Vegetation and climate in Amazonia during the last glacial to the Holocene transition (LG-HT) have been controversial for decades. To further explore the vegetation and climate in LG-HT, here we reanalyzed 8 palynological records (from Laguna El Pinal, Sardinas, Angel, swamp Curia & uacute;, Lagoa da Curu & ccedil;a, wetland Pantano da Mauritia, Lagoa da Cachoeria) from Amazonian forests and from adjacent savanna and gallery forests. The results show that (I) the percentage of arboreal pollen increased but with fluctuations in LG-HT, indicating forests expanded; (II) the vegetation taxa composition in LG-HT was distinct from the Holocene in each record, but it was heterogeneous in different sites, and cold-adapted taxa (mainly Podocarpus) occurred in eastern Amazonia. The reanalyzed results with other paleorecords from tropical South America, we found that the Amazonia forest area was relatively large, although with longer dry seasons in LG-HT. We also found that the Amazonian climate in LG-HT was under the background of Orbital Cycles superimposed by short-term colder (warmer) Greenland (Antarctica) and lower Atlantic Sea Surface Temperature, intensifying South American Summer Moonsum (SASM). It caused a cold and wet climate, maintaining forests in Amazonia. However, the transported moisture was unstable, and the climate could be even drier, which allows the existence of patches of savanna in areas with less SASM effect.

Tropical rainforests harbor exceptional biodiversity and function, but are increasingly threatened by agricultural expansion. Whether landscape heterogeneity mitigates these impacts, as in temperate systems, remains unclear. Here, we quantified how local land use and landscape heterogeneity shape multidiversity and ecosystem multifunctionality, using 34 biodiversity metrics and 21 functions across 128 plots in Sumatra. Relative to rainforests, plantations reduced multidiversity and multifunctionality by ~25%, with stronger aboveground declines, lower plant and animal but higher microbial diversity. Contrary to temperate systems, landscape heterogeneity did not buffer local land-use effects but exacerbated declines in multidiversity and multifunctionality, and benefits of surrounding-rainforest cover were confined to rainforest fragments rather than plantations. Our results highlight the irreplaceability of continuous tropical rainforests, and the limited transferability of temperate-based landscape conservation strategies.

The Mongolian Altai Mountain range in Central Asia has an extreme continental and sensitive climate. The Altai Tavan Bogd National Park at elevations of 2000 m above sea level in the southeastern part of the mountain range near Lake Dayan belongs to the high mountain subalpine forest-steppe ecosystem. It is characterized by rich plant diversity and is sensitive to impacts of human activities. Paleoecological research by pollen and charcoal analysis has been carried out on sediments deposits from a small lake to reconstruct past environmental changes in this area. Four radiocarbon dates indicate that the record spans back to the last 1180 cal yr BP years (since AD 770). Four periods have been identified.During the first recorded period from 1180 – 720 cal yr BP (AD 770-1230), the area was covered by mountain forest-steppe. The small areas of forests in the region were pseudo-taiga forests dominated by Larix sibirica and some Picea obovata. The little occurrence of Betula reflects a close forest. Palynological data suggest relatively humid climatic conditions due to the presence of Picea obovata, but due to the lower lake level of the studied lake, conditions might be not so humid. The rare occurrence of dung spores suggests low influence of grazing. During the period from 720 – 210 cal yr BP (AD 1230-1750), conditions shifted from pseudo-taiga to a subalpine forest with less Picea obovata and more open forests. Increasing lake levels suggest more wetter conditions. Moderate grazing was also detected by the increase of dung spores. During the following period from 210 – (-40) cal yr BP (AD 1750-1990), the area was subalpine vegetation, characterized by a forest openness and intensive grazing. Higher lake levels reflect wetter conditions. During the period (-40) cal yr BP (AD 1990 to the present), the subalpine forest was more open. Marked higher lake levels indicate more humid conditions. High grazing activity is also recorded. This study shows that vegetational changes were caused climate changes and by human activities. The more recent increase in the water level of the thermokarst lake is suggested to be the melting of glaciers and snow that has resulted from global warming as well as the degradation of permafrost.

