Palaeoecological Evidence Research Articles

Fire drives major Holocene vegetation shifts between subtropical and Mediterranean‐type ecosystems: a case study from a biodiversity hotspot in South Africa

Fire plays a pivotal role in driving ecological shifts between Mediterranean‐type vegetation and subtropical ecosystems in South Africa. This study investigates long‐term environmental dynamics and ecological regime changes at the Mediterranean‐type vegetation /subtropical boundary using a 6000‐year palaeoecological sequence from the Baviaanskloof – a region of South Africa characterized by high levels of biodiversity and climate dynamism. Combining fossil pollen and microcharcoal data from a rock hyrax Procavia capensis midden, we analyse vegetation responses to environmental changes. Our findings reveal that Mediterranean‐type vegetation resilience prevailed until ca 2800 cal year BP when a major fire event triggered a transition to a subtropical thicket‐dominated environment. This abrupt ecological turnover underscores the significance of fire as a major driver of vegetation change at the Mediterranean‐type vegetation /subtropical boundary. Our study emphasizes the vulnerability of Mediterranean‐type vegetation ecosystems to global environmental change, suggesting potential implications for similar biome boundaries worldwide. By integrating multi‐proxy palaeoecological evidence, we gain insights into the resilience and vulnerability of these ecosystems, aiding in understanding future responses to climate change scenarios.

Camelus knoblochi genome reveals the complex evolutionary history of Old World camels

Extant Old World camels (genus Camelus) contributed to the economic and cultural exchanges between the East and West for thousands of years.1,2 Although many remains have been unearthed,3,4,5 we know neither whether the prevalent hybridization observed between extant Camelus species2,6,7 also occurred between extinct lineages and the ancestors of extant Camelus species nor why some populations became extinct while others survived. To investigate these questions, we generated paleogenomic and stable isotope data from an extinct two-humped camel species, Camelus knoblochi. We find that in the mitochondrial phylogeny, all C.knoblochi form a paraphyletic group that nests within the diversity of modern, wild two-humped camels (Camelus ferus). In contrast, they are clearly distinguished from both wild and domesticated (Camelus bactrianus) two-humped camels on the nuclear level. Moreover, the divergence pattern of the three camel species approximates a trifurcation, because the most common topology is only slightly more frequent than the two other possible topologies. This mito-nuclear phylogenetic discordance likely arose due to interspecific gene flow between all three species, suggesting that interspecific hybridization is not exclusive to modern camels but a recurrent phenomenon throughout the evolutionary history of the genus Camelus. These results suggest that the genomic complexity of Old World camels' evolutionary history is underestimated when considering data from only modern species. Finally, we find that C.knoblochi populations began declining prior to the last glacial maximum and, by integrating palaeoecological evidence and stable isotope data, suggest that this was likely due to failure to adapt to a changing environment.

Alpine travellers in the Carpathians: The story of two rock‐dwelling snails told by genes and fossils

AbstractAimVarious species distributed in the Alps have their disjunct occurrences in the Carpathians. Fossil evidence for some woodland snails of Alpine distribution suggests that they colonized the Carpathians during the Holocene forest optimum or later. Here, we focus on disjunct Carpathian populations of the rock‐dwelling alpine snail Pyramidula saxatilis. As it occupies very stable habitats, that is, high‐elevation limestone rocks, one can assume its potential survival in Carpathian refugia over the glacial period(s). For comparison, the more widespread and warm‐climate P. pusilla is analysed.LocationEurope.TaxonPyramidula saxatilis and P. pusilla.MethodsWe analysed the genetic diversity of P. saxatilis and P. pusilla populations across their entire ranges using mitochondrial DNA and nuclear DNA markers. Seven fossil mollusc successions from the area where P. saxatilis occurs in the Carpathians were analysed and dated using the radiocarbon method. Habitat suitability models of both species were calculated for selected time periods since the Last Glacial Maximum.ResultsAll Carpathian P. saxatilis populations were genetically homogeneous and similar to those from the Eastern Alps. In P. pusilla, we found a genetically distinct lineage in the southern Western Carpathians. Both species were found in three fossil profiles since the Middle Holocene, and in one already in the Late Glacial. Habitat suitability models suggested the fluctuations of suitable conditions in the Carpathians driven by summer precipitation, especially for P. saxatilis.Main ConclusionsOur results suggest that the Carpathian populations of P. saxatilis represent a post‐LGM colonization from the Eastern Alps triggered by climatic changes, mainly by the increase in summer precipitation during the Late Glacial interstadials and Middle Holocene. The evidence for P. pusilla is similar, but also suggests rare long‐term survival in the Carpathian microrefugia. The palaeoecological evidence indicates a possible threat to high‐elevation species from future fluctuations in precipitation regimes.

