In fire-prone regions globally, evolution of plant traits that confer resilience to historical fire regimes is widespread. However, many common plant species are currently declining due to a mismatch between historical and contemporary fire regimes. These changes threaten long term community trajectories of plants and the animal species relying on them for food or habitat. Understanding plant responses to fire at critical life stages is needed to improve conservation of plant-animal interactions. We investigated how fire history affected reproductive traits (i.e., proportion germination, time to 50% germination, reproductive output, population age structure) relevant to critical life history stages of Allocasuarina littoralis and A. torulosa (Casuarinaceae). In southeast Queensland, Australia, these species are primary food trees of the nationally vulnerable Glossy black-cockatoo (Calyptorhynchus lathami, Cacatuidae). For both species, fire-cues (heat and smoke) did not increase the proportion of seed germinated, but proportion germination increased with seed weight. Heavier seeds were associated with exposure to more extreme environments such as environments with higher fire frequencies and temperature variability. In A. torulosa, seed weight generally increased germination time, except when seeds were collected from frequently burned sites which could be linked to a trade-off between resprouting and seed production. Heat and smoke slowed germination of A. torulosa (recorded as time to 50% germination) but had no effect on A. littoralis. Fire history did not influence reproductive output or population age structure in either species, but reproductive output was greater in sites with more woody vegetation cover, potentially reflecting greater establishment success. For restoration, our results indicate that fire is not necessary for successful germination in A. littoralis or A. torulosa, but when collecting seeds the local fire history and seed weight should be considered, especially for A. torulosa. Our results can inform Glossy black-cockatoo conservation by guiding fire management practices associated with their food trees.

The past similar to 50,000 years encompass a series of major climatic transitions, including Marine Isotope Stage 2, the Marine Isotope Stage 2/1 transition, and the onset of the Holocene, when the Earth underwent large shifts in temperature, ice volumes, sea levels and atmospheric circulation patterns. There is a growing body of research focused on the behaviour of the Indo-Australian Summer Monsoon (IASM) during these periods from sites close to Australia's northern coastlines and currently within the zone of direct monsoon precipitation. However, the relative contributions of latitudinal shifts and/or moisture carrying capacity of the monsoon system on changes in hydroclimate remain uncertain. Here, we present the results from a 46,000-year sediment record obtained at the modern southern extent of rainfall penetration into north-west Australia associated with the IASM. Our results show that the region experienced reduced precipitation until the end of the glacial. During the MIS 2/1 transition and the early Holocene, there is evidence of an increase in wet-season precipitation, likely limited to extreme events occasionally reaching the site. More pronounced and sustained shifts in precipitation were limited to the late Holocene, during which the variability recorded at the site aligned with that interpreted from records further to the north in Australia. We interpret this as reflecting a time-transgressive southward shift in the southern limit of the monsoon system.

Phytoliths are a valuable tool for reconstructing localized past vegetation, particularly in Restionaceae rich peatlands of subtropical Australia. Despite the significance of subtropical Australia for understanding vegetation-climate dynamics during the Last Glacial Maximum (LGM), no continuous phytolith records have previously been reported from subtropical eastern Australia. Jumping Grass Marsh, located on Minjerribah (North Stradbroke Island), preserves a 2.5 m organic-rich sequence extending from 27 ka BP to the present. This study reconstructs long-term vegetation dynamics using the phytolith record and evaluates how wetland taxa, grasses, and fire responded to past environmental changes in the subtropics. Phytoliths were extracted at 10 cm intervals, with 22 morphotypes identified and classified following ICPN 2.0 standards. A modern reference collection from wetland plants and soils supported taxonomic attribution, while complementary evidence from microcharcoal, sediment organic matter, and particle-size analysis refined palaeoenvironmental interpretation. The phytolith record demonstrates long-term persistence of restiad wetlands from the early glacial period (> 22 ka) to the present, with Restionaceae morphotypes dominating throughout. Grass abundance increased during the Last Glacial Maximum and reached its peak in the deglacial phase (similar to 15.7 ka). Enhanced moisture availability in the Holocene (similar to 12-0 ka) supported the expansion of Cyperaceae-specific morphotypes. Microcharcoal and discolored phytoliths suggest fire episodes around similar to 14.4 ka and similar to 3.3 ka. Diatom evidence (Pinnularia sp.) indicates acidic wetland conditions in the early Holocene. Modern soils show increased Panicoideae morphotypes, reflecting natural inputs and introduced grasses. Phytoliths robustly reflect vegetation history and enhance multi-proxy reconstructions of subtropical wetlands.

