Northwest Western Australia Research Articles

Native-plant amendments and topsoil addition enhance soil function in post-mining arid grasslands

One of the most critical challenges faced in restoration of disturbed arid lands is the limited availability of topsoil. In post-mining restoration, alternative soil substrates such as mine waste could be an adequate growth media to alleviate the topsoil deficit, but these materials often lack appropriate soil characteristics to support the development and survival of seedlings. Thus, addition of exogenous organic matter may be essential to enhance plant survival and soil function. Here, we present a case study in the arid Pilbara region (north-west Western Australia), a resource-rich area subject to intensive mining activities. The main objective of our study was to assess the effects of different restoration techniques such as soil reconstruction by blending available soil materials, sowing different compositions of plant species, and addition of a locally abundant native soil organic amendment (Triodia pungens biomass) on: (i) seedling recruitment and growth of Triodia wiseana, a dominant grass in Australian arid ecosystems, and (ii) soil chemical, physical, and biological characteristics of reconstructed soils, including microbial activity, total organic C, total N, and C and N mineralisation. The study was conducted in a 12-month multifactorial microcosms setting in a controlled environment. Our results showed that the amendment increased C and N contents of re-made soils, but these values were still lower than those obtained in the topsoil. High microbial activity and C mineralisation rates were found in the amended waste that contrasted the low N mineralisation but this did not translate into improved emergence or survival of T. wiseana. These results suggest a short- or medium-term soil N immobilisation caused by negative priming effect of fresh un-composted amendment on microbial communities. We found similar growth and survival rates of T. wiseana in topsoil and a blend of topsoil and waste (50:50) which highlights the importance of topsoil, even in a reduced amount, for plant establishment in arid land restoration.

Marine heatwave causes unprecedented regional mass bleaching of thermally resistant corals in northwestern Australia

In 2015/16, a marine heatwave associated with a record El Niño led to the third global mass bleaching event documented to date. This event impacted coral reefs around the world, including in Western Australia (WA), although WA reefs had largely escaped bleaching during previous strong El Niño years. Coral health surveys were conducted during the austral summer of 2016 in four bioregions along the WA coast (~17 degrees of latitude), ranging from tropical to temperate locations. Here we report the first El Niño-related regional-scale mass bleaching event in WA. The heatwave primarily affected the macrotidal Kimberley region in northwest WA (~16°S), where 4.5–9.3 degree heating weeks (DHW) resulted in 56.6–80.6% bleaching, demonstrating that even heat-tolerant corals from naturally extreme, thermally variable reef environments are threatened by heatwaves. Some heat stress (2.4 DHW) and bleaching (<30%) also occurred at Rottnest Island (32°01’S), whereas coral communities at Ningaloo Reef (23°9’S) and Bremer Bay (34°25’S) were not impacted. The only other major mass bleaching in WA occurred during a strong La Niña event in 2010/11 and primarily affected reefs along the central-to-southern coast. This suggests that WA reefs are now at risk of severe bleaching during both El Niño and La Niña years.

Theoretical effects of industrial emissions on colour change at rock art sites on Burrup Peninsula, Western Australia

Burrup Peninsula in northwest Western Australia, with an estimated one million petroglyphs, has the world's largest concentration of ancient rock art. It is one of a few places in the world where a continuous history of people living with a changing environment for over 40,000years is recorded through rock art. The art is under threat due to high concentrations of acidic and nitrate-rich pollution from nearby industrial complexes. Maintenance of the outer, rock or desert varnish, layer of the rocks is essential for preservation of the art. An increase in acidity of rock surfaces through acid rain and organic acids from nitrate-stimulated microbial growth may alter the mineral composition, integrity and colour of the rock varnish. This paper describes analyses of distilled water washings from rocks on Burrup Peninsula compared with rocks collected prior to industrialisation. Acidity of rock surfaces has increased from near neutral to a pH just above 4. The increasing acidity has been associated with a logarithmic increase in solubilisation of manganese (Mn) and iron (Fe) compounds from the rock surfaces. A theoretical evaluation using electrochemical equilibrium principles confirms that increasing acidity will increase the solubilisation of Mn and Fe compounds. Removal of darker Mn and Fe mixed M(II)/M(III) compounds from the outer, rock varnish layer and the relative increase in ferrous oxide and illite/kaolin compounds will result in the rock surface layers becoming thinner, lighter, redder and more white/yellow over time. The impact on engraved surfaces would be expected to be greater because the rock varnish is thinner than on the non-engraved surface rock. Pollution from industry on Burrup Peninsula is likely to destroy the rock art over time.

