Australian Continent Research Articles

Bradyrhizobium commune sp. nov., isolated from nodules of a wide range of native legumes across the Australian continent.

Bradyrhizobia are particularly abundant in Australia, where they nodulate native legumes growing in the acidic and seasonally dry soils that predominate in these environments. They are essential to Australian ecosystems by helping legumes to compensate for nutrient deficiencies and the low fertility of Australian soils. During a survey of Australian native rhizobial communities in 1994-1995, several Bradyrhizobium genospecies were identified, among which genospecies B appeared to be present in various edaphic and climatic conditions and associate with a large range of leguminous hosts across the whole continent. We took advantage of the recent sequencing of the genome of strain BDV5040T, representative of Bradyrhizobium genospecies B, to re-evaluate the taxonomic status of this lineage. We further characterized strain BDV5040T based on morpho-physiological traits and determined its phylogenetic relationships with the type strains of all currently described Bradyrhizobium species using both small subunit (SSU) rRNA gene and complete genome sequences. The digital DNA-DNA hybridization relatedness with any type strain was less than 35 % and both SSU rRNA gene and genome phylogenies confirmed the initial observation that this strain does not belong to any formerly described species within the genus Bradyrhizobium. All data thus support the description of the novel species Bradyrhizobium commune sp. nov. for which the type strain is BDV5040T (=CFBP 9110T=LMG 32898T), isolated from a nodule of Bossiaea ensata in Ben Boyd National Park in New South Wales, Australia.

The temporality of community sentiment on the Australian continent: mineral extraction, waste storage and Indigenous protest writing

ABSTRACT The Australian federal government has recently recommenced a previously paused process to select a site for a national nuclear waste storage facility despite significant opposition from Australian Indigenous communities and others. This article considers what some might understand as a contemporary issue by examining its relationship to previous events. It emphasizes how Western linear temporality facilitates disregard for negative community sentiment and the consigning of previous wrongs to the past. In contrast, Indigenous temporalities – where time is understood as immanent and space and time intermingled – emphasize positive relationships and require the remediation of past wrongs to support just futures. Thus, historical nuclear weapons testing in Australia, current plans for waste storage, and historical and ongoing ecological and social consequences of resource extraction are all related, reflecting the violence of British colonization and contemporary settler colonial governance. Using a literary studies approach, this article examines historically significant moments of Indigenous Australian protest writing regarding extractive industries, nuclear waste storage, and settler colonial governance, to show that some Indigenous communities in Australia have clearly communicated their negative sentiments. It argues for equitable relationships as a first step towards the restitution of past wrongs and the creation of just futures.

Phylogenomics reveals extreme gene tree discordance in a lineage of dominant trees: hybridization, introgression, and incomplete lineage sorting blur deep evolutionary relationships despite clear species groupings in Eucalyptus subgenus Eudesmia

Eucalypts are a large and ecologically important group of plants on the Australian continent, and understanding their evolution is important in understanding evolution of the unique Australian flora. Previous phylogenies using plastome DNA, nuclear-ribosomal DNA, or random genome-wide SNPs, have been confounded by limited genetic sampling or by idiosyncratic biological features of the eucalypts, including widespread plastome introgression. Here we present phylogenetic analyses of Eucalyptus subgenus Eudesmia (22 species from western, northern, central and eastern Australia), in the first study to apply a target-capture sequencing approach using custom, eucalypt-specific baits (of 568 genes) to a lineage of Eucalyptus. Multiple accessions of all species were included, and target-capture data were supplemented by separate analyses of plastome genes (average of 63 genes per sample). Analyses revealed a complex evolutionary history likely shaped by incomplete lineage sorting and hybridization. Gene tree discordance generally increased with phylogenetic depth. Species, or groups of species, toward the tips of the tree are mostly supported, and three major clades are identified, but the branching order of these clades cannot be confirmed with confidence. Multiple approaches to filtering the nuclear dataset, by removing genes or samples, could not reduce gene tree conflict or resolve these relationships. Despite inherent complexities in eucalypt evolution, the custom bait kit devised for this research will be a powerful tool for investigating the evolutionary history of eucalypts more broadly.

