Pilbara Region Research Articles

Regional Partnerships: Building a Future Regional Workforce in Western Australia

Following the success of a pre-service teacher hub in the Pilbara region of Western Australia, a decision was made to establish a second hub within the same region in another town. The second hub will be a collaboration between the Pilbara Universities Centre (PUC) and the Western Australian Department of Education. Although the PUC does not currently train teachers, it does, however, provide administrative, academic and pastoral support to a range of local education students studying at both bachelor and post-graduate levels in the field of education. The PUC also has students from many other disciplines who can add to the depth of the pre-service teacher hub. The PUC has the potential to grow, and it makes sense for the Department of Education’s pre-service teacher hub to work in collaboration with the PUC to develop regional employees. The hub provides a way to connect and upskill not just pre-service teachers, but also students from other disciplines.

Understanding and improving temporary road sign stability

Temporary road signage is used throughout road networks to regulate traffic and provide warnings to road users. Wind and other factors induce frequent falling of temporary road signage and are a major road safety concern that needs to be addressed. The main aim of this paper was to gain an understanding of temporary road sign stability in the presence of passing road trains and investigate the possibility of stabilising temporary road signage through appropriate design modifications. Simulations and experimental trials were carried out to assess the stability of current temporary road signs used in the industry. This analysis used Ansys Fluent to simulate fluid dynamics in order to infer road sign stability. A field experimental trial was performed in Western Australia’s Pilbara Region using a modified temporary road sign developed based on the outcome of the Ansys simulation. The findings from the simulations showed that the current design is unstable and highly prone to wind induced failure. The simulations suggest that road train transit at 100 km/h is capable of inducing approximately 8 m/s wind velocity in the proximity of the sign, which is greater than that permissible for a rigid sign with no leg mobility. Field trials showed that the modified sign remained stable at 1.2 m from the edge line although it was still prone to falling over at closer distances.

Aerial abundance estimates for two sympatric dolphin species at a regional scale using distance sampling and density surface modeling

Monitoring wildlife populations over scales relevant to management is critical to supporting conservation decision-making in the face of data deficiency, particularly for rare species occurring across large geographic ranges. The Pilbara region of Western Australia is home to two sympatric and morphologically similar species of coastal dolphins—the Indo-pacific bottlenose dolphin (Tursiops aduncus) and Australian humpback dolphin (Sousa sahulensis)—both of which are believed to be declining in numbers and facing increasing pressures from the combined impacts of environmental change and extensive industrial activities. The aim of this study was to develop spatially explicit models of bottlenose and humpback dolphin abundance in Pilbara waters that could inform decisions about coastal development at a regional scale. Aerial line transect surveys were flown from a fixed-wing aircraft in the austral winters of 2015, 2016, and 2017 across a total area of 33,420 km2. Spatio-temporal patterns in dolphin density were quantified using a density surface modeling (DSM) approach, accounting for imperfect detection as well as both perception and availability bias. We estimated the abundance of bottlenose dolphins at 3,713 (95% CI = 2,679–5,146; average density of 0.189 ± 0.046 SD individuals per km2) in 2015, 2,638 (95% CI = 1,670–4,168; 0.159 ± 0.135 individuals per km2) in 2016 and 1,635 (95% CI = 1,031–2,593; 0.101 ± 0.103 individuals per km2) in 2017. Too few humpback dolphins were detected in 2015 to model abundance, but their estimated abundance was 1,546 (95% CI = 942–2,537; 0.097 ± 0.03 individuals per km2) and 2,690 (95% CI = 1,792–4,038; 0.169 ± 0.064 individuals per km2) in 2016 and 2017, respectively. Dolphin densities were greatest in nearshore waters, with hotspots in Exmouth Gulf, the Dampier Archipelago, and Great Sandy Islands. Our results provide a benchmark on which future risk assessments can be based to better understand the overlap between pressures and important dolphin habitats in tropical northwestern Australia.