The forest-steppe ecosystems of central Mongolia are particularly sensitive to both climatic variability and long-term human land use, especially in the ecotonal Orkhon Valley, a major political and cultural centre for successive nomadic empires. In this study, we present a high-resolution, multiproxy reconstruction of vegetation dynamics (pollen), fire regimes (charcoal), and land-use patterns (non-pollen palynomorphs, NPPs) over the past 1260 years, based on sedimentary archives from Lake Deliin Burd, located about 35 km from the historic site of Karakorum, the former capital of the Mongol Empire. The record reveals persistent dominance of herbaceous taxa such as Artemisia and Amaranthaceae, with little fluctuations in arboreal pollen (e.g. Pinus sibirica, Betula) reflecting both climatic variability and land-use intensity. Charcoal data indicate increased fire frequency during the Khitan (similar to 800 cal. yr BP) and Mongol (similar to 630 cal. yr BP) periods, associated with higher woody fuel input. Coprophilous fungal spores (Sordaria, Sporormiella) peak between 1050 and 390 cal. yr BP, while Poaceae Cerealia-type pollen appears consistently from ca. 2500 cal. yr BP, suggesting enduring agropastoral activities. These results underscore the complex interplay between climate, fire, vegetation, and imperial land-use strategies, as well as the spatial and temporal variability of human impact. They highlight the resilience and transformation of forest-steppe landscapes in response to shifting socio-political regimes, offering new perspectives on the long-term environmental history and heritage value of Inner Asia's imperial centers.

The long-term interactions between forest and grassland in Southern Brazil remain poorly understood, despite the region's ecological importance and the ongoing debate about natural versus anthropogenic drivers of landscape dynamics. In this study we present a multi-proxy palaeoecological study of the Matematico sediment core from the Southern Brazilian highlands, with the aim of disentangling the roles of climate and human activity in shaping late Holocene Araucaria Forest and Campos (grassland) dynamics. We combined pollen, non-pollen palynomorphs (NPPs), charcoal, and compound-specific hydrogen isotopes (delta H-2) from leaf-wax n-alkanes, making this the first study in Southern Brazil to integrate these proxies within a single core. Between similar to 3.500 and 2.100 cal yr BP (calibrated years before present), the landscape was dominated by Campos under relatively dry conditions, with low fire activity and limited forest cover. Subsequent Araucaria Forest expansion happened in two phases, which were identified at similar to 1700 and similar to 500 cal yr BP. Both phases correspond with shifts to more negative delta H-2 values, indicating a forest expansion due to wetter climatic conditions. However, the earlier wet phase, corresponding to the wettest interval of the last 8000 years in Southern Brazil, did not trigger lasting forest establishment, suggesting that climate alone was insufficient to drive large-scale forest expansion. Meanwhile, the later expansion at similar to 500 cal yr BP a coincides with increased charcoal influx and archaeological evidence of intensived occurrence of Southern J & ecirc; groups of the Taquara/Itarar & eacute; Tradition, suggesting potential human influence in this latter expansion. This integrated multi-proxy approach provides new insights into the ecological and cultural legacies of the today's threatened Araucaria Forest-Campos mosaic.

For millennia, climate changes and Indigenous peoples have influenced Earth’s tropical and subtropical forests. Their relative importance affects our understanding of these ecosystems’ resilience to current anthropogenic changes, so is subject to intensive research and debate. South America’s Atlantic Forest, a global biodiversity hotspot, has been largely absent from this conversation. Here we focus on one of this region’s most iconic, ancient and threatened formations—southern Brazil’s highland mosaic of Araucaria Forest and Campos grasslands. Using novel integrations of palaeo-data and ecological modelling, we assess how climatic and human drivers shaped these landscapes, often through changes to fire dynamics, over the last 6,000 years. We show that climate changes made significant contributions to Araucaria Forest expansions over the last several thousand years, driven by non-linear responses of fire-forest feedback loops to minor climatic shifts. However, within Araucaria Forest areas that experienced more intense human use and occupation, Indigenous people cultivated crops, modified fire dynamics, and profoundly affected vegetation structure and composition. Our results challenge binary views of climate- versus human-driven past vegetation change. Climate, humans and fire all shaped these landscapes through space and time in complex and interacting ways, all of which must be considered to understand or effectively conserve them.

