The Australasian Pollen and Spore Atlas (APSA)

The Australasian Pollen and Spore Atlas (APSA) is designed to enable free online accessibility to the largest collection of pollen and spores information in the Australasian region. The collection currently holds details on over 15,000 speciesThe APSA project is supported by the ANU Supercomputing FacilityDataset -- Poster -- User Documentatio

Pollen and spores of Southern Chile and the Juan Fernandez Archipelago

Contains 63 pollen and spore image sheets from the flora of southern Chile (Region XI) and the Juan Fernandez Archipelago

Macro Charcoal Analysis: A modified technique used by the Department of Archaeology and Natural History

The 'macro charcoal' analysis outline here is designed to be carried out on contiguously sampled sediments; ie. the whole core is able to be analysed. The need to develop a fast, low cost method for charcoal extraction has arisen from the realization that low resolution analysis does not give an adequate indication of the frequency or concentration of charcoal being deposited in a sediment column. Continuous sampling enables the researcher to assess the frequency of charcoal peak events or episodes and therefore provides a window into the nature of past fire regimes. Different methods fro charcoal extraction and analysis have been developed (see reading list below). Here we outline a method adopted at the Department of Archaeology and Natural History which is adapted from a method developed by Rhodes, A.N. (1995 A method for the preparation and quantification of microscopic charcoal from terrestrial and lacustrine sediment cores. The Holocene 8, 113-117.). Using this approach we have been able to complete extraction and analysis of around 32 samples in 2 half-day sessions in the lab

Peopled Landscapes (Terra Australis 34)

This impressive collection celebrates the work of Peter Kershaw, a key figure in the field of Australian palaeoenvironmental reconstruction. Over almost half a century his research helped reconceptualize ecology in Australia, creating a detailed understanding of environmental change in the Late Pleistocene and Holocene. Within a biogeographic framework one of his exceptional contributions was to explore the ways that Aboriginal people may have modified the landscape through the effects of anthropogenic burning. These ideas have had significant impacts on thinking within the fields of geomorphology, biogeography, archaeology, anthropology and history. Papers presented here continue to explore the dynamism of landscape change in Australia and the contribution of humans to those transformations. The volume is structured in two sections. The first examines evidence for human engagement with landscape, focusing on Australia and Papua New Guinea but also dealing with the human/environmental histories of Europe and Asia. The second section contains papers that examine palaeoecology and present some of the latest research into environmental change in Australia and New Zealand. Individually these papers, written by many of Australia’s prominent researchers in these fields, are significant contributions to our knowledge of Quaternary landscapes and human land use. But Peopled Landscapes also signifies the disciplinary entanglement that is archaeological and biogeographic research in this region, with archaeologists and environmental scientists contributing to both studies of human land use and palaeoecology. Peopled Landscapes reveals the interdisciplinary richness of Quaternary research in the Australasian region as well as the complexity and richness of the entangled environmental and human pasts of these lands

Testing peat humification analysis in an Australian context: identifying wet shifts in regional climate over the past 4000 years