The Kimberley region of north-west Australia offers a valuable lens to examine the variability of multiple regional climate systems within the context of human migration and settlement of the Sahul and now Australian continent. Despite its importance, reconstruction of past hydroclimate in the Kimberley has been challenged by its semi-arid environment, which limits archive preservation, and by its remoteness. In recent years, however, a growing body of work has demonstrated the potential of a diverse range of atypical archives for reconstructing Kimberley hydroclimate. Here we present the current state of understanding of the hydroclimate of the Kimberley, drawing on environmental reconstructions spanning the last 65,000 years. Our synopsis is that the Kimberley experienced a drier climate during the last glacial compared with the Holocene, although there remains much discrepancy between records, particularly those from early Marine Isotope Stage 3, when precipitation levels higher than present are indicated by some records. Records suggest that either dry conditions or high variability marked the MIS 2/1 transition before a wet early Holocene, leading into increased hydroclimate variability in the mid-late Holocene. There remains a sparsity of records for this vast region. The obtainment of long, high temporal resolution records is required to resolve discrepancies between existing records, and to shed light on possible causes of local scale palaeoclimate variability and extremes.

Tropical peatland wildfire incidence has risen in recent decades, driven by drainage for land use and intensified by severe droughts with global climate change. These disturbances have altered vegetation structure, disrupted ecosystem functioning, and increased carbon emissions, particularly in Southeast Asia. However, the long-term history and characteristics of wildfires in tropical peatlands remain largely unknown. Here, we compiled fifty-eight macro-charcoal records from peatlands across the tropics, ranging from lowland forested to montane peatlands, to assess millennia-scale changes and controlling factors of tropical peatland burning. We divided the datasets into four main sub-regions: Neotropical, Afrotropical, Indomalayan and Australasian ecoregions to explore regional variability. Tropical peatlands had high burning levels between 0 and 850 ce, followed by a relatively low and stable period until a marked increase during the 20th century. The general trend in tropical peatland burning follows changes in global temperature, and climate variables that control the length and severity of drought events have a notable influence on peat burning before 1900 ce. During the 20th century, regional differences were observed, with declining fire trends in the Neotropical and Afrotropical regions and increasing fire trends in the Indomalayan and Australasian regions. This difference is likely attributable to human activities, and such intervention is also evident in palm swamps and hardwood swamps under similar wet, weakly seasonal climates. With the increase in anthropogenic pressures on peatlands and greater climate variability, future wildfires in peatlands are likely to become more frequent and widespread across all tropical ecoregions. Conservation and sustainable land-use practices could be used to mitigate and control peatland burning and protect these carbon-rich sinks.

The last glacial cycle is a key period in the environmental and cultural history of the Australian continent, yet the climate of this time period remains poorly understood. Conflicting evidence from spatially disparate lacustrine records and discontinuous fluvial archives have hindered consensus on environmental change during this period. Here, we present two new, highly resolved organic sedimentary records from the Thirlmere Lakes (NSW) and Minjerribah (North Stradbroke Island, QLD) regions of eastern Australia that provide new constraints on long-term climate and environmental variability through the last glacial cycle.Australian aquatic systems often deviate from biogeochemical frameworks developed largely from Northern Hemisphere environments. The prevalence of low-nutrient conditions results in unusual carbon isotope signatures, complicating the identification of organic carbon sources and their transport between terrestrial and aquatic reservoirs. Through characterisation of modern aquatic carbon isotopes, we develop alternative threshold values for distinguishing organic matter sources and, in turn, demonstrate the utility of sedimentary stable carbon isotopes as robust tracers of environmental and climatic change in southern mid-latitude systems.Applying these newly developed isotope thresholds, we reconstruct millennial-scale climate variability in eastern Australia from Marine Isotope Stage 5 to the present. The resulting records reveal strong coupling between regional carbon cycling and Southern Hemisphere high-latitude climate, with limited evidence for Northern Hemisphere forcing. These findings highlight the importance of regionally calibrated carbon isotope frameworks and demonstrate the value of stable carbon isotopes for reconstructing past Earth system change in under-represented Southern Hemisphere environments.