Forest mosaics, not savanna corridors, dominated in Southeast Asia during the Last Glacial Maximum.

The dominant paradigm is that large tracts of Southeast Asia's lowland rainforests were replaced with a "savanna corridor" during the cooler, more seasonal climates of the Last Glacial Maximum (LGM) (23,000 to 19,000 y ago). This interpretation has implications for understanding the resilience of Asia's tropical forests to projected climate change, implying a vulnerability to "savannization". A savanna corridor is also an important foundation for archaeological interpretations of how humans moved through and settled insular Southeast Asia and Australia. Yet an up-to-date, multiproxy, and empirical examination of the palaeoecological evidence for this corridor is lacking. We conducted qualitative and statistical analyses of 59 palaeoecological records across Southeast Asia to test the evidence for LGM savannization and clarify the relationships between methods, biogeography, and ecological change in the region from the start of Late Glacial Period (119,000 y ago) to the present. The pollen records typically show montane forest persistence during the LGM, while δ13C biomarker proxies indicate the expansion of C4-rich grasslands. We reconcile this discrepancy by hypothesizing the expansion of montane forest in the uplands and replacement of rainforest with seasonally dry tropical forest in the lowlands. We also find that smooth forest transitions between 34,000 and 2,000 y ago point to the capacity of Southeast Asia's ecosystems both to resist and recover from climate stressors, suggesting resilience to savannization. Finally, the timing of ecological change observed in our combined datasets indicates an 'early' onset of the LGM in Southeast Asia from ~30,000 y ago.

The Pleistocene grassland-dominated mammal fauna from Tham Kra Duk (Nakhon Si Thammarat, Peninsular Thailand)

ABSTRACT Controversy exists as to whether the Pleistocene vegetation in northern Sundaland was dominated by lowland tropical grasslands or rainforests, due to limited palaeoecological evidence recorded from the region. We describe a new Pleistocene large mammal fauna from Tham Kra Duk, a cave in the Tham Phedan mountain, Nakhon Si Thammarat Province in Peninsular Thailand, with emphasis on its palaeoecological and palaeoenvironmental investigations using the stable isotope analysis of mammalian tooth enamel. The fossil site has yielded at least nine mammalian taxa almost comparable to late middle to latest Pleistocene faunas in the mainland, thus suggesting the same biogeographic mammal elements with a range extension south of the Kra Isthmus. The stable isotope results indicate that mixed woodland to grassland ecosystems were dominated by C4 vegetation in the area. This supports the assumption that the expansion of Pleistocene tropical savanna ecosystems might have held the key to facilitating the southward distribution range of grazing mammals such as gaurs and Himalayan gorals into the Thai-Malay Peninsula. The presence of the Tham Kra Duk fauna was probably linked to some major biogeographic events of Pleistocene hominin and mammal migration through the land-bridge peninsula into the islands of Southeast Asia during a period of glaciation.

