Search

The authors have requested that this preprint be removed from Research Square.

Human activity has fundamentally altered wildfire on Earth, creating serious consequences for human health, global biodiversity, and climate change. However, it remains difficult to predict fire interactions with land use, management, and climate change, representing a serious knowledge gap and vulnerability. We used expert assessment to combine opinions about past and future fire regimes from 98 wildfire researchers. We asked for quantitative and qualitative assessments of the frequency, type, and implications of fire regime change from the beginning of the Holocene through the year 2300. Respondents indicated that direct human activity was already influencing wildfires locally since at least ~12,000 years BP, though natural climate variability remained the dominant driver of fire regime until around 5000 years BP. Responses showed a ten-fold increase in the rate of wildfire regime change during the last 250 years compared with the rest of the Holocene, corresponding first with the intensification and extensification of land use and later with anthropogenic climate change. Looking to the future, fire regimes were predicted to intensify, with increases in fire frequency, severity, and/or size in all biomes except grassland ecosystems. Fire regime showed quite different climate sensitivities across biomes, but the likelihood of fire regime change increased with higher greenhouse gas emission scenarios for all biomes. Biodiversity, carbon storage, and other ecosystem services were predicted to decrease for most biomes under higher emission scenarios. We present recommendations for adaptation and mitigation under emerging fire regimes, concluding that management options are seriously constrained under higher emission scenarios.Competing Interest StatementThe authors have declared no competing interest. Introduction Methods and materials Results and discussion Timing and type of future fire regime change Consequences of fire regime change Our capacity to prevent, control, or adapt to future fire regimes Charting a course in a world of uncertainty Expert assessment application in fire management

The North-east Australian Coastal Catchments (NACC) are host to nationally significant wetland complexes, many of which, are ecologically connected to the Great Barrier Reef World Heritage area. However, these wetlands are subject to ongoing and increasing pressure from human activities such as the intensification of land use. Current wetland condition is monitored across the NACC, being assessed against a pre-development static baseline, which includes the use of Regional Ecosystem mapping of remnant and pre-clearing vegetation to provide a broadscale present-day biotic reference. Two sediment cores from wetlands within the Fitzroy Basin were analysed to establish a history of wetland variability and to identify the potential influence of climate and land-use changes over the past ~1000 years. Our results have provided long-term environmental reconstructions, showing wetland histories influenced by natural climate variability (El Niño–Southern Oscillation, the Little Ice Age), and environmental changes associated with European land-use intensification. This study is the first of its kind for wetlands located within the Fitzroy Basin.

We revisited a location to study previously individually marked Tagula Honeyeaters Microptilotis vicina in 2019, 3 years after the original 2016 study on Junet Island, Louisiade Archipelago, Papua New Guinea. Re-encountered Tagula Honeyeaters indicated sedentary behaviour across years and an average annual adult survival rate of ≥0.75. We made the first observations of building and laying at two nests, and recorded nesting habits in the species. Tagula Honeyeaters showed the general trend in the honeyeater family of only the female building the nest and incubating. Nests were similar to those previously observed and to those of related species. Clutch-size in both nests was two and laying was on consecutive days. Eggs were white to off-white, with a ring of liver-brown spots and markings around the larger end. Incubation began on the day that the second egg was laid and lasted 14 days in both nests. Males visited the nest area only after the eggs hatched. At one nest, the nestling period was suspected to be 12 days. These limited observations of the only endemic island representative in Microptilotis indicate that, like plumage characters, breeding parameters remain similar within the genus.

This study presents three records of environmental change during the late-Holocene from wetlands across Bentinck Island in the South Wellesley Islands, northern Australia. Radiometric dating provided ages for sediment cores with the longest chronology spanning the last 1250 cal. yr BP. Palynological results show the diverse mangrove community transitioned to woodland- and wetland-dominated vegetation over the last 850 years on the southeast coast. The key driver of this landscape change was likely late-Holocene sea level regression and coastal progradation in the Gulf of Carpentaria. This study found freshwater wetlands expanded across Bentick Island over the last 500 years, with sedges and rushes peaking in the last 350 years. Macroscopic and microscopic charcoal records, coupled with archaeological evidence, highlights the spatial and temporal variation in fire regimes across the island, reflecting the traditional fire management practices of the Kaiadilt people during the late-Holocene. This study finds a significant increase in charcoal accumulation in the 1900s when Kaiadilt fire practices were disrupted and the South Wellesley Islands were abandoned. The pollen record reflects little change in the vegetation despite the shifting fire regime, highlighting the importance of multi-proxy approaches to reconstructing past environments in tropical northern Australia where vegetation is adapted to fire.