The Brazil-Malvinas Confluence (BMC) in the southwestern South Atlantic plays a crucial role in regulating ocean current circulation and climate change by exchanging water masses between the subtropical gyre and the Antarctic Circumpolar Current (ACC). Previous studies suggest that the BMC shifted to its northernmost position during the Last Glacial Maximum (LGM) and migrated poleward under global warming scenarios. However, the driving mechanisms of these shifts remain poorly understood. In this study, dinoflagellate cyst (dinocyst) and pollen assemblages from marine sediment core GeoB2714-1 in the southern South Atlantic were analyzed to reconstruct oceanographic and regional climate changes. The results reveal three distinct intervals of oceanic environmental change. From ca. 50 to 32 kyr BP, surface waters were dominated by cold-water masses. During this period, the high abundance of reworked dinocysts, particularly Deflandrea antarctica, likely reflects intensified Antarctic upwelling and strengthened Southern Westerlies. Between 32 and 14.5 kyr BP, both upwelling intensity and erosion processes weakened. Since 14.5 kyr BP, the results reflect strengthened Antarctic upwelling and a southward shift of the Southern Westerlies. Since 14.5 kyr BP, the high abundance of the warm-water taxon Operculodinium centrocarpum indicates a shift toward warmer oceanic conditions, likely driven by an intensified Brazil Current and a poleward displacement of the BMC. This transition in the oceanographic regime of the southern South Atlantic provides valuable insights into high-latitude paleoceanographic variability and offers important implications for predicting future oceanic and climate changes.

The Tripa Peat Swamp Forest (TPSF) within the Leuser Ecosystem is a representation of a biodiversity hotspot, providing critical habitat for endangered mammals and containing significant carbon stocks in northern Sumatra. The ecosystem has been fragmented by agricultural land-use conversion, primarily for oil palm plantations, contributing to environmental crises including forest fires and haze pollution. The TPSF is located in a coastal zone adjacent to an ancient volcano and subject to human activity since the 17th century, as indicated by the local archaeological site of the Seuneuam Kingdom. Vegetation and environmental dynamics of the TPSF in the Holocene period remain poorly understood, thereby forming the objective of this study. Pollen, spores, non-pollen palynomorphs, micro-charcoal, macro-charcoal, and total organic carbon (TOC) content were analysed from a 2.5 m-long peat core. Radiocarbon dating of seven samples was used to establish the core chronology. Two main time periods were distinguished in the chronology, specifically the first period from 2500 to 1600 cal yr BP was marked by grass marshes as well as a mix of dipterocarp and swamp vegetation, followed by Pandanus-dominated peat swamp vegetation. The second period after 1600 cal yr BP represented a more stable plant community comprising the families Dipterocarpaceae, Fagaceae, Anacardiaceae, and Myrtaceae (lowland dipterocarp mixed swamp rainforest). Vegetation and ecosystem dynamics of the TPSF were influenced by natural disturbances in the first period and anthropogenic activity during the second.

The postglacial pollen records from South America indicate that different ecosystems were not stable during the Holocene. The variation in Atlantic sea level was probably the major factor in paleoenvironmental changes for the low-lying Amazon Basin region. Large areas of seasonally inundated Várzea and Igapó forests developed after about 3,000 yr. Relatively high water stands might also be due to greater annual rainfall in western, central, and eastern Amazonia, which is also indicated by the marked expansion of Amazon rainforest, both north and south of the equator since the mid-Holocene, but especially during the late Holocene period. This climate change contrasts with that of the Caatinga region in northeastern Brazil. Evidence of significant vegetational and climate change is also found in southeastern Brazil by the marked expansion of semideciduous forest and Atlantic rainforest reducing the Cerrado area during mid- and late Holocene and in southern Brazil by the expansion of Araucaria forests, reducing the area of Campos during the late Holocene, specially during the last 1 kyr. The amount of annual precipitation must have been higher and the length of the annual dry season must have been shorter than during early and mid-Holocene times. The strongest human impact is evident from pollen records specially for the late Holocene period.

