South-eastern Australia Research Articles

Size-dependent thermal limits in Australian hybrid abalone: implications for productivity shifts with ocean warming

Ocean warming and extreme heatwaves threaten marine species supporting commercial fisheries and aquaculture. Predicting the responses of these industries to chronic and acute warming depends on understanding which life stages are most vulnerable, the potential for stocks to adapt to changing thermal environments, and the availability of thermally adapted genotypes to help enhance stock resilience through strategic interventions. Here, we shed light on some of these knowledge gaps by quantifying the critical thermal maximum (CTmax) of ~ 10–210 g hybrid abalone (Haliotis rubra × H. laevigata) from two farms representing contrasting thermal environments from south-eastern Australia. CTmax was not dependent on body size or provenance (farm) when heating rates were rapid (1 °C per h), but a significant relationship between CTmax and body size was observed when heating rates were slower and more ecologically realistic (1 °C per 12 h). Histological analyses revealed a negative relationship between CTmax and the stage of gonadal development when abalone were exposed to chronic thermal stress conditions. These results suggest that marine heatwaves and ongoing ocean warming might favour smaller, less fecund animals in natural and farm settings. This could potentially impact future harvestable biomass, recruitment and population dynamics in wild-capture fisheries, and production of larger, high-value animals in farm settings. This study adds to a growing body of literature pointing to complex and often negative effects of climate change on commercial fisheries, and the potential need for interventions aimed at bolstering fisheries resilience against the effects of ocean warming.

Morphological evolution of a complex drift‐aligned prograded barrier

AbstractPrograded barriers are coastal landforms with a worldwide distribution that provide a paleoenvironmental record within a sequence of successive ridges and intervening swales. Most barriers with variable terrestrial morphologies, also known as complex barriers, have been poorly studied. At the main entrance of Western Port, a bay in southeastern Australia, a morphologically complex barrier was formed as a function of its somewhat sheltered position and orientation in relation to sporadic swells and tidal circulation. LiDAR‐derived topography shows highly truncated and asymmetrical ridges both across and along the Somers–Sandy Point barrier plain. These uncommon morphologies are associated with an intricate hydrodynamic circulation subject to sporadic storms approaching at a sharp angle to the shoreline that eliminate a significant part of the sedimentary record but also redistribute vast quantities of sand to the downdrift shoreline, and a large and variable sandy bank that undergoes intense sediment movement. Optically stimulated luminescence (OSL) dating within a limited area on the western side revealed an age of ~2600 years for the innermost dated ridge, located about halfway across the plain. Significant erosion of the ridges' record occurred on the western side of the barrier between 2600 and 700 years ago and between 600 and 240 years ago, whereas undated ridges on the eastern side were preserved. This creates an opportunity for future research on past erosional events that would be of great value for coastal management and adaptation. Textural and elemental (XRF) sediment characteristics suggest that the type of material provided for barrier accretion remained the same throughout the late Holocene. Given the sustained growth of the barrier and other sandy parts of the bay, a net supply of marine sand from Bass Strait must have occurred. The proposed evolutionary model contributes to the understanding of the sediment budget for the bay as a whole.

Unburnt refugia support post-fire population recovery of a threatened arboreal marsupial, Leadbeater’s possum