The MJO-driven Indo-Pacific barotropic see-saw

Recent discovery of a see-saw in intraseasonal barotropic sea level driven by boreal winter Madden-Julian Oscillation winds in the tropical Indo-Pacific basin has renewed interest in the barotropic dynamics in the tropics, which was otherwise known to be prominently a region of baroclinic dynamics at intraseasonal timescales. In this study, using a reference model simulation and several sensitivity experiments, we provide comprehensive details of the dynamics associated with this see-saw. It is found that the narrow Indonesian straits are instrumental in relaying barotropic excitations from one basin to the other. The intraseasonal barotropic circulation associated with this see-saw dynamics appears well organized at basin scale, both in the Indian Ocean and in the Pacific Ocean. During the positive phase of the see-saw, the Madden-Julian Oscillation winds over the Maritime Continent drive a basin-wide anti-clockwise circulation of ∼2 Sv around the Australian Continent with the eastern arm of this circulation located along the west African coast. Concurrently, it also drives a clockwise circulation in the southern Pacific Ocean. This circulation pattern reverses during the negative phase of the see-saw. In the Indonesian Throughflow region, the relatively narrow Ombai Strait and Lombok Strait facilitate this circulation in comparison to the wider Timor Passage. We discuss and point out the significant differences in this flow pattern with the mean flow across the Indonesian seas. We also address how some regions in the northern Pacific Ocean are decoupled from this large-scale dynamics. We show that it takes about a week for both the basins to adjust and to establish the see-saw, once the Madden-Julian Oscillation winds reach the Maritime Continent.

A New Shear‐Velocity Model of Continental Australia Based on Multi‐Scale Surface‐Wave Tomography

AbstractThe Australian Seismological Reference Model (AuSREM) represents a state‐of‐the‐art geophysical synthesis of the Australian continent. To date, its shear‐wave component has limited resolution at lower‐crustal to uppermost‐mantle depths, where it is mainly constrained by sparse measurements collected at the local scale. In this study, we compile a large data set of surface‐wave phase velocities based on seismic ambient noise and teleseismic earthquakes, to produce Rayleigh and Love phase‐velocity maps of continental Australia in a broad period range (4–200 s). Via transdimensional Bayesian inversion, we translate the phase‐velocity maps into a 3‐D shear‐wave velocity model extending to 300 km depth. Owing to the unprecedented seismic coverage and to the joint use of ambient‐noise and teleseismic data, the retrieved model fills a tomographic gap in the known shear‐wave velocity structure of the continent, comprising lower‐crustal to uppermost mantle depths. Consistent with AuSREM, strong velocity heterogeneities in our model highlight the (faster) cratonic blocks and the (slower) sedimentary basins at upper‐crustal depths. At mantle depths, the most prominent feature of the continent is a large‐scale eastward decrease in shear‐wave velocity. We interpret our observations in light of the relevant literature, and produce depth maps of the Moho and lithosphere‐asthenosphere boundary (LAB). Notably, our LAB proxy features a stripe of thicker lithosphere extending to the east coast, which is not visible in the AuSREM LAB model. This observation supports the idea that lateral variations in lithospheric thickness control both the composition and volume of surface volcanism in eastern Australia.

Deformation feature and tectonic model of the Timor Trough: New interpretation of the evolution and mechanism of Banda arc-continent collision

The deformation of the Timor Trough is controlled by the combined dynamics of Australian Plate subduction and the arc–continent collision between Australian continent and Banda arc, and its development remains controversial. Based on the seismic, earthquake, and well datasets, we focus on these controversial problems and analyzed the deformation features and mechanism of the Timor Trough, and we established a tectonic model to discuss the arc–continent collision evolution and plate coupling. Our results and model suggest that the subsidence of the Timor Trough and uplift of the Timor Island begin at ∼3.3 Ma and marked the deformation of the Australian northwestern continental margin. We propose that the arc–continent collision underwent two phases and transformed the subduction zone into collision zone. The earliest phase uplifted and closed the forearc basin since ∼6 Ma, and the second phase of regional deformations at ∼3.3 Ma is represented by the development of backarc thrust, the cessation of volcanism, the uplift of Banda arc, and the subsidence of Timor Trough. The tearing oceanic crust provides a window for the development of backarc thrust to the southeastward. The outer and inner Banda arcs may have become a cohesive block after the collision; consequently, it is possible for them to move northward as a whole along the backarc thrust.