Peat humification analysis is presented as a robust palaeoclimatic proxy, suitable for use on mid�late Holocene peat sequences situated in the Southern Hemisphere. The proxy is shown to permit the identification of wet and dry shifts in a peat sequence from the humid tropics of north-eastern Australia. A significant correlation is found between the humification record and other proxies indicative of past climate conditions such as pollen, ?13C, C/N and macrocharcoal. Sixteen wet shifts detected in the humification record for Bromfield Swamp occur at the following dates (with 2? range): 3830 (3920�3740), 3560 (3640�3480), 3490 (3560�3420), 3380 (3450�3300), 3120 (3250�2970), 2950 (3100�2790), 2560 (2710�2450), 2430 (2600�2260), 2120 (2330�1910), 1750 (1980�1520), 1430 (1660�1200), 1170 (1390�960), 1010 (1220�820), 620 (770�500), 300 (400�200) and 100 (200�10) cal. yr BP. Eleven dry shifts are also identified in the record at 4220 (4330�4110), 3670 (3750�3590), 3330 (3420�3220), 3020 (3170�2870), 2350 (2530�2160), 2020 (2230�1800), 1730 (1980�1510), 1290 (1510�1070), 700 (870�560), 400 (470�300) and 260 (360�150) cal yr BP. Blechnum and Poaceae are identified by pollen analysis to be the dominant plants of the swamp surface over the past 4000 years. The ratio of these two plant taxa in the pollen record correlates well with identified wet and dry shifts. It is suggested that a ratio ?1 possibly indicates dry conditions, a ratio of >1�3 indicates wet or dry conditions, and a ratio >3 implies wet conditions. Large macrocharcoal peaks are recorded during the initiation phase of the peat sequence at approximately 4090 cal. yr BP, and at 3700�3620 cal. yr BP, both of these time periods being coincident with dry phases. Isolated minor macrocharcoal peaks at ca. 2860, 2820, 2620, 2560, 2130, 1930, 1740 and 200 cal. yr BP are found to coincide with periods of average effective precipitation (based on the humification proxy) and so may reflect fire on the swamp surface, transport and re-deposition down-slope of old charcoal after a high rainfall event, or burning in the landscape by indigenous people

A fire driven shift from forest to non-forest: evidence for alternative stable states?

We test the validity of applying the alternative stable state paradigm to account for the landscape-scale forest/non-forest mosaic that prevails in temperate Tasmania, Australia. This test is based on fine-scale pollen, spore, and charcoal analyses of sediments located within a small patch of non-forest vegetation surrounded by temperate forest. Following nearly 500 years of forest dominance at the site, a catastrophic fire drove an irreversible shift from a forested Cyperaceae-Sphagnum wetland to a non-forested Restionaceae wetland at ca. 7000 calibrated (cal) yr BP. Persistence of the non-forest/Restionaceae vegetation state over 7000 years, despite long fire-free intervals, implies that fire was not essential for the maintenance of the non-forest state. We propose that reduced interception and transpiration of the non-forest state resulted in local waterlogging, presenting an eco-hydrological barrier to forest reestablishment over the succeeding 7000 years. We further contend that the rhizomatous nature of the non-forest species presented a reinforcing eco-physical barrier to forest development. Our results satisfy a number of criteria for consideration as an example of a switch between alternative stable states, including different origin and maintenance pathways, and they provide insights into the role of threshold dynamics and hysteresis in forest-non-forest transitions

Holocene Dynamics of Temperate Rainforests in West-Central Patagonia

Analyses of long-term ecosystem dynamics offer insights into the conditions that have led to stability vs. rapid change in the past and the importance of disturbance in regulating community composition. In this study, we (1) used lithology, pollen, and charcoal data from Mallín Casanova (47°S) to reconstruct the wetland, vegetation, and fire history of west-central Patagonia; and (2) compared the records with independent paleoenvironmental and archeological information to assess the effects of past climate and human activity on ecosystem dynamics. Pollen data indicate that Nothofagus-Pilgerodendronforests were established by 9,000 cal yr BP. Although the biodiversity of the understory increased between 8,480 and 5,630 cal yr BP, forests remained relatively unchanged from 9,000 to 2,000 cal yr BP. The charcoal record registers high fire-episode frequency in the early Holocene followed by low biomass burning between 6,500 and 2,000 cal yr BP. Covarying trends in charcoal, bog development, and Neoglacial advances suggest that climate was the primary driver of these changes. After 2,000 cal yr BP, the proxy data indicate (a) increased fire-episode frequency; (b) centennial-scale shifts in bog and forest composition; (c) the emergence of vegetation-fire linkages not recorded in previous times; and (d) paludification in the last 500 years possibly associated with forest loss. Our results therefore suggest that Nothofagus-Pilgerodendrondominance was maintained through much of the Holocene despite long-term changes in climate and fire. Unparalleled fluctuations in local ecosystems during the last two millennia were governed by disturbance-vegetation-hydrology feedbacks likely triggered by greater climate variability and deforestation