ABSTRACTNorthern Australia experiences extreme seasonality via the Indo‐Australian summer monsoon, with high inter‐annual variability in hydroclimate. Understanding the influence of hydrological variability on the landscape through the period of human occupation provides important environmental context to support the interpretation of the rich archaeological and rock art records of the region. The development of terrestrial records of environmental change has remained challenging due to the limited traditional palaeoenvironmental archives in the region. This study reports on the potential of sediments from ecologically significant monsoon rainforest patches to further elucidate the palaeoenvironmental history of the Kimberley. An ~19 000‐year record of monsoon rainforest variability is presented, inferred from pollen, charcoal and major element geochemical analysis. Monsoon rainforest‐associated taxa vary in abundance through the deglacial and the Holocene, which is compared to broad‐scale hydroclimate variability inferred from previous studies in the region. The persistence of arboreal, riparian and monsoon rainforest‐associated taxa suggest a positive moisture balance at the site throughout the period archived. Fire activity inferred from micro‐ and macrocharcoal is greatest over the last ~6000 years, and broadly corresponds to periods when monsoon rainforest‐associated taxa are less abundant. Challenges remain in using this type of site as an archive of environmental change, but they also present an opportunity to extend previous records both spatially and temporally with thousands of monsoon rainforest patches present across the Kimberley, and similar ecosystems found across northern Australia.

Amazonian peatlands are carbon-rich ecosystems that act as long-term carbon sinks but have faced increasing fire risks in recent decades. As a legacy of past fires, the contribution of pyrogenic carbon (PyC) to carbon cycling in these peatlands remains poorly understood. Here, we assess PyC accumulation variability using six cores spanning peatlands in northwestern Amazonia using hydrogen pyrolysis. We also estimate the PyC stock for the entire Amazonian peatlands by combining our field dataset with published sources. The PyC to total organic carbon ratio averaged 1.2% across our sites and increased with peat age. We estimate a total peatland PyC stock of 0.73 ± 0.61 Pg for the Amazon Basin, representing 1.6% of their TOC stock. Due to the slower turnover of PyC in peatland ecosystems, our findings indicate the importance of PyC generated by past fires and highlight the potential long-term carbon sequestration role of PyC in the future carbon cycle.

Peatlands are globally significant ecosystems, influencing carbon and water cycles at local, regional and planetary scales, as well as harbouring a uniquely adapted biodiverse flora and fauna. However, peatlands in Oceania have received relatively little research or policy attention. This review aimed to document existing knowledge of peatlands in Oceania and identify gaps and opportunities to enhance their management to contribute to national and global outcomes for biodiversity conservation and carbon sequestration. We reviewed and synthesised existing published scientific literature, grey literature accessed via professional affiliations and, where written material was missing or sparse, shared and documented expert practitioner and professional experiences in peatlands across the Oceania region. We found that Oceania contains a diversity of peatlands spread across all five ecological zones from the tropics to temperate environments and from the lowlands up to mountain and alpine regions. There is a notable dominance of the Restionaceae family in the formation of peatlands in Oceania, in contrast to other regions where moss and tree species are recognised as the most important peat forming species. The knowledge gaps uncovered in this review are substantial. There is little documentation regarding peatlands of Pacific Island nations. Mapping is incomplete or out of date in many parts of Oceania and detailed understanding of ecohydrological function is rare in this region. The findings of this review highlight five opportunities nascent within Oceania's peatlands: (1) local and global carbon, biodiversity and water regulation benefits via restoration and protection; (2) partnerships between Indigenous and community groups and government; (3) South to South regional collaboration; and (4) global knowledge sharing including (5) support to implement existing international policies and agreements. Recommendations across the domains of research, management and policy outline seven key actions that could contribute towards realising the full potential of Oceania's peatlands, both in terms of their intrinsic value and ‘Natures Contributions to People’.

Recent global fire activity has highlighted the importance of understanding fire dynamics across time and space, with records of past fire (palaeofire) providing valuable insights to inform us on current and future management challenges. New records from the recent increase in palaeofire studies from Australia and surrounds have not been captured in any database for broader comparisons, and Australasia is poorly represented in current international databases used for global modelling of palaeofire trends. These problems are addressed by SahulCHAR, a new collection of sedimentary charcoal and black carbon records from Sahul (Australia, New Guinea, and offshore islands) and Aotearoa / New Zealand. Data are stored in the OCTOPUS relational database platform, with a structure designed for compatibility with the existing Global Paleofire Database. Metadata are captured at the site level and observation level, with observations including age determinations and charcoal or black carbon data. SahulCHAR version 1 contains 687 records of charcoal or black carbon, including digitized data, unchanged and modified records from the Global Paleofire Database, and original author-submitted data. SahulCHAR is a much-needed update to past regional palaeofire compilations that will also provide greater representation of records from Sahul and Aotearoa / New Zealand in future global syntheses.