Climate and atmospheric circulation during the Early and Mid‐Holocene inferred from lake‐carbonate oxygen‐isotope records from western Ireland

ABSTRACTThe Early to Mid‐Holocene experienced marked climate change over the northern hemisphere mid‐latitudes in response to changing insolation and declining ice volume. Oxygen isotopes from lake sediments provide a valuable climate proxy, encoding information regarding temperature, hydroclimate and moisture source. We present oxygen‐isotope records from two lakes in western Ireland that are strongly influenced by the North Atlantic. Excellent replication between the records suggests they reflect regional, not local, influences. Carbonate oxygen‐isotope values peaked at the start of the Holocene, between 11.2 and 11.1 cal ka bp, and then decreased markedly until 6 cal ka bp at both sites. Palaeoecological evidence supports only modest change in temperature or hydroclimate during this interval and we therefore explain the decrease primarily by a reduction in the oxygen‐isotope composition of precipitation (δ18Oppt). We show a similar decrease in δ18O values in a forward model of carbonate isotopes between 12–11 and 6–5 cal ka bp. However, the inferred reduction in δ18Oppt between the Early and Mid‐Holocene in the model is mainly linked to a decrease in the δ18O of the ocean source water from ice sheet melting whereas the lake carbonate isotope records are more consistent with changes in the transport pathway of moisture associated with atmospheric circulation change as the dominant cause.

Putting the Dark Emu debate into context

ABSTRACTIn this review of the Dark Emu debate we start out by summarising Bruce Pascoe's original work and Peter Sutton and Keryn Walshe's critique. However, the majority of this contribution is to place this Australian‐focussed debate into broader conceptual, methodological and evidential contexts generally associated with the investigation of early agriculture in other parts of the world. If we are to apply the term “agriculture” to Aboriginal plant management practices, then this requires a global, rather than a continental‐centric comparative perspective. We argue debates regarding the character of plant exploitation practices on the Australian mainland, including whether they included forms of agriculture or experimental horticulture, have been hindered by a lack of terminological clarity, the absence of a methodological framework to assess empirically verifiable evidence, and – even more problematically – a lack of relevant data on the putative plants and practices involved. Here, terminology is clarified and a bottom‐up, practice‐based method is advocated for the assessment of recent (using oral, visual and written histories) and ancient (using archaeological, archaeobotanical and palaeoecological evidence) forms of food plant exploitation in Australia. The terminology and methodological framework are heuristically applied to three scenarios: (1) ethnographic and historical records for the exploitation of underground storage organs (USOs) on the Australian mainland; (2) historical documentation regarding the botany, potential human roles in dispersal, and Aboriginal exploitation of banana (Musa spp.), taro (Colocasia esculenta) and greater yam (Dioscorea alata) in northern Australia and (3) archaeobotanical evidence for the exploitation of USOs and other plants from The Top End.

The Clacton-on-Sea (Essex, UK) GCR site and SSSI: New data and continuing importance

The complex Geological Conservation Review (GCR) site at Clacton-on-Sea, Essex, was notified in 1986 as a Site of Special Scientific Interest. It is an internationally important geosite and Britain's only Lower Palaeolithic type locality, giving its name to the Clactonian stone-tool industry. Fossil- and artefact-bearing channel-fill deposits laid down by the River Thames ~420,000 years ago, during the Hoxnian Interglacial (Marine Isotope Stage 11c), have been observed in foreshore and cliff exposures, and beneath developed and open ground in an inland arcuate footprint. These sediments provide a record of the lower reaches and estuary of the Thames during this lengthy and warm interglacial, an important partial analogue for the Holocene. Palaeoclimatic and palaeoecological evidence has been obtained from assemblages of fossil molluscs, ostracods and vertebrates, together with pollen and plant macrofossils; Clacton is also the type locality for several of the represented animal taxa, including the biostratigraphically significant ostracod Scottia browniana and a large subspecies of fallow deer, Dama dama clactoniana. This paper provides an overview of the continuing importance of the Clacton GCR site and Site of Special Scientific Interest (SSSI), summarizing recently acquired data that have enhanced understanding of the Hoxnian and the palaeoenvironments that prevailed at the time of deposition. The wider geosite has benefitted from sustained Palaeolithic archaeological interest, with the local planning authority mandating investigation of the sediments as a condition for development projects. SSSI status ensures that the significant collections of palaeontological and archaeological material amassed from the Clacton deposits over almost two centuries can be related to their context, and studies of both these archived collections and new material from the protected in situ sediments continue to provide new data and contribute to the development of cutting-edge techniques.