Two new species of burrowing scorpions (Urodacidae: Urodacus) from the Pilbara region of Western Australia with identical external morphology†

Two new species of urodacid scorpion are described from the Pilbara region in Western Australia, where they are both patchily distributed along creek lines in the north-east of the region. Urodacus uncinus sp. nov. and Urodacus lunatus sp. nov. are indistinguishable based on external morphology: adults are medium-sized, yellow burrowing scorpions with remarkable sexual dimorphism in the telson, in which males have a uniquely swollen vesicle and an aculeus that is more strongly curved than other known species of Urodacus. The species are superficially similar to Urodacus similis L.E. Koch, 1977 and Urodacus yaschenkoi Birula, 1903 in the morphology of the first four metasomal segments, which are extremely short and not much longer than high. The two new species can only be discerned from each other based on the morphology of their hemispermatophores, which highlights the extremely conserved morphology of species in the genus and suggests that many new species await description with careful examination of their genitalia.

A review of progress of a research program for the endangered northern quoll (Dasyurus hallucatus) in the multi-use landscapes of the Pilbara

Maximising conservation outcomes for threatened species in multi-use landscapes is likely to require a multi-stakeholder, coordinated approach that is tenure blind. Here, we conduct a review of a research program targeting the endangered northern quoll (Dasyurus hallucatus) in the Pilbara region of Western Australia; an area with a high concentration of mining and pastoral activities. To inform ongoing investment to support northern quoll conservation, we identify future directions that either add value to research already undertaken or are based on the original priorities that have not been addressed. The original program was developed using a collaborative process involving workshops attended by multiple stakeholders to identify research priorities. To date, the program has significantly improved our knowledge of Pilbara northern quolls, particularly in relation to effective survey and monitoring techniques, the influence of habitat quantity, configuration, and composition on occupancy, movement ecology, population dynamics and structure, and the threat posed by introduced predators. The efficacy of artificial refuges that were created to replicate natural denning habitat has also been investigated. Suggested future research directions focus on refining the northern quoll regional monitoring program, understanding how interacting threats such as introduced predators, fire, and herbivore grazing influence northern quoll populations in the Pilbara, and how best to mitigate other threats such as mining associated activities and the impending cane toad invasion.

Flash flaming is a valid seed enhancement for a diverse range of species and seed morphologies

Flash flaming has shown promise as a seed enhancement technology that improves the handling properties of bulky or irregularly shaped seed material, which in turn benefits logistical and ecological aspects of large-scale direct seeding. To date, only a small number of grass species, that possess similar morphological characteristics, have been tested. This paper describes the application of flash flaming to diaspores (i.e. the dispersal unit comprising the seed and any surrounding or attached tissues) of 19 diverse dryland species from the Amaranthaceae, Asteraceae, Chenopodiaceae and Poaceae critical to ecological restoration in the mining intensive Pilbara region of Western Australia. Flash flaming parameters for each species were tested to identify and maximise volume and mass reduction, reduce particle cohesiveness and maximise flow through a mechanical seeding device, whilst maximising germination. Flaming of all species resulted in reductions in batch volume and mass, and improvements to flow characteristics. For 17 species, flaming either benefited or did not impact on germinability. For two species in the Amaranthaceae, flaming with the settings tested here resulted in a reduction in germinability; however, flaming enabled the diaspores to pass through a mechanical seeding device enabling mechanical distribution which is critical if the species are to be used in large scale restoration.