Evolution of Geotourism in Australia from Kanawinka Global Geopark and Australian National Landscapes to GeoRegions and Geotrails: A Review and Lessons Learned

The geological heritage of Australia’s landscapes and World Heritage areas has generally been underpromoted to the public by the tourism industry. However, in 2008, the fledgling world of geotourism in Australia received a significant boost with two events: the Inaugural Global Geotourism Conference ‘Discover the Earth beneath our Feet’ held in Fremantle, Western Australia, and the declaration of the UNESCO Kanawinka Global Geopark, which linked volcanic regions in South Australia and Victoria. Simultaneously the Australian Federal Government launched the ‘Australian National Landscapes’ (ANL) program. However, this impetus was not sustained when the Kanawinka Global Geopark was deregistered as a UNESCO-branded geopark in 2012, and the ANL program faded within a decade. Despite these setbacks, as an outcome of the 2008 Fremantle conference, several productive lines of geotourism have developed across Australia. This paper reviews the history of Australian geotourism since 2008. It examines the impacts of the experiences, lessons learned, problems for geology as perceived by National Parks and the Environment movement, geological communication problems, and the subsequent evolution of Australian geotourism. From these issues, new non-government bodies and initiatives have arisen, including the Australian Geoparks Network, the Australian Geoscience Council, and the recent development of a National Geotourism Strategy. Strong elements emerging from these initiatives are the increasing development of geotrails (which suit the large Australian continent) and the new Australian concept of ‘GeoRegions’. These are in response to an awareness that geotourism requires a flexible outlook to widen the appreciation and appeal of geological heritage and landscapes to the broader public. A further new direction is suggested: for Australian geotourism to combine with some elements of ICOMOS Cultural Routes. An outstanding example, the ICOMOS Overland Telegraph Line (OTL) Cultural Route that crosses Australia from south to north, is considered. For 2000 km, the construction of this line in the 1870s followed the regional geology and hydrology, relying upon the available biota but bringing about a clash of human cultures. The six colonies of Australia were finally linked to the world by wire, but the arrival of the OTL had a significant impact on the country’s Indigenous inhabitants. In Australia and globally, geotourism is incorporating the A–B–Cs (abiotic, biotic and cultural elements) to more effectively encourage the public to value their landscapes and the associated stories. The OTL provides an example of a newly introduced fourth dimension for geotourism, which gives consideration to the socio-political context of landscape adaptation.

Tending to tradition: Dating stone arrangement maintenance in northwest Australia using optical methods

Despite the ubiquity of Aboriginal stone arrangements around the Australian continent, there is very little data-driven information about the antiquity or development of these sites. The lack of chronological controls for these sites has limited our understanding of the timing, development, and functions of stone arrangement culture. Here, we present geochronological investigations of a stone arrangement complex near the Packsaddle Valley in the Pilbara region of Western Australia using optically stimulated luminescence (OSL) dating. Sedimentary OSL samples were collected from directly beneath the boulders that comprise the stone arrangements to estimate the timing of their emplacement. The process of boulder erection by Aboriginal people involved partial removal of the topsoil, which would only have provided the sediments with brief periods of sunlight exposure. Hence, the OSL signals of our samples were not expected to have been fully bleached during boulder erection. Consequently, the single-grain OSL equivalent dose (De) data were modelled using the unlogged Minimum Age Model to identify those grains that reflect boulder emplacement. The OSL characteristics (proportion of zero-dose grains, skewness of De distribution, and Central Age Model De) from the stone arrangement OSL samples were compared to those from natural soil samples taken adjacent to the boulders, and results show that the stone arrangement samples retain a record of boulder emplacement and do not simply reflect natural soil processes. Consequently, ages for all samples were calculated to generate a chronology for boulder emplacement at the site.Boulder emplacement proceeded from ∼1,410 years ago until ∼420 years ago, with data from four recumbent boulders indicating they collapsed ∼380 years ago. The data clearly clusters into three discrete, self-consistent phases of boulder emplacement occurring at 1,360 ± 90 years ago, 800 ± 30 years ago, and 480 ± 20 years ago. We conclude that (i) the stone arrangement complex was constructed at least 1,360 years ago, (ii) the boulders tend to fall down by natural processes and, thus, the site was subsequently visited and maintained at least twice (800 and 480 years ago) when the fallen boulders were re-emplaced, and (iii) this process ended ca. 380 years ago after which the site has not been maintained. The maintenance of the stone arrangement complex over at least 900 years demonstrates a strong connection between people, the landscape, and their imprint on the landscape.