The Brazil-Malvinas Confluence (BMC) is a highly dynamic convergence of surface currents in the southwestern South Atlantic, where the warm Brazil Current (BC) from the tropical Atlantic meets the cold Malvinas Current (MC) that originates from the northern branch of the Antarctic Circumpolar Current. Meridional shifts of the BMC play an important role in controlling the heat transfer from the tropical Atlantic to the higher latitudes of the South Atlantic. In this study, the marine core GeoB13861-1 is analyzed for pollen, spores, freshwater algae, and organic-walled dinoflagellate cysts (dinocysts) to reconstruct marine and terrestrial paleoenvironmental changes in southeastern South America since the Last Glacial Maximum (LGM). The results indicate that during LGM, the BMC was at its northernmost location due to the strong influence of the MC. During that period, exposed coastal areas of Argentina were dominated by salt marshes shaped by low global sea level. From similar to 18 to 15 cal kyr BP, the BMC migrated southward, contributing to more humid conditions on the adjacent continent. As sea level rose, former salt marshes along the coast were gradually flooded. The increased presence of Nothofagus and Podocarpus pollen in the marine record suggests a slight expansion of Andean forests during the Late Glacial, indicating the adjacent continental regions shifted to wetter conditions. Notably, our study confirms that the signals of abrupt climate events, such as Heinrich Stadial 1 (HS1) and Younger Dryas (YD), are wellpreserved in the marine sediment records. Our new findings provide clear evidence of the bi-polar sea saw effect during HS1, marked by abrupt ocean warming in the South Atlantic.

The Central Asian (CA) steppe ecosystem and its fauna experienced a marked transition during the Miocene Climatic Optimum (MCO), though the specific process and dynamics remain elusive. We selected the Duolebulejin (DLB) section within the Junggar Basin to reconstruct vegetation and climate changes, using proxies such as particle size, mammalian fossils, and previously reported data including pollen, delta 13CTOC, and magnetic susceptibility. The results reveal three distinct phases of transformation in regional vegetation and fauna from 18.8 to 13.2 Ma. During the pre-MCO (18.8-17.0 Ma), the landscape was dominated by desert scrubland, primarily inhabited by rodents. The MCO (17.0-14.5 Ma) witnessed a shift towards steppe vegetation, initially with herbaceous taxa followed by the establishment of C4 plants, alongside a diversity of large mammals adapted to open habitats. This suggests the emergence of savanna-like woodland steppes. In the post-MCO (14.5-13.2 Ma), the region transitioned to a dry steppe, accompanied by a decline in animal populations, although a significant proportion of species remained adapted to steppe environments. These findings underscore a co-evolutionary relationship between the development of steppe ecosystems and mammalian adaptations, driven by global MCO warming and subsequent cooling, with regional hydroclimatic changes acting as a modulating factor. The steppe-fauna biome emerged in the Junggar Basin during the MCO warming, with mechanisms resembling those of tropical savannas in the late Miocene. These insights enhance our understanding of early steppe ecosystem evolution through past warming periods, shedding light on the pathways to modern steppe formation.

The scope and scale of past human impacts on both historic and current vegetation is of widespread interest in the historical sciences. In the Atlantic Forest of southern Brazil (Portuguese: Mata Atlântica), previous work has identified Amerindian settlement and land-use as a probable driver of the extent and composition of forest cover, with time-extended legacies that remain detectable in modern floristic inventories. Previously published investigations into the ecological history of the southern Atlantic Forest have either eschewed the role of humans or, where anthropogenic drivers are explicitly examined, utilized spatially restricted environmental datasets, necessarily limiting the generalizability their conclusions. This study aims to redress this gap, and to quantify the impact of past Amerindian Pre-Columbian settlement and associated land use on the modern-day distribution of several key plant species across the entire southern Atlantic Forest. We fit Maxent species distribution models (SDMs) using Indigenous archaeological site locations (Tupi-Guarani and southern Jê) and modern plant species occurrence data (35 unique species) in a comparative analytical framework to investigate Indigenous influence on the likelihood of occurrence of culturally significant or medicinal plant species. Our results indicate that (i) the inclusion of archaeological settlement location data and SDM predictions as covariates can improve the performance of contemporary floristic species distribution modeling and should be incorporated into ecological models of plant species in landscapes with long-standing human presence, especially when they are used to inform policy that explicitly aims to preserve “natural” biomes and; (ii) a synanthropic relationship can be demonstrated between the southern Jê and Araucaria angustifolia, a finding that complements previously published phylogeographic and palaeoenvironmental studies exploring the same link.