Morphometric classification of kangaroo bones reveals paleoecological change in northwest Australia during the terminal Pleistocene

Specimen identification is the backbone of archeozoological research. The challenge of differentiating postcranial skeletal elements of closely related wild animals in biodiverse regions can prove a barrier to understanding past human foraging behaviours. Morphometrics are increasingly being employed to classify paleozoological animal remains, however, the potential of these methods to discriminate between wild animal groups has yet to be fully realised. Here we demonstrate the applicability of a traditional morphometric approach to taxonomically classify foot and ankle bones of kangaroos, a large and highly diverse marsupial family. Using multiple discriminant analysis, we classify archaeological specimens from Boodie Cave, in northwest Australia and identify the presence of two locally extinct macropod species during the terminal Pleistocene. The appearance of the banded hare-wallaby and northern nail-tail wallaby in the Pilbara region at this time provides independent evidence of the ecological and human responses to a changing climate at the end of the last Ice Age. Traditional morphometrics provides an accessible, inexpensive, and non-destructive tool for paleozoological specimen classification and has substantial potential for applications to other diverse wild faunas.

<i>Corrigendum to</i>: Cryptic diversity down under: defining species in the subterranean amphipod genus <i>Nedsia</i> Barnard & Williams, 1995 (Hadzioidea: Eriopisidae) from the Pilbara, Western Australia

Amphipod crustaceans comprise a significant and enigmatic component of Australian groundwater ecosystems, particularly in the Pilbara region of Western Australia. Many amphipod species in the Pilbara, including species in the genus <i>Nedsia</i> <a href="#R1">Barnard & Williams, 1995</a>, are considered short range endemics, poorly or contentiously defined by taxonomic treatments based on morphology alone and have uncertain distributions as a consequence of this taxonomy. A modern systematic revision of <i>Nedsia</i> is presented here, utilising both molecular and morphological analyses alongside distributional data to delineate species. We describe 13 new species of <i>Nedsia</i>, confirm three existing species and synonymise eight previously described species. <i>Nedsia</i> species are confirmed to be functionally morphologically cryptic, with <i>COI</i> divergences at the 5–20% level. We present comparatively reduced taxonomic descriptions for these cryptic amphipod species in an effort to provide an accelerated pathway for future taxonomic work. The research provides the basis for future environmental impact assessments involving <i>Nedsia</i> species and ongoing monitoring of the groundwater communities these form part of in the resource-rich Pilbara region.

Comparison of Regionalisation Techniques for Peak Streamflow Estimation in Small Catchments in the Pilbara, Australia

Arid and semi-arid regions typically lack high-resolution river gauging data causing difficulties in understanding rainfall-runoff patterns. A common predictive method for discharge estimation within ungauged catchments is regional flood frequency estimation (RFFE), deriving peak discharge estimates from similar, gauged catchments and applying them to the catchment of interest. The majority of RFFE equations are developed for larger catchments where flow events may be larger and of greater interest. We test a series of RFFE methods derived for the Pilbara region, applying them to new ungauged small catchments under 10 km2. Rainfall values are derived from a guideline Australian design rainfall database, Australian Rainfall and Runoff 2019 (ARR2019) which was recently updated with an additional 30 years of rainfall data. RFFE equations are compared to a direct rainfall model to evaluate their performance within small catchments, identifying key limitations and considerations when modelling small headwater catchments.

Phosphorus sorption characteristics and interactions with leaf litter-derived dissolved organic matter leachate in iron-rich sediments of a sub-tropical ephemeral stream

This study investigated the influence of dissolved organic matter (DOM) additions on phosphate sorption kinetics of iron-rich sediments (39–50% hematite and goethite) from an ephemeral stream in the arid Pilbara region of sub-tropical northwest Australia. While phosphate sorption in stream sediments is known to be strongly influenced by sediment mineralogy as well as interactions with DOM, the mechanisms and significance of DOM on P-release from sediments with high sorption capacities, are largely undescribed. We assessed phosphorus (P) sorption behaviours by adding a range of solutions of known inorganic P concentrations that were amended with variable loadings of DOM derived from leachates of leaf litter to sediments from stream pools during the non-flowing phase. We compared the sorption capacity of the sediments and concurrent changes in DOM composition measured using fluorescence spectroscopy. We show that the low-dose DOM addition (~ 4 mg L−1 DOC) had the effect of reducing sediment P adsorption capacity, while for the high-dose DOM addition (~ 45 mg L−1 DOC), it was increased. The high-dose DOM was similar to pore water DOC and likely saturated sediment surface adsorption sites and produced P–OM–Fe complexes. This resulted in increased removal of P from solution. Sediment P sorption characteristics were well fitted to both Freundlich and Langmuir isotherm models regardless of DOC concentration. Langmuir P sorption maxima ranged from 0.106 to 0.152 mg g−1. General P sorption characteristics of these iron-rich sediments did not differ among pools of contrasting hydrological connectivity. Our results show how humic-rich DOM can modulate the sediment P availability in dryland streams. Unravelling the complexities of P availability is of particular significance to further our understanding of biogeochemical processes in aquatic ecosystems where P often acts as a limiting nutrient.

