The ecological and socio-economic services that deltas provide are central to regional infrastructure, sustainable development and climate-change adaptation strategies. Approximately 45% of the global deltaic population resides within South and Southeast Asian mega-deltas. The two principal Vietnamese deltas (Mekong and Song Hong/Red River) account for almost half of that total and have been the subject to sedimentological, hydrogeological and seismic research. However, some inconsistencies remain. Analysis of tidal notches provides an independent, complementary dataset for studying relative sea-level change and associated processes. We present a Late Pleistocene–Late Holocene inundation chronology for the Red River Delta. Pleistocene dates (52–29 cal. kBP) are cautiously attributed to late phases of the Vinh Phuc transgression. Periods of sea-level stabilisation are confirmed leading up to, during and after the Dong Da/Flandrian transgression (6–4 cal. kBP). Results highlight the complexity of past sea-level change in tropical deltaic settings and the value of palaeoecological records to capture sea-level dynamics outside the reach of modern instrumentation. Potential linkage between relative sea level and variability in the strength of the Asian Summer Monsoon/El Niño-La Niña system is posited. Coupling of sea-level regression to climate conditions during the 4.2 and 2.8 ka Cold Events in particular warrants further investigation.

The Holocene fossil record of human and animal ectoparasites comprises specimens from sites worldwide, providing a unique perspective on human mobility, domestication and zoonotic disease. Lice, fleas, bedbugs, louse flies, ticks and mites have been recovered from sites with diverse preservation conditions, ranging from desiccated deposits to permafrost. Relevant contexts include mummies, coprolites, caves and house floors. The overall record includes 52 taxa from in excess of 110 sites from different chronological periods extending from Asia to South America. The global geographic distribution of ectoparasites, along with patterns of diversity and the abundance of records from different periods, offers insight into their relationships with humans and animals, both wild and domestic. From the earliest records of human lice in Brazil and the Levant to the spread of fleas from the New World to the Old World, the close association of ectoparasites with their hosts provides refined information regarding the development of immediate human environments.

A new series of 11 radiocarbon (AMS) dates were obtained to the Biśnik Cave, one of the most important Central European sites. New AMS dates contributed to a more precise stratigraphic model for the complex sequence of sediments in this site. Received results showed that layer 1a is younger than 15 kyr, and layers 1b, 1 and 2 are dated on 25–15 kyr. Layers 4–3 were dated on 40–35 kyr, while layers 7–5 on 70-40 kyr. Layer 7 is the first and the uppermost strata in the whole profile out of the radiocarbon method. The new re-examination of chronology and fauna shed new light on the history of Biśnik fauna. The obtained UTh date of an age of 225 ± 27 kyr confirmed assignation layer 18 to MIS 7. Results of AMS dating were compared with optically stimulated luminescence (OSL), thermoluminescence (TL) and uranium-thorium dates as well as with results of biostratigraphic analysis. Results of data received from different direct dating methods (AMS, UTh, OSL, and TL) are confirmed also by data obtained from the biostratigraphic analysis. Only the maximum age of the lowermost sediments is still debatable. The whole, exceptionally abundant fauna, documented last ∼340 kyr, roughly between MIS 10/9-1. Among mammals, ancient species, early and mid-Middle Pleistocene faunal markers are absent.

Understanding past relative sea level (RSL) is important for constraining the timing and magnitude of changes in the cryosphere, providing critical benchmarks for models used to project future sea-level change, and supplying a datum for constraining past vertical motion. Past sea-level records from Antarctica can help determine the extent to which small or large changes in ice cover induce a response of the solid Earth in tectonically active settings. Here, we examine raised beaches located at Duthoit Point, Nelson Island, Antarctica. We combine geomorphic mapping and high-resolution topographic surveys to reconstruct RSL change and glacial fluctuations during the Holocene. Our study is the first record from Duthoit Point and identifies sea-level changes associated with up to four Holocene ice advances, likely occurring between ∼7000 and ∼4800 cal yr BP, at ∼2000 cal yr BP, at ∼500 cal yr BP, and during a more recent advance younger than ∼500 cal yr BP. Our findings support assertions that uplift rates are primarily driven by glacial isostatic adjustment and changes in ice extent modulate isostatic responses at centennial to millennial timescales. Improved constraints on Holocene uplift histories provide important benchmarks for evaluating isostatic adjustment models used to reconstruct past ice-sheet change and project future sea-level change.