Explanations for the Upper Pleistocene extinction of megafauna from Sahul (Australia and New Guinea) remain unresolved. Extinction hypotheses have advanced climate or human-driven scenarios, in spite of over three quarters of Sahul lacking reliable biogeographic or chronologic data. Here we present new megafauna from north-eastern Australia that suffered extinction sometime after 40,100 (±1700) years ago. Megafauna fossils preserved alongside leaves, seeds, pollen and insects, indicate a sclerophyllous forest with heathy understorey that was home to aquatic and terrestrial carnivorous reptiles and megaherbivores, including the world’s largest kangaroo. Megafauna species diversity is greater compared to southern sites of similar age, which is contrary to expectations if extinctions followed proposed migration routes for people across Sahul. Our results do not support rapid or synchronous human-mediated continental-wide extinction, or the proposed timing of peak extinction events. Instead, megafauna extinctions coincide with regionally staggered spatio-temporal deterioration in hydroclimate coupled with sustained environmental change., The causes of the Upper Pleistocene megafauna extinction in Australia and New Guinea are debated, but fossil data are lacking for much of this region. Here, Hocknull and colleagues report a new, diverse megafauna assemblage from north-eastern Australia that persisted until ~40,000 years ago.

Lehrer and Woolfolk are major figures who have led the field of stress management for four decades. Here they have assembled a gifted team of expert authors, ranging from Jonathan Smith on relaxation to Alice Meuret and Thomas Ritz on capnometric training to Shirley Telles and colleagues on yoga for stress management. The text Principles and Practice of Stress Management has long provided the most comprehensive scientifically informed resource for understanding stress and stress management. The fourth edition updates the scientific research, introduces new topics, and sharpens the focus in many chapters. Nevertheless, the preface of the fourth edition emphasizes the continued relevance of this book for the lay audience, human beings seeking guidance for managing their life stress.

Mwanganda's Village (MGD) and Bruce (BRU) are two open-air site complexes in northern Malawi with deposits dating to between 15 and 58 thousand years ago (ka) and containing Middle Stone Age (MSA) lithic assemblages. The sites have been known since 1966 and 1965, respectively, but lacked chronometric and site formation data necessary for their interpretation. The area hosts a rich stone artifact record, eroding from and found within alluvial fan deposits exhibiting poor preservation of organic materials. Although this generally limits opportunities for site-based environmental reconstructions, MGD and BRU are located at the distal margins of the alluvial fan, where lacustrine lagoonal deposits were overprinted by a calcrete paleosol. This has created locally improved organic preservation and allowed us to obtain ecological data from pollen, phytoliths, and pedogenic carbonates, producing a regional-to site-scale environmental context for periods of site use and abandonment. Here, we integrate the ecological data into a detailed site formation history, based on field observations and micromorphology, supplemented by cathodoluminescence microscopy and mu-XRF. By comparing local, on-site environmental proxies with more regional indicators, we can better evaluate how MSA hunter-gatherers made decisions about the use of resources across the landscape. Our data indicate that while tree cover similar to modern miombo woodland and evergreen gallery forest prevailed at most times, MSA hunter-gatherers chose more locally open environments for activities that resulted in a lithic artifact record at multiple locations between 51 and 15 ka.(C) 2022 The Authors. Published by Elsevier Ltd. info:eu-repo/semantics/publishedVersion

We collected contemporary foraminiferal training sets from two salt marshes to enable more precise and accurate proxy historical sea-level reconstructions from southeastern Australia. Combined with an existing training set from Tasmania, this new regional set consists of 112 samples and 16 species of foraminifera, of which 13 are agglutinated. Cluster analyses group the regional training set into a high–elevation cluster, dominated by 'Trochamminita salsa', a mid–elevation cluster, dominated by 'Entzia macrescens' and 'Trochammina inflata', and a mid–low elevation cluster dominated by Miliammina fusca and tidal-flat species. We develop transfer functions using local and regional training sets and assess their performance. Our resulting site-specific and chosen regional models are capable of predicting sea level with decimetre-scale precision (95% confidence intervals of 0.12–0.22 m). These results are comparable to other examples from around the world. When developing regional training sets, we advocate that the similarity in the environmental settings (particularly salinity) should be assessed as an alternative way of grouping sites, rather than simply using spatial proximity. We compare our findings with global results and conclude that salt marshes along microtidal coasts yield models with the lowest vertical uncertainties. Studies with the lowest uncertainties are located in the western Pacific and the western Atlantic, whereas those from the eastern Atlantic generally have larger tidal ranges and carry larger vertical uncertainties. Our models expand the existing region available for sea-level reconstruction and can be used to generate new late Holocene sea-level reconstructions across southeastern Australia.