Extensive gene flow in a threatened bat (Rhinonicteris aurantia) in an arid landscape

The bat fauna of Australia comprises some 25% of all terrestrial species, yet we know very little of the demography, dispersal, and movement dynamics of most bat species. The Pilbara leaf-nosed bat ( Rhinonicteris aurantia Pilbara form) is a threatened microbat that roosts exclusively in caves that occur in mineral rich deposits in the Pilbara region. Due to their specific roost microclimate requirements these bats cannot survive for long without a suitable roost and are sensitive to roost disturbance. Understanding the connectivity of roosts throughout the Pilbara is crucial for informed decisions to mitigate potential impacts to persistence of this species in areas under economic development. Along with mitochondrial DNA (mtDNA) markers, we used reduced representation genomic sequencing of over 150 individuals from eight roost sites throughout the Pilbara and tested for landscape-scale population differentiation associated with the two major subregions — the Hamersley and Chichester, as well as finer-scale among roost variation. We found evidence of high rates of dispersal and low population structure within the Pilbara, indicating one panmictic population, with mtDNA results suggesting evidence of some female philopatry. Our results highlight the ongoing need for detailed genetic studies to provide critical insight to species dispersal, particularly in multi-use landscapes. We discuss the importance of identifying and retaining connectivity of key habitat to maintain genetic diversity and gene flow throughout panmictic populations.

Extracting new information from old stones: An analysis of three quarries in the semi-arid Pilbara region, northwest Australia

Quarries are important archaeological sites in Australia. They represent the starting point for conditioning variability in stone artefact assemblages (e.g. raw material availability, accessibility, quality, size and shape) and serve as a basis to track human movement from source to discard. Despite this, there is relatively little published research on quarries. For example, in the Pilbara, Western Australia, where stone artefact assemblages are ubiquitous, the paucity of published quarry research makes it difficult to accurately reconstruct patterns of past human behaviour. This research begins to address these issues through the application of a suite of analytical techniques to three quarry sites located in Puutu Kunti Kurrama and Pinikura (PKKP) Country in the inland Pilbara. Some variability in site use and reduction occurs between the three quarries. However, a clear pattern of assemblage formation involving natural heat fracture, non-intensive reduction, core transport, high proportions of non-intensively used tools and non-economic tool selection, was identified at all sites. The results demonstrate clear planning and manipulation of stone resources by Aboriginal people in the raw material rich Hamersley Range and demonstrate the vital importance of quarries as multi-functional locations in understanding wider systems of Aboriginal interaction with the Pilbara landscape.