Multiband 2D InSAR deformation models with error estimates from natural neighbour interpolation: Case study in the Latrobe Valley, Australia

A long term objective for Australia is to develop a continent-wide 2D deformation model based on satellite interferometric synthetic aperture radar (InSAR). Nation-wide InSAR processing has been demonstrated in European countries and Japan. However, there are some key differences to the Australian situation for a 2D model (i.e., vertical and east–west surface movement rates) where SAR data from ascending and descending satellite orbits are needed. The primary difference is that while ESA’s Sentinel-1 ascending and descending satellite observations underpin 2D models in other parts of the world, the Australian continent is only covered by descending Sentinel-1 SAR data in most areas. Combined with Australia’s large size of 7.63 million km2, this means a different approach is needed to realise 2D deformation models. In this article, we propose the novel approach of (1) combining supplementary multiband SAR (ascending X-band and L-band) with the descending C-band Sentinel-1 data, and (2) using natural neighbour (NN) interpolation as a computationally efficient interpolation method for combining the multiband InSAR data on common grids prior to 2D model computation. This is an alternative to the computationally intensive Ordinary Kriging (OK) approach. A disadvantage of NN compared to OK is that it does not compute an error estimate, which we address by deriving an error estimate for the NN interpolation so that errors are provided for each 2D rate to aid with their correct interpretation. To demonstrate our new approach, we compute experimental 2D deformation models that propagate the full error budget from InSAR, a GNSS connection to ITRF2014 and NN interpolation into an error grid in the Latrobe Valley in southeast Australia. The significance of our approach is that it provides a suitable combination of methods that may be used to develop 2D continental deformation models for Australia’s unique circumstances. Our results demonstrate the accuracy of NN and OK interpolation are at the same level (within error), and the error estimates from both interpolation techniques are also comparable: X band (TerraSAR-X) ∼ 1 mm/yr; C band (Sentinel-1) ∼ 2.5 mm/yr, and L band (ALOS PALSAR1) 4 mm/yr. For the first time, we reveal 2D deformation in the Latrobe Valley region showing horizontal east–west deformation in the area surrounding an above-ground mine and reaching 20 mm/yr, with vertical subsidence rates reaching −40 mm/yr.

Investigating hafting and composite tool repair as factors creating variability in backed artefacts: Evidence from Ngungara (Weereewa/Lake George), south‐eastern Australia

ABSTRACTAcross the Australian continent, backed artefacts are produced in enormous numbers during the mid‐late Holocene. Previous examinations have revealed variation in the average shape of these artefacts, at both continental and regional scales. To better understand the factors creating this variability, we examine a large assemblage of backed artefacts from Ngungara (Weereewa/Lake George), in south‐eastern Australia. This is one of the few open sites in Australia which has high‐resolution evidence for spatially distinct, short‐term workshops. Within these well‐bounded workshops both locally manufactured and imported backed artefacts are present. However, across this landscape the shape of these artefacts is not uniform; rather, similarly shaped backed artefacts are concentrated in different workshop areas. Through the analysis of backed artefacts in different workshops, we suggest that “insert copying” or the replacement of spent inserts with similarly shaped, locally manufactured artefacts creates variability in backed artefact shape.