Large wildfires have the potential to create heterogeneous landscapes in forest ecosystems. Range-restricted species in fire-prone regions have evolved to persist in the face of periodic disturbance due to wildfire. However, the factors that enable them to do so are often poorly understood. Whether post-fire population recovery is driven by survival of individuals within the burnt area (in situ recovery) or by recolonisation from unburnt habitat outside the fire perimeter (ex situ recovery), and over what timeframe this occurs, is valuable knowledge for conservation management. Understanding post-fire population dynamics is important when considering whether management interventions are required to prevent local extinctions. We examined the influence of fire-derived landscape context on site occupancy by the critically endangered Leadbeater’s possum Gymnobelideus leadbeateri in south-eastern Australia, 6–11 years after a large wildfire in 2009. Our aim was to assess whether site occupancy was influenced by fire extent in the local landscape, distance from unburnt habitat outside the fire perimeter, and/or pre-fire disturbance history. We used arboreal camera trapping to survey Leadbeater’s possums within the burnt area, using 732 cameras at 245 sites. We used occupancy modelling to estimate the effects on site occupancy of (1) unburnt habitat surrounding sites (500 m radius), (2) distance from unburnt habitat at the fire perimeter, and (3) whether the site had been disturbed by either fire or timber harvesting in the decades prior to the 2009 fire. Leadbeater’s possums were detected at 78 of the 245 sites (32 %). Site occupancy was positively influenced by the presence of unburnt habitat within 500 m, and was higher at sites that had experienced disturbance between the 2009 fire and the previous major wildfire in 1939. Proximity to unburnt habitat outside the fire perimeter did not influence occupancy. Our results suggest that population recovery was driven primarily by in situ survival and recovery, rather than via recolonisation from source populations outside the burnt area. Our findings indicate that Leadbeater’s possum populations are more likely to recover from fires that are more heterogeneous in their severity, leaving relatively more unburnt patches within their perimeter. Post-fire management interventions such as translocation to facilitate population recovery are likely unnecessary for this species, provided surviving individuals have spatial continuity of habitat to enable recolonisation. Management strategies aimed at the retention of unburnt patches within the footprint of future fires will likely promote the post-fire recovery of arboreal mammal species in fire-prone forests, particularly under a changing climate with increased frequency and intensity of wildfires.

Assessing the diet and seed dispersal ability of non-native sambar deer (Rusa unicolor) in native ecosystems of south-eastern Australia.

Understanding the influence of non-native herbivores on ecosystems by means of dietary foraging and seed dispersal is important for understanding how non-native species can alter an invaded landscape, yet requires multiple methodologies. In south-eastern Australia, introduced sambar deer (Rusa unicolor) are rapidly expanding in range and placing native ecosystems at risk through browsing and as vectors for seed dispersal. We simultaneously investigated sambar deer dietary composition and seed dispersal using DNA sequencing and germination trials, from faecal pellets collected in alpine and wet forest ecosystems. This allowed us to contrast the dietary impacts of introduced sambar deer in different environments, and to explore the potential for habitat-specific variation in diet. DNA sequencing of the trnL, ITS2 and rbcL gene regions revealed a diverse plant species dietary composition comprising 1003 operational taxonomic units (OTUs). Sambar deer exhibited intermediate feeder behaviours dominated by forbs in alpine and shrubs in wet forest ecosystems. A large proportion of plant OTUs were considered likely to be native, however, the proportion of exotic species in the diet in both ecosystems was greater than would be expected based on the proportion of exotic species in each of the two landscapes. Seed germination trials indicated that sambar deer can disperse a substantial number of native and exotic species in both alpine and wet forest ecosystems. In alpine ecosystems, an individual sambar deer was estimated to disperse on average 816 (±193) seeds per day during the study period, of which 652 (±176) were exotic. Synthesis and applications. Our results suggest that native plant species comprise the majority of sambar deer diets in Australian ecosystems and that the introduced species is dispersing both native and exotic plant species via endozoochory. However, exotic species seedling germination numbers were significantly higher in alpine ecosystems, and given the large daily movements of sambar deer, represents a significant vector for the spread of exotic plant species. Management of native plant species and vegetation communities of conservation significance, or at risk to sambar deer browsing is of high priority, through either the removal of sambar deer or implementation of exclusion-based methods.

Genotype-by-environment interaction analysis of dry matter yield of perennial ryegrass cultivars across south-eastern Australia using factor analytic models

Genotype-by-environment interaction analysis of dry matter yield of perennial ryegrass cultivars across south-eastern Australia using factor analytic models

