Northwest Western Australia Research Articles

Healing country together: A seagrass restoration case study from Gathaagudu (Shark Bay)

Ecological restoration is a key part of the global solution to help repair damaged ecosystems and moderate climate change. However, there are enormous challenges to contemporary restoration. Solutions that integrate western science and traditional ecological knowledge offer great opportunities to overcome these challenges. Partnerships with Indigenous Ranger programs can assist with solutions to some of the age-old restoration challenges. Managing and caring for a living and dynamic Country is at the heart of wellbeing for all Indigenous Peoples. The act of participating in restoration activities On Country assists with connecting to Country, healing people and Country. We describe the development of a successful partnership between western science and Indigenous traditional knowledge via a collaborative Malgana Aboriginal Corporation Ranger program that included On Country workshop-based knowledge sharing in north-west Western Australia, with a focus on seagrass restoration. Field-based restoration workshops helped people reconnect with Country through two-way knowledge sharing. Additional benefits of the partnership included education and preservation of Malgana language, educating western scientists and general public about Malgana culture, and adapting and field trialling seagrass restoration methods for Gathaagudu. Restoration can be successfully implemented through partnerships that share western science and traditional ecological knowledge.

Spatiotemporal variation in ecophysiological traits align with high resolution niche modelling in the short-range banded ironstone endemic Aluta quadrata.

Defining plant ecophysiological responses across natural distributions enables a greater understanding of the niche that plants occupy. Much of the foundational knowledge of species' ecology and responses to environmental change across their distribution is often lacking, particularly for rare and threatened species, exacerbating management and conservation challenges. Combining high-resolution species distribution models (SDMs) with ecophysiological monitoring characterized the spatiotemporal variation in both plant traits and their interactions with their surrounding environment for the range-restricted Aluta quadrata Rye & Trudgen, and a common, co-occurring generalist, Eremophila latrobei subsp. glabra (L.S.Sm.) Chinnock., from the semi-arid Pilbara and Gascoyne region in northwest Western Australia. The plants reflected differences in gas exchange, plant health and plant water relations at sites with contrasting suitability from the SDM, with higher performance measured in the SDM-predicted high-suitability site. Seasonal differences demonstrated the highest variation across ecophysiological traits in both species, with higher performance in the austral wet season across all levels of habitat suitability. The results of this study allow us to effectively describe how plant performance in A. quadrata is distributed across the landscape in contrast to a common, widespread co-occurring species and demonstrate a level of confidence in the habitat suitability modelling derived from the SDM in predicting plant function determined through intensive ecophysiology monitoring programmes. In addition, the findings also provide a baseline approach for future conservation actions, as well as to explore the mechanisms underpinning the short-range endemism arid zone systems.

The Health Outcomes and Health Service Needs of the Martu and Nyiyaparli People of Northwest Western Australia: A Grey Literature Review

The Health Outcomes and Health Service Needs of the Martu and Nyiyaparli People of Northwest Western Australia: A Grey Literature Review

Taking eDNA underground: Factors affecting eDNA detection of subterranean fauna in groundwater.

Stygofauna are aquatic fauna that have evolved to live underground. The impacts of anthropogenic climate change, extraction and pollution on groundwater pose major threats to groundwater health, prompting the need for efficient and reliable means to detect and monitor stygofaunal communities. Conventional survey techniques for these species rely on morphological identification and can be biased, labour-intensive and often indeterminate to lower taxonomic levels. By contrast, environmentalDNA (eDNA)-based methods have the potential to dramatically improve on existing stygofaunal survey methods in a large range of habitats and for all life stages, reducing the need for the destructive manual collection of often critically endangered species or for specialized taxonomic expertise. We compared eDNA and haul-net samples collected in 2020 and 2021 from 19 groundwater bores and a cave on Barrow Island, northwest Western Australia, and assessed how sampling factors influenced the quality of eDNA detection of stygofauna. The two detection methods were complementary; eDNA metabarcoding was able to detect soft-bodied taxa and fish often missed by nets, but only detected seven of the nine stygofaunal crustacean orders identified from haul-net specimens. Our results also indicated that eDNA metabarcoding could detect 54%-100% of stygofauna from shallow-water samples and 82%-90% from sediment samples. However, there was significant variation in stygofaunal diversity between sample years and sampling types. The findings of this study demonstrate that haul-net sampling has a tendency to underestimate stygofaunal diversity and that eDNA metabarcoding of groundwater can substantially improve the efficiency of stygofaunal surveys.

