North Queensland Research Articles

First records of Herald Petrel Pterodroma heraldica on Phillip Island (Norfolk Island Group)

The Herald Petrel Pterodroma heraldica is a medium-sized gadfly petrel that breeds primarily on islands across the tropical and subtropical South Pacific Ocean. Its only confirmed breeding site in the Australasian region is Raine Island off North Queensland, where it occurs in very small numbers. Here we report on the presence of a Herald Petrel ashore on Phillip Island (Norfolk Island Group) in June 2021, and subsequent sightings in May and June 2022. On most occasions that a Herald Petrel was observed on the ground, it was seen under a shrub, behaviour which is consistent with prospecting for a nest site in this surface-nesting species. These sightings make Phillip Island one of just four locations in Australian territory at which the Herald Petrel has been recorded ashore away from Raine Island. Our new records reinforce the importance of active island restoration and the value of long-term intensive monitoring efforts. Future observations will confirm whether the species attempts to establish on Phillip Island, a location free from introduced predators and with ample suitable habitat.

Pacific Emerald Doves Chalcophaps longirostris socially signal with shoulder marking

Pacific Emerald Doves Chalcophaps longirostris attracted to a constantly available artificial food resource within North Queensland upland tropical rainforest often simultaneously numbered up to six individuals, resulting in frequent aggressive interaction. Observing and photographing Pacific Emerald Doves near and at the food source showed that individuals approaching feeders with conspecifics already at the feeders fully exposed their white shoulder-patch and held the wing joint just slightly away from the body, possibly as a flight-intention movement. Birds more distant from the feeders, or approaching them in the absence of conspecifics, exposed but a small part of their shoulder-patch, holding the wing tight against the body with body contour feathers covering the edge of the wing to give the usual appearance of the species. Thus, exposing the entire white shoulder-patch, which makes it appear whiter, functions as a ‘fight or flee’ social signal previously undocumented in the species or in any of the other Chalcophaps species.

Abundant post‐fire recruitment and rapid seedling maturity emphasise regular burning is beneficial for conserving the Vulnerable Purple‐flowered Wattle (Acacia purpureopetala)

SummaryPurple‐flowered Wattle (Acacia purpureopetala) has a Vulnerable status under the Queensland Nature Conservation Act (1992) and is listed as Critically Endangered under the Environment Protection and Biodiversity Conservation Act (1999). It grows in eucalypt woodlands of North Queensland. Its post‐fire response was examined to better understand its ecology and management requirements. Before and after fire surveys found Purple‐flowered Wattle is a fire‐killed ‘obligate seeder’ with abundant fire‐promoted germination, but limited recruitment in the absence of fire, highlighting the importance of regular burning for generating new plants. Nearly half of Purple‐flowered Wattle seedlings began producing seed in their second year, indicating a population tolerant of frequent burning. Combined, the abundant fire‐promoted recruitment and rapidly maturing seedlings suggest regular patchy fires that allow some mature plants to survive unburnt while promoting recruitment in burnt areas would benefit the population. A laboratory trial found percentage germination after 3 weeks was significantly higher for seeds treated by soaking in hot water for 5 minutes (31% germination), compared with those soaked in ambient temperature water (4% germination). However, by 5 weeks, germination differences between seed treatment were not statistically significant. The apparent discrepancy where unheated seeds eventually germinated in a laboratory setting, yet in situ germination was almost completely restricted to the post‐fire environment, warrants further investigation. It may be that successful germination and seedling establishment in woodlands requires the rapid removal of physical dormancy, or perhaps keeping unheated seed constantly moist for 5 weeks in a laboratory trial is simply an unnatural treatment producing a germination response not relevant to ecosystem function. The abundant fire‐triggered germination and rapid maturity of seedlings, combined with the known population number (>4,000 plants) and distribution range (850 km2), support existing recommendations that Purple‐flowered Wattle warrants a Vulnerable rather than Critically Endangered Environment Protection and Biodiversity Conservation Act (1999) status, as is current at the state level. Management that includes regular patchy burning with good soil moisture that reduces the extent and intensity of individual fires is likely to benefit the long‐term preservation of this restricted species and associated species of its ecosystems.

