Browsing by Author "Haberle, SG"

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    Building a future on knowledge from the past: what paleo-science can reveal about climate change and its potential impacts in Australia
    (Commonwealth Scientific and Industrial Research Organisation, 2005-06) Harle, KJ; Etheridge, DM; Whetton, P; Jones, R; Hennessy, K; Goodwin, ID; Brooke, BP; van Ommen, TD; Barbetti, M; Barrows, TT; Chappell, J; De Deckker, P; Fink, D; Gagan, MK; Haberle, SG; Heijnis, H; Henderson-Sellers, A; Hesse, PP; Hope, GS; Kershaw, P; Nicholls, N
    In Australia, high quality instrumental climate records only extend back to the late 19th century and therefore only provide us with a brief snapshot of our climate, its mean state and its short-term variability. Palaeo-records extend our knowledge of climate back beyond the instrumental record, providing us with the means of testing and improving our understanding of the nature and impacts of climate change and variability in Australia. There is a vast body of palaeo-records available for the Australian region (including Antarctica), ranging from continuous records of sub-decadal up to millennial scale (such as those derived from tree rings, speleothems, corals, ice cores, and lake and marine sediments) through to discontinuous records representing key periods in time (such as coastal deposits, palaeo-channels, glacial deposits and dunes). These records provide a large array of evidence of past atmospheric, terrestrial and marine environments and their varying interactions through time. There are a number of key ways in which this evidence can, in turn, be used to constrain uncertainties about climate change and its potential impacts in Australia.
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    Climate change reduces resilience to fire in subalpine rainforests
    (Wiley, 2019-03-24) Mariani, M; Fletcher, MS; Haberle, SG; Chin, HJ; Zawadzki, A; Jacobsen, GE
    Climate change is affecting the distribution of species and the functioning of ecosystems. For species that are slow growing and poorly dispersed, climate change can force a lag between the distributions of species and the geographic distributions of their climatic envelopes, exposing species to the risk of extinction. Climate also governs the resilience of species and ecosystems to disturbance, such as wildfire. Here we use species distribution modelling and palaeoecology to assess and test the impact of vegetation–climate disequilibrium on the resilience of an endangered fire‐sensitive rainforest community to fires. First, we modelled the probability of occurrence of Athrotaxis spp. and Nothofagus gunnii rainforest in Tasmania (hereon “montane rainforest”) as a function of climate. We then analysed three pollen and charcoal records spanning the last 7,500 cal year BP from within both high (n = 1) and low (n = 2) probability of occurrence areas. Our study indicates that climatic change between 3,000 and 4,000 cal year bp induced a disequilibrium between montane rainforests and climate that drove a loss of resilience of these communities. Current and future climate change are likely to shift the geographic distribution of the climatic envelopes of this plant community further, suggesting that current high‐resilience locations will face a reduction in resilience. Coupled with the forecast of increasing fire activity in southern temperate regions, this heralds a significant threat to this and other slow growing, poorly dispersed and fire sensitive forest systems that are common in the southern mid to high latitudes. © 1999-2025 John Wiley & Sons, Inc or related companies.
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    History of human impact on Lake Kutubu, Papua New Guinea: the geochemical signatures of oil and gas mining activities in sediments
    (Elsevier, 2016-04-01) Schneider, L; Haberle, SG; Maher, WA; Krikowa, F; Zawadzki, A; Heijnis, H
    Lake Kutubu, a large tropical lake in Papua New Guinea, is well known for its ecological importance; however, there have been recent changes to the pristine nature of this lake due to activities associated with the largest oil and gas project in PNG. The aim of this study was to determine the geochemical profile of sediment cores of Lake Kutubu and to comprehend the contamination changes undergone in this lake due to mining activities utilising the hydraulic fracturing method. Sediment core profiles of Na, Mg, Al, Si, P, Ca, Ti, Cr, Fe, Mn, Ni, Cu, Zn, As, Se, Sr, Cd, Ba, Ce, Pb and U, grain size and dating analyses were conducted for five sites in the lake. Grain size and dating demonstrated that the northwest side of Lake Kutubu has sediments of allocthonous origin while the southeast sediments are of autochthonous origin. Ba was the element with the largest changes in concentrations since 1990 and the best tracer of mining activities near the lake. Sites KTB 02 and KTB 10 northwest of the lake showed the most distinct changes in element concentrations. Element enrichment factors (EF = 2.8, 4.2 and 3.2 respectively) demonstrated that Mn, Se and Ba have undergone a moderate enrichment in the lake since mining activities started. Ni, Cd and Se concentrations exceed sediment guidelines in some samples. No guideline is available for Ba, and special attention should be given to this element in this lake. This study demonstrated that Lake Kutubu oil/gas extraction activities are significant sources of elements to this lake and highlights the need for studies on the partitioning and speciation of elements to understand organism metal exposure. © 2016, Elsevier Ltd.