Benefits of adopting seed-based technologies for rehabilitation in the mining sector: a Pilbara perspective

The use of native plant seeds is fundamental to large-scale rehabilitation and the re-establishment of self-sustaining ecosystems after high-impact mining activity has ceased. However, many of the biological attributes of seeds are often overlooked in large-scale rehabilitation programs. Multi-disciplinary, long-term research collaborations are required to improve seed-based mine rehabilitation. In this paper, we review the steps that BHP Western Australia Iron Ore (WAIO), a large iron ore mining company that operates in the Pilbara bioregion of north-west Western Australia, has taken over the past 9 years to ensure continuous improvement in rehabilitation procedures. We introduce the mining activities that WAIO undertake in the Pilbara, and emphasise specific examples of how research findings have led to incremental improvements in the seed management cycle, growth media management and mine rehabilitation practices. Specifically, we outline how the implementation of structured seed collection and storage programs has created the capacity to maintain high-quality seed stocks sufficient for 3–5 years of future rehabilitation. Research has documented the prevalence of seed dormancy in the flora (&gt;70% of 105 species examined produce dormant seeds), with physical and physiological classes of dormancy most commonly encountered. We discuss the development of seed-treatments such as optimised wet-heat and dry after-ripening that have increased the germination capacity of many previously dormant seed batches. In addition, we highlight how seed enhancement technologies, such as hydro-priming with smoke-derived germination stimulants and polymer seed coating, and a greater understanding of the biological and physical limitations present in the growing environment, have vastly improved seedling emergence performance under field conditions for key framework Triodia species. Ongoing industry support (e.g. construction of a purpose-built rain manipulation shelter) has ensured research in the Pilbara will continue to unpack and resolve the complex challenges associated with seed regeneration of biodiverse native plant communities after mining.

Ending isolation? Leprosy, welfare and Indigenous Australians 1950–86

When Derby leprosarium in north-west Western Australia closed its doors in 1986, it finally ended the century-old Australian public health policy of detaining people with leprosy at special sites of isolation. As with its counterparts in the Northern Territory and northern Queensland - East Arm and Fantome Island, which closed in 1982 and 1973 respectively - the vast majority of patients were Indigenous Australians, mostly from remote parts of the continent. Under state and territory health legislation, these people could be compelled to enter the leprosarium and submit to treatment for as long as departmental authorities deemed. Members of other races were also susceptible to leprosy, but, from the late 1950s, most were treated for short periods in hospitals or at home, rather than in a leprosarium.

Reducing primary health care outpatient "did not attends": Responding to community preferences.

[Extract] This study site is an acute-care 12 bed hospital situated in remote north-west Western Australia and which services around 3500 residents. Sixty per cent of the township population is Aboriginal, increasing to 100% in the catchment region. Community access to health care is via the Hospital Emergency Department (ED) generating a high volume of Triage Level 4 (Semi-urgent) and Level 5 (Non-urgent) cases into an acute-care system.

Potato spindle tuber viroid: alternative host reservoirs and strain found in a remote subtropical irrigation area