Longstanding behavioural stability in West Africa extends to the Middle Pleistocene at Bargny, coastal Senegal

Middle Stone Age (MSA) technologies first appear in the archaeological records of northern, eastern and southern Africa during the Middle Pleistocene epoch. The absence of MSA sites from West Africa limits evaluation of shared behaviours across the continent during the late Middle Pleistocene and the diversity of subsequent regionalized trajectories. Here we present evidence for the late Middle Pleistocene MSA occupation of the West African littoral at Bargny, Senegal, dating to 150 thousand years ago. Palaeoecological evidence suggests that Bargny was a hydrological refugium during the MSA occupation, supporting estuarine conditions during Middle Pleistocene arid phases. The stone tool technology at Bargny presents characteristics widely shared across Africa in the late Middle Pleistocene but which remain uniquely stable in West Africa to the onset of the Holocene. We explore how the persistent habitability of West African environments, including mangroves, contributes to distinctly West African trajectories of behavioural stability.

Simulating land use dynamics and the role of marine resources in diets during the Early Bronze Age-II (ca. 4900 – 4700 cal. BP) at Gökçeada (ancient Imbros) in the northern Aegean

Islands represent small-scale ecosystems that often represent nutritional challenges and require mixed subsistence strategies. This research focuses on Gökçeada (ancient Imbros) in the northern Aegean, where an Early Bronze Age-II (ca. 4900–4700 cal. BP) site has been subjected to agent-based modeling experiments to explore whether a mixed subsistence strategy was necessary to sustain the population, and to explore the scale and intensity of long-term anthropogenic impacts. Yenibademli Höyük was excavated for a quarter century and researchers have conducted a wide variety of interdisciplinary research to supplement archaeological data. Based on this broad dataset (which contains zooarchaeological, palaeobotanical, and palaeoecological evidence), it is possible to test six scenarios that present different paleoclimatic conditions, along with agro-pastoral subsistence at varying levels of intensity. The results suggest that anthropogenically induced environmental change has been negligible around the site, mainly due to an insufficient level of agro-pastoral production to sustain the population. The high density of shellfish and other marine sources found at the site supports the results of agent-based modeling, which shows that the population had to supplement their diet with seafood.

Disturbance and Succession in Early to Mid-Holocene Northern English Forests: Palaeoecological Evidence for Disturbance of Woodland Ecosystems by Mesolithic Hunter-Gatherers

Forest succession can be monitored in the present, modelled for the future, but also reconstructed in the past on the records of forest history, including through the use of palaeo-ecological techniques. Longer-term records from pollen data can show changes over centennial and millennial timescales that are impacted by climate, migration or soil development. Having knowledge of previous phases of post-disturbance seral stages of woodland regeneration however, as after fire, can provide insights regarding successional process and function over short-term decadal timescales. The aim of this paper is to test the high-resolution pollen record as a source of new insights into processes of succession, assisted by the supplementary data of microscopic charcoal analyses. On short-term timescales, multiple phases of forest disturbance and then recovery have been identified in early to mid-Holocene peat records in northern England, many from the uplands but also from lowland areas. We identify and describe a typology of recovery patterns, including the composition and rate of recovery, and then test the processes and factors that impacted on different seral trajectories, concentrating on fire disturbance which might have had a natural origin, or might have been caused by pre-agricultural Mesolithic hunter-gatherers. Factors considered include the spatial location and intensity of the fire event, the duration of the disturbance phase, the structure and dynamics of the successional regeneration vegetation communities and the pre-disturbance tree cover. Data from examples of fire disturbance of woodland have been examined from both upland and lowland sites in northern England and indicate that they had different successional pathways after disturbance. Fire disturbances in the denser lowland forests were mostly single burn events followed by natural successions and regeneration to forest, whereas fire disturbances in the upland woods usually showed continued or repetitive fire pressure after the initial burning, arresting succession so that vegetation was maintained in a shrub phase, often dominated by Corylus, for an extended period of time until disturbance ceased. This creation of a kind of prolonged, almost plagioclimax, ‘fire-coppice’ hazel stage suggests controlled rather than natural successional pathways, and strongly suggests that Mesolithic foragers were the fire starters in the upland English woodlands where hazel was naturally common and could be maintained in abundance in later-stage successions, along with other edible plants, for human use. All post-fire seral stages would have been attractive to game animals, providing a reliable food source that would have been of great benefit to hunter-gatherer populations.