The use of baited stygofauna traps as a complimentary sampling method for sampling groundwater bores in the Pilbara, Western Australia

Stygofauna sampling predominantly comprises active sampling methods, such as net hauling or hand netting, which although highly effective at collecting specimens, can cause significant specimen damage and is unlikely to collect vagrant species. Studies assessing the efficacy of using stygofauna traps (both baited and unbaited) have been conducted with varying levels of success. Thus, the development of a robust and effective stygofauna trap design may be advantageous. Between 2021 and 2022, in conjunction with Rio Tinto, Biologic began developing and trialling a stygofauna trap designed to sample groundwater bores or drill holes intersecting groundwater, with the aim of evaluating the following hypotheses: The stygofauna trap design and method used would successfully collect stygofauna in groundwater bores and drill holes intersecting groundwater. Some taxa collected in stygofauna traps may differ from those collected in net haul samples, due to differences in ecological habit of fauna (crawling taxa colonising traps) or vagrant stygofauna (fauna travelling between suitable habitats). Specimens collected in traps will be in better condition than those collected in net haul samples. This has positive implications for taxonomic and molecular identification, as well as the collection of voucher specimens. The stygofauna trap design and method used would successfully collect stygofauna in groundwater bores and drill holes intersecting groundwater. Some taxa collected in stygofauna traps may differ from those collected in net haul samples, due to differences in ecological habit of fauna (crawling taxa colonising traps) or vagrant stygofauna (fauna travelling between suitable habitats). Specimens collected in traps will be in better condition than those collected in net haul samples. This has positive implications for taxonomic and molecular identification, as well as the collection of voucher specimens. Based on a fish funnel or box trap, the stygofauna traps consist of a 90mm cylindrical PVC frame, with a 150µm mesh inner lining. Both ends of the trap are capped with a removable funnel, allowing fauna to enter. In September 2021, a preliminary trial was conducted on sites intersecting the Robe and Bungaroo aquifers, in the coastal Pilbara region of Western Australia. These shallow aquifers are characterised by a highly abundant and rich stygofauna assemblage, typically dominated by crustaceans. Stygofauna traps (one trap per site) were deployed in seven groundwater bores or drill holes intersecting groundwater. The traps, baited with algae pellets, were set at the bottom of the bore, and collected between 12 and 24 hours of deployment. For comparison, net haul sampling was conducted at each site immediately prior to trap deployment. Results from the initial trial were promising, prompting a two season (wet and dry) study. This study commenced in March 2022, where traps were deployed in 11 sites across both aquifers. Two baited traps per site were deployed, one within 1m of the groundwater level and one at the end of the hole, for 72 hours, to determine if a longer deployment and an additional trap would yield better results. The final phase of sampling is planned for August 2022. Results from both the preliminary trial and first (wet) season of the 2022 study were very promising, with stygobitic taxa collected in four (of the seven) and nine (of eleven) trap sites respectively. The traps recorded a rich assemblage of stygofauna comprising Amphipoda, Copepoda, Gastropoda, Isopoda, Ostracoda and Thermosbaenacea. Compared to the respective net haul samples, the stygofauna traps yielded lower abundances and taxa richness. However, specimens collected in traps were in excellent morphological condition. At the conclusion of this study, taxonomic composition and abundance of stygofauna from the traps and net hauls will be analysed to provide further contextualisation of results.

Can the Karaman-Chappuis method significantly enhance understanding of stygofauna ecology?