The African Middle Stone Age (MSA, typical range ~ 320–30 ka) has been the subject of intense research interest in recent decades as a culture-chronological Unit associated with the emergence and dispersal of our species. Recent results of this work have shown that sites designated as “MSA” contain common approaches to lithic reduction, but that within this rubric, there is much diversity in overall assemblage characteristics and the timing of their appearance across the continent. As researchers recover more data from more sites, especially from undersampled geographic regions, this more complex picture of the MSA reveals technological and other behavioral diversity in early modern human populations that may inform about the ultimate success of our species. Here we add to this growing database by describing the environmental context and characteristics of two concentrations of stone artifacts from the late MSA (~ 43–21 ka) open-air locality of Chaminade-I (CHA-I), near the town of Karonga in northern Malawi. The CHA-I lithic artifacts show a flexible approach to stone tool production and use that is common to assemblages in Karonga but distinctive from MSA sites reported elsewhere. Radial and minimally reduced cores typify an unelaborated lithic assemblage, in which raw material choice is driven by toolstone clast size and shape rather than preferential use or treatment of specific materials, as found in MSA assemblages in the East African Rift, South Africa, and the North African coast. Lithic reduction at CHA-I took place within a woody, riparian context embedded within a more open woodland landscape. Most artifacts occurred in near-channel sandy deposits dated to ~ 41 ka, and were buried under alluvial fan deposits that began aggrading by at least ~ 21 ka and continued beyond ~ 5.5 ka within a grassy, open landscape. The site’s late MSA age and lack of elaboration in lithic technology challenges straightforward ideas of increasing complexity in human technological behavior over time and provides important insight into the diversity of MSA technologies and the environmental conditions in which they existed.

Aim: To understand the long‐term drivers of biomass burning in the sclerophyll‐dominated forests of Australia. Location: Swallow Lagoon, North Stradbroke Island, Queensland, Australia. Time period: Last ca. 8 kyr. Major taxa studied: Eucalyptus sensu lato, Leptospermum and Casuarinaceae. Methods: High‐resolution pollen and charcoal analyses were undertaken on a ca. 8 kyr sediment record and compared with an independent quantitative precipitation reconstruction inferred from leaf carbon isotopes from the same site. We performed Principal Component Analysis to extract the main vegetation trends around Swallow Lagoon. We then compared vegetation changes to local charcoal records to understand the climate‐vegetation‐fire relationships under different rainfall regimes. The trends in pollen, charcoal and rainfall were analysed using Generalized Additive Models and wavelet coherence. Results: Relatively high Casuarinaceae pollen abundance and high charcoal influx were found prior to 3.4 ka, during a phase of high rainfall. Between 3.4 and 1.5 ka there was an increase in Leptospermum ‐type pollen abundance in concert with a decline in both rainfall and charcoal influx. After 1.5 ka low rainfall was generally maintained and a significant increase in Eucalyptus was detected, along with an increase in microscopic charcoal. Main conclusions: Our study, from a sclerophyll forest setting that is typical of ~30% of Australia's vegetation, provides a unique example of complex climate‐biomass‐fire feedbacks and highlights biomass limitation of fire activity. High rainfall at Swallow Lagoon is linked to dense Casuarinaceae‐dominated forests and high fire activity prior to 3.4 ka. Between 3.4 and 1.5 ka, a decline in rainfall leads to reduced biomass burning during a phase dominated by shrub communities. After 1.5 ka, a change in fuel type was related to a transition to an open eucalypt forest and greater microscopic charcoal influx.

Background: The 2019-20 Australian bushfire season was the most environmentally detrimental bushfire season on record. The extreme heat and drought exposed normally fire-resistant communities to uncharacteristically dry fuel loads and abnormally high severity burning. In eastern Australia this included mesic rainforest environments (including the World Heritage listed Gondwana Rainforests of Australia), which are often highly sensitive to fire, contain high biodiversity values, are critical habitat for threatened species, embody distinct endemism, provide valuable ecosystem services and are critical for terrestrial carbon storage. East coast rainforests are also highly fragmented, with less than half of pre-European levels remaining. Increases in fire frequency and intensity associated with climate change may threaten these already fragmented rainforest environments. This study considers the efficacy of rainforest refugia under a heightened bushfire climate, via spatial analysis of burn extent, burn severity and topographic characteristics for rainforests during the 2019-20 bushfire season within the Eastern Australian Temperate and Subtropical Forests Conservation Management Zone.Results: Burn severity, vegetation and elevation datasets were merged and analysed across mid-eastern Australia. A significant portion of rainforest was fire affected across the study area (~17%), with ~5% burnt to a high or very high severity. Elevation, topographic position (i.e. valleys), slope and aspect all contributed to maintaining rainforest fire refugia. The study resulted in a mapping product that can be utilised by researchers and protected area managers to locate and assess burnt rainforest in mid-eastern Australia.Conclusions: This study enables the identification of rainforest fire refugia and threatened rainforest communities for future research and conservation efforts in eastern Australia. The results also demonstrate the potential of climate change to enact widespread rainforest declines, with potentially dire consequences for biodiversity and ecosystem services. This event and recurrent fire events may enact positive climate feedback systems by enabling pyrophytic vegetation expansion and converting rainforest carbon pools into a carbon source.