A range‐wide postglacial history of Swiss stone pine based on molecular markers and palaeoecological evidence

AbstractAimKnowing a species' response to historical climate shifts helps understanding its perspectives under global warming. We infer the hitherto unresolved postglacial history of Pinus cembra. Using independent evidence from genetic structure and demographic inference of extant populations, and from palaeoecological findings, we derive putative refugia and re‐colonisation routes.LocationEuropean Alps and Carpathians.Taxa Pinus cembra. MethodsWe genotyped nuclear and chloroplast microsatellite markers in nearly 3000 individuals from 147 locations across the entire natural range of P. cembra. Spatial genetic structure (Bayesian modelling) and demographic history (approximate Bayesian computation) were combined with palaeobotanical records (pollen, macrofossils) to infer putative refugial areas during the Last Glacial Maximum (LGM) and re‐colonisation of the current range.ResultsWe found distinct spatial genetic structure, despite low genetic differentiation even between the two disjunct mountain ranges. Nuclear markers revealed five genetic clusters aligned East–West across the range, while chloroplast haplotype distribution suggested nine clusters. Spatially congruent separation at both marker types highlighted two main genetic lineages in the East and West of the range. Demographic inference supported early separation of these lineages dating back to a previous interstadial or interglacial c. 210,000 years ago. Differentiation into five biologically meaningful genetic clusters likely established during postglacial re‐colonisation.Main ConclusionsCombining genetic and palaeoecological evidence suggests that P. cembra primarily survived the LGM in ‘cold period’ refugia south of the Central European Alps and near the Carpathians, from where it expanded during the Late Glacial into its current Holocene ‘warm period’ refugia. This colonisation history has led to the distinct East–West structure of five genetic clusters. The two main genetic lineages likely derived from ancient divergence during an interglacial or interstadial. The respective contact zone (Brenner line) matches a main biogeographical break in the European Alps also found in herbaceous alpine plant species.

Q56The Midlands of England: Economic Backwater or an Agricultural Powerhouse? Environmental Evidence from Prehistory to Modern Times Recorded in Sediments from Aqualate Mere, Central England, UK

ABSTRACT Archaeological and palaeoecological evidence relating to human activity in the English Midlands is scant compared to elsewhere in Britain. Knowledge of human activity in pre-Roman and Roman times is often fragmentary and disparate in parts of the region where it could be assumed that the resident population was small with little Roman impact. To examine these contentions, a palaeoenvironmental investigation from Aqualate Mere near Newport, Staffordshire, has been undertaken on the sediment record extending back to c. 1300 cal. BC. An analysis of microfossils, microscopic charcoal, sediment chemistry and mineral magnetism from a core dated by 14C, SCPs, 210Pb and 137Cs has provided an opportunity to reconstruct land use changes and atmospheric pollution from the later prehistoric period onwards. The results challenge the idea this region was a backwater as there is near-continuous agricultural activity around the mere since the Late Bronze Age through to modern times. This is characterised by phases of woodland decline, an intensification of farming, soil erosion, evidence for possible eutrophication and regional lead pollution.

Radiocarbon sampling efforts for high-precision lake sediment chronologies

High-resolution chronologies with the best time control are key for comparing palaeoenvironmental studies with independent high-precision historical, archaeological or climatic data. Precise chronologies are also essential for inter-site comparisons of palaeo records at decadal to centennial time scales. We present an updated sediment chronology from Burgäschisee, a small and well-studied lake in the Swiss lowlands. The new age-depth relationship was generated using a large number of new radiocarbon samples of terrestrial plant remains extracted from the Burgäschisee sediments and Bayesian age-depth modelling. The results reveal 2σ uncertainties of only ±19 years for the entire record covering the Early Bronze Age (3800 cal. BP) to the Early Middle Ages (1150 cal. BP). The differences between four age-depth modelling techniques (Bayesian and non-Bayesian) are minor (around 25 years) and remain stable with lower radiocarbon date availability. The maximum age offset between the preliminary previously published and the refined chronology from Burgäschisee is 225 years. Our results demonstrate the importance of a rigorous subsampling strategy that includes a careful selection of the best terrestrial plant material and avoiding radiocarbon calibration plateaus whenever possible. The new chronology from Burgäschisee now allows a more accurate site-to-site comparison with archaeological, historical and other palaeoecological evidence from the region.