Unpacking the recruitment potential of seeds in reconstructed soils and varying rainfall patterns

Context Seeding is common practice for ecological restoration, but establishment rates can be low. For seeds to successfully establish they must transition through early life stages of germination, emergence, and (initial) survival. Examining these demographic processes for seeds sown under a range of abiotic conditions can identify failure points and inform techniques to improve seed use. Aims Here we quantified seed and seedling life-stage transitions in five reconstructed soils across four varying levels of simulated rainfall using five species (Acacia hilliana, Acacia inaequilatera, Indigofera monophylla, Triodia pungens, and Triodia wiseana) commonly seeded for mined land restoration of the Pilbara bioregion in north-west Western Australia. Methods Germination, emergence, and survival were measured over a 6 week period and transition probabilities between each life-stage transition were modelled for each treatment combination. Key results For four species, both rainfall amount and/or soil substrate significantly influenced germination probability. Rainfall was the more significant determinant, with germination greatest under the higher rainfall regimes of 120–280 mm, irrespective of soil type. Following germination, emergence of both Acacia spp. was positively influenced by soils containing topsoil, suggesting the microenvironment of soils containing topsoil was most favourable during this emergence phase. The effect of substrate was less clearcut for I. monophylla and Triodia spp, where emergence was most limited in substrates comprised solely of overburden waste material and the lowest rainfall regime exacerbated emergence failure, relative to germination success. When compared to the well-watered, 100% topsoil substrate, seedling survival of all species was most constrained in the 100% overburden waste, demonstrating these reconstructed mining substrates compromise seedling recruitment. Conclusions This study underscores that successful seedling recruitment in this ecosystem is dependent on frequent, and repeated, rainfall events above a certain threshold (≥120 mm) and highlights the beneficial effects of sowing seeds in a substrate containing topsoil. Implications Future seeding technologies should focus on improving the moisture relations of the microsite to offset the recruitment challenges experienced by seeds sown in hostile growing environments such as the overburden wastes tested here.

Historical persistence and isolation by distance of

Context Empirical studies of intraspecific genetic diversity and population structure can inform the evolutionary and demographic history of individual species and of landscapes at the bioregional level. Aims We aimed to assess intraspecific genetic variation at macroevolutionary and microevolutionary temporal scales for Mirbelia viminalis, a key species present on the Hamersley Range in the ancient and highly diverse landscape of the Pilbara bioregion of northwest Western Australia. Methods We sampled extant populations and assessed diversity and structure using sequences (chloroplast DNA, 1759 base pairs) and microsatellite markers (nuclear DNA, 15 loci) data. Key results Significant phylogeographic structure and a lack of historical demographic signals of population contraction or expansion suggest historical population persistence. Moderate chloroplast haplotype diversity (h = 15) and moderate divergence among extant haplotypes indicates a degree of historical connectivity via seed dispersal across central populations on the Hamersley Range. Levels of nuclear genetic diversity were low to moderate (allelic richness = 3.554, expected heterozygosity = 0.489, observed heterozygosity = 0.462) and depauperate compared to another member of the Mirbelia genus present further south in the Midwest region. Nuclear diversity revealed a strong signal of isolation by distance with localised admixture among populations and some contemporary genetic clustering along a north-west to south-east transect of the Hamersley Range. Conclusions Low nuclear genetic diversity may be related to recent reductions in population size for M. viminalis. Historical population persistence with few barriers to dispersal other than geographic distance may be common for members of the Fabaceae across the Hamersley Range.

Monitoring Rock Art Decay: Archival Image Analysis of Petroglyphs on Murujuga, Western Australia

ABSTRACTThis paper considers the effects of industrialisation upon one of the world’s most significant rock art sites, Murujuga (Burrup Peninsula), located in north-west Western Australia. Photographs of 26 petroglyphs taken prior to or early in the industrialisation of the area were compared with recent photographs to assess whether the presence of industry is accelerating degradation. Fifty per cent of the petroglyphs showed indications of changes, and two showed substantial damage. The bulk of the changes can be attributed directly to industrial activity in the area which commenced in the 1960s. All changed petroglyphs, with two exceptions, were in relative proximity to industry. A reduction in industrial emissions is considered essential if damage to the rock art is to be limited and this iconic cultural place is to remain largely intact for future generations.