Peatlands are impacted by climate and land-use changes, with feedback to warming by acting as either sources or sinks of carbon. Expert elicitation combined with literature review reveals key drivers of change that alter peatland carbon dynamics, with implications for improving models. The carbon balance of peatlands is predicted to shift from a sink to a source this century. However, peatland ecosystems are still omitted from the main Earth system models that are used for future climate change projections, and they are not considered in integrated assessment models that are used in impact and mitigation studies. By using evidence synthesized from the literature and an expert elicitation, we define and quantify the leading drivers of change that have impacted peatland carbon stocks during the Holocene and predict their effect during this century and in the far future. We also identify uncertainties and knowledge gaps in the scientific community and provide insight towards better integration of peatlands into modelling frameworks. Given the importance of the contribution by peatlands to the global carbon cycle, this study shows that peatland science is a critical research area and that we still have a long way to go to fully understand the peatland-carbon-climate nexus.

The El Niño-Southern Oscillation (ENSO) is a driver of global atmosphere-ocean dynamics, but projections of frequency and magnitude in different climate states remain uncertain. Palaeoclimate records offer the potential to improve our understanding of ENSO behaviour but most are fragmentary, suffer low resolution, and/or typically do not cover periods warmer than present day. The Last Interglacial (129-116 kyr BP) was the most recent period during which global temperatures were close to 21st century projections, and potentially provides insights into operation of climate modes of variability in the future. Here we report a continuous, inter-annually resolved record of hydroclimate spanning 220-80 ka from Lynch’s Crater in tropical northeast Australia, a region highly sensitive to ENSO. Our reconstruction is based on a micro-X-ray fluorescence (XRF)-generated elemental profile at 200 µm resolution, combined with loss-on-ignition, magnetic susceptibility, and pollen analysis. We find that during globally warmer periods (including super-interglacial Stage 5e, and 5c), there are significantly larger amplitudes in high-frequency ENSO spectral range (3-8 years), which are absent from the record during the glacial stages MIS6 and MIS4. Our results imply an ENSO dependence on mean climate, with enhanced ENSO variance during interglacials globally warmer than present. These results are consistent with climate model projections for a future slowdown of the Walker circulation and more extreme El Niño events under greenhouse warming.

The carbon sink potential of peatlands depends on the balance of carbon uptake by plants and microbial decomposition. The rates of both these processes will increase with warming but it remains unclear which will dominate the global peatland response. Here we examine the global relationship between peatland carbon accumulation rates during the last millennium and planetary-scale climate space. A positive relationship is found between carbon accumulation and cumulative photosynthetically active radiation during the growing season for mid- to high-latitude peatlands in both hemispheres. However, this relationship reverses at lower latitudes, suggesting that carbon accumulation is lower under the warmest climate regimes. Projections under Representative Concentration Pathway (RCP)2.6 and RCP8.5 scenarios indicate that the present-day global sink will increase slightly until around AD 2100 but decline thereafter. Peatlands will remain a carbon sink in the future, but their response to warming switches from a negative to a positive climate feedback (decreased carbon sink with warming) at the end of the twenty-first century.

At present, knowledge of late Quaternary variability of the Indonesian-Australian summer monsoon in the Australian tropics is limited. Organic spring deposits, which occur throughout the Kimberley region of northwest Australia, are valuable archives that contain records spanning the past ∼14,500 years. In this study we compare multiple proxies from three organic springs. Principal Components Analyses demonstrates similar patterns of change in the elemental and non-pollen palynomorph (NPP) datasets between the springs, implying regional drivers are responsible for changes in these proxies. By comparison, the pollen records differ between each of the springs, with the assemblage at each thought to be influenced by spring recharge and evolution rather than climate variability. In order to empirically and objectively assess the synchronicity of changes, we applied Monte Carlo empirical orthogonal function (MCEOF) analysis to one variable in each μXRF and NPP dataset (Si/Ti ratios and Pseudoschizaea accumulation rates, as these proxies are expected to reflect hydrological conditions in springs) to assess regional patterns of change in site moisture. This analysis revealed periods of increased monsoonal precipitation from ∼14,500–7500 cal. yr BP corresponding with deglacial sea level rise, high orbital tilt coupled with warmer sea surface temperatures, and with possible links to a southward migration of the Inter Tropical Convergence Zone (ITCZ) during the Younger Dryas. Monsoonal precipitation was reduced from 7500 cal. yr BP coinciding with the culmination of deglacial sea level rise and a possible northward shift in the mean position of the ITCZ, in addition to between 2600 and 1000 cal. yr BP corresponding with increased moderate-to-strong ENSO events.

A revised Holocene sea-level history for the southern Gulf of Carpentaria is presented based on new data from the South Wellesley Archipelago and age recalibration of previous research. Results confirm that rising sea levels during the most recent post-glacial marine transgression breached the Arafura Sill ca. 11,700 cal. yr BP. Sea levels continued to rise to ca. –30 m by 10,000 cal. yr BP, leading to full marine conditions. By 7700 cal. yr BP, sea-level reached present mean sea-level (PMSL) and continued to rise to an elevation of between 1.5 m and 2 m above PMSL. Sea level remained ca. + 1.5 between 7000 and 4000 cal. yr BP, followed by rapid regression to within ± 0.5 m of PMSL by ca. 3500 cal. yr BP. When placed into a wider regional context results from this study show that coastal landscape evolution in the tropical north of Australia was not only dependent on sea-level change but also show a direct correlation with Holocene climate variability. Specifically, the formation and preservation of beach-rock deposits, intertidal successions, beach and chenier ridge systems hold valuable sea-level and Holocene climate proxies that can contribute to the growing research into lower latitude Holocene sea-level and climate histories.