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    How significant is atmospheric metal contamination from mining activity adjacent to the Tasmanian Wilderness World Heritage Area? A spatial analysis of metal concentrations using air trajectories models
    (Elsevier, 2019-03-15) Schneider, L; Mariani, M; Saunders, KM; Maher, WA; Harrison, JJ; Fletcher, MS; Zawadzki, A; Heijnis, H; Haberle, SG
    This study investigated metal contamination from historical mining in lakes in the Tasmanian Wilderness World Heritage Area (TWWHA) and surrounding region. The largest increase in sedimentation and metal contamination occurred ca. 1930 when open-cut mining commenced and new mining technology was introduced into the region. The geochemical signal of lake sediments changed from reflecting the underlying geology and lithology to that reflecting mining activities. The HYSPLIT air particle trajectory model explains metal distribution in the lakes, with those in the northwest region closest to the mines having the highest metal contamination. Lake metal concentrations since mining activities commenced are in the order: Owen Tarn > Basin Lake > Perched Lake > Lake Dove > Lake Dobson > Lake Cygnus, with Perched Lake and Lakes Dove, Dobson and Cygnus in the TWWHA. Metal contamination affected centres up to 130 km down-wind of mining sites. Enrichment factors (EF) for Pb, Cu, As and Cd are >1 for all lakes, with Owen Tarn and Basin Lake having very high EFs for Cu and Pb (98 and 91, respectively). Pb, Cu, As and Cd concentrations are above the Australia/New Zealand lower sediment guidelines, with Pb, Cu and As above the high guidelines in Owen Tarn and Basin Lake. This study demonstrated the legacy of metal contamination in the TWWHA by mining activities and the consequences of a lack of execution of environmental regulations by past governments in Tasmania.© 2018 Elsevier B.V
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    Integration of ice-core, marine and terrestrial records for the Australian Last Glacial Maximum and Termination: a contribution from the OZ INTIMATE group
    (Wiley, 2006-10) Turney, CSM; Haberle, SG; Fink, D; Kershaw, AP; Barbetti, M; Barrows, TT; Black, M; Cohen, TJ; Corrège, T; Hesse, PP; Hua, Q; Johnston, R; Morgan, VI; Moss, PT; Nanson, GC; van Ommen, TD; Rule, S; Williams, NJ; Zhao, JX; D'Costa, D; Feng, YX; Gagan, MK; Mooney, SD; Xia, Q
    The degree to which Southern Hemisphere climatic changes during the end of the last glacial period and early Holocene (30-8 ka) were influenced or initiated by events occurring in the high latitudes of the Northern Hemisphere is a complex issue. There is conflicting evidence for the degree of hemispheric ‘teleconnection’ and an unresolved debate as to the principle forcing mechanism(s). The available hypotheses are difficult to test robustly, however, because the few detailed palaeoclimatic records in the Southern Hemisphere are widely dispersed and lack duplication. Here we present climatic and environmental reconstructions from across Australia, a key region of the Southern Hemisphere because of the range of environments it covers and the potentially important role regional atmospheric and oceanic controls play in global climate change. We identify a general scheme of events for the end of the last glacial period and early Holocene but a detailed reconstruction proved problematic. Significant progress in climate quantification and geochronological control is now urgently required to robustly investigate change through this period. © 2006 John Wiley & Sons, Ltd.