Culturally appropriate psychotherapy and its retention: An example from Far North Queensland (Australia)

BackgroundCulturally appropriate mental health care is essential in remote Australia. However, while associated with the development of an effective therapeutic alliance, current literature insufficiently reports the retention and psychotherapy outcomes of Indigenous adults. We aimed to describe the characteristics and retention of clients attending the Far North Mental Health and Wellbeing Service (FNS). MethodsWe conducted a retrospective cross-sectional study on clients who received one or more psychotherapy consultations between 1st July 2019 and 31st December 2020. Population, entrance, and treatment characteristics were described, with retention compared between the major cultural groups. Entrance characteristics comprised referral pathway and reason for presentation and were investigated as alternative predictors of client retention. FindingsThere were 186 non-Indigenous (68.3 % female) and 174 Indigenous (62.6 % female) clients, with a median number of 3.0 consultations (IQR 2.0–5.3). Indigenous status did not significantly predict retention. Referral pathway significantly predicted the number of consultations (Wald X2(6) = 17.67, p = .0071) and immediate discontinuation (Wald X2(6) = 12.94, p = .044), with self-referred clients having the highest retention. Initial presentation reason significantly predicted the number of consultations (Wald X2(5) = 13.83, p = .017), with clients with potential health hazards related to socioeconomic and psychosocial circumstances having the lowest retention. Significantly more Indigenous clients presented for this reason (20.1 % vs 4.3 %). InterpretationComparable retention of Indigenous clients suggests cultural appropriateness of the psychotherapy being delivered by the FNS. Services might use the described therapeutic approach as a guide for culturally appropriate care.

Cultural, sociopolitical, environmental and built assets supporting health and well-being in Torres Strait Island communities: protocol for a scoping review

IntroductionRisks to an individual’s health should be considered alongside the environmental, sociocultural and sociopolitical context(s) in which they live. Environmental mapping is an approach to identifying enablers and barriers to...

Working for the Saints

This article presents some of the main dynamics of the social reproduction of an Italian community through an ethnographic study of the Feast of the Three Saints in Silkwood, North Queensland. It has been celebrated annually there since being imported from the Sicilian village of St Alfio in 1950. As a celebration of Italian sociality and the Italian way of life, the Feast offers a particular opportunity to study the relationship between popular religion, food production and consumption, the senses, memory and materiality. From this perspective, I argue that the Feast as ‘lived religion’ should be understood not only as an expression of Catholic devotion, but also in terms of the construction of a ‘domus’, defined as a social unit and a community based on shared values and practices enacted and continually renewed by the preparation of food and the sensorial aspects of commensality. In the ‘sacred street theatre’ of the Feast, it is by means of these food practices that a community comes into being by sharing knowledge, memories and feelings. [A religious feast in Sicily] is, above all, an existential explosion. (Sciascia 1965: 30)1 This completely irreligious way of understanding and professing a religion … has its roots in a profound materialism, a total rejection of all that entails mystery, invisible revelation, metaphysics. (Sciascia 1965: 21)

Family photograph of past lives and future portents

Capturing an important day in the life of a community, a photograph from the author’s family collection records a group that has gathered to welcome the Italian aviator Francesco De Pinedo to Innisfail in 1925. De Pinedo’s record-breaking 55,000-kilometre flight from Rome to Tokyo via Australia and back was an extraordinary feat, and a demonstration of Italian technological advancement and participation in the drive towards global connectivity of those times. He had been feted by the public and dignitaries, including the Prime Minister, at each stage of his journey around Australia. But the photograph reveals much more. De Pinedo’s visit was particularly welcome where Italians were denigrated and viewed with suspicion. At the time, there was unrest about the impact of ‘foreign’ – specifically Italian – immigration in North Queensland, to provide labour for its sugar industry. The men in the photograph were among the leaders of the North Queensland Italian communities, and three of them had been invited as witnesses before the Ferry Royal Commission just months earlier. The Commission was set up to investigate attitudes towards the increasing numbers of Italians, and those views were to result in widespread internment of North Queensland Italians during World War II. All but two of the Italian leaders photographed were interned. This article situates the personal histories and contributions of these individuals within their historical circumstances.

Doing research with busy people: Enacting rapid walking methodologies with teachers in a primary school

Teachers are busy people. How do we, as researchers, address the challenges of doing research with busy people—especially if we wish to enact ethical, more radical futures? How do we adhere to the pressures of fast-paced urban life when research, especially interviews, takes away people's time? This paper presents a novel method for doing research with busy people, combining the ‘walking interview’ method with a ‘free listing technique.’ The interviews were carried out with teachers at a north Queensland primary school in a rapidly urbanising neighbourhood, and formed part of a larger project exploring the barriers and opportunities of incorporating community gardens (as important green spaces) into schools. The method itself yielded important findings and this paper is a reflective analysis of how simple factors such as the weather, noise, and interruptions shaped 20 min of a teacher's day. We extend these ideas to explore how conditioned and situational temporalities, along with more-than-human influences, affect the knowledge produced in rapid walking interviews. Keeping track of these affections can yield important data relevant to the project. The research will be invaluable for other researchers struggling with ethical and other issues shaping access to stakeholders in a diverse range of urban environments.