Biofilm colonization of stone materials from an Australian outdoor sculpture: Importance of geometry and exposure

The safeguarding of Australian outdoor stone heritage is currently limited by a lack of information concerning mechanisms responsible for the degradation of the built heritage. In this study, the bacterial community colonizing the stone surface of an outdoor sculpture located at the Church of St. John the Evangelist in Melbourne was analysed, providing an overview of the patterns of microbial composition associated with stone in an anthropogenic context. Illumina MiSeq 16S rRNA gene sequencing together with confocal laser microscope investigations highlighted the bacterial community was composed of both phototrophic and chemotrophic microorganisms characteristic of stone and soil, and typical of arid, salty and urban environments. Cardinal exposure, position and surface geometry were the most important factors in determining the structure of the microbial community. The North-West exposed areas on the top of the sculpture with high light exposure gave back the highest number of sequences and were dominated by Cyanobacteria. The South and West facing in middle and lower parts of the sculpture received significantly lower levels of radiation and were dominated by Actinobacteria. Proteobacteria were observed as widespread on the sculpture. This pioneer research provided an in-depth investigation of the microbial community structure on a deteriorated artistic stone in the Australian continent and provides information for the identification of deterioration-associated microorganisms and/or bacteria beneficial for stone preservation.

Diversity in Australia: An Evolutionary Confirmation through Darwin’s Explanation

This article aims to study and analyse the factors mentioned by Charles Darwin in his book, On the Origin of Species with respect to the unique flora and fauna found in the Australian continent. Natural selection and adaptability of the organisms meet at an inimitable point to develop their progeny. The way of utilization of the process, natural selection to convince the successful formation of new progeny is admirable and it has a factual strength of science.

Large-scale quantification of groundwater recharge threshold conditions using machine learning classifications: An attempt over the Australian continent

The large-scale quantification of groundwater recharge threshold conditions is a bottleneck in the field of research, considering that groundwater recharge processes can be quite complex and affected by different factors in different regions. Traditional statistical approaches have either focused on local to regional scales or are limited to a single factor such as rainfall, resulting in a lack of a comprehensive understanding of groundwater recharge mechanisms on large scales. Considering that finding a threshold to instantly determine whether the groundwater is in the state of recharge or discharge is a classification task involving multiple factors, machine learning techniques with self-learning capabilities, efficient processing of big data, and mining relationships between multiple factors is, thus, applied to this study. In this study, three traditional machine learning classification techniques are explored; Classification and Regression Tree (CART), Random Forest (RF), and Logistical Regression (LR), to quantify specific threshold values for each condition (including rainfall, evaporation, soil moisture, runoff and vegetation) since they are more interpretable compared to advanced machine learning techniques such as neural networks. Using the Australian continent as an example, CART is the fastest method and provides an average classification accuracy (76%) at almost the same levels compared to RF (77–78%) and LR (79–80%). Meanwhile, CART is the only method to rank the importance of conditions while providing a specific threshold for each condition. When inferring the groundwater recharge mechanism through threshold conditions, the CART method suggests that a primary (the most important) threshold condition is sufficient for most parts of the Australian continent, e.g., rainfall as the primary threshold condition in northern Australia indicates a direct recharge mechanism. Only the coastal areas of southeastern and southwestern Australia are dominated by multiple threshold conditions, showing the complex groundwater recharge mechanism. Overall, the significance of this work is to provide the spatial maps of threshold conditions that mainly control groundwater recharge and their specific threshold values, which are crucial for managers to carry out a good plan over a large area. More importantly, this study demonstrates the potential of traditional machine learning methods to reveal groundwater recharge mechanisms, which may help further refine the development of groundwater models in the future.

Soil respiration-driven CO2 pulses dominate Australia's flux variability.

The Australian continent contributes substantially to the year-to-year variability of the global terrestrial carbon dioxide (CO2) sink. However, the scarcity of in situ observations in remote areas prevents the deciphering of processes that force the CO2 flux variability. In this study, by examining atmospheric CO2 measurements from satellites in the period 2009-2018, we find recurrent end-of-dry-season CO2 pulses over the Australian continent. These pulses largely control the year-to-year variability of Australia's CO2 balance. They cause two to three times larger seasonal variations compared with previous top-down inversions and bottom-up estimates. The pulses occur shortly after the onset of rainfall and are driven by enhanced soil respiration preceding photosynthetic uptake in Australia's semiarid regions. The suggested continental-scale relevance of soil-rewetting processes has substantial implications for our understanding and modeling of global climate-carbon cycle feedbacks.