Palaeoecological evidence of pollen morphological changes: A climate change adaptation strategy?

Pollen records have been used to reconstruct changes in climate, based on the presence of taxa as proxies for environmental conditions. Pollen grains have morphological features that allow for the identification of different species, genera, and families of flowering plants. However, ecologically distinct species share similar pollen types that may make biogeographic and climate reconstructions problematic. Also, the responses of populations and species to climate changes adjusted through either plasticity or adaptation have been overlooked. Such adjustments are most probably the product of long-lasting in situ persistence in local refugia under favourable microclimates despite hostile regional climate. In southern South America three species of the dominant tree cover of the subgenus Nothofagus are present, two deciduous (N. antarctica and N. pumilio) and one evergreen (N. betuloides), identified in the pollen group Nothofagus dombeyi type. Here we present a pollen record from Punta Arenas (~53°S) that documents significant changes in pollen size that took place during the Late glacial and Early Holocene. The occurrence of smaller Nothofagus dombeyi type pollen grains during the Late glacial may indicate rapid local adaptation to colder and possibly wetter conditions. Our findings are supported by Ecological niche modelling which suggests limited availability of Nothofagus refugia during the Last Glacial Maximum. The local refugia may also have fostered interbreeding between congeneric species that led to unique morphological features that increased the fitness of the recipient pool. We postulate that such modifications were due to the potential transient hybridization between species that later diverged by backcrossing with each deciduous and evergreen taxa.

A Hierarchical Meta-Analytical Approach to Western European Dietary Transitions in the First Millennium AD

During the first millenniumad,Europe saw much socio-environmental change, which is reflected in the archaeological and palaeoecological evidence. Using published and new isotope data from across western Europe, the author examines changing resource use fromc.ad350 to 1200. The geographical limits of millet and substantial marine consumption are identified and comparisons between childhood and adult diets made across regions. Cross-cultural interaction at a broad scale is emphasized and patterns within early medieval England form the subject of an in-depth case study. While doubt is cast onto the uptake of marine resource consumption in England following the Fish Event Horizon, changes in agricultural practices, the impact of Christianization, and the role of freshwater fish in diets are explored. The author's hierarchical meta-analytical approach enables identification of human–environment interactions, with significant implications for changing foodways in Europe during the first millenniumad.

Learning from the past: opportunities for advancing ecological research and practice using palaeoecological data.

Palaeoecology involves analysis of fossil and sub-fossil evidence preserved within sediments to understand past species distributions, habitats and ecosystems. However, while palaeoecological research is sometimes made relevant to contemporary ecology, especially to advance understanding of biogeographical theory or inform habitat-based conservation at specific sites, most ecologists do not routinely incorporate palaeoecological evidence into their work. Thus most cross-discipline links are palaeoecology → ecology rather than ecology → palaeoecology. This is likely due to lack of awareness and/or the misnomer that palaeoecology invariably relates to the "distant past" (thousands of years) rather than being applicable to the "recent past" (last ~ 100-200years). Here, we highlight opportunities for greater integration of palaeoecology within contemporary ecological research, policy, and practice. We identify situations where palaeoecology has been, or could be, used to (1) quantify recent temporal change (e.g. population dynamics; predator-prey cycles); (2) "rewind" to a particular point in ecological time (e.g. setting restoration/rewilding targets; classifying cryptogenic species); (3) understand current ecological processes that are hard to study real-time (e.g. identifying keystone species; detecting ecological tipping points); (4) complement primary data and historical records to bridge knowledge gaps (e.g. informing reintroductions and bioindicator frameworks); (5) disentangle natural and anthropogenic processes (e.g. climate change); and (6) draw palaeoecological analogues (e.g. impacts of pests). We conclude that the possibilities for better uniting ecology and palaeoecology to form an emerging cross-boundary paradigm are as extensive as they are exciting: we urge ecologists to learn from the past and seek opportunities to extend, improve, and strengthen their work using palaeoecological data.