The effectiveness of ARIMAX model for prediction of summer rainfall in northwest Western Australia

Inherent climate mechanism plays a large role in Australian rainfall events, while most interestingly, such influence of climate drivers on rainfall generation depends largely on a place’s geographical location and the season it has been passing through. For Northwest Western Australia (NWWA), summer has been the main rainfall season; therefore, it became necessary to develop a seasonal forecast model several months ahead of the event. This study involves the selection of potential climate drivers for NWWA and using them to forecast and model long-term seasonal summer rainfall (Dec to Feb) several months advance. Two rainfall stations (Bidyadanga and Gogo) were selected considering the availability of continuous monthly rainfall data (from 1915 to 2015) with a minimal missing value. Simple multiple linear regression (MLR) and ARIMAX have been performed on acquired rainfall data and lagged climate indices. It has been observed that the Southern Oscillation Index (SOI) and the Western Indian Ocean Index (WIO) has a great influence on NWWA rainfall. As such, the WIO-SOI model (4 months advance) shows a significantly higher correlation in the ARIMAX model (0.68 and 0.65 for Bidyadanga and Gogo station, respectively) compared to the MLR model (0.35 and 0.36) and confirms its effectiveness to be used for rainfall prediction in the region. It is believed that the simple but effective nature of the developed models can produce optimum benefit on stakeholder’s decision making to tackle future socio-economic challenges.

Evaluating human responses to ENSO driven climate change during the Holocene in northwest Australia through macrobotanical analyses

The Holocene is recognised as a period through which a number of climatic fluctuations and environmental stresses occur—associated with intensifying El Niño–Southern Oscillation (ENSO) climatic conditions from c. 5000 years—contemporaneous with technological and social changes in Australian Aboriginal lifeways. In the Kimberley region of northwest Western Australia, human responses to ENSO driven climate change are most evident archaeologically in technological transformations observed in lithic records, with little research on changes in plant use during this time. Using nine archaeological sites across the Kimberley, this paper synthesises previously published macrobotanical data (Carpenter’s Gap 1, Moonggaroonggoo, Mount Behn, and Riwi), reports unpublished data (Brooking Gorge 1, Djuru, and Wandjina rockshelter), and presents results of sites reanalysed for this study (Widgingarri Shelters 1 and 2) to develop a picture of localised and regional patterns of plant use during the Holocene. We conclude that food plants associated with monsoon rainforest environments dominate both mid- and late Holocene macrobotanical records and, although monsoon rainforest likely retreated to some extent because of decreased precipitation during the late Holocene, no human responses associated with ENSO driven climate change occurred in relation to human uses of plants.

The effect of ecological factors on eye morphology in the western rainbowfish, Melanotaenia australis.

Ecological factors such as spatial habitat complexity and diet can explain variation in visual morphology, but few studies have sought to determine whether visual specialisation can occur among populations of the same species. We used a small Australian freshwater fish (the western rainbowfish, Melanotaenia australis) to determine whether populations showed variation in eye size and eye position, and whether this variation could be explained by environmental (light availability, turbidity) and ecological (predation risk, habitat complexity, invertebrate abundance) variables. We investigated three aspects of eye morphology - (1) eye size relative to body size, (2) pupil size relative to eye size and (3) eye position in the head - for fish collected from 14 sites in a major river catchment in northwest Western Australia. We found significant variation among populations in all three measures of eye morphology, but no effect of sex on eye size or eye position. Variation in eye diameter and eye position was best explained by the level of habitat complexity. Specifically, fish occurring in habitats with low complexity (i.e. open water) tended to have smaller, more dorsally located eyes than those occurring in more complex habitats (i.e. vegetation present). The size of the pupil relative to the size of the eye was most influenced by the presence of surrounding rock formations; fish living in gorge habitats had significantly smaller pupils (relative to eye size) than those occupying semi-gorge sites or open habitats. Our findings reveal that different ecological and environmental factors contribute to habitat-specific visual specialisations within a species.