Changes in Blue/Green Water Partitioning Under Severe Drought

AbstractMuch attention has been given to the disproportionate streamflow deficits (relative to rainfall deficits) experienced by many catchments during the Millennium Drought (1998–2009) in southeastern Australia, along with lack of post‐drought streamflow recovery in some cases. However, mechanisms behind the coupled hydrologic and ecosystem dynamics are poorly understood. We applied a process‐based ecohydrologic model (RHESSys) in a Melbourne water supply catchment to examine changes in ecohydrologic behavior during and after the drought. Our simulations suggested that average transpiration (green water) was maintained under drought despite a substantial (12%) decrease in average rainfall, meaning that the entire rainfall deficit translated to reduced streamflow (blue water). Altered spatial patterns of vegetation behavior across the terrain helped the ecosystem maintain this unexpectedly high green water use. Decreased transpiration upland was compensated by increases in the riparian zone, which was less water limited and therefore able to meet higher water demand during drought. In the post‐drought period, we found greater transpiration and reduced subsurface water storage relative to pre‐drought, suggesting a longer‐term persistence in altered water partitioning. The post‐drought outcome was attributed to a combination of warmer climate and the persisting effects of the drought on nutrient availability. Given the importance of shifting ecohydrologic patterns across space, our results raise concerns for applying lumped conceptual hydrologic models under nonstationary or extreme conditions. Additionally, the processes we identified have important implications for water supply in Australia's second largest city under projected drying.

An overview of groundwater response to a changing climate in the Murray-Darling Basin, Australia: potential implications for the basin system and opportunities for management

The Murray-Darling Basin (MDB) is a highly allocated and regulated, mostly semiarid basin in south-eastern Australia, where groundwater is a significant water resource. Future climate predictions for the MDB include an expansion of arid and semiarid climate zones to replace temperate areas. The impacts of climate change are already evident in declining groundwater levels and changes in the connection status between rivers and groundwater, and modelling has predicted a further reduction in future groundwater recharge and ongoing declines in groundwater levels. This is predicted to further reduce river baseflow and negatively impact groundwater-dependent ecosystems (GDEs), and these system responses to a changing climate and extreme events are complex and not always well understood. This report provides an overview of the current state of knowledge of groundwater response to a changing climate for the MDB, and outlines challenges and opportunities for future groundwater research and management. Opportunities for the region include improving data systems and acquisition through automation and novel data sources, and growing capability in integrated, risk-based modelling. Quantification of the groundwater/surface-water connection response to declining groundwater levels, and assessing GDE water requirements and thresholds, would enable identification of vulnerable systems and inform the development of metrics for adaptive management, improving the ability to respond to climate extremes. There is potential to adapt policy to support active management of groundwater where required, including conjunctive use and water banking. Improving knowledge sharing and water literacy, including understanding community values of groundwater and GDEs, would support future decision-making.

The Presence of a Parasite in the Head Tissues of a Threatened Fish (Bidyanus bidyanus, Terapontidae) from South-Eastern Australia.

The silver perch, Bidyanus bidyanus (Mitchell) (Terapontidae) is a freshwater fish, endemic to the Murray-Darling river system in south-eastern Australia. Population declines have led to the fish being listed as critically endangered by the Australian Government. Knowledge about parasites and diseases of wild populations of freshwater fish are limited in Australia. During an examination of wild-caught silver perch, digenean mesocercaria were observed in the head tissues. A total of five of the 11 silver perch collected from the Wakool River, New South Wales, were infected with mesocercaria. All mesocercaria were found in the head tissues; no mesocercaria were found encysted in the eye lens. The mesocercaria were found to belong to the family Strigeidae based on the sequences of their internal transcribed spacer (ITS) region. The lack of comparable sequences of strigeid digeneans from Australian hosts precludes being able to determine if the mesocercaria found in this study are a new species or representatives of an already described species. However, genetic results confirm that this is a different species to other digeneans previously described from silver perch, thus increasing the number of digeneans reported from B. bidyanus to three species. The presence of digenean mesocercaria in the head tissues of a wild population of silver perch, as found in the present study, is of potential conservation significance. Given the critically endangered conservation status of B. bidyanus, and previous evidence of strigeid infection altering fish behaviour, ecology, and predation mortality, further research on the potential impacts of infection on wild populations is warranted.

Sex and Age Bias in Australian Magpies Struck by Aircraft

Wildlife–aircraft collisions represent a safety and financial challenge, necessitating site-specific hazard assessments, which are generally based on species’ attributes and collision frequencies. However, for many bird species, collision probability and risk may not be distributed equally among individuals, with sex and age differences possible but rarely examined. We examine Australian Magpies, a resident, grassland species of bird in southeastern Australia frequently involved in collisions with aircraft at airports, and which can be sexed (adults) and aged. We compared collision rates recorded at Melbourne Airport, Victoria, Australia, with airside counts of magpies, recording, when observable, the sex and age of the birds. Adult females and males were similarly abundant at the airport (46.6% female), but females were struck relatively more frequently than males (78.1% female). Juvenile (first-year) magpies were struck more frequently than expected based on their representation in bird counts. We show an example of where some demographic groups within species represent higher hazard potential to aircraft than others, and management which manipulates demography of magpies at and near the airport (such as discouraging local breeding and targeted harassment/dispersal) may be fruitful.