A ‘civil minority’

The figure of Costante Danesi (1884–1969) stands out as an unrelenting defender of the rights of Italian migrants in Queensland’s history between the two world wars. Although his activism as an anti-fascist is documented in archival records and mainstream and Italian-migrant newspapers of the time, his role has received little more than cursory attention by scholars to date. This has led not only to confusion about his politics but also neglect of an opportunity for a deeper appreciation of the intercultural dimensions of resilience during the interwar years. Arriving in Australia in 1921, Danesi was not alone in speaking up to defend Italian migrants’ contributions to society or in aiding their wellbeing, and his activism in protecting their rights aligned with the principles of democracy. Yet an examination of those struggles reveals how the experiences of Italian sugarcane workers in North Queensland exposed overt and covert racism alongside Australia’s democratic ideals of the time. Drawing from the works of Joan Beaumont and Arjun Appadurai, this discussion repositions an Italian-born British subject as significant not only within the history of Queensland but also, more generally, in the demonstration of a minority community’s resilience over this tumultuous era.

Flood Hazard Assessment in Australian Tropical Cyclone-Prone Regions

This study investigated tropical cyclone (TC)-induced flooding in coastal regions of Australia due to the impact of TC Debbie in 2017 utilising a differential evolution-optimised random forest to model flood susceptibility in the region of Bowen, Airlie Beach, and Mackay in North Queensland. Model performance was evaluated using a receiver operating characteristic curve, which showed an area under the curve of 0.925 and an overall accuracy score of 80%. The important flood-influencing factors (FIFs) were investigated using both feature importance scores and the SHapely Additive exPlanations method (SHAP), creating a flood hazard map of the region and a map of SHAP contributions. It was found that the elevation, slope, and normalised difference vegetation index were the most important FIFs overall. However, in some regions, the distance to the river and the stream power index dominated for a similar flood hazard susceptibility outcome. Validation using SHAP to test the physical reasoning of the model confirmed the reliability of the flood hazard map. This study shows that explainable artificial intelligence allows for improved interpretation of model predictions, assisting decision-makers in better understanding machine learning-based flood hazard assessments and ultimately aiding in mitigating adverse impacts of flooding in coastal regions affected by TCs.

The burden of head trauma in rural and remote North Queensland, Australia

BackgroundHead trauma is a leading cause of death and disability worldwide. Young males, Indigenous people, and rural/remote residents have been identified as high-risk populations for head trauma, however, Australian research is limited. Our aim was to define and describe the incidence, demographics, causes, prehospital interventions, and outcomes of head trauma patients transported by aeromedical services within North Queensland, Australia. We hypothesized that young, Indigenous males living remotely would be disproportionately affected by head trauma. MethodsWe conducted a retrospective study of all head trauma patients transferred by air to or between Townsville, Cairns, Mount Isa and Mackay Hospitals between January 1, 2016 and December 31, 2018. Patients were identified from the Trauma Care in the Tropics data registry and followed for a median 30-months post-injury. Primary endpoints were patient and injury characteristics. Secondary outcome measures were hospital stay and mortality. ResultsA total of 981 patients were included and 31.1 % were Indigenous. Sixty-seven percent of injuries occurred remotely and the median time from injury to hospital was 5.8-hours (range 67–3780 min). Eighty percent of severe head injuries occurred in males (p = 0.007). Indigenous and remote patients were more likely to sustain mild injuries. The most common mechanism of injury overall was vehicle accident (37.5 %), compared to assault in the Indigenous subgroup (46.6 %, p<0.001). The overall mortality rate was 4.9 %, with older age and lower initial Glasgow Coma Score significant predictors of in-hospital mortality. Prehospital intubation was associated with a 7-fold increased risk of mortality (p = 0.056), while patients that received tranexamic acid (TXA) were almost 5-times more likely to die. ConclusionsIn North Queensland, young Indigenous males are at highest risk of traumatic head injuries. Vehicle accidents are an important preventable cause of head injury in the region. TXA administration is an important consideration for remote head trauma retrievals, in which time to emergency care is prolonged. Appropriate treatment and risk stratification strategies considering time to definitive care, severity of injury, and other prehospital patient factors require further investigation.