During 2007–2012, Potato spindle tuber viroid (PSTVd) was detected in volunteer cultivated, wild and native plants during studies to determine whether Pospiviroids occur within the isolated, sub-tropical, Gascoyne Horticultural District (GHD) in central coastal Western Australia (WA). PSTVd was detected infecting volunteer crop plants of tomato, pepper and chilli; introduced weed species Solanum nigrum (blackberry nightshade), Datura leichhardtii (thornapple) and Nicandra physalodes (apple-of-Peru) (Solanaceae), and Conyza bonariensis (flaxleaf fleabane) (Asteraceae); and Australian native species Atriplex semilunaris (annual saltbush), Rhagodia eremaea (thorny saltbush) (Chenopodiaceae), and Streptoglossa sp. (Asteraceae). PSTVd was also detected infecting Physalis angulata (wild gooseberry) in the Ord River Irrigation Area (ORIA), Kimberley region in north-west WA. Comparison of sequences from the three complete and 18 partial RNA nucleotide sequences obtained from 20 GHD and one ORIA isolates with those of published sequences showed that their highest nucleotide sequence identities were to isolate AY962324 belonging to the Chittering strain from south-west WA. On phylogenetic analysis, the three completely sequenced GHD PSTVd isolates grouped within a cluster of isolates from tomato and P. peruviana. These results show that a naturally occurring PSTVd inoculum reservoir is present in the GHD. This reservoir explains the occurrence of repeated PSTVd infections in different years in field crops of tomato, pepper and chilli growing in its market gardens and small farms. These findings have implications concerning PSTVd spread in intensive solanaceous crop field production systems in other subtropical regions of the world.

Changes in Tropical Cyclone Activity over Northwest Western Australia in the Past 50 Years and a View of the Future 50 Years

Abstract In the first half of this research, this study examines the trend in tropical cyclone (TC) activity over the economically important northwest Western Australia (NWA) TC basin (equator–40°S, 80°–140°E) based on statistical analyses of the International Best Track Archive for Climate Stewardship (IBTrACS) and large-scale environmental variables, which are known to be closely linked to the formation and longevity of TCs, from NCEP–NCAR reanalyses. In the second half, changes in TC activity from climate model projections for 2000–60 are compared for (i) no scenario change (CNTRL) and (ii) the moderate IPCC Special Report on Emission Scenarios (SRES) A1B scenario (EGHG). The aims are to (i) determine differences in mean annual TC frequency and intensity trends, (ii) test for differences between genesis and decay positions of CNTRL and EGHG projections using a nonparametric permutation test, and (iii) use kernel density estimation (KDE) for a cluster analysis of CNTRL and EGHG genesis and decay positions and generate their probability distribution functions. The main findings are there is little difference in the mean TC number over the period, but there is a difference in mean intensity; CNTRL and EGHG projections differ in mean genesis and decay positions in both latitude and longitude; and the KDE reveals just one cluster in both CNTRL and EGHG mean genesis and decay positions. The EGHG KDE is possibly disjoint, with a wider longitudinal spread. The results can be explained in terms of physical, meteorological, and sea surface temperature (SST) conditions, which provide natural limits to the spread of the genesis and decay points.

Sensitivity of Tropical Cyclone Tracks and Intensity to Ocean Surface Temperature: Four Cases in Four Different Basins

This study investigates the sensitivity of tropical cyclone (TC) motion and intensity to ocean surface fluxes that, in turn, are directly related to sea surface temperatures (SSTs). The Advanced Research version of the Weather Research and Forecast (WRF-ARW) model is used with an improved parameterisation of surface latent heat flux account for ocean salinity. The WRF-ARW simulations compare satisfactorily with the NCEP/NCAR reanalysis for atmospheric fields and remotely sensed precipitation fields, with the model providing details lacking in coarse resolution observations. Among four TCs investigated, except the one re-developed from a previous TC remnant, the stretching term dominates the relative vorticity generation, and a bottom-up propagation mechanism holds for the three TCs. For the Tropical Rainfall Measuring Mission (TRMM) precipitation, the spatial ranges are accurate but actual rainfall rates are significantly larger than those remotely sensed. This indicates the value of numerical simulation in quantitative rainfall precipitation estimation (QPE) for TCs. Sensitivity experiments are performed with altered SSTs and changes in tracks and intensity are examined. A TC-dependent threshold wind speed is introduced in defining total kinetic energy, a measure of TC intensity, so arbitrariness in domain setting is avoided and inter-basin comparisons are possible. The four TCs selected from different global basin show that the intensity increases with increasing SST. Within a domain, a power–law relationship applies. More important, warmer SST indicates a more rapid intensification, quicker formation and reduced warning issuance time for emergency services. The influence of SSTs on TC track is more complex and lacks a generic relationship. For the South Pacific basin, higher SSTs favour a more northerly track. These TCs occasionally cross continental Australia and redevelop in the southern Indian Ocean basin, affecting the resource-rich onshore and offshore industrial developments in northwest Western Australia. In the Atlantic basin (e.g. Katrina 2005), when SSTs increase, the TC tracks tend to curve over warm pools but generally have a shorter ocean-residence time. When the synthesised SST fields are raised 2°C above Katrina (i.e. >32°C), the possibility exists of generating two TCs in close proximity. That lack of unanimity of the impacts on TC tracks, in response to synthesised SSTs, partly arises from the complicated response of subtropical highs, which may be disintegrated into several pieces and dispersed with relatively lower pressure regions, which may become the shortcuts when a TC traces the periphery of the subtropical high.