Dinoflagellate cyst distribution over the past 9 kyrs BP from offshore east Tasmania, southeast Australia

Southeastern Australia’s marine waters are notably warming, surpassing global averages. This region has emerged as a strategic location for researching planktic microfossils, particularly dinoflagellate cysts, in modern and Late Quaternary sediments, offering crucial insights into the biophysical properties of mid-latitude waters. This study examined cyst distribution in marine sediment cores near Maria Island, Tasmania, southeastern Australia, up to 9000 years before present (kyrs BP). Dominant cysts included Protoceratium reticulatum, Protoperidinium spp. (P. avellana, P. conicum, P. oblongum, P. subinerme, P. shanghaiense), and Spiniferites spp. (S. bulloideus, S. hyperacanthus, S. membranaceus, S. mirabilis, S. pachydermus, and S. ramosus). Inshore, Spiniferites spp. constituted a higher proportion (up to 61%), while offshore was dominated by P. reticulatum (up to 80%). Impagidinium spp. and Nematosphaeropsis labyrinthus were exclusively found offshore and displayed increased abundance from ∼6 kyrs BP, suggesting a shift from a shallow to a deep-water habitat. Alexandrium tamarense species complex cysts were present over 140 years inshore and approaching 9 kyrs BP offshore, indicating a longstanding endemic presence. Gymnodinium catenatum cysts were detected exclusively inshore from ∼50 years ago, indicating a relatively recent bloom phenomenon. The East Australian Current’s limited southward reach is suggested by the absence of the warm-water cyst-producing taxon Lingulodinium polyedra. Similarly, the non-detection of the cold-water species Spiniferites antarctica and Impagidinium pallidum reflects Subtropical Front boundaries against subantarctic incursions from the south. In contrast to coccolithophores in the same core, no noticeable shift from cold to warm-water dinoflagellate cyst species was observed. This documentation of dinoflagellate cysts aids in predicting environmental impacts on local communities and beyond.

Primary moult in the annual cycle of adult African Oystercatchers Haematopus moquini

African Oystercatchers Haematopus moquini are sedentary, intertidal foraging birds, range-restricted to Namibia and South Africa. Their annual cycle has two components: breeding and moult. The Underhill–Zucchini model estimated a primary moult duration of 154 days, and mean start and completion dates of 1 April and 2 September. Most eggs (90%) are laid between mid-November and mid-February; thus, on average, oystercatchers have 2–3 months between moult completion and egg laying. The completion date confirms an overlap between moult and the period of post-fledging dependence of juveniles on their parents. The 154-day primary moult duration spreads the energetic demands of feather production to cope with this overlap and with the fact that primary moult extends through winter when storms make intertidal areas inaccessible for days. There are approximately 50 quantitative studies of primary moult for migrant waders (suborder Charadrii); this is the third for a resident species. The other two species of resident waders studied are in south-eastern Australia: the Hooded Dotterel Thinornis cucullatus and Sooty Oystercatcher Haematopus fuliginosus. The Hooded Dotterel has one of the longest estimated moult durations (203 days) and its moult and breeding overlap. The annual schedules for the Sooty Oystercatcher and African Oystercatcher are similar, as is the estimated moult duration: 149 and 154 days, respectively. Preliminary studies of the primary moult of the Eurasian Oystercatcher H. ostralegus indicate the duration to be 100 days, which is two-thirds that of the two sedentary oystercatchers. This is likely a consequence of Eurasian Oystercatchers having migration and harsh winter conditions as additional components of their annual cycle, and thus a limited period for primary moult. This study was based largely on photographic records of African Oystercatchers in flight, with contributions by citizen scientists. We make two key conclusions: the need for more studies of the moult strategies of the Haematopidae and resident waders; and digital photography of free-ranging birds can be used to study primary moult.