Comprehensive surveys on subterranean fauna are an emerging need for assessing species diversity patterns and for developing biodiversity conservation strategies considering anthropogenic changes to the environment (e.g., mineral and water extraction, climate change). Subterranean habitats comprise mainly terrestrial and aquatic aspects of caves and fissures, as well as interstitial waters. Sampling stygofauna in Northern Western Australia is different to other parts of the world due to the predominance of meso- and micro-caverns, and thus methods are largely constrained to net hauling or pumping of either drill holes or bores installed for mineral or groundwater exploration. Water is also encountered at shallower depths beneath water courses (the interstitial or hyporheic zone) and although it is known to share fauna with subterranean systems, is largely excluded in stygofauna studies. Interstitial fauna can be sampled with the well-known Karaman-Chappuis (KC) method, which involves digging a hole in saturated alluvial deposits, letting interstitial water accumulate, and use of a scoop net to collect invertebrates. However, the application of the KC as a standard complementary method for stygofauna surveys has to date been largely unexplored. In collaboration with Rio Tinto, we included the KC method alongside traditional subterranean fauna sampling at five study areas in the Hamersley Range of Pilbara region, Western Australia. We aimed to determine its utility to better understand the ecology of subterranean fauna recorded, and therefore improve conservation outcomes. Here, we summarise the faunal groups collected using the KC method (43 samples) from surveys conducted between 2016 and 2019. We found that the stygofaunal groups more frequently collected by the KC method were Ostracoda (30.4%), Cyclopoida (28.0%), Haplotaxida (12.5%) and Amphipoda (10.7%), but other groups – Harpacticoida, Syncarida, Aphanoneura, Isopoda, Enchytraeida and Trombidiformes – were also collected in lower frequency (total of 4.9% of the records). Notably, the KC method also collected troglofaunal groups as by catch. Pauropoda (28.1%), Symphyla (21.9%), Hemiptera (12.5%), Diplura (12.5%), Zygentoma (9.4%) and Chilopoda (6.3%) were the groups most frequently collected using the KC method, but Isopoda, Palpigradi and Polyxenida were also recorded (total of 9.3% of the records). Additionally, for one project where low level taxonomic data was available (based on morphological and molecular identification), we also assessed differences in species composition of stygofauna sampled with the KC method (10 samples) compared to the traditional haul net sampling method (139 samples). We found significant differences in stygofauna species composition between the KC and haul net methods, with 13 species (out of 78 species) collected exclusively with the KC method. However, there was also a considerable overlap of species collected by the two methods (11 species). Despite the current limited data, our findings demonstrate that the KC method could be complementary to traditional stygofauna sampling methods. It also allows sampling of potentially connected groundwater habitats to occur beyond the areas drilled for minerals or water. While this method usually targets stygofauna, the collection of troglofauna as by catch is significant and provides a potential way to evaluate the ecology of troglobitic taxa. Further study is needed to assess the KC method as a valuable addition to sampling methods aiming to produce comprehensive inventories of stygofauna that integrate species found in interstitial subterranean environments.

Limited phylogeographic and genetic connectivity in Acacia species of low stature in an arid landscape.

Widespread plant species are expected to maintain genetic diversity and gene flow via pollen and seed dispersal. Stature is a key life history trait that affects seed and potentially pollen dispersal, with limited stature associated with limited dispersal and greater genetic differentiation. We sampled Hill’s tabletop wattle (Acacia hilliana) and curry wattle (Acacia spondylophylla), two co‐distributed, widespread, Acacia shrubs of low stature, across the arid Pilbara region of north‐western Australia. Using chloroplast sequence and nuclear microsatellite data we evaluated patterns of population genetic and phylogeographic diversity and structure, demographic signals, ratios of pollen to seed dispersal, evidence for historical refugia, and association between elevation and diversity. Results showed strong phylogeographic (chloroplast, G ST = 0.831 and 0.898 for A. hilliana and A. spondylophylla, respectively) and contemporary (nuclear, F ST = 0.260 and 0.349 for A. hilliana and A. spondylophylla, respectively) genetic structure in both species. This indicates limited genetic connectivity via seed and pollen dispersal associated with Acacia species of small stature compared to taller tree and shrub acacias across the Pilbara bioregion. This effect of stature on genetic structure is superimposed on moderate levels of genetic diversity that were expected based on widespread ranges (haplotype diversity h = 25 and 12; nuclear diversity He = 0.60 and 0.47 for A. hilliana and A. spondylophylla, respectively). Contemporary genetic structure was congruent at the greater landscape scale, especially in terms of strong genetic differentiation among geographically disjunct populations in less elevated areas. Measures of diversity and connectivity were associated with traits of greater geographic population proximity, population density, population size, and greater individual longevity, and some evidence for range expansion in A. hilliana. Results illustrate that low stature is associated with limited dispersal and greater patterns of genetic differentiation for congenerics in a common landscape and highlight the complex influence of taxon‐specific life history and ecological traits to seed and pollen dispersal.