Identifying floral resources used by honey bees and stingless bees is essential for sustainable beekeeping and understanding pollination ecology. This study compared the diversity of floral resources utilized by the honey bee Apis cerana and stingless bees Geniotrigona thoracica and Heterotrigona itama based on pollen in honey. Bee colonies were in the same Flora Nauli Beekeeping area, Pematang Siantar, North Sumatra, Indonesia, ensuring equal access to similar surrounding floral resources. Honey samples were collected, and pollen grains were extracted, acetolysed, and analyzed by counting 1,200 grains to determine frequency classes. Pollen diversity was calculated using the Shannon–Wiener index (H′). Stingless bee honey contained more diverse pollen than A. cerana, which only contained pollen from the Arecaceae family. Heterotrigona itama and G. thoracica honey contained pollen from 20 and 11 plant families, respectively. Each species had a distinct predominant pollen type (>45%): Cocos nucifera (A. cerana), Sapotaceae type (G. thoracica), and Casuarinaceae type (H. itama). A higher pollen diversity index was also observed in H. itama (1.05-1.83) than in G. thoracica (0.34–1.64) and A. cerana (0.66). These results indicate that stingless bees are more generalist than honey bees, highlighting their ecological role in supporting pollination networks in tropical agroecosystems.

The Bananal Island is a seasonal wetland, included in the extensive Araguaia floodplain. To investigate the landscape dynamic of Bananal Island during the Late Holocene, four sediment and soil profiles were collected from both Araguaia and Javaés rivers margins and analyzed for sedimentological aspects, soil textures, mineralogy and whole chemistry. The results demonstrate a dynamic landscape characterized by recurring cycles of erosion, sedimentation, and ferruginization, primarily driven by seasonal river dynamics. The study highlights the formation of distinctive sedimentary features, including iron-stained sands and floodplain deposits, as well as the influence of these processes on the region’s biodiversity. The findings highlight the ongoing transformation of Bananal Island’s landscape and the significant role of both ancient and modern riverine influences in shaping its unique geological and ecological characteristics.

Predictions of tropical cyclone (TC) frequencies are hampered by insufficient knowledge of their natural variability in the past. A 30-m-long sediment core from the Great Blue Hole, a marine sinkhole offshore Belize, provides the longest available, continuous, and annually resolved TC-frequency record. This record expands our understanding, derived from instrumental monitoring (73 years), historical documentations (173 years), and paleotempestological records (2000 years), to the past 5700 years. A total of 694 event layers were identified. They display a distinct regional trend of increasing storminess in the southwestern Caribbean, which follows an orbitally driven shift in the Intertropical Convergence Zone. Superimposed short-term variations match Holocene climate intervals and originate from solar irradiance-controlled sea-surface temperature anomalies and climate phenomena modes. A 21st-century extrapolation suggests an unprecedented increase in TC frequency, attributable to the Industrial Age warming.