Continuous, high-resolution sedimentary records from the Great Basin are rare. By combining physical sedimentology with charcoal analysis to document changes in lake level and biomass burning, we explore the coevolution of climate and fire ecology over the past 7000 years. Elemental data from scanning X-ray fluorescence (XRF) measurements suggest persistently low lake levels during the Middle Holocene (7000–4000 cal yr BP). Two prolonged low lake stands between 4200–3800 cal yr BP and 2600–2400 cal yr BP occurred during widely documented periods of abrupt environmental change throughout the Great Basin. Significant correlations between the first principal component of the XRF record (which explains >75% of the variance) and a bristlecone pine–derived temperature reconstruction suggest warmer temperatures were a major driver of reduced precipitation–evaporation balance. Spectral analysis shows interannual and multidecadal periodicities typical of Pacific Ocean–atmosphere systems have been influential across the region after 4000 cal yr BP. Severe fire events became more commonplace as precipitation increased, highlighting the role of fuel availability on biomass burning in this semiarid region. These results suggest that while near-term warming will likely lead to increased biomass burning, prolonged periods of warmth and aridity will catalyze returns to the fire regimes of the Middle Holocene.

Six AMS 14C dates from an ice wedge tested in the Holocene wetland on the Pur-Taz interfluve in northwest Siberia are shown here. In the Pur-Taz peatland, peat accumulation started between 11 and 10 cal ka BP, and in the detail studied site, it started after 9.5 cal ka BP. Within the studied peatland, intense ice wedge growth took place between 5.3 and 3.4 cal ka BP. The growth of ice wedges near their southern limit occurred at least 3–4 ka after the formation of the host peat, according to the results of AMS 14C direct dating of ice wedges. Mean January air temperatures ranged from –30 to –27°C during the ice wedge growth phase, which is 2–4°C colder than the current temperature.

We present isotopic data from mammalian megafauna from the Jirau Paleontological Site (Itapipoca, Ceará State, Brazil) and Rio Miranda (Mato Grosso do Sul State), both located in the Brazilian Intertropical Region, dating to the Mid–Late Holocene. The isotopic composition (δ13C) of eight tooth fragments was determined for the following taxa: E. laurillardi, N. platensis, T. platensis, S. populator, X. bahiense, and P. major. Results indicate that the herbivorous taxa had mixed diets, consistent with deciduous to semi deciduous forest and wooded savannah environments. S. populator likely preyed upon herbivores with mixed diets and inhabited wooded savannahs. E. laurillardi, N. platensis, and T. platensis exhibited generalist feeding behavior with a high proportion of C₃ plants in their diet, associated with the fragmentation and reduction of open environments (savannah and wooded savannah) and the concurrent expansion of forested areas during the Holocene Climatic Optimum. X. bahiense and P. major exhibited browser-type diets in Itapipoca, suggesting adaptation to the expansion of deciduous and semi deciduous forests during the Holocene Climatic Optimum. By comparing isotopic data with paleoecological, palynological, and paleobiogeographical evidence, we infer that the Intertropical Region represented one of the last environmental refuges for extinct meso- and megamammal faunas during the Holocene.

The Kovrizhka sites are some of the most studied and highly informative for the entire northern Cis-Baikal region of Siberia and illustrate the history and development of ancient cultures in the Vitim area during the Late Upper Paleolithic to Early Neolithic. To better understand human settlement practices during this time, we constructed a model of Late Quaternary landscape formation and human occupation in the Vitim River valley based on a geomorphological study and radiocarbon dating of archaeological sites Kovrizhka I–VI in the Baikal-Pathom Highlands. The model reconstructs human habitation of the valley from 19.9 to 6.7 ka and connects settlement patterns to general landscape features, stone (mineral) and food resources, the flood regime of the Vitim River, and dynamics of landscape formation. A secondary focus of this study is to assess the timing and geomorphological remnants of megafloods originating from breakthroughs of the Muya (Vitim) glacial paleolake in Marine Isotope Stages (MIS) 3 and 2, and their impact on human settlement. The last megaflood could not have been later than the earliest settlement on Kovrizhka II (19.9 ka). However, erosive flood activity is observed at all stages, especially a shift in floods at the Pleistocene–Holocene boundary.

Changes in settlement patterns are often argued to reflect climatic change, which may make certain areas more or less hospitable depending on the adaptability of subsistence practices. This study models the impact of El Niño-Southern Oscillation (ENSO) events on phases of occupation and abandonment over the past 4500 years at Pashimbi in the Ecuadorian Amazon. While earlier occupations and abandonments seem to correlate with climatic events, associations post-3000 BP are less clear, potentially indicating that populations adapted to wetter conditions and, the authors argue, that the El Niño-Southern Oscillation was not the main determinant in the decision to abandon settlements.