Use of expert elicitation in the field of occupational hygiene: Comparison of expert and observed data distributions.

The concept of professional judgement underpins the way in which an occupational hygienist assesses an exposure problem. Despite the importance placed on professional judgement in the discipline, a method of assessment to characterise accuracy has not been available. In this paper, we assess the professional judgement of four occupational hygienists (‘experts’) when completing exposure assessments on a range of airborne contaminants across a number of job roles within a surface mining environment in the Pilbara region of Western Australia. The job roles assessed were project driller, mobile equipment operator, fixed plant maintainer, and drill and blast operator. The contaminants of interest were respirable crystalline silica, respirable dust, and inhalable dust. The novel approach of eliciting exposure estimates focusing on contaminant concentration and attribution of an exposure standard estimate was used. The majority of the elicited values were highly skewed; therefore, a scaled Beta distribution were fitted. These elicited fitted distributions were then compared to measured data distributions, the results of which had been collected as part of an occupational hygiene program assessing full-shift exposures to the same contaminants and job roles assessed by the experts. Our findings suggest that the participating experts within this study tended to overestimate exposures. In addition, the participating experts were more accurate at estimating percentage of an exposure standard than contaminant concentration. We demonstrate that this elicitation approach and the encoding methodology contained within can be applied to assess accuracy of exposure judgements which will impact on worker protection and occupational health outcomes.

Demonstrating the potential of amberat middens for understanding late Quaternary palaeoenvironments in the Central Pilbara, western Australia

The Pilbara region in Western Australia (WA) is of high biological and archaeological significance, though our understanding of its environmental history is limited. Potentially valuable palaeoenvironmental archives exist throughout the Central Pilbara in caves and rockshelters in the form of amberat middens (crystallised animal urine), which are known from elsewhere to preserve botanical and faunal remains. Here we report a pilot study aimed at assessing how a multiproxy analysis of these middens could be used to infer past environmental change in response to climate change and therefore help to characterise the nature of past human-environmental relationships in the Pilbara region. Findings show that rockshelters of the inland Pilbara contain some of the oldest known amberat middens in Australia, extending fully back to the Last Glacial Maximum (LGM). Well preserved pollen and macrofossils in the middens tentatively suggest that vegetation throughout the late Pleistocene was likely dominated by an open woodland with a shift after 6000 BP to a more heterogenous pattern of vegetation with the increasing dominance of grassland communities. Several hiatuses in midden accumulation are apparent, which are tentatively interpreted as indicating that the region was affected by prolonged dry periods in the past. This may help explain concomitant patterns of decreased human occupation in the corresponding archaeological record. This pilot study has demonstrated the value of amberat middens for providing much needed local paleoenvironmental data in arid and semi-arid regions of Australia.

Reef to island sediment connections within an inshore turbid reef island system of the eastern Indian Ocean

Reef islands are low-lying sedimentary landforms formed from the accumulation of unconsolidated skeletal material generated by carbonate-producing reef organisms. The coupling between ecological (extant community assemblage) and sedimentary processes (sediment composition and supply) that maintain these reef-fronted landforms make them increasingly sensitive to the impacts of future environmental change. To understand this interconnection we examine the benthic reef community assemblage and sediment characteristics (composition and texture) at Eva Island, an inshore turbid reef island system located in the Pilbara region of Western Australia. Benthic surveys and sediment composition identified molluscs as a unique primary sand-sized sediment constituent (34% of reef and sediments, respectively), alongside coral, despite low mollusc abundance in the reef ecology (n = 94 extant individuals). This result, alongside homogeneity within reef and island biosedimentary facies, suggest a coupling between source (reef) and sink (island) environments may exist, with the sediment reservoir providing suitable sand-grade material for island nourishment. In light of these findings, assuming island building can keep up with rising sea levels, Eva may be resilient to the immediate impacts of climate change. However, dependency on a few primary sediment constituents (molluscs and coral that are sensitive to environmental perturbations) may compromise long-term resilience (over decades), particularly the direct effect on sediment producing habitats and sensitive calcifying organisms under future changing climatic conditions.