Organic spring deposits have the potential to provide to outstanding records of palaeoenvironmental and climatic change, particularly in arid and semi-arid environments where establishing robust records of environmental change is challenging due to a lack of classic sedimentary records, e.g. perennial lakes and extensive wetlands. However, despite the potential of organic spring deposits a number of studies demonstrate complications in the application of standard 14C techniques which has, in several cases, led to confusing chronologies. This implies that dynamic carbon pathways commonly occur within spring systems. Because of the importance of springs as critical palaeoenvironmental archives, this study sought to better understand the behaviour of 14C and other radionuclides used in geochronology within organic springs, and ultimately, establish a protocol for building reliable chronologies in these environments. To do this, we utilised multiple geochronological methodologies to investigate cores collected from three springs in the Kimberley region of northwest Australia. This included 14C dating of different carbon fractions, 210Pb dating, the application of 239+240Pu, and novel, high spatial resolution, luminescence techniques as indicators of geochronological structure. The natural sensitivity-corrected luminescence (Ln/Tn) signal indicated the studied springs contained a relatively complete stratigraphic record, however 14C results were found to be convoluted by contamination attributed to a combination of roots, groundwater fluctuations and allochthonous input of “old” carbon affecting ages. Whilst it was found that no single carbon fraction is universally reliable in dynamic spring environments, dating the stable polycyclic aromatic carbon (SPAC), isolated by hydrogen pyrolysis (HyPy) pre-treatment, appeared to remove the effects of post-depositional modification which otherwise perturbed the age of carbon fractions with respect to sedimentary development of the spring. By contrast, the ability of 210Pb and 239+240Pu to provide detailed chronologies for recent spring sediments (i.e. the past 100 years) was found to be complicated due to the behaviour of springs as an open system with regards to uranium. Therefore, it may not be possible to construct 210Pb chronologies in many spring environments. Overall, the results of this study indicate that it is possible to construct 14C based chronologies in spring systems, however it is necessary to understand the effects of physical and biological processes within springs on 14C pathways. In particular, the application of HyPy pre-treatment of SPAC appears to offer a viable approach to constructing chronologies in these environments. Furthermore, although this study pertains to springs, the sources of geochronological complexity described here are not exclusive to these systems and our results are therefore more widely applicable.

Background: There is growing evidence supporting the many benefits of interprofessional education (IPE) amongst students of varying medical professions. Since anatomy education is necessary for all healthcare pro-viders, an anatomy laboratory can provide an excellent environment for IPE activities. Unfortunately, due to the high cost of maintaining an anatomy laboratory, many programs do not have access to learn in a cadaver-based environment. The purpose of this study was to examine the outcomes of an interprofessional teaching and learning opportunity between doctorate of physical therapy (DPT) students and certified registered nurse anesthetist (CRNA) students during a cadaver-based anatomy review course. Methods: A group of DPT students taught different sections of clinically relevant anatomy to the CRNA students under the direction and provision of faculty from both programs. At the completion of the course, students from both disciplines were given an anonymous survey to complete regarding their overall experience in a cadaver-based setting as well as their thoughts regarding the interprofessional teaching/learning opportunity with students in another healthcare discipline. Results: Of the 11 DPT students and 60 CRNA students who completed a survey, 82.0% of the DPT students and 86.0% of the CRNA students felt they better understood another healthcare profession after the experience and that IPE is beneficial for other healthcare professions. One hundred percent of the CRNA students found it beneficial to have a cadaver-based anatomy course and felt the course enhanced their three-dimensional understanding of human anatomy, which they believed would be beneficial in future anesthesia procedures. In addition, 100% of the DPT students agreed that teaching the cadaver-based anatomy course helped with their own retention of human anatomy, and 82.0% felt that by teaching the course, it helped improve their communication skills with other healthcare providers. Conclusions: The results suggest that exposure to anatomy through cadaver-based learning for CRNA students may be valuable to their clinical understanding of anatomy. Additionally, the results support the benefits of IPE to include: learned respect of fellow colleagues, exposure to another profession’s expertise, decreased barriers to communication and a new understanding of how two varying professions can work together clinically.