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    Late quaternary fire regimes of Australasia
    (Elsevier, 2011-01) Mooney, SD; Harrison, SP; Bartlein, PJ; Daniau, AL; Stevenson, J; Brownlie, KC; Buckman, S; Cupper, ML; Luly, J; Black, M; Colhoun, EA; D’Costa, D; Dodson, JR; Haberle, SG; Hope, GS; Kershaw, P; Kenyon, C; McKenzie, M; Williams, N
    We have compiled 223 sedimentary charcoal records from Australasia in order to examine the temporal and spatial variability of fire regimes during the Late Quaternary. While some of these records cover more than a full glacial cycle, here we focus on the last 70,000 years when the number of individual records in the compilation allows more robust conclusions. On orbital time scales, fire in Australasia predominantly reflects climate, with colder periods characterized by less and warmer intervals by more biomass burning. The composite record for the region also shows considerable millennial-scale variability during the last glacial interval (73.5–14.7 ka). Within the limits of the dating uncertainties of individual records, the variability shown by the composite charcoal record is more similar to the form, number and timing of Dansgaard–Oeschger cycles as observed in Greenland ice cores than to the variability expressed in the Antarctic ice-core record. The composite charcoal record suggests increased biomass burning in the Australasian region during Greenland Interstadials and reduced burning during Greenland Stadials. Millennial-scale variability is characteristic of the composite record of the sub-tropical high pressure belt during the past 21 ka, but the tropics show a somewhat simpler pattern of variability with major peaks in biomass burning around 15 ka and 8 ka. There is no distinct change in fire regime corresponding to the arrival of humans in Australia at 50 ± 10 ka and no correlation between archaeological evidence of increased human activity during the past 40 ka and the history of biomass burning. However, changes in biomass burning in the last 200 years may have been exacerbated or influenced by humans. © 2011, Elsevier Ltd.
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    The legacy of mid-Holocene fire on a Tasmanian montane landscape
    (Wiley Blackwell, 2014-03-01) Fletcher, MS; Wolfe, BB; Whitlock, C; Pompeani, DP; Heijnis, H; Haberle, SG; Gadd, PS; Bowman, DMJS
    AimTo assess the long-term impacts of landscape fire on a mosaic of pyrophobic and pyrogenic woody montane vegetation. LocationSouth-west Tasmania, Australia. MethodsWe undertook a high-resolution multiproxy palaeoecological analysis of sediments deposited in Lake Osborne (Hartz Mountains National Park, southern Tasmania), employing analyses of pollen, macroscopic and microscopic charcoal, organic and inorganic geochemistry and magnetic susceptibility. ResultsSequential fires within the study catchment over the past 6500years have resulted in the reduction of pyrophobic rain forest taxa and the establishment of pyrogenic Eucalyptus-dominated vegetation. The vegetation change was accompanied by soil erosion and nutrient losses. The rate of post-fire recovery of widespread rain forest taxa (Nothofagus cunninghamii and Eucryphia spp.) conforms to ecological models, as does the local extinction of fire-sensitive rain forest taxa (Nothofagus gunnii and Cupressaceae) following successive fires. Main conclusionsThe sedimentary analyses indicate that recurrent fires over several centuries caused a catchment-wide transition from pyrophobic rain forest to pyrophytic eucalypt-dominated vegetation. The fires within the lake catchment during the 6500-year long record appear to coincide with high-frequency El Nino events in the equatorial Pacific Ocean, signalling a potential threat to these highly endemic rain forests if El Nino intensity amplifies as predicted under future climate scenarios. © 2014, Wiley-Blackwell.
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    A new late Quaternary palaeohydrological record from the humid tropics of northeastern Australia
    (Elsevier, 2016-06-01) Burrows, MA; Heijnis, H; Gadd, PS; Haberle, SG
    High resolution X-ray fluorescence (XRF) is presented as a robust palaeoclimatic proxy, suitable for use on Late Pleistocene to Holocene sediments located in a volcanic crater on the Atherton Tableland in northeastern Queensland, Australia. The proxy allows identification of wet and dry shifts in a complex sedimentary sequence comprised of peat, gyttja, laminated organic rich muds and fine clastic silt-rich sediments. Significant correlation is found between the XRF record and other proxies including magnetic susceptibility, humification, grain size, macrocharcoal, δ13C and C/N and pollen. Sixteen wetter periods are identified in the 37 ka sedimentary record for Bromfield Swamp. Three wetter periods commence in late Marine Isotope Stage 3, nine in the early glacial, one in the late de-glacial and four in Holocene. Nineteen drier periods are identified, four in late MIS 3, seven in the early glacial, one during the LGM, one in the late de-glacial period and six in the Holocene. The XRF record for Bromfield Swamp is specifically used to identify periods of abrupt climate change. Marked changes in effective precipitation are detected at 32,690, 30,080, 24,660, 21,870, 11,880, 10,020, 9170 and 5120 cal. yr BP. The detection of these abrupt climate events may allow correlation with records from terrestrial sites across the Southern Hemisphere and potentially, the Northern Hemisphere. © 2016 Elsevier B.V.
