and sediments across a gradient of burned and unburned forest in southwest China, and analyzed the microcharcoals and phytoliths in these samples to understand the relationships between these microfossils (ratios of microcharcoal to phytolith particles (Ch/Ph)), fire activity, and vegetation cover. We show that the Ch/Ph ratios recorded fire activity and were significantly different across the gradient of burned to unburned forest. The highest and lowest ratios (0.25 and 0.01) were found in burned forest (Bs1) and unburned forest samples (Us2), respectively. The ratios gradually decreased with increasing distance from the fire. This study suggests the ratio (Ch/Ph) to be a useful proxy for studying fire activity and/or history using soils and sediments. [ABSTRACT FROM AUTHOR]

The present study tests the usefulness of SoLIM software and GIS techniques for the reconstruction of large vegetation formations from the mid‐Holocene period in Romania. We used current reference climate data (temperature, precipitation) and the current extent of ecological regions in Romania to derive climate optimality functions for each vegetation formation. The optimality functions were used to simulate current and past distributions of vegetation. The results showed that the current and mid‐Holocene simulated spatial distributions of vegetation are quite similar. Changes were found for about 14% of the Romanian territory (33 946 km2), the most important being the retreat of coniferous forests in favor of mixed forests and of mixed forests in favor of forest steppe. The former is validated by previous pollen‐based studies showing the transition from coniferous forests to mixed forests that occurred in several areas of the country after the mid‐Holocene. The study demonstrates the potential of this methodological approach to reconstruct past vegetation formations, and at the same time that it is a straightforward and expert knowledge‐based method. Although our application uses only climate factors, the results can be further refined by incorporating additional drivers (soil and landform information, site‐specific pollen and fossil data, wildfire data) for a more accurate inference of paleovegetation. [ABSTRACT FROM AUTHOR]

The Piacenzian (3.60–2.58 Ma) covers the last stage of the Neogene just before the Earth's climate turned from relatively stable warm conditions to the cooler climate with high amplitude glacial‐interglacial oscillations of the Pleistocene. Even during this period early fluctuations towards cooler conditions occurred, and sea surface temperature (SST) reconstructions show stepwise increasing gradients. The zonal Pacific SST gradient which indicates the strength of the Walker circulation appears to have increased in two steps starting in the Piacenzian. We investigated vegetation and climate change in western equatorial South America under the influence of the Walker circulation and to detect signs for the onset of cooling in the tropics. We studied vegetation changes in western Ecuador using palynological analysis of 88 sediment samples from marine Ocean Drilling Program Site 1239 dated between 3.9 and 2.7 Ma. A general trend towards more open vegetation is observed. The climate changes towards cooler conditions, which is manifested by a lowering of the forest line from 3.3 Ma on. The increase of Amaranthaceae pollen after 3.1 Ma suggests drier conditions along the coast. A comparison with mid‐Piacenzian warm period (mPWP) modeling shows that data and models agree regarding a drier coastal climate during the mPWP. The isochronous occurrence of environmental changes in the presented record, that is, cooling and coastal drying, with the first major pulse of ice‐rafted debris and cooling temperatures in the Northern Hemisphere (between 3.28 and 3.31 Ma) suggests that these changes might have been a precursor of the intensification of the Northern Hemisphere glaciation. Plain Language Summary: Around 3.6 to 2.6 million years ago was a time in Earth's history when many conditions were similar to today like the arrangement of the continents, vegetation, and greenhouse gas concentrations. However, the Arctic was not yet covered by ice sheets, and the global climate was warmer, making this time period well suited to study the drivers and mechanisms of warm climates. Towards the end of this period, global climate started to cool, which is known mainly from Northern Hemisphere climate reconstructions. We wanted to find out if cooling and drying conditions found in other records also occurred in the South American tropics. Fossil pollen assemblages preserved in marine sediments can tell us which plants grew in our study area (broadly western Ecuador). Since plants have different (known) climatic requirements, we can reconstruct past rainfall and temperatures as well. We find cooling and drying of neotropical climate, possibly linked to the period preceding the intensification of the Northern Hemisphere glaciations. Studying past climates can help us to better understand and constrain present and future climate developments. Key Points: We present a marine pollen record of climate and vegetation change in western equatorial South America during the PiacenzianFrom around 3.3 Ma, the vegetation became more open, the climate became cooler and the coastal area became drierThe inferences from the pollen record are in agreement with climate modeling results for the mid‐Piacenzian warm period [ABSTRACT FROM AUTHOR]