Understanding the local to regional history of extreme events such as debris flows and floods provides context to plan for and mitigate these hazards to life, property, and infrastructure. The Klamath Mountains of northwestern California have experienced both debris flows and devastating wildfires. Whiskeytown National Recreation Area (WHIS) is at the heart of this range and has a wealth of debris flow–related landforms. Gaining an understanding of prehistoric flows and their relationship with fire or other potential triggers can help mitigate future problems. Optically stimulated luminescence and radiocarbon analyses from sediment and entrained organics in undisturbed facies, including beneath partially buried boulders, establishes a chronology of paleo-events in WHIS. The levee deposits indicate a repetition of debris flows during the latest Holocene, every 125–150 years, since 850 yr. Larger flows occurred, with a record elucidated from debris-flow deposits along Clear Creek, with Middle Holocene ages, ca. 2600 to 5500 yr, most of which have sufficient concentrations of charcoal to indicate origins as postfire debris flows. Deposits at higher elevations show events from the latest Pleistocene ca. 13,000 yr. This geochronology indicates that these are not singular events but are relatively common and inherent to the geomorphic processes shaping this landscape.

Our analysis of 61 versions of the Great Basin (GB) Indigenous oral-history narrative, Theft of Pine Nuts, provides valuable new paleoecological insights into late Pleistocene (LP) and Holocene biogeography of pinyon pine (Pinus monophylla). Pinyon homelands indicated by Indigenous sources were located not only within the current pinyon distribution but also north of the known range, in northern California and Nevada, southern Oregon and Idaho, and western Wyoming. These extramarginal pinyon locations corroborate and expand a Western science hypothesis that proposed LP or Early Holocene refugial populations for pinyon in northern GB that subsequently became extirpated. The narratives also provide new evidence for pre-contact distributions of native mammals in the GB. From analysis of the “ice-barrier” accounts in the Indigenous narratives, we propose parts of this oral-history narrative may have been transmitted since LP times. Whereas most prior efforts have assessed Indigenous oral histories that describe catastrophic geologic events, we document that important ecological dynamics are also embedded in these stories. Our analysis joins other studies in recognizing that oral-history narratives can contain reliable eyewitness observations that are useful for reconstructing paleoenvironmental events and conditions.

This study presents a comparative analysis of the radiocarbon dates obtained on paired samples of various organic materials extracted from a lake sediment core. AMS radiocarbon dating of bulk sediment, chironomid capsules, and Trapa seeds was conducted to assess whether systematic offsets exist in the dates obtained on material that are commonly used to develop chronological frameworks for lake-based paleoenvironmental research. The findings reveal significant discrepancies between 14C dates obtained on bulk sediment, chironomid capsules, and on the Trapa seeds used to develop a previously published age-depth model for a sediment core recovered from Deoria Tal, Garhwal Himalaya, India. The systematic offset between the bulk sediment, and to a lesser extent chironomid remains, and the Trapa seeds is attributed to the integration of allochthonous carbon in the bulk sediment, leading to older apparent ages. The 3.6‰ shift in the δ13C value of the bulk sediment at 252 cm is inferred to reflect an increase in the contribution of C4 plant matter to the lake. The increase in enriched δ13C organic matter, coincident with the increasing offset between the dates obtained on bulk sediment and chironomids, and those obtained on the Trapa seeds, between 800 and 400 cal BP, was likely driven by anthropogenic land use changes, as evidenced by the four-fold increase in Cerealia-type pollen during this interval. This study underscores the necessity of selecting appropriate materials for radiocarbon dating to ensure accurate chronological reconstruction and highlights the potential of using chironomids remains to develop robust radiocarbon chronologies for lake sediment records.

A 9200-year-long Holocene record of pollen, magnetic susceptibility (MS), and sedimentation rates from Pup Lake, northern Lower Michigan, USA, along with comparative pollen data from regional paleoecological sites and optically stimulated luminescence dates from inland sand dunes across the Great Lakes region, reveals emerging relationships among climate, vegetation, and erosion. Tsuga (hemlock) pollen was used to track local- and regional-scale hydroclimate variability owing to the taxon’s moisture sensitivity and close association with modern lake-effect snowfall gradients. Two periods of elevated MS and Tsuga values, 6800–5200 cal yr BP and 3200–800 cal yr BP, are interpreted as millennial-scale phases of greater effective moisture that drove key changes in forest composition and resulted in accelerated erosion. Overall, the lake’s MS record broadly tracks changes in Tsuga pollen frequencies and sedimentation rates, particularly during the Late Holocene, suggesting the emergence of a well-defined lake-effect climate system between 5200 and 1000 cal yr BP. Additionally, Pup Lake’s MS record exhibits notable connections with widely recognized hemispheric-scale climate deterioration episodes, including the 9.2, 8.2, and 5.2 ka BP events.