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    Paleoclimate studies and natural-resource management in the Murray-Darling Basin II: unravelling human impacts and climate variability
    (Taylor and Francis Group, 2013-08-09) Mills, K; Gell, PA; Gergis, J; Baker, PJ; Finlayson, CM; Hesse, PP; Jones, R; Kershaw, P; Pearson, S; Treble, PC; Barr, C; Brookhouse, MT; Drysdale, RN; McDonald, J; Haberle, SG; Reid, M; Thoms, M; Tibby, J
    The management of the water resources of the Murray-Darling Basin (MDB) has long been contested, and the effects of the recent Millennium drought and subsequent flooding events have generated acute contests over the appropriate allocation of water supplies to agricultural, domestic and environmental uses. This water-availability crisis has driven demand for improved knowledge of climate change trends, cycles of variability, the range of historical climates experienced by natural systems and the ecological health of the system relative to a past benchmark. A considerable volume of research on the past climates of southeastern Australia has been produced over recent decades, but much of this work has focused on longer geological time-scales, and is of low temporal resolution. Less evidence has been generated of recent climate change at the level of resolution that accesses the cycles of change relevant to management. Intra-decadal and near-annual resolution (high-resolution) records do exist and provide evidence of climate change and variability, and of human impact on systems, relevant to natural-resource management. There exist now many research groups using a range of proxy indicators of climate that will rapidly escalate our knowledge of management-relevant, climate change and variability. This review assembles available climate and catchment change research within, and in the vicinity of, the MDB and portrays the research activities that are responding to the knowledge need. It also discusses how paleoclimate scientists may better integrate their pursuits into the resource-management realm to enhance the utility of the science, the effectiveness of the management measures and the outcomes for the end users. © 2020 Informa UK Limited
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    Preliminary paleolimnological data from a Santiago island coastal lagoon, Galapagos Archipelago, Ecuador
    (Elsevier, 2007-07) Natt, A; Haberle, SG; Jacobsen, GE
    The Galapagos Islands are arguably the most famous islands in the world. This fame derives from the Islands’ rich biological history and unique locality that provides opportunities for research in the fields of evolution, geomorphology and biodiversity. Furthermore, the unique geographical location of the archipelago has in the past and continues to provide excellent potential for palaeoclimatology, palaeolimnology and palaeoecology. In particular the location of the islands within what is essentially the heart of the ENSO region ensures the islands are frequently influenced by El Niño driven precipitation events. These El Niño precipitation events are extremely influential, given that the islands location within the Pacific Dry Zone (PDZ) ensures the islands have a semi-arid climate (< 500 m asl). Due to the influential nature of El Niño variability in the Galapagos, the numerous saline to hyper-saline coastal lagoons throughout the archipelago have the potential of recording past hydrological changes associated with El Niño-related climate variability. Furthermore, the influence of humans via the introduction of goats and burning may have influenced erosion rates in the catchment. The Preliminary multi-proxy analysis of a laminated sediment sequence raised from Espumilla 2 lagoon, Santiago Island, will be presented. The data include a 14C AMS radiocarbon chronology, fossil diatom analysis, magnetic susceptibility and mineralogical analysis. This research is also part of a larger collaborative project, which will be briefly summarised, and the potential for comparison discussed. © 2007 Published by Elsevier Ltd.