Analisis Dan Inventarisasi Famili Annonaceae Di Perumahan Gading Junti Asri, Desa Sangkanhurip, Kabupaten Bandung

The Annonaceae family is generally known as the Soursop family, which has a distribution of around 128 genera and consists of approximately 2,300 species. Annonaceae have lifeforms from bushes to trees. The family produces fruit and various other benefits. Anonnaceae family is commonly found on the Australian continent, the Asian continent, the Americas, and the African continent and tropical climates but is rarely in areas with sub-tropical climates. This descriptive study has conducted at the Gading Junti Asri Housing Complex, Sangkanhurip Village, Bandung Regency. The tool used is a smartphone camera. The materials used are identified Annonaceae plant species around the residential area of ​​Gading Junti Asri. The data used to describe is descriptive qualitative data generated by reading, studying, and reviewing literature related to morphology, taxonomy, and the benefits of plants from the Anonnaceae family found based on observations at Gading Junti Asri Housing, Sangkanhurip Village, Bandung Regency. there are five Soursop trees (Annona muricata L.) and one Srikaya tree (Annona squamosa L.). These plants have a similar morphology and live well in tropical climates. These plants have a variety of uses besides their fruit-eaten parts of trees are also beneficial in the medical field, especially pharmacology.

Pandemic Implication on Muslim Women Religiosity

The purpose of this research is to find phenomena, positive implications and negative implications of the Covid-19 pandemic on Muslim women religiosity. Allah, the Exalted and Glorious, tests men with a touch of fear, loss of property, and death. Among the forms of testing for men is the presence of disease plague. Corona virus disease (Covid-19) began to spread in Wuhan China in December 2019. Covid-19 is now a pandemic that occurs in many countries around the world. Australia is a country in the southern hemisphere consisting of the mainland of the Australian continent, the island of Tasmania and various small islands in the Indian Ocean and Pacific Ocean. Malaysia is a federal state in Southeast Asia. Indonesia is the largest archipelago country in the world and the country with the largest Muslim population in the world. The researcher chose three countries to get comprehensive results about the problem formulation in this study. The religiosity of a Muslim woman is the extent to which a Muslim woman adheres to religious values in her beliefs and practices in everyday life. The approach in this research was use a qualitative approach with the research type of case study and the design of this research is multi sites in three countries; Australia, Malaysia and Indonesia. The data were collected by using purposive sampling from key informants and snowball sampling. The result of this study indicates that: (1) There is a similar phenomenon of the Covid-19 pandemic that occurred in Australia, Malaysia and Indonesia. (2) The positive implications of the Covid-19 pandemic on the religiosity of Muslim women are on the sides: external individual religiosity, inner individual religiosity, and religiosity for social benefits. (3) The negative implication of the Covid-19 pandemic on Muslim women religiosity is on the side of religiosity which is direct-encounter and has the potential to cause crowds.

The costs of managing key threats to Australia's biodiversity

Abstract Budgeting for biodiversity conservation requires realistic estimates of threat abatement costs. However, data on threat management costs are often unavailable or unable to be extrapolated across relevant locations and scales. Conservation expenditure largely occurs without a priori cost estimates of management activities and is not recorded in ways that can inform future budgets or cost‐effective management decisions. We provided transparent, broadly applicable cost models for 18 Threat Abatement Strategies aimed at managing the processes threatening Australia's biodiversity. We defined the actions required to implement each strategy and used a consistent structure to classify costs of labour, travel, consumables and equipment. We drew upon expert knowledge and published literature to parameterise each model, estimating the implementation cost of each strategy across the Australian continent, accounting for spatial variables such as threat presence, terrain, and travel distance. Estimated annualised costs for the threat abatement strategies varied considerably between strategies and across Australia, ranging from $24 to $879,985 per km2 ($0.24–$8880 per ha). On average, labour was the largest cost component (49%), followed by consumables (37%), travel (13%) and equipment (2%). Based on national scale variables and assumptions, cost estimates across Australia for each threat abatement strategy ranged from +44% and −33% of the most common cost estimate. Policy implications. We provide a consistent and transparent approach to budgeting for threat abatement strategies, aiming to improve conservation planning processes, outcomes, and reporting across Australia. In addition, understanding the budget required to achieve threat management outcomes can aid revenue‐raising and target setting. The models, cost layers and estimates we generate provide the basis for a nationally consistent approach for estimating and recording the cost of biodiversity management strategies, which should be continually updated and improved with local‐scale information over time.