Detailed mapping of technical capacities and economics potential of offshore wind energy: A case study in South-eastern Australia

Australia has significant offshore wind resources that can support ever-increasing power demand and hence provide a long-term contribution to the net-zero target by 2050. Although some offshore wind farm projects are proposed in Australia, the industry is not mature enough to justify the benefits and display economic opportunities. More specifically, the techno-economic analysis of offshore wind energy has not been systematically mapped in Australia. Therefore, the investigation of the spatial variation of technical feasibility and economic potential of offshore wind is vital to identify the potential regions and to develop strategies for future offshore wind farm developments in Australia. This paper presents detailed mappings of the techno-economic potential of offshore wind energy in Victoria-Tasmania’s exclusive economic zone. Offshore wind energy resources are assessed in the paper in terms of energy availability and variability and the feasibility of various offshore wind technologies is investigated, including turbines, foundation types and transmission topologies. In addition, the high-fidelity life-cycle cost models and two innovative evaluation matrices are developed to assess the economic potential of offshore energy farms in South-eastern Australia. The impact of local power system regulation costs and future carbon prices on the viability of offshore wind is also investigated in this paper. It is concluded that the detailed mapping approach and analysis in the paper can provide a systematic tool for industry partners, investors and policymakers at the pre-planning stage of developing offshore renewable energy systems.

Evidence of seasonal heat acclimatisation in recreationally active adults during a mild summer

ObjectivesTo assess the magnitude of seasonal heat acclimatisation in recreationally active adults and contextualise the process by documenting the factors that influence adaptations. DesignLongitudinal, repeated measures design. MethodsSeventeen (7 females) recreationally active adults (28 ± 8 yr, V̇O2peak 54 ± 8 mL·kg−1·min−1) exercising outdoors a minimum of 5 h·wk−1 completed a 45-min heat response test running at 60 % V̇O2peak in 40 °C and 30 % relative humidity prior to, midway through, and following summer. Self-reported physical activity diaries were completed at the beginning and end of summer. Daytime wet-bulb globe temperature was calculated for each day of summer. Data were analysed using Bayesian ordinal regressions. ResultsDaytime wet-bulb globe temperature was 22.0 ± 4.4 °C, with the most common hour for recreational exercise being 17:00 to 18:00. Following summer, the rise in oesophageal temperature and mean skin temperature during the heat response test was lower by 0.12 °C [90 % credible interval: −0.30, 0.06; probability of direction = 87 %] and 0.43 °C [−0.74, −0.10; 98 %], respectively. Moreover, forearm local sweat rate increased by 0.26 mg·cm−2·min−1 [0.15, 0.36; 100 %]. There was minimal evidence of a change in the increase in heart rate (1 beat·min−1 [−3, 5; 62 %]), or whole-body sweat rate (0.03 L·h−1 [−0.11, 0.15; 68 %]) during the heat response test. ConclusionsAlthough there was evidence of partial heat adaptation in recreationally active adults following summer, a combination of exercising later in the day and the prevailing environmental conditions (La Niña in South-Eastern Australia) may have blunted the development of further adaptations.

Mycobacterium ulcerans not detected by PCR on human skin in Buruli ulcer endemic areas of south eastern Australia.

Mycobacterium ulcerans (MU) causes Buruli ulcer (Buruli), a geographically restricted infection that can result in skin loss, contracture and permanent scarring. Lesion-location maps compiled from more than 640 cases in south eastern Australia suggest biting insects are likely involved in transmission, but it is unclear whether MU is brought by insects to humans or if MU is already on the skin and inoculation is an opportunistic event that need not be insect dependent. We validated a PCR swab detection assay and defined its dynamic range using laboratory cultured M. ulcerans and fresh pigskin. We invited volunteers in Buruli-endemic and non-endemic areas to sample their skin surfaces with self-collected skin swabs tested by IS2404 quantitative PCR. Pigskin validation experiments established a limit-of-detection of 0.06 CFU/cm2 at a qPCR cycle threshold (Ct) of 35. Fifty-seven volunteers returned their self-collected kits of 4 swabs (bilateral ankles, calves, wrists, forearms), 10 from control areas and 47 from endemic areas. Collection was timed to coincide with the known peak-transmission period of Buruli. All swabs from human volunteers tested negative (Ct ≥35). M. ulcerans was not detected on the skin of humans from highly Buruli endemic areas.