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    Preliminary paleolimnological data from a Santiago island coastal lagoon, Galapagos Archipelago, Ecuador
    (Vacuum Society of Australia, 2007-11) Natt, A; Haberle, SG; Jacobsen, GE; Tibby, J
    The Galapagos Islands are arguably the most famous islands in the world. This fame derives from the Islands’ rich biological history and unique locality that provides opportunities for research in the fields of evolution, geomorphology and biodiversity. Furthermore, the unique geographical location of the archipelago has in the past and continues to provide excellent potential for palaeoclimatology, palaeolimnology and palaeoecology. In particular the location of the islands within what is essentially the heart of the ENSO region ensures the islands are frequently influenced by El Niño driven precipitation events. These El Niño precipitation events are extremely influential, given that the islands location within the Pacific Equatorial Dry Zone (PEDZ) ensures the islands have a semi-arid climate (<500 m above sea level). Due to the influential nature of El Niño variability in the Galapagos, the numerous saline to hyper-saline coastal lagoons throughout the archipelago have the potential of recording past hydrological changes associated with El Niño-related climate variability. Furthermore, the influence of humans via the introduction of goats and burning may have influenced erosion rates in the catchment. Preliminary multi-proxy analysis of a laminated sediment sequence raised from the Espumilla lagoon system, Santiago Island, will be presented. The data includes a 14C AMS radiocarbon chronology, fossil diatom analysis, magnetic susceptibility and 2mm resolution ITRAX x-ray fluorescence geochemistry. The preliminary results show that the sediment core raised from this site has vast potential for reconstructing El Niño driven rainfall over the past 2500 calibrated years BP, while at the same time revealing a detailed and interesting history of the evolution of this ecologically significant lagoon system.
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    Reconsidering precolumbian human colonization in the Galapagos Islands, Republic of Ecuador
    (Society for American Archaeology, 2016-03-01) Anderson, A; Stothert, K; Martinsson-Wallin, H; Wallin, P; Flett, I; Haberle, SG; Heijnis, H; Rhodes, E
    Fifty years ago, Heyerdahl and Skjølsvold (1956, 1990) collected material from five archaeological sites in the Galápagos Islands. They retained earthenwares of possible precolumbian origin and discarded ceramic, metal, and glass artifacts postdating the arrival of the Spanish in A.D. 1535. Consequently, they argued that each site was formed as the results of a series of discard events from unrelated short-term occupations extending from the precolumbian to the historical era, and that the earthenwares represented occasional visits by fishermen from precolumbian Peru and Ecuador. In 2005, we re-excavated the sites and collected all the excavated materials. Our results show that each class of material, irrespective of age or origin, was distributed spatially and stratigraphically in the same pattern, contradicting the former assumption of multiple, unrelated occupations. We reject the palimpsest model in favor of the null hypothesis of single-phase site occupation. Analysis of putatively precolumbian pottery using optically-stimulated luminescence dating indicates that it is mostly of historical age. Radiocarbon dating confirms that the archaeological sites are younger than the sixteenth century. Research on sedimentary cores shows probable anthropogenic impacts as restricted to the last 500 years. We conclude that there was no human occupation in the Galápagos Islands until the historical era. © Society for American Archaeology 2016
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    Tracking abrupt climatic changes of the Holocene using organic sediments from NE Australia
    (International Union for Quaternary Research (INQUA), 2019-07-30) Burrows, MA; Heijnis, H; Haberle, SG; Gadd, PS
    Sediment cores recovered from Bromfield maar provide a continuous, high resolution record of climate variability through the Holocene for northeastern Australia. X-ray fluorescence (XRF-Itrax) is used in the generation of a long-term record of relative precipitation, supported by a suite of established proxies including humification, macrocharcoal and pollen. Together, these proxy data allow precise identification of wet and dry shifts in a sedimentary sequence comprised of laminated organic-rich muds, gyttja and peat. In this presentation we describe and provide new interpretations on changes in the Early Holocene as recorded at Bromfield maar, with particular emphasis on laminated organic-rich muds at 4.80m (9.2 ka) and 4.42m (8.3 ka). Additional changes are detected in the Late Holocene peat sequence at 1.37m (2.9 ka) and 1.28m (1.5 ka). Abrupt climate change events as identified in this study are significant as they allow the correlation of sedimentary records from sites throughout the wet tropics of Australia. The detection of these abrupt climate events also signals possible correlation with records from terrestrial sites across the Southern Hemisphere and potentially, the Northern Hemisphere. Such correlations may prove useful in demonstrating teleconnections, linking climates at a global scale.