We present a Late Pleistocene paleoecological record from King Island in western Bass Strait, Tasmania, and compare this to existing records from the eastern Bass Strait islands to improve our understanding of the region’s paleoecology and paleoclimatology. Vegetation change across the region followed similar trajectories during the late glacial–Middle Holocene, characterized by homogeneous warming and wetting trends. Spatial divergence occurred during the Middle Holocene when sea level rose, and different drivers began influencing western and eastern Bass Strait islands. In eastern Bass Strait, Middle Holocene sea-level rise caused replacement of woodland by coastal heathland, while in the west, a drier period accompanied by fires transformed forests to forest–scrub. The comparative analysis suggests that Westerly driven climatic anti-phasing was pronounced at higher latitudes of Tasmania during the late glacial–Early Holocene. A combination of weak Leeuwin Current, positive Indian Ocean Dipole (IOD), and El Niño–Southern Oscillation (ENSO) intensification contributed to Middle Holocene aridity across Bass Strait. Strong Westerlies and negative IOD phases led to greater regionalization of rainfall across western Bass Strait during the Late Holocene, while ENSO intensification drove rainfall declines in eastern Bass Strait. These findings provide new insights into the complexity of Late Pleistocene environmental dynamics across southeast Australia.

The cold, low carbon dioxide (CO2) conditions of the Pleistocene epoch fundamentally structured ecosystems, profoundly influencing the evolutionary trajectory of Homo sapiens and other large mammals. Although often considered uniquely stable, the Holocene is more usefully viewed as just another Pleistocene interglacial interval that was naturally trending towards a renewed glacial phase. However, rapid anthropogenic greenhouse gas emission rates have reversed this trajectory and might have now foreclosed the prospect of returning to cyclic glacial climates for millennia. A large set of flora and fauna has benefited from low CO2 conditions, which we define as low-CO2 dependents. By elevating atmospheric CO2 concentrations beyond levels seen for millions of years, we have accelerated global warming beyond the adaptive capacities of many species and ecosystems. African savannas and grasslands are particularly relevant in this context because this was the environment in which the human species evolved. These biomes have been previously maintained by fire and carbon scarcity but are now experiencing woody encroachment driven by rising CO2. The resultant global reforestation further threatens biodiversity adapted to open ecosystems, while rewilding initiatives must therefore pair prehistoric analogues with explicit climate-fitness tests that anticipate mid-century CO2 trajectories. Addressing these complex challenges requires both targeted local interventions and systemic policy reforms, grounded in a pragmatic recognition of the transient nature of the Holocene. Recognising the transience of any single baseline allows conservation and agriculture to plan for a dynamic, overshoot-prone future.

Paleoecological reconstructions provide valuable insights into the impacts of environmental change on key functions of wetland ecosystems. Here, we integrate biological and sedimentological proxies to provide a baseline of vegetation and hydrological change since the Middle Holocene at a riparian marsh, with the goal of informing wetland restoration within a regional biodiversity hotspot in the Great Lakes coastal zone. Four stages of wetland development are identified, reflecting the combined impacts of Lake Erie fluctuations, fluvial processes, regional paleoclimate, and anthropogenic influence. Wetland establishment took place ∼6000 cal yr BP during a Lake Erie high stand, and pollen assemblages indicate that the site was initially a forested wetland. Subsequently, water levels remained elevated as a transition to an emergent marsh with silty, organic-rich sediments took place ∼5300 cal yr BP. Once water levels stabilized in the Late Holocene, a thicket swamp established in sandier sediments, suggesting closer proximity to the meandering channel. The intensification of European settlement from 1850 CE marked a major transition, resulting from disturbances caused by land clearance and hydrological alterations, including higher rates of sediment accretion, novel diatom communities, and increases in herbaceous vegetation. These paleoecological records demonstrate the importance of considering whole-watershed measures in restoration planning, including controls on mineral sediment influxes, maintenance of local water tables, and management of invasive species producing high biomass.

Understanding biotic responses to environmental changes will help identify extinction risks and direct conservation efforts to mitigate negative effects associated with anthropogenic-induced environmental changes. Here we use the Quaternary fossil record of mole salamanders (Ambystoma) from the southwestern United States and northern Mexico to reveal geographic patterns of extirpation since the Pleistocene. Ambystoma are known to have previously inhabited regions of central Texas on the Edwards Plateau; however, they are largely absent from the region today. We used a well-dated fossil record of Ambystoma from Hall’s Cave combined with other fossil sites in the region to deduce why Ambystoma was ultimately extirpated from the Edwards Plateau and to test hypotheses related to temperature-driven body-size changes in line with the temperature–size rule. We propose that Ambystoma was likely extirpated from the region due to changing temperature and precipitation regimes that caused increased mortality and disruptions to breeding and larval development. We found some support for decreased body size in Ambystoma with increased temperature during the late Pleistocene, suggesting that body size may be an important feature to monitor in modern populations of Ambystoma as salamanders become subjected to increasingly hotter temperatures in the coming decades.