The Holocene history of Australia's climate is surprisingly poorly understood. This is, in part, because of the relatively weak forcing of Holocene climate versus that of the late Pleistocene. However, it is commonly suggested that eastern Australia dried during the mid- to late-Holocene and that this was in response to increased activity in the El Ni & ntilde;o-Southern Oscillation (ENSO), in particular, the intensification of the El Ni & ntilde;o phase of ENSO. While this has been inferred from numerous locations, data from K'gari (a subtropical sand island adjacent to the east coast) was amongst the first used to develop this hypothesis and features heavily in the discussion of ENSO intensification. This study examines published and new data from three >= 4.5 m deep K'gari lakes that demonstrate a strong drying event during the middle Holocene (from 7640 to 5600 cal a BP), followed by a wetter late Holocene climate. This contrasts somewhat with previous arguments about K'gari's history that suggest a late Holocene drying. In turn, this indicates a need to re-evaluate the notion that ENSO intensification drove late-Holocene drying in the region. It also indicates that even large, deep lakes on K'gari, which are iconic landmarks with substantial cultural, ecological and economic values, are vulnerable to drying.

Understanding of the Indo-Australian Summer Monsoon's (IASM) response to climate forcings under glacial conditions is limited by a significant knowledge gap regarding the hydroclimate in northern Australia during the last glacial. We present a continuous geochemical record from the eastern Kimberley, Australia, which spans similar to 65 ka to the Last Glacial Maximum (LGM). The record comes from the floodplain of the Bullo River, which is currently directly impacted by the IASM, and represents variations in the hydroclimate of its 2000 km(2) catchment. Results show that the hydroclimate during the glacial lacked the prolonged and high-amplitude changes that marked the hydroclimate following the LGM. Flooding was less frequent or of reduced magnitude than during the deglacial and early Holocene. While there was an absence of substantial long-term change, there is evidence of a subtle shift in mid Marine Isotope Stage 3 to less frequent or lower magnitude flooding and longer instances of dry conditions in the catchment. The low temporal resolution of these results means that centennial or shorter scale periods of enhanced IASM activity cannot be ruled out. These results extend our understanding of the long-term hydroclimate of monsoonal Australia during the glacial, which has, to date, largely been inferred from discontinuous geomorphic records.

Unlike the dominant Australian savanna-sclerophyll vegetation, tropical rainforests do not burn easily. Any evidence of fire in Australian rainforests therefore invites explanations of its source. Analysis of 187 radiocarbon dates that include selected charcoal fragments from 23 soil pits and 7 archaeological sites from the Wet Tropics Bioregion (WTB) in far North Queensland, suggests a strong relationship between natural and cultural firing regimes over many millennia. The magnitude and frequency of fire represented in the charcoal chronology challenge previous arguments that rainforest experienced a reduction in firing through the Holocene. The results throw new light on the origin and continuation of isolated eucalypt forest pockets within Australia's tropical rainforest. Contrairement & agrave; la v & eacute;g & eacute;tation scl & eacute;rophylle dominante de la savane australienne, les for & ecirc;ts tropicales humides ne br & ucirc;lent pas facilement. Toute trace d'incendie dans les for & ecirc;ts tropicales australiennes appelle donc une explication de son origine. L'analyse de cent quatre-vingt-sept datations au radiocarbone, incluant des fragments de charbon de bois s & eacute;lectionn & eacute;s provenant de 23 fosses p & eacute;dologiques et de sept sites arch & eacute;ologiques de la bior & eacute;gion des tropiques humides (WTB), dans l'extr & ecirc;me nord du Queensland, sugg & egrave;re une forte relation entre les r & eacute;gimes de feu naturels et culturels sur plusieurs mill & eacute;naires. L'ampleur et la fr & eacute;quence des incendies repr & eacute;sent & eacute;s dans la chronologie du charbon de bois remettent en cause les arguments ant & eacute;rieurs selon lesquels la for & ecirc;t tropicale a connu une r & eacute;duction des incendies au cours de l'Holoc & egrave;ne. Ces r & eacute;sultats apportent un nouvel & eacute;clairage sur l'origine et la persistance de poches isol & eacute;es de for & ecirc;ts d'eucalyptus au sein de la for & ecirc;t tropicale humide australienne.