Ecosystem type and species’ traits help explain bird responses to spatial patterns of fire

BackgroundUnderstanding how temporal and spatial attributes of fire regimes, environmental conditions, and species’ traits interact to shape ecological communities will help improve biodiversity conservation in fire-affected areas. We compared the influence of time since the last fire at a site, and the area and diversity of post-fire successional vegetation surrounding a site (i.e., the “spatial context” of fire), on bird species and functional groups in two ecosystems in south-eastern Australia. These ecosystems, semi-arid “mallee” woodlands and temperate “foothill” forests, differ in stand-regeneration patterns, climate, and topography. For 22 bird species in mallee woodlands, 33 species in foothill forests and four functional groups of birds in both ecosystems, we fitted non-linear models that differed in fire regime predictor variables.ResultsIn foothill forests, models that included both time since fire and a spatial context variable explained more variation in bird abundances than models that included only time since fire or a spatial variable. In mallee woodlands, the addition of spatial attributes of fire helped explain the occurrence of several species, but this finding was muted when measured across all species. There were key differences between ecosystems in functional group responses to fire regimes. Canopy/upper-midstorey foragers were positively associated with the amount of late-successional vegetation in mallee woodlands, but not in foothill forests. Lower-midstorey foragers showed a decline response to the amount of late-successional vegetation in mallee woodlands and a contrasting incline response in foothill forests. However, lower-midstorey foragers showed a similar response to the amount of surrounding early-successional vegetation in both ecosystems—decreasing in abundance when > 50% of the surrounding vegetation was early-successional.ConclusionsThe influence of fire regimes on birds varies among species within sites, across landscapes and between ecosystems. Species’ foraging traits influence bird associations with fire regimes, and help to make sense of a myriad of relationships, but are usefully understood in the context of ecosystem types and the regeneration patterns of their dominant flora. The spatial context of fire regimes is also important—the amount of successional vegetation surrounding a site influences bird abundance. Fire management strategies that incorporate the spatial contexts of fire regimes, as well as the temporal and ecological contexts of fire regimes, will have the greatest benefits for biodiversity.

Holocene estuary infill leads to coastal barrier initiation from fluvial sand supply in southeastern Australia

A morphodynamic approach to coastal evolution involves recognition of internal thresholds, feedbacks and boundary conditions and should underpin coastal management. The Holocene evolution of the Bega River estuary and Tathra Beach coastal barrier was examined integrating existing sediment cores and radiocarbon dating, airborne terrestrial and marine Lidar and OSL dating. Sediment coring reveals the Bega River estuary began infilling with fluvial sand once sea levels stabilised at or near their present elevation. Radiocarbon dating suggests a prograding fluvial delta reached the coast approximately 4000–2250 years BP. Barrier deposition commenced ~3200 years ago coinciding with the arrival of fluvial sand at the coast. Shoreline progradation of the Tathra barrier occurred at 0.15 m/year from ~3200 years to present forming a sequence of ~17 foredune ridges which were each active for an average of ~190 years. In the past ~500 years, a sand spit has restricted the entrance of the Bega River estuary to the northern end of the embayment. The infill of the Bega River estuary over the Holocene represents an internal morphodynamic threshold or tipping point, which then enabled coastal barrier deposition as fluvial sand reached the coast. The coastal system approaches another threshold as the Tathra embayment infills, and sediment may be transported northward out of the embayment. At Tathra Beach, the positive sediment budget which resulted in barrier progradation is approximately 0.55 m3/m/year. This signal is masked on the yearly to decadal scale by fluctuations in beach volume an order of magnitude greater (5–20 m3/m/year depending on the timeframe examined). Thus longer-term datasets of beach change or reconstructions from the geological record are needed to underpin management decisions which will impact shorelines decades or centuries into the future.