The Great Blue Hole is a prominent flooded karst sinkhole, located in the lagoon of Lighthouse Reef atoll off the coast of Belize. Short cores recovered from varved bottom sediments have been used in previous studies as climate and cyclone archives covering as much as the past ca 1.7 ka BP. A new 30 m long sediment core, encompassing the entire Holocene and the latest Pleistocene, allows a reconstruction of the development of this geoscientifically significant site in the light of the postglacial and Holocene sea‐level rise. The sedimentary succession in the core is tripartite. The lowermost sedimentary unit A (30.0–28.6 m) comprises grey‐brown to black organic‐rich carbonate sediments, which contain freshwater snails ( Pyrgophorus ), tropical forest pollen (Myrtaceae) and a low‐diversity dinocyst assemblage. The intermediate unit B (28.6–24.65 m) is a dark greyish‐green to greyish‐brown, weakly laminated carbonate silt, which comprises marine fossils, that is, euryhaline foraminifera ( Elphidium ) and Halimeda (codiacean algal) platelets. Unit B contains abundant red mangrove ( Rhizophora ) pollen and a dinocyst assemblage indicating high productivity in surface waters. The uppermost unit C (24.65–0 m) is an annually layered buff and light green carbonate silt with abundant marine fossils. A total of 574 intercalated, coarser‐grained and lighter‐coloured event (storm) beds usually rich in Halimeda and coral fragments were identified in unit C. Fully marine conditions, including trophic seasonality, are also indicated by the dinocyst spectrum. The pollen spectrum derives from a variety of trees (largely pine, oak, podocarp), shrubs and herbs. The sedimentary succession represents the transition from an initial terrestrial cenote phase on a vegetated limestone island (unit A: 12.5–7.2 ka BP), via a subsequent restricted marine phase on an initially flooded carbonate platform with mangrove swamps (unit B: 7.2–5.7 ka BP), to a fully marine phase in an open, well‐circulated atoll lagoon (unit C: 5.7–0 ka BP).

The Amazon region is characterized by its tropical rainforest and its great fluvial and lacustrine drainage basins. In the Southwest Amazonia, there are at least three great hydrographic basins (Juruá, Purus and Madeira rivers), where the oxbow lakes are very common. The Amapá Lake is on the right margin of Acre River – one of the principal tributaries of the Purus River -, close to the capital of the State of Acre, Rio Branco, as a typical oxbow lake that it was isolated from that river. Physical-chemical parameters measurements of the waters of Amapá Lake were accomplished during dry and rainy seasons in three stations to have an idea of the implications of the seasonal variation on the observed parameters. Samples were collected for elementary chemical analysis of the waters and suspended material, besides mineralogical analyses of the suspended mineral solids (load sediments). Bottom sediments were collected in three survey holes, using a Livingstone-type manual probe, in the dry season, and they were submitted to chemical, mineralogical (XRD and SEM), grain size and geochronologic analyses. The waters of Amapá Lake present high turbid, STS, ammonia, (phosphate) and chloride values that indicate anthropic action. The high concentrations of Na, Mg, K, Fe, Al, Mn, Ba and Sr are related to clay minerals (smectite and illite). The sediments of Amapá Lake are silt-clayey fine, distributed in beds (clear and dark), sometimes with organic particulate matter. The mineralogy of the sediments is homogeneous along the three holes, and it is mainly represented by quartz, kaolinite, illite and smectite, besides albite and K- feldspars. The vivianite occurs as pseudomorphs after organic matter debris. They are sediments with acid pH (4-5), unlike the waters, that are alkaline, and with low values of organic matter. The sediments are mainly composed by SiO2, Al2O3 and Fe2O3, besides K2O, MgO, TiO2, CaO, Na2O, P2O5 and MnO. That composition reflects abundance of quartz and clay minerals (illite and smectite). Iron contents are probably represented by amorphous sulphides or by clay minerals (smectite). The chemical results were compared with mean of the terrestrial Earth Upper Crust and Post-Archean Australian Shales (PAAS). The sediments are impoverished in Na2O, CaO, MgO, K2O and SiO2 in small proportion, and enriched in MnO, TiO2, Fe2O3 and Al2O3. The values of Al2O3, Fe2O3, MnO and TiO2 are like the PAAS, being the sediments of the Amapá Lake comparable to those. They are immature sediments related to the clay minerals such illite and smectite and feldspars. Among the trace elements, As and Sb are more enriched in relation to the upper terrestrial crust. They are like PAAS, too. The sediments also resemble those shales via REE’s being more enriched in Eu, Gd, Tb and Dy. The suspended sediments are compatible with those of the Acre River in mineralogy and chemical composition, partially diverging in the grain size. The Amapá Lake was formed on Early Holocene, at 3160 years BP, presenting average sedimentation rate of 1,1 mm/yr., in colmatation stage, still receiving load in suspension from Acre River, mainly when the inundations occur. The anthropic action centered in fish farming, deforestations, disordered human expansion, besides an earth highway around the lake, contributes to its colmatation and eutrophication