The Development of an Interpretive Experience to Foster Positive Tourist Encounters and Manage Turtle Tourism in Northwest Western Australia: Implications for Further Research

In understanding the importance of interpretation in guiding sustainable turtle tourism, this article reports on the effect of an interpretation program, the Jurabi Turtle Experience (JTE), on the behavior of turtle-watching tourists at the Jurabi Coastal Park, on the Northwest Cape of Western Australia. Ninety-seven turtle-watching tourists in the Jurabi Coastal Park, including people who attended the JTE and others who did not, were sampled during the peak turtle nesting season (December–January) using participant observation and a questionnaire. People participating in the JTE showed increased compliance with a behavioral code of conduct for turtle watching and higher satisfaction with the experience compared with people who did not participate. These increases strengthen the case for continuing the JTE and possibly requiring all Jurabi Coastal Park visitors to participate in a JTE-like experience.

Multi year observations reveal variability in residence of a tropical Demersal Fish, Lethrinus nebulosus: implications for spatial management.

Off the Ningaloo coast of North West Western Australia, Spangled Emperor Lethrinus nebulosus are among the most highly targeted recreational fish species. The Ningaloo Reef Marine Park comprises an area of 4,566 km2 of which 34% is protected from fishing by 18 no-take sanctuary zones ranging in size from 0.08–44.8 km2. To better understand Spangled Emperor movements and the adequacy of sanctuary zones within the Ningaloo Reef Marine Park for this species, 84 Spangled Emperor of a broad spectrum of maturity and sex were tagged using internal acoustic tags in a range of lagoon and reef slope habitats both inside and adjacent to the Mangrove Bay Sanctuary zone. Kernel Utilisation Distribution (KUD) was calculated for 39 resident individuals that were detected for more than 30 days. There was no relationship with fish size and movement or site fidelity. Average home range (95% KUD) for residents was 8.5±0.5 km2 compared to average sanctuary zone size of 30 km2. Calculated home range was stable over time resulting in resident animals tagged inside the sanctuary zone spending ∼80% of time within the sanctuary boundaries. The number of fish remaining within the array of receivers declined steadily over time and after one year more than 60% of tagged fish had moved outside the sanctuary zone and also beyond the 28 km2 array of receivers. Long term monitoring identified the importance of shifting home range and was essential for understanding overall residency within protected areas and also for identifying spawning related movements. This study indicates that despite exhibiting stable and small home ranges over periods of one to two years, more than half the population of spangled emperor move at scales greater than average sanctuary size within the Ningaloo Reef Marine Park.