The Indo-Australian Summer Monsoon (IASM) is the dominant climate feature of northern Australia, affecting rainfall/runoff patterns over a large portion of the continent and exerting a major control on the ecosystems of Australia's Top End, including the viability of wetland ecosystems and the structure of the woody savanna. We examined the behaviour the IASM from 35 kyr using proxy data preserved in the sediments of Table Top Swamp, a small seasonal swamp in northern Australia. Elemental data, stable C and N isotopes, pollen and sedimentary data were combined to develop a picture of monsoon activity and landscape and ecosystem response. Results demonstrated that between 35 and 25 ka conditions were drier and more stable than present, with a more grass dominated savanna and limited wetland development, implying reduced IASM activity. After ~25 ka, there is evidence of increased moisture at the study site, but also increased IASM variability. However, despite evidence of at least periodic increases in moisture, including periods of wetland establishment, the IASM displayed a subdued response to peak precession insolation forcing by comparison to the other global monsoon systems. Instead, the greatest change occurred from ~10 ka when the continental shelf flooded, increasing moisture advection to the study site and resulting in establishment of a quasi-permeant wetland. Whereas the early Holocene was marked by both the onset of pollen preservation and a wetter vegetation mosaic, indicative of a consistently active IASM, the mid-late Holocene was marked by drier vegetation, increased fire, but also increased C3 vegetation and runoff, implying increased IASM variability. Holocene changes in ecosystem dynamics occur coincident with an expansion in human population, which likely also influenced vegetation and landscape response at the study site.

Archaeological survey, excavations, and analyses of the Murdumurdu shell midden on Bentinck Island, Gulf of Carpentaria are reported. Patterns of subsistence as well as the timing and periodicity of site use are investigated through quantification of cultural materials, AMS radiocarbon dating, stable isotopic analysis of Marcia hiantina shell carbonates (δ18O and δ13C), magnetic susceptibility analysis of the deposits and palaeoenvironmental reconstruction. Exploitation of shellfish focused on sandy-mud flat species (especially M. hiantina and Gafrarium pectinatum) with occupation occurring exclusively during the dry season (May-August). Radiocarbon dating reveals that the main period of occupation was short, albeit intense and occurred c.300 years ago. Initiation of occupation closely follows the establishment of freshwater conditions in the adjacent Marralda Swamp. These factors suggest that use of Murdumurdu was limited, potentially representing a single deposition event or multiple short, discrete episodes, in a landscape rich with similar archaeological deposits.

Understanding of the late Quaternary environment of Australia's vast Kimberley region has to date been hindered by the region's lack of classic palaeoenvironmental archives such as deep lake sediments. However, mound spring peat deposits in the region have been found to be a potentially rich archive of palaeoenvironmental data. Here we present a high resolution record from Black Springs mound spring in the Kimberley's northwest, filling some of the current gaps in knowledge of the region's environmental history. This builds on a ∼6000 year record developed from the same site and indicates that since the Last Glacial-Interglacial Transition the Australian summer monsoon has varied greatly in intensity, with an increase in monsoonal precipitation from ∼14,000 yr BP and pronounced drying in the late Holocene. Despite some chronological uncertainties thought to be due to the inclusion of younger, microscopic root fragments, changes in the record compare well with other records of climatic change from the Kimberley, and across tropical northern Australia.

Few Australian wetlands have persisted since the Last Glacial Maximum, with fewer still in existence through the entire last glacial cycle. The absence of wetlands, which itself indicates periods of moisture deficit, means there are few continuous climate and environmental change records covering this critical period. The lack of wetland persistence also raises the question of how plant and animal species that require permanent wetlands survived the last glacial cycle. Sixteen wetlands have been cored and dated on North Stradbroke Island (Minjerribah) – a large east Australian sand island – with basal dates reported from 10 sites for the first time. These wetlands range in age to over 200 000 years old, with six dating to the Last Glacial Maximum or earlier. There is no evidence of a stratigraphic discontinuity in the radiocarbon-based age–depth profiles, suggesting continuous deposition of highly organic sediment through the period covered by these ages (c. 40 ka). The persistence of these wetlands suggests that for much of the last 40 000 years, and for perhaps much longer, the regional moisture balance has been positive. Over the last glacial cycle, persistently wet conditions may have provided a refuge from regional drying, and thus contributed to the high genetic diversity of rainforest plants in the region. Vegetation and climate records from these sites will allow hypothesis testing about the drivers of both local and regional climate variability. Copyright © 2017 John Wiley & Sons, Ltd.

Palynomorphs from the ODP Site 820 marine core have provided a detailed record of terrestrial environmental responses to glacial–interglacial forcing over the last 250 000 years in the Australian Wet Tropics. The development of an accurate geochronological framework for this key sequence has proved challenging. Consequently, different dominant forcing mechanism(s) have been proposed to drive environmental change in the low latitudes. A new chronology for the last 60 000 years, based on accelerator mass spectrometry radiocarbon (C) dates of pollen concentrate material and the existing Marine Isotope Stage boundaries (MIS 4 to 1) has been produced. This new chronology provides a robust geochronological framework for interpreting environmental records across the region. In particular, our age model helps to resolve several debates concerning the timing of climatic changes and their impacts on both the marine and the terrestrial systems, as well as possible human arrival and associated impacts on the region's ecosystems. Our findings suggest C dating of terrestrial pollen concentrate in marine sediments is a valuable tool for resolving major chronological uncertainties in potentially diagenetically altered marine CaCO sediments and should play a role in future multi-dating strategies. Copyright