Sedimentary and geomorphic evidence of Saharan megalakes: A synthesis

It has long been recognised that the Sahara Desert contains sediment, landform and palaeoecological evidence for phases of increased humidity during the Quaternary period. Many authors have also suggested that during some of these humid periods very large lakes, termed megalakes, developed in several basins within the Sahara. Recent work has questioned their existence. In particular it has been argued that the lack of well-developed and spatially extensive shorelines in these basins suggests that discrete groundwater and spring deposits have been misinterpreted as evidence for megalakes. In this paper we re-evaluate the evidence used to identify megalakes. Firstly, we apply a comprehensive remote sensing and GIS analyses to the megalake shorelines, their catchments and the wider Sahara. This not only supports the previously proposed existence of numerous megalakes, but also indicates a previously unrecognised megalake in the Niger Inland Delta region, here named Megalake Timbuktu. Secondly, we review the geomorphic and sedimentary evidence for the megalakes, highlighting the importance of the sedimentary record in identifying lake highstands, particularly through the example of the Chotts Megalake in southern Tunisia where we provide new sedimentary information on lake shorelines. This analysis demonstrates that in much of the Sahara the dynamic aeolian systems preclude the preservation of well-developed shorelines, but the distribution of fragmented geomorphic features and localised lake deposits provide robust evidence for Quaternary megalake formation. The paper concludes by highlighting that although extensive evidence for Saharan megalake formation exists, the current chronology of lake highstands indicates that the vast majority date to Marine Isotope Stage (MIS) 5 or earlier. Only megalakes Chad and Timbuktu, which derive much of their water from outside the desert, show evidence for Holocene (African Humid Period or AHP) shorelines. The AHP record of the other megalakes indicate the existence of much smaller water bodies than those that developed earlier in the Pleistocene indicating that it was significantly drier than these earlier humid phases.

Vegetation history of SE Sicily from feudal land management to post-war agricultural industrialization

A new marine pollen record from SE Sicily is presented. The pollen study was done at a sub-decadal resolution to assess the role and extent of human impact in driving regional environmental and land cover changes over the last four hundred years. The combination of palaeoecological evidence and historical documents provides a detailed report of the main ecological dynamics in relation to socio-economic events, past land use, and land management regulations in Sicily. Our palaeovegetational reconstruction reveals a remarkably stable landscape, preserved by traditional land use practices that have persisted through the long-lasting feudal history of Sicily. After centuries of human-induced environmental stability, an abrupt change in vegetation structure occurred around 1950 AD, reflecting the modern land use policies and agricultural reforms following the Second World War. This vegetational breakpoint in SE Sicily corresponds to a suggested date for the onset of the Anthropocene.

Constraining the chronology and ecology of Late Acheulean and Middle Palaeolithic occupations at the margins of the monsoon

South Asia hosts the world’s youngest Acheulean sites, with dated records typically restricted to sub-humid landscapes. The Thar Desert marks a major adaptive boundary between monsoonal Asia to the east and the Saharo-Arabian desert belt to the west, making it a key threshold to examine patterns of hominin ecological adaptation and its impacts on patterns of behaviour, demography and dispersal. Here, we investigate Palaeolithic occupations at the western margin of the South Asian monsoon at Singi Talav, undertaking new chronometric, sedimentological and palaeoecological studies of Acheulean and Middle Palaeolithic occupation horizons. We constrain occupations of the site between 248 and 65 thousand years ago. This presents the first direct palaeoecological evidence for landscapes occupied by South Asian Acheulean-producing populations, most notably in the main occupation horizon dating to 177 thousand years ago. Our results illustrate the potential role of the Thar Desert as an ecological, and demographic, frontier to Palaeolithic populations.