Cytogeography of essential oil chemotypes of Eremophila longifolia F. Muell (Scrophulariaceae)

Previous studies have demonstrated that the widely distributed desert plant Eremophila longifolia has at least six geographically defined essential oil chemotypes. The focus of the present study is to extend and enhance information concerning known chemotypes and to investigate the involvement of cell nuclei ploidy in this variation. Forty field collected specimens of E. longifolia were taken from most of the mainland states of Australia then subjected to hydrodistillation to produce essential oils, which were then chemically characterised. Ploidy was determined using relative fluorescence of cell nuclei stained with propidium iodide, measured in a flow cytometer. Using principal component analysis (PCA), at least three essential oil chemotypes, in addition to the six already described, were identified in the present study. Previously described high yielding essential oil chemotypes were also characterised in terms of diploidy. For the first time diploid populations were identified in New South Wales, correlating with high yielding isomenthone/menthone and karahanaenone chemotypes. Furthermore, the separate diploid population previously described from Western Australia was demonstrated to be the safrole/methyl eugenol type, which is restricted to a small geographic range in far north-west Western Australia (Murchison District). All other chemotypes were shown to be tetraploid, including apparently randomly emerging individuals, representative of chemotypes producing low yields of isomenthone/menthone and karahanaenone similar in composition to the high yielding diploid types.

Links between Central West Western Australian Rainfall Variability and Large-Scale Climate Drivers

AbstractOver the past century, and especially after the 1970s, rainfall observations show an increase (decrease) of the wet summer (winter) season rainfall over northwest (southwest) Western Australia. The rainfall in central west Western Australia (CWWA), however, has exhibited comparatively much weaker coastal trends, but a more prominent inland increase during the wet summer season. Analysis of seasonally averaged rainfall data from a group of stations, representative of both the coastal and inland regions of CWWA, revealed that rainfall trends during the 1958–2010 period in the wet months of November–April were primarily associated with El Niño–Southern Oscillation (ENSO), and with the southern annular mode (SAM) farther inland. During the wet months of May–October, the Indian Ocean dipole (IOD) showed the most robust relationships. Those results hold when the effects of ENSO or IOD are excluded, and were confirmed using a principal component analysis of sea surface temperature (SST) anomalies, rainfall wavelet analyses, and point-by-point correlations of rainfall with global SST anomaly fields. Although speculative, given their long-term averages, reanalysis data suggest that from 1958 to 2010 the increase in CWWA inland rainfall largely is attributable to an increasing cyclonic anomaly trend over CWWA, bringing onshore moist tropical flow to the Pilbara coast. During May–October, the flow anomaly exhibits a transition from an onshore to offshore flow regime in the 2001–10 decade, which is consistent with the observed weaker drying trend during this period.

Keeping Australia’s islands free of introduced rodents: the Barrow Island example

Islands are important reservoirs of endemic and threatened species, but anthropogenic influences have impacted their biotas. Australia has over 8000 islands, both continental and oceanic, but because of considerably increased traffic, both tourist and commercial, many of these islands have been and are subject to increased threats from invasive species. The invasive Black Rat Rattus rattus is of particular concern as it can negatively impact mammal, bird, reptile, invertebrate and plant populations. Barrow Island, in northwest Western Australia, is an island requiring particular protection from Black Rats as it is a Class A nature reserve with many unique and threatened taxa that is subject to major disturbances from activities associated with oil extraction and a large liquefied natural gas processing plant. Strict quarantine is currently imposed on all materials and persons being sent to the island and there is an intense on-island surveillance programme. So far the protocols used have prevented Black Rats establishing on this island, but such a level of biosecurity is clearly impossible for all islands. In this paper we discuss the effectiveness of quarantine inspections and surveillance together and alone in protecting high-risk, high-value Australian islands against introduced rodents and we document eradication costs for other islands. World-wide, it has only been possible so far to eradicate rats from relatively small islands, mostly with no non-target indigenous mammals and larger islands only where there are no non-target indigenous mammals. Models based largely on economic considerations have suggested it is more cost effective to use surveillance alone without quarantine for Black Rats on Barrow Island and that if rats become widespread (an estimated 4% risk), it may be more cost effective not to attempt eradication. Such models provide useful guidance for managers where biodiversity values are relatively low or where there are no non-target species, but for Barrow island we argue for continuation of quarantine as well as surveillance and an increased level of quarantine controls at the point of departure on all people, vessels and aircraft visiting other vulnerable Australian islands.