There are few continuous Australian palaeoclimate records that extend beyond the Last Glacial Maximum (LGM), meaning that knowledge of regional climates before, during and after this period is limited. Understanding late-Pleistocene climates of the subtropics is important because of the fundamental role the region plays in the large-scale, global transfer of energy from low latitudes. Palaeoclimate studies of subtropical regions can help define the extent of warming/cooling during the large global climatic events which characterise the late-Pleistocene. Here we report the results from a multi-proxy analysis of a sediment record from Welsby Lagoon on North Stradbroke Island, in the eastern Australian subtropics, spanning the past ca. 25,000 years. Stable C and N isotope analysis and high resolution contiguous records of macrocharcoal deposition and sediment organic content are interpreted in conjunction with a previously published pollen record. Sediment organic content displayed a very strong correlation with total organic carbon (TOC) content as determined through elemental analysis and, given the peaty nature of the sediment, is interpreted as indicative of moisture balance. The proxies reflect wet subtropical climates in the lead up to the LGM which led to an expansion of the wetland. This was followed by a cool, dry and windy LGM (ca. 22.3–19.7'000 years before present; kyr BP), which was punctuated by a brief wet phase ca. 21.7–20.4 kyr BP. A salient feature of the deglacial period is a rapid increase in TOC around 15 kyr BP, coincident with the Antarctic Cold Reversal and Bolling-Allerod warm phase. Increased fire frequency is evident in the Holocene, which is characterised by otherwise stable climate and vegetation. This study supports the notion of variable climates during the LGM and finds an onset of deglacial warming in the Australian subtropics that predates the Holocene.

This paper presents the results of a palynological investigation into the late Last Glacial Maximum (LGM) and last deglaciation (ca. 20 000–9000 cal a BP) from Little Llangothlin Lagoon, in the sub-tropics of eastern Australia. The Lagoon held permanent water during the late LGM and early deglaciation but was intermittently dry during the late deglaciation. During the late LGM, local vegetation was dominated by a sub-alpine herbfield but the significant presence of rainforest taxa in the pollen record indicates the survival of rainforest, rainforest margin or wet sclerophyll communities close to the site. By ca. 17 000 cal a BP, open Eucalyptus forest replaced the alpine herbfield vegetation indicating that warming had commenced. Rainforest taxa disappeared at this time but re-appeared at the end of the deglaciation. The LGM conditions are consistent with a dominant circulation system whereby persistent high pressure over eastern Australia brings onshore easterlies to this region and maintains humid conditions along the east coast and highlands of the Great Dividing Range. This is similar to modern winter circulation but the persistence of rainforest and wet sclerophyll taxa suggests an increase in easterly flow over modern conditions during the LGM.

The loss and degradation of wetlands in the Mekong Delta has been caused by a combination of human activities (social systems) and natural events (ecological systems). However, the complexity and interaction of these socio-ecological factors are poorly understood. This study provides a better understanding of the complex social-ecological factors affecting land-cover change in the Phu My Lepironia grassland conservation area, part of Kien Giang Biosphere Reserve, Vietnam. A systems thinking approach was used to determine the interaction between the social system and land-use and land-cover changes. Results indicate that ensuring food supply and improving income are the key endogenous drivers of wetland degradation in the study area. Over-exploitation of wetland resources and inappropriate agricultural practices are accelerating wetland conversion and degradation. The conflict and unclear land tenure, coupled with a desire for higher income, has driven the community to convert and reclaim large parts of the wetland. This process is also driven exogenously by wetland access and the fluctuation of commodity prices, which in-turn results in transition from traditional to extensive cropping systems and expansion of cultivated land into the protected wetland. The relationship between people and wetlands must be central to the development of wetland policies and wetland management approaches. This will improve how land use policy supports sustainable sources of food and income for the local community and concurrently reduce pressures on wetland degradation. Any efforts made to protect the remnant wetland grassland and its diverse ecosystem by regulation should be supplemented by developing and sustaining the relationship between social systems and ecological systems.

A late Quaternary pollen and charcoal record from Hazards Lagoon on the east coast of Tasmania provides a continuous record of vegetation and climate change. The pollen record shows an Epacridaceae and Poaceae dominated grassland community replaced dry sclerophyll forest during the Last Glacial Maximum (LGM ∼22–18 cal ka BP). Eucalyptus and Casuarinaceae increased from the beginning of the deglacial period (∼18–12 cal ka BP) indicating early warming on the east coast of Tasmania. Abundant Myriophyllum and sedimentary characteristics indicate Hazards Lagoon was a permanent source of water throughout the LGM and until 16 cal ka BP suggesting either increased precipitation and/or decreased evaporation rates. A positive moisture balance throughout the LGM contrasts with records from the west coast of Tasmania and parts of mainland Australia. Fire was suppressed at the site until 14 cal ka BP, corresponding with reduced woody vegetation and a positive moisture balance. Dry sclerophyll forest established during the deglacial period, remaining stable throughout the Holocene. A coastal vegetation community developed in response to sea-level rise, characterised by abundant Eucalyptus pollen and increasing values of Casuarinaceae. By the mid-Holocene, the Hazards Lagoon pollen record is typical of a Tasmanian coastal site dominated by Casuarinaceae. This research highlights the need for spatially diverse studies throughout the Southern Hemisphere to identify drivers of environmental change during the late Quaternary.