The climate of the Kimberley region in tropical northwest Australia is dominated by the Indo‐Australian summer monsoon (IASM). Understanding of the palaeoclimate since the Last Glacial Maximum in this region, which is well placed to record IASM variations, is currently based on few records. Many of these are confounded by local environmental factors such as topography, anthropogenic activity or marine processes. Here, we present a geochemical record spanning the last 17 ka, in conjunction with pollen and charcoal records from 5.4 ± 0.1 ka (1 sigma uncertainty) to the present. The record comes from the floodplain of the Bullo River and as such represents variations in the hydroclimate of its 2000 km 2 catchment. Results show that the deglacial was characterised by a variable monsoon until the onset of a wet interval beginning at 12.9 ± 0.9 ka. The exact onset and intensity of a dry period following 5 ka are uncertain, but conditions became progressively drier until the climate amelioration to modern conditions. These results are broadly consistent with previous research and extend our understanding of deglacial and Holocene hydroclimate variability to the eastern Kimberley, 350 km east of previously published Kimberley palaeoenvironmental records.

Archaeological and palaeoenvironmental investigations at Juukan 2 rockshelter have yielded new information on the ancient Aboriginal occupation of the Pilbara uplands in northwest Australia. Using multiple lines of evidence, including lithic, faunal, pollen, ancient DNA, radiocarbon dating, optically stimulated luminescence, and Bayesian chronological modelling, we show that Aboriginal people occupied the western Hamersley Plateau as early as 47,000 years ago (47 ka). Late Pleistocene populations utilised a diverse range of tool technologies, including bone points, grindstones, and flaked stone artefacts. Palaeoclimatic conditions at Juukan 2 rockshelter varied greatly over the past 47 ka, with repeated site visits by people, including during the peak hyper-arid phase of the Last Glacial Maximum (LGM) c. 21 +/- 2 ka. Ancient starch analyses of the ground stone artefacts show the processing of Ipomoea (Bush Potato) from around 42 ka to the present day. Pronounced increases in the discard of stone artefacts and bone in the last 3500 years are interpreted to be the result of increased frequency of site use. A braided hair fragment dated to this period has demonstrated genetic links between the earlier rockshelter occupants and contemporary Puutu Kunti Kurrama and Pinikura peoples, who have maintained strong cultural connections to the area.

Cryptotephra subsampling techniques were used to identify a high concentration (c. 700 shards/g) of glass shards within the Yellow Marsh sediments in northwest Tasmania, Australia. Radiocarbon dating from the overlying sediments coupled with geochemical analysis of the glass shards indicate their similarity to the KawakawaOruanui Tephra (KOT), derived from the Oruanui supereruption of 25,568 f 232 cal yr BP (f2sd) from the Taupo Volcanic Zone, New Zealand. Although cryptotephra from this eruption has previously been identified in Antarctica and modelled to have been transported over parts of southern and eastern Australia, to date glass shards from this eruption have not been identified in Australia. If the correlation of the cryptotephra to the Oruanui supereruption is correct, this finding has the potential to allow Last Glacial deposits in the SW Pacific (including those in Australia, New Zealand and Antarctica) to be irrefutably linked.

Secure archaeological evidence for human occupation on the eastern seaboard of Australia before ~ 25,000 years ago has proven elusive. This has prompted some researchers to argue that the coastal margins remained uninhabited prior to 25 ka. Here we show evidence for human occupation beginning between 30 ± 6 and 49 ± 8 ka at Wallen Wallen Creek (WWC), and at Middle Canalpin Creek (MCA20) between 38 ± 8 and 41 ± 8 ka. Both sites are located on the western side of Minjerribah (North Stradbroke Island), the second largest sand island in the world, isolated by rising sea levels in the early Holocene. The earliest occupation phase at both sites consists of charcoal and heavily retouched stone artefacts made from exotic raw materials. Heat-treatment of imported silcrete artefacts first appeared in sediment dated to ~ 30,000 years ago, making these amongst Australia’s oldest dated heat-treated artefacts. An early human presence on Minjerribah is further suggested by palaeoenvironmental records of anthropogenic burning beginning by 45,000 years ago. These new chronologies from sites on a remnant portion of the continental margin confirm early human occupation along Sahul’s now-drowned eastern continental shelf.