Creating a 3D image from 2D data using structurally conformable interpolation: a case study from the Beagle Sub-basin, NSW, Australia

2D seismic data still provides key information for companies evaluating new permits on offer or entering new basins. However, working on multi-vintage 2D data can be time-consuming for several reasons, including getting correct navigation, variability of physical parameters like amplitude, time and phase between different vintages, and then interpreting the 2D data itself, which often results in gridding artefacts. In a step change to the use of traditional 2D data, TGS has developed a methodology called ‘structurally conformable interpolation’ – also known as 2Dcubed. It is created using input data from available 2D migrated stacks and velocities from available vintages. The workflow includes survey matching of different vintages, data-driven geological model building to interpolate large distances between existing data, and a 3D post-stack migration to minimise the 2D migration artefacts. The merging of these datasets successfully creates a 3D migrated image from legacy 2D data, offering better structure and continuity while increasing confidence in its interpretation. Interpretation of a 3D volume is much more efficient than when using 2D data and is free from 2D artefacts. With this methodology TGS has completed a project covering a 40000km2 area in the Beagle Sub-basin, north-west Western Australia, using existing 2D data from over 42 different vintages. The resulting output ‘Beagle Cube’ interpolated 3D volume has been interpreted for major regional trends and structures. The results are very consistent with the original 2D data, but with better definition of major structures. Another study comparing the interpretation between the interpolated 3D volume and the real open-file 3D shows excellent preservation of the structural picture within the interpolated 3D volume, not at the same level as real 3D, but it gives greater confidence in the regional interpretation conducted within areas that do not have 3D coverage. This paper will address how the interpolation methodology works stage by stage, the results of the final product and how it assists in performing regional interpretation in a quick timeframe.

Archaeobotany of Aboriginal plant foods during the Holocene at Riwi, south central Kimberley, Western Australia

Riwi, a limestone cave located in the south central Kimberley, northwest Western Australia, has one of the most accurately dated archaeological sequences in Australia, with human occupation beginning between 46,400 and 44,600 cal bp. Macrobotanical remains are well preserved at the site, particularly in upper stratigraphic units 1 and 2 dated to the late and mid-Holocene, respectively. Macrobotanical materials (excluding wood charcoal) are uncommon in Pleistocene contexts, and direct dating of some of the macrobotanical remains recovered from Pleistocene hearths suggest that they derive from the directly superposed Holocene layers. Analysis of the macrobotanical remains from the Holocene layers reveals a pattern where Aboriginal groups occupying Riwi intermittently between 7,000 years ago and the present principally exploited monsoon rainforest ecosystems for food plants, especially Vitex cf. glabrata. Fruiting times of dominant monsoon rainforest taxa indicate that the site was occupied seasonally, corresponding with periods of rainfall when people were able to move away from rivers and other permanent water sources. Results demonstrate a strong cultural preference for fruits associated with monsoon rainforest—a vegetation type restricted in distribution—highlighting the importance of moisture retaining limestone outcrops in foragers’ subsistence organisation in the south central Kimberley.

Stratigraphic Revision of the Miocene Trealla Limestone (cape Range, Western Australia): Implications For Australasian Foraminiferal Biostratigraphy

AbstractOutcrops of Miocene coral-rich limestones mapped as Trealla Limestone are widespread along the coast of north-west Western Australia. Despite their central importance in Australian Miocene stratigraphy, the age of these outcrops is poorly constrained as they were only dated in their type area, and as the age assignation was based only on off-centred sections of sparse planktonic foraminifera and a broad correlation based on larger benthic foraminiferal species.This study aims to refine the dating of the Trealla Limestone in its type area, and to provide the first dating of outcrops located elsewhere in the Cape Range Anticline. Results are based on microscopic observations made on large acetate peels, which allowed the observation of numerous planktonic foraminifera, and also of serial sections of species.The coral-rich deposits mapped as “Trealla Limestone” can be divided into three age-based units in the Cape Range Anticline: (1) upper Burdigalian, (2) Langhian to lower Serravallian, and (3) Serravallian. This revised stratigraphic framework provides a standard for future correlations with sections located elsewhere in Australia. The Trealla Limestone at its type section on Mt Lefroy contains mainly upper Burdigalian strata of the mid-neritic zone, with the top of the formation marked by an erosion surface. It may in part be equivalent to the Tulki Limestone mapped elsewhere in the anticline. Further north in the anticline, the Trealla Limestone ranges stratigraphically higher into the Langhian and Serravallian in shallower water facies. An influx of quartz sand in the Cape Range Anticline, probably indicative of a wetter environment in the hinterland to the east, started during or after the Serravallian.This study also brings new insight into the environmental and stratigraphic ranges of larger benthic foraminifera from north-west Western Australia. Austrotrillina asmariensis was recorded above levels with Orbulina universa. This suggests that the species has a more extended stratigraphic range in this area than in Asia. A re-examination of the soritids reveals that Marginopora, previously recorded here, is not present in the deposits. Borelis is replaced by Flosculinella after the end of the Te Letter Stage, a zone based on larger benthic foraminifera recognized throughout the Indo-West Pacific region. The morphology of Flosculinella may be environmentally controlled, with the most globular specimens more abundant in protected and shallow environments. Finally, Cycloclypeus from the Cape Range Anticline had a similar bathymetric range to its modern analogue found in the lower part of the photic zone, as indicated by its co-occurrence with minute planktonic foraminifera.