A continuous, record encompassing the termination of the Last Glacial cycle (defined here as ca. 30–18 cal. kyr BP) has been developed using multiple proxies (viz. clastic sediment flux, grain size, moisture content, pollen and charcoal) archived in lake sediments from Tortoise Lagoon, North Stradbroke Island, Australia. The record indicates an extended Last Glacial Maximum, with an onset at ca. 30 kyr BP. The presence of rainforest and arboreal taxa for the 30–18 kyr BP period indicate a positive moisture balance, while the presence of the now regionally extinct Asteraceae (Tubuliflorae) and Tubulifloridites pleistocenicus indicate relatively cool temperatures. Total clastic sediment flux and the vegetation assemblage suggest that, at least in subtropical Australia, the Last Glacial Maximum was characterized by two peaks in aridity at ca. 29–26 kyr BP and 24.5–20 kyr BP.

This study presents a marine palynological record of the Asian summer monsoon and sea level change in the Last Glacial Maximum (LGM) and the deglacial period in the northern South China Sea (SCS). A fossil core STD 235 (855 cm in length) and 273 surface sediment samples from the northern SCS were pollen analysed to reconstruct the paleoenvironment of the continental shelf during the last glacial period. Results from fossil pollen show that the main pollen source region fundamentally changed from the LGM to the deglacial period as sea level rapidly rose. The modern marine surface samples show that pollen concentrations in the estuary of the Pearl River are extremely high, and modern pollen assemblages are in good agreement with the regional vegetation. However, wind transport becomes more important in the deeper ocean as the percentages of Pinus, a taxon with very high pollen production and dispersal capacity, is highest in these sediments, which otherwise have very low pollen concentrations. The concentration of total pollen between surface and fossil pollen samples is compared in order to determine the possible vegetation sources areas for the marine core. Pollen concentration as high as >100 grains/g at the LGM suggested that the paleo-shoreline was located within 80 km of the core. Consequently, pollen would mostly have derived from the exposed continental shelf in the northern SCS. By contrast, pollen concentrations were very low due to a much greater transport distance (318 km at present, core STD 235) under higher sea levels, and windblown pollen played a more important role because of the limitation of riverine input into the deep ocean during this highstand period. Such alternation of pollen flux and source distance should be repeated during all glacial-interglacial cycles, reflecting closely sea level and climate dynamics. According to fossil pollen assemblages from Core STD 235, we conclude that wetland and/or grassland communities with sparse subtropical trees dominated most of the exposed shelf during the LGM rather than forest that characterizes the region today. The existence of a predominantly open landscape on the exposed continental shelf suggests lower precipitation during the LGM, which in turn indicates a weaker Asian summer monsoon. This finding is supported by other records from the Okinawa Trough and the East China Sea, suggesting that a weaker summer monsoon was a key characteristic of the LGM in East Asia.

In the version of this Analysis originally published, the following affiliation for A. Lohila was missing: ‘Finnish Meteorological Institute, Climate System Research, Helsinki, Finland’. This affiliation has now been added, and subsequent affiliations renumbered accordingly, in the online versions of the Analysis.

Acid-free palynological processing was performed on Permian material from a borehole of the southern Galilee Basin, eastern Australia, to test the efficacy compared to standard processing techniques. Both techniques yielded well-preserved assemblages of terrestrial and aquatic palynomorphs. The proportion of phytoclasts was much higher than in samples that underwent standard acid processing, while spores and pollen grains occur in lower abundances. A slightly higher species count was gained from samples with acid-free treatment but biostratigraphical index taxa were present in both sets of samples and, in general, the assemblages appeared to be quantitatively comparable. To improve the efficacy for future application, in particular more accurate statistical analyses with higher counts, absolute abundance calculations using a Lycopodium spike and refinement of the acid-free technique using hydrogen peroxide treatments, multiple density separation steps or sonication during sieving are suggested to remove phytoclasts. Further work is required to determine if the higher abundances of phytoplankton are influenced by the processing technique or if they better reflect a true proportion within a given sample.

This study investigates the palynological remains (both fossil pollen and charcoal) recovered from the Thundiy shell midden deposit, Bentinck Island, Gulf of Carpentaria, northern Australia, to provide a vegetation and fire record for this site, which sheds light on human occupation of the southern Wellesley Archipelago over the late Holocene. Results show that the development of a high-density shell deposit by human activities was directly responsible for pollen preservation, possibly through the creation of a moist, anaerobic environment that reduces oxidation of pollen grains. The presence of recoverable pollen from a shell midden deposit from Bentinck Island provides a valuable new proxy to provide greater context for archaeological records, particularly in terms of local vegetation information and potential insight into human land management practices.