Learning landscapes through technology and movement: blurring boundaries for a more-than-human pedagogy

ABSTRACT Interest in the role of technology and movement is growing in outdoor environmental education (OEE) research. However, there are many unexamined assumptions involving both non-digital technology and movement for outdoor learners. In this paper, we explore learning landscapes through non-digital technology and movement involving canoe journeys in south-eastern Australia. We examine ways that technology and movement come together to help shape learning orientations through situated examples from OEE fieldwork. Our investigations utilise posthumanist and process-relational theories for exploring onto-epistemological dimensions of outdoor learning. We bring such theory into conversation with photos, videos and student essays to analyse our fieldwork contexts. We highlight that technology and movement cannot be taken for granted; rather, they help constitute the ways we come to know places. We also acknowledge some cultural and conceptual aspects that overlap to influence learning. This paper offers alternative insights for learning landscapes and the mediating influence of technologies.

An integrated public health response to an outbreak of Murray Valley encephalitis virus infection during the 2022-2023 mosquito season in Victoria.

Murray Valley encephalitis virus (MVEV) is a mosquito-borne flavivirus known to cause infrequent yet substantial human outbreaks around the Murray Valley region of south-eastern Australia, resulting in significant mortality. The public health response to MVEV in Victoria in 2022-2023 included a climate informed pre-season risk assessment, and vector surveillance with mosquito trapping and laboratory testing for MVEV. Human cases were investigated to collect enhanced surveillance data, and human clinical samples were subject to serological and molecular testing algorithms to assess for co-circulating flaviviruses. Equine surveillance was carried out via enhanced investigation of cases of encephalitic illness. Integrated mosquito management and active health promotion were implemented throughout the season and in response to surveillance signals. Mosquito surveillance included a total of 3,186 individual trapping events between 1 July 2022 and 20 June 2023. MVEV was detected in mosquitoes on 48 occasions. From 2 January 2023 to 23 April 2023, 580 samples (sera and CSF) were tested for flaviviruses. Human surveillance detected 6 confirmed cases of MVEV infection and 2 cases of "flavivirus-unspecified." From 1 September 2022 to 30 May 2023, 88 horses with clinical signs consistent with flavivirus infection were tested, finding one probable and no confirmed cases of MVE. The expanded, climate-informed vector surveillance system in Victoria detected MVEV in mosquitoes in advance of human cases, acting as an effective early warning system. This informed a one-health oriented public health response including enhanced human, vector and animal surveillance, integrated mosquito management, and health promotion.

Utility of a modified lightweight recreational scallop dredge for surveys of estuarine ark clams (cockles)

Arcid cockles support extensive subsistence, recreational and commercial fisheries across the world. In south-eastern Australia, there is minimal published research and a lack of quantitative surveys for the primary harvested species, Sydney Cockle Anadara trapezia, with which to inform management of the resource. Here, we describe the modification and application of an off-the-shelf lightweight recreational scallop dredge for conducting scientific surveys of arcid clams in estuarine soft sediment habitats. Specifically, we look at performance of the gear for sampling medium-large (>45 mm shell length) cockles, and report on the outcomes of preliminary trials of the gear for surveying Sydney Cockle. Efficiency trials showed that the gear captured and retained ∼95% of the cockles in the tow path, however efficiency decreased in compacted sediments (∼66%). Trial surveys captured cockles between 33 and 78 mm shell length, at densities as high as 186 individuals 100 m−2. The modified scallop dredge provides a robust and portable (∼10 kg weight) fishing gear for sampling estuarine soft sediment habitats from small vessels. Both the sampling gear, and the methodology presented here, are broadly applicable for surveying arcid cockles and other bivalve species from similar soft sediment habitats elsewhere.

Subtropical coral expansion into SE Australia: a haven for both temperate and expatriating tropical reef fishes

We examined reef fish assemblages in and adjacent to a newly established coral bed (subtropical Pocillopora aliciae) in temperate south-eastern Australia, to understand whether novel coral habitat is facilitating assemblages of range-expanding tropical and local temperate fishes. This is the first comprehensive assessment of fish species associating with this novel coral habitat within a temperate environment. Twenty fish species were observed associating with the coral (8 tropical and 12 temperate). Both temperate and tropical species were observed at greater (up to 48 times higher) densities on the coral than on nearby temperate rocky reef in the area, suggesting that the corals generally concentrate fish and may aid in tropicalisation for species that use subtropical coral as habitat. Future research should investigate the ongoing expansion of this coral, the relative quality of coral habitat for fish in temperate regions and the potential implications for functioning of temperate rocky reef ecosystems.