Exploring Australian hazard map exceedance using an Atlas of historical ShakeMaps

This article explores several area-based tests of long-term seismic hazard forecasts for the Australian continent. Using the observed seismicity, ShakeMaps are calculated for earthquakes that are expected to have generated moderate-to-high levels of ground shaking within continental Australia in the past 50 years (January 1972 through December 2021). A “composite ShakeMap” is generated that extracts the maximum peak ground acceleration “observed” in this 50-year period for any site within the continent. The fractional exceedance area of this composite map is compared with four generations of Australian seismic hazard maps for a 10% probability of exceedance in 50 years (~1/500 annual exceedance probability) developed since 1990. In general, all these models appear to forecast higher seismic hazard relative to the ground motions that are estimated to have occurred in the last 50 years, with the most recent hazard model yielding a fractional exceedance area most similar to the target 1/500 annual exceedance probability. The sensitivity of these results to various modeling assumptions was tested by exploring an alternative ground-motion characterization model that forecasts higher overall ground-shaking intensities. The sensitivity of these results is also tested with the interjection of a rare scenario earthquake with an expected regional recurrence of approximately 8700 years. While these area-based analyses do not provide a robust assessment of the performance of the candidate seismic hazard for any specific location given the limited independent data, they do provide—to the first order—a guide to the performance of the respective maps at a continental scale.

An Overview of the Phytochemical and Pharmacological Profile of the Spurred Mangrove <i>Ceriops tagal</i> (Perr.) C. B. Rob

Plant-based natural compounds have played a significant role in developing a variety of clinically useful therapeutic agents. Mangroves are special salt-tolerant plant communities which are known to produce a range of natural products with unique pharmacological activities. An attempt has been made to review such properties in the mangrove plant Ceriops tagal (Perr.) C. B. Rob. belonging to the Rhizophoraceae family. This species is widely spread across the coastal lines of African, Asian and Australian continents and is also commonly found in India. Traditional healers have been using this plant and its extracts to treat ailments such as ulcers, diabetes and malaria. The plant is a rich source of phytochemicals such as tannins, flavonoids, terpenes, terpenoids, phytosterols and many more novel metabolites which have conferred remarkable pharmacological activities. Reports of antibacterial, antiviral, antioxidant, antifeedant, antifouling and anticancer activities from different parts of this plant highlight its importance as a natural remedy and the need to perform more investigations to discover novel bioactive compounds to further exploit its therapeutic potential.

Litter accumulation and fire risks show direct and indirect climate-dependence at continental scale

Litter decomposition / accumulation are rate limiting steps in soil formation, carbon sequestration, nutrient cycling and fire risk in temperate forests, highlighting the importance of robust predictive models at all geographic scales. Using a data set for the Australian continent, we show that among a range of models, most of the variance in litter mass over a 40-year time span can be accounted for by a parsimonious model with elapsed time, and indices of climate and litter quality, as independent drivers. Climate is an important driver of variation in both the species identity of dominant eucalypts and litter accumulation across the continent. Litter quality shows emergent properties of climate-dependence and contributes to explained variance. Nonetheless, elapsed time dominated explained variance in litter mass (up to 90%) at continental scale. Results provide guidance for future decomposition studies. Algorithms reported here can significantly improve accuracy and reliability of predictions of carbon and nutrient dynamics and fire risk.