Costacosa, a new genus of wolf spider (Araneae, Lycosidae) from coastal north-west Western Australia

– A new genus of wolf spider (family Lycosidae Sundevall, 1833), Costacosa gen. nov. is described from north-west Western Australia to include C. torbjorni sp. nov. (type species) and C. dondalei sp. nov.

Testing Potential New Sites for Optical Telescopes in Australia

AbstractIn coming years, Australia may find the need to build new optical telescopes to continue local programmes, contribute to global survey projects, and form a local multi-wavelength connection for the new radio telescopes being built. In this study, we refine possible locations for a new optical telescope by studying remotely sensed meteorological infrared data to ascertain expected cloud coverage rates across Australia, and combine these data with a digital elevation model using a geographic information system. We find that the best sites within Australia for building optical telescopes are likely to be on the highest mountains in the Hamersley Range in northwest Western Australia, while the MacDonnell Ranges in the Northern Territory may also be appropriate. We believe that similar seeing values to Siding Spring should be obtainable and with significantly more observing time at the identified sites. We expect to find twice as many clear nights as at current telescope sites. These sites are thus prime locations for future on-site testing.

Growing Up the Future: Children's Stories and Aboriginal Ecology

Growing Up the Future: Children's Stories and Aboriginal Ecology

‘In view of the obvious animus’. The discrediting of Ralph Piddington

A study describing Chief Protector of Aborigines in Western Australia, AO Neville's successful attempt to discredit Ralph Piddington by scrutinising his personal behaviour, to avert the veracity of the allegations made by Piddington, and the inadequacies of Neville's department. By this strategy the seriousness of the allegations made by Piddington about the ill-treatment and conditions of Aborigines at La Grange Bay in Northwest Western Australia are expunged. It is my contention that there was a deliberate effort by Neville to mislead the Australian National Research Council (ANRC), his Minister (W.H. Kitson) and the Royal Commissioner (H.D. Moseley), with regard to the substance of Piddington's allegations, and with regard to the recommendations made by a departmental inquiry and police reports. The consequences for Piddington were considerable.

Twentieth Century Winter Changes in Southern Hemisphere Synoptic Weather Modes

During the last sixty years, there have been large changes in the southern hemisphere winter circulation and reductions in rainfall particularly in the southern Australian region. Here we examine the corresponding changes in dynamical modes of variability ranging from storm tracks, onset-of-blocking modes, northwest cloud-band disturbances, Antarctic low-frequency modes, intraseasonal oscillations, and African easterly waves. Our study is performed using a global two-level primitive equation instability-model with reanalyzed observed July three-dimensional basic states for the periods 1949–1968, 1975–1994, and 1997–2006. We relate the reduction in the winter rainfall in the southwest of Western Australia since the mid-1970s and in south-eastern Australia since the mid-1990s to changes in growth rate and structures of leading storm track and blocking modes. We find that cyclogenesis and onset-of-blocking modes growing on the subtropical jet have significantly reduced growth rates in the latter periods. On the other hand there is a significant increase in the growth rate of northwest cloud-band modes and intraseasonal oscillation disturbances that cross Australia and are shown to be related to recent positive trends in winter rainfall over northwest Western Australia and central Australia, in general. The implications of our findings are discussed.

On Dreams, Innovation and the Emerging Genre of the Individual Artist

Amongst Bardi of north-west Western Australia, ilma is a genre of dreamt material that has three interrelated components: song, dance and ‘totem’ (a string and plywood object carried during the dance). These constituent parts, along with the whole, are referred to as ilma. This article considers the social tensions surrounding the commodification of one of these elements, the ‘totem’, as art. The production of ilma for the art market largely precludes the development of associated songs and dances, and their integration into group repertoire, giving rise to tensions between social expectations about such dreamt material and those of the person who dreams them. These tensions reflect Bardi understandings of the provenance of this dreamt material, as ancestrally revealed: hence dreamt songs, dances and objects belonging to this ritual genre are not considered as creative works produced by a person or persons. Contestations over ‘tradition’ and ‘culture’ in this context highlight the tensions between the forces of convention and those of innovation in times of social change, in which the emergence of persons as creative individuals may be understood as signalling broader societal transformation.