First Assessment of Mercury (Hg) Concentrations in Skin and Carapace of Flatback Turtles (Natator depressus) (Garman) From Western Australia

Mercury pollution in the surface ocean has more than doubled over the past century. Within oceanic food webs, sea turtles have life history characteristics that make them especially vulnerable to mercury (Hg) accumulation. In this study we investigated Hg concentrations in the skin and carapace of nesting flatback turtles (Natator depressus) from two rookeries in Western Australia. A total of 50 skin samples and 52 carapace samples were collected from nesting turtles at Thevenard Island, and 23 skin and 28 carapace samples from nesting turtles at Eighty Mile Beach. We tested the influence of turtle size on Hg concentrations, hypothesising that larger and likely older adult turtles would exhibit higher concentrations due to more prolonged exposure to Hg. We compared the rookeries, hypothesising that the turtles from the southern rookery (Thevenard Island) were more likely to forage and reside in the Pilbara region closer to industrial mining activity and loading ports (potential exposure to higher environmental Hg concentrations) with turtles from the northern rookery (Eighty Mile Beach) more likely to reside and feed in the remote Kimberley. Turtles from the Eighty Mile Beach rookery had significantly higher skin Hg concentrations (x̄ = 19.4 ± 4.8 ng/g) than turtles from Thevenard Island (x̄ = 15.2 ± 5.8 ng/g). There was no significant difference in carapace Hg concentrations in turtles between Eighty Mile Beach (x̄ = 48.4 ± 21.8 ng/g) and Thevenard Island (x̄ = 41.3 ± 16.5 ng/g). Turtle size did not explain Hg concentrations in skin samples from Eighty Mile Beach and Thevenard Island, but turtle size explained 43.1% of Hg concentrations in the carapace of turtles from Eighty Mile Beach and 44.2% from Thevenard Island. Mercury concentrations in the flatback turtles sampled in this study are relatively low compared to other sea turtles worldwide, likely a result of the generally low concentrations of Hg in the Australian environment. Although we predicted that mining activities would influence flatback turtle Hg bioaccumulations, our data did not support this effect. This may be a result of foraging ground overlap between the two rookeries, or the predominant wind direction carrying atmospheric Hg inland rather than seaward. This is the first Hg study in skin and carapace of flatback turtles and represents a baseline to compare Hg contamination in Australia’s surrounding oceans.

Resolution of the Eremophila tietkensii (Scrophulariaceae) species complex based on congruence between morphological and molecular pattern analyses

Eremophila R.Br. comprises at least 238 species endemic to Australia, with many more having not yet been formally described. Three putative new taxa, namely, E. sp. Hamersley Range (K. Walker KW 136), E. sp. Calvert Range (A. A. Burbidge 738) and E. sp. Rudall River (P. G. Wilson 10512), were segregated from a broadly defined E. tietkensii F.Muell. & Tate by J. Hurter at the Western Australian Herbarium in 2012. Both E. sp. Hamersley Range and E. sp. Rudall River are listed as being of conservation concern in Western Australia, the former occurring in the Pilbara region in areas of prospective interest for mining development. We sought to determine whether these phrase-named entities should be formally described as new species, using multivariate analyses of morphometric and molecular data derived from specimens in the Western Australia Herbarium. Eremophila sp. Rudall River could not be adequately separated from E. tietkensii by either morphological or molecular data, and is here included within that species. By contrast, E. sp. Hamersley Range and E. sp. Calvert Range are clearly morphologically and genetically distinct. We thus describe them here as the new species E. naaykensii A.L.Curtis & K.R.Thiele and E. hurteri A.L.Curtis & K.R.Thiele. The recognition of these taxa will help inform their conservation prioritisation and subsequent management.