Water availability drives the effectiveness of inorganic amendments to increase plant growth and substrate quality

In a time when global climate variability threatens the sustainability and productivity of arid ecosystems, the development of effective strategies to recover and protect soil resources and biota is crucial for the survival of these landscapes. With 20% of arid systems degraded and estimates of up to 10 Mha of land degrading each year, this issue is of global importance. In the semi-arid Pilbara region of north-west Western Australia, climatic projections suggest reductions in annual rainfall and high unpredictability of rain events. However, as these ancient landscapes are already degraded due to meteorological processes and anthropogenic activities, such as mining, the rehabilitation of this land is severely challenging. Here, we present a case study that examines, under different rainfall scenarios, the effect of two inorganic amendments (gypsum and urea) on substrate quality and growth of two plant species (Acacia inaequilatera and Triodia wiseana) native to the Pilbara region. Through an extensive glasshouse experiment, two doses of inorganic amendments were tested and compared to unamended mining waste (overburden) substrates extracted from an iron-ore mine of moderately alkaline pH and low nitrogen status. Our results showed that the addition of urea (nitrogen-based fertiliser) produced a three-fold increase of plant growth in A. inaequilatera and up to a 25-fold increase in T. wiseana compared to unamended substrates when grown under the higher watering regime but this effect was not evident in the lower water regimes. The inorganic amendments decreased pH and increased EC, total nitrogen and N-mineralisation but did not have a significant effect on soil microbial activity. Overall, water was the dominant driver for determining the effectiveness of the substrate amendments to improve the quality of mine waste substrates and increase plant growth. This study contributes to unravelling the role of inorganic amendments in post-mining rehabilitation in arid regions faced with climate change.

Making it official—formal description of two orange-flowered Tephrosia (Fabaceae: Millettieae) species from north-west Western Australia

Making it official—formal description of two orange-flowered <i>Tephrosia</i> (Fabaceae: Millettieae) species from north-west Western Australia

Murujuga at a crossroads: considering the evidence of nineteenth-century contact, Dampier Archipelago, northwest Australia

Mounting evidence indicates that the production of petroglyphs within what is now the Dampier Archipelago on the Pilbara coast of northwest Western Australia spans a period beginning 30,000–40,000 years ago until the nineteenth century. Despite the testimony of sites on the Pilbara mainland, there is little in Dampier rock art that indicates continued production after European settlement, some 150 years ago. Considering the abundance of rock art in the Dampier Archipelago, there are remarkably few images depicting subjects of European origin. What does occur has the appearance of being made by Europeans. Looking at the early colonial history of the area and examining the occurrence of introduced items in Dampier rock art I infer minimal rock art production by Aboriginal people post-1860s. Why this is and why the production of rock art stopped is tackled here.