Ban on toxic mercury looms in sugar cane farming, but Australia still has a way to go

This month, federal authorities finally announced an upcoming ban on mercury-containing pesticide in Australia. We are one of the last countries in the world to do so, despite overwhelming evidence over more than 60 years that mercury use as fungicide in agriculture is dangerous

Background concentrations of mercury in Australian freshwater sediments: the role of catchment’s physico-chemical parameters on mercury deposition

Waterways in the Australian continent are facing increasing levels of mercury contamination due to industrialisation, agricultural intensification, energy production, urbanisation and mining. Mercury contamination undermines the use of waterways as a source of potable water and also has a deleterious effect on aquatic organisms. When developing management strategies to reduce mercury levels in waterways, it is crucial to set appropriate targets for mitigation of these contaminated waterways. These mitigation targets could be (1) trigger values or default guideline values provided by water and sediment quality guidelines or (2) background (pre-industrialisation) levels of mercury in the waterway. The aims of this study were to: (1) quantify the differences between existing environmental guideline values for mercury in aquatic systems, and background mercury concentrations, and (2) determine key factors affecting the spatial differences in background mercury concentrations in freshwater lake systems in Australia. Mercury concentrations were measured in background sediments from 21 lakes in Australia. Organic matter and precipitation were the main factors to explain mercury concentrations in sediments of lakes. These data indicate that background mercury concentrations in lake sediments can vary significantly across the continent, and the background concentrations are up to nine times lower than current sediment quality guidelines in Australia and New Zealand. This indicates that if waterway managers are aiming to restore systems to ‘pre-industrialisation’ mercury levels, it is highly important to quantify the site-specific background mercury concentration. We found that the geology of the lake catchment correlates to the background mercury concentration of lake sediments, with the highest mercury background levels being identified in lakes in igneous mafic intrusive regions and the lowest in areas underlain by regolith. Taking into account these findings, we provide a preliminary map of predicted background mercury sediment concentrations across Australia that could be used by waterway managers for determining management targets

Holocene Dynamics of Temperate Rainforests in West-Central Patagonia

Analyses of long-term ecosystem dynamics offer insights into the conditions that have led to stability vs. rapid change in the past and the importance of disturbance in regulating community composition. In this study, we (1) used lithology, pollen, and charcoal data from Mallín Casanova (47°S) to reconstruct the wetland, vegetation, and fire history of west-central Patagonia; and (2) compared the records with independent paleoenvironmental and archeological information to assess the effects of past climate and human activity on ecosystem dynamics. Pollen data indicate that Nothofagus-Pilgerodendron forests were established by 9,000 cal yr BP. Although the biodiversity of the understory increased between 8,480 and 5,630 cal yr BP, forests remained relatively unchanged from 9,000 to 2,000 cal yr BP. The charcoal record registers high fire-episode frequency in the early Holocene followed by low biomass burning between 6,500 and 2,000 cal yr BP. Covarying trends in charcoal, bog development, and Neoglacial advances suggest that climate was the primary driver of these changes. After 2,000 cal yr BP, the proxy data indicate (a) increased fire-episode frequency; (b) centennial-scale shifts in bog and forest composition; (c) the emergence of vegetation-fire linkages not recorded in previous times; and (d) paludification in the last 500 years possibly associated with forest loss. Our results therefore suggest that Nothofagus-Pilgerodendron dominance was maintained through much of the Holocene despite long-term changes in climate and fire. Unparalleled fluctuations in local ecosystems during the last two millennia were governed by disturbance-vegetation-hydrology feedbacks likely triggered by greater climate variability and deforestation.This work was supported by grants from the National Science Foundation (0966472, 0956552, 0602166), the National Geographic Society (7988-06), and the Department of Archaeology and Natural History at the Australian National University