Cyanobacteria inoculation enhances carbon sequestration in soil substrates used in dryland restoration

Despite significant efforts to restore dryland ecosystems worldwide, the rate of success of restoration is extremely low in these areas. The role of cyanobacteria from soil biocrusts in reestablishing soil functions of degraded land has been highlighted in recent years. These organisms are capable of improving soil structure and promoting soil N and C fixation. Nevertheless, their application to restore functions of reconstructed soils in dryland restoration programs is yet to be harnessed. In this study, we used microcosms under laboratory conditions to analyse the effects of inoculating soil substrates used in post-mine restoration with a mixture of N-fixing cyanobacteria isolated from soil biocrust (Nostoc commune, Tolypothrix distorta and Scytonema hyalinum) on i) the recovery of the biocrust, and ii) the carbon sequestration and mineralisation rates of these substrates. Soils were collected from an active mine site in the mining-intensive biodiverse Pilbara region (north-west Western Australia) and consisted of previously stockpiled topsoil, overburden waste material, a mixture of both substrates, and a natural soil from an undisturbed area. Our results showed that cyanobacteria rapidly colonised the mine substrates, with biocrust coverage ranging from 23.8 to 52.2% and chlorophyll a concentrations of up to 12.2 μg g−1 three months after inoculation. Notably, soil organic C contents increased 3-fold (P < 0.001) in the mine waste substrate (from 0.6 g kg−1 to 1.9 g kg−1) during this period of time. Overall, our results showed that cyanobacteria inoculation can rapidly modify properties of reconstructed soil substrates, underpinning the potential key role of these organisms as bio-tools to initiate recovery of soil functions in infertile, reconstructed soil substrates.

Wave ensemble forecast system for tropical cyclones in the Australian region

Forecasting of waves under extreme conditions such as tropical cyclones is vitally important for many offshore industries, but there remain many challenges. For Northwest Western Australia (NW WA), wave forecasts issued by the Australian Bureau of Meteorology have previously been limited to products from deterministic operational wave models forced by deterministic atmospheric models. The wave models are run over global (resolution 1/4∘) and regional (resolution 1/10∘) domains with forecast ranges of + 7 and + 3 day respectively. Because of this relatively coarse resolution (both in the wave models and in the forcing fields), the accuracy of these products is limited under tropical cyclone conditions. Given this limited accuracy, a new ensemble-based wave forecasting system for the NW WA region has been developed. To achieve this, a new dedicated 8-km resolution grid was nested in the global wave model. Over this grid, the wave model is forced with winds from a bias-corrected European Centre for Medium Range Weather Forecast atmospheric ensemble that comprises 51 ensemble members to take into account the uncertainties in location, intensity and structure of a tropical cyclone system. A unique technique is used to select restart files for each wave ensemble member. The system is designed to operate in real time during the cyclone season providing + 10-day forecasts. This paper will describe the wave forecast components of this system and present the verification metrics and skill for specific events.

The influence of tropical cyclones on long-term riverine flooding; examples from tropical Australia

Luminescence chronologies for two new slackwater flood deposit (SWD) sites (Broken River northeast Queensland and Ord River northwestern Western Australia) are presented and these along with other SWD chronologies from the same regions are compared with recently developed high resolution, isotope tropical cyclones (TC) records. Heightened TC activity occurred between 1400 and 1850 CE in Queensland and between 1500 and 1850 CE in Western Australia. A distinct clustering of flood events in northwest Western Australia during the period of enhanced TC activity suggests the two may be related. The SWD records in northeast Queensland do not cluster specifically during the period of heightened TC activity however several major floods do occur during this time suggesting that TCs may have been involved.

Rock-art microbiome: influences on long term preservation of historic and culturally important engravings

The Burrup Peninsula in north-west Western Australia is home to one of the most substantial collections of rock engravings, or petroglyphs, in the world. These petroglyphs are carved through the dark coloured patina, commonly referred to as rock varnish, into the weathering rind of the local parent rock. Rock varnish is essentially a thin layer of manganese (Mn) and iron (Fe) oxides and hydroxides with embedded clay minerals, the formation of which is relatively poorly understood. It is generally considered to be a hostile environment for microorganisms due to extreme environmental conditions including low nutrient availability, lack of water, exposure to extreme ultraviolet radiation and intense seasonal and diurnal temperature fluctuations. However, despite these environmental extremes, microorganisms have been found on and in rock varnish and have been reported as playing a significant role in the formation of rock varnish. Given this, it is likely that any change in local environmental conditions will influence the types and activities of microorganisms found in and on rock varnish and associated rock art. This article focuses on the major influences on the microbiome of culturally important rock art in the Burrup Peninsula and the implications of any environmental change on the rock art itself.