Making Waves: The Role of Indigenous Water Beings in Debates about Human and Non‐Human Rights

ABSTRACTRejecting nature‐culture dualism, contemporary anthropology recognises the mutually constitutive processes that create shared human and non‐human lifeworlds. Such recognition owes much to ethnographic engagement with diverse indigenous cosmologies many of which have, for millennia, upheld ideas about indivisible worlds in which all living kinds occupy a shared ontological space and non‐human species and environments are approached respectfully, with expectations of reciprocity and partnership. As many societies confront the global chaos caused by the anthropocentric prioritisation of human interests, anthropologists and indigenous communities are therefore well placed to articulate alternative models in which the non‐human domain is dealt with more equitably and inclusively. This paper is located comparatively in long‐term ethnographic research with indigenous communities in Australia, alongside the Mitchell River in North Queensland and the Brisbane River in South Queensland. It draws more specifically on involvement in legal claims for water rights by Māori iwis in New Zealand; in land claims by the Kunjen language group in Cape York; and in a recent ‘sea country’ case brought against a major multi‐national by the Tiwi Islanders in Australia's Northern Territory. It also makes use of a major comparative study of water beings in diverse cultural and historical contexts, and considers the central importance of water beings such as Māori taniwha and the Australian Rainbow Serpent in such legal conflicts, and in broader debates about human and non‐human rights. Like other water deities around the world, these beings personify the generative (and potentially punitive) powers of water and its co‐creative role in shaping human and non‐human lives. They are resurfacing today with an important representational role in contemporary conflicts over land and water.

Marine heatwaves in the Great Barrier Reef and Coral Sea: their mechanisms and impacts on shallow and mesophotic coral ecosystems

The Great Barrier Reef (GBR) World Heritage Area and adjacent Coral Sea Marine Park are under serious threat from global climate change. This study used Daily Optimally Interpolated Sea Surface Temperature (DOISST) data to identify major marine heatwaves (MHWs) that have occurred in this region over the last three decades (1992–2022). We then used Himawari-8 (H-8) SST data to map significant MHW events that occurred between 2015 and 2022. We investigated the mechanisms underlying the MHWs, assessed thier impact on shallow and mesophotic coral reef ecosystems and identified potential coral refugia. MHWs in this region have increased in frequency, intensity and spatial extent. El Niño, especially when it is in phase with positive Indian Ocean Dipole, was the key remote driver leading to intense MHWs. However, the more recent strong MHWs (e.g., 2017 and 2022) occurred in the abscence of these climatic events, signifying the impacts of long-term climate change and local drivers. We also found that reduced wind speed and shoaling mixed layer depth, often together with reduced cloudiness, were the main local drivers pre-conditioning these MHWs. Anomalous air-sea heat flux into the ocean, mainly controlled by shortwave solar radiation (cloudiness) and latent heat flux (wind), was the most constant contributor to the 2015–16 and 2019–20 MHW events. However, local oceanographic dynamics, especially horizontal advection and turbulent mixing, played important roles in MHW heat budgets. This study confirmed that shallow-water coral bleaching severity was positively related to the cumulative MHW intensity in the 2015–16 and 2019–20 MHW events. We identified shallow reefs along the path of the North Queensland Current as potential coral refugia from bleaching because of the cooler waters upwelled from the ocean current. We also found that, except during weather events such as tropical cyclones, mesophotic reefs in the Coral Sea Marine Park may be less susceptible to severe bleaching as the MHWs were more confined within the shallow mixed layer.

The Functions of Prosody in Action Formation in Australian Greek Talk-in-Interaction

This study takes us to the Greek diasporic community in Cairns, Far North Queensland, Australia. The data analyzed derive from audio-recorded conversations with first-generation Greek immigrants collected during fieldwork in 2013. Drawing on interactional linguistics and contact linguistics, this paper analyzes the prosody of bilingual discourse markers and bilingual repetition in Australian Greek talk-in-interaction. It is shown that the prosodic features of code switches, namely pitch, intensity and duration, shape action formation and ascription. In the case of bilingual discourse markers, pitch serves as a contextualization cue that conveys the speaker’s stance and frames the different functions of the code-switched items. In bilingual repetition, speakers mobilize duration and intensity to prosodically differentiate the first iteration delivered in English from the second iteration delivered in Greek and, thus, frame the interpretation of the code switch as participant-related. This study sheds light on the pragmatic aspects of the phonetics of the Greek variety spoken in Cairns, and demonstrates that prosody shapes the functions of language contact-induced speech behavior in specific interactional contexts.

Provenance of the Papuan Peninsula (Papua New Guinea): Zircon Inheritance from Miocene–Pliocene Volcanics and Volcaniclastics

Plate tectonic reconstructions of Papua New Guinea prior to the late Cenozoic are characterized by a lack of provenance data to constrain the relative origin of the allochthonous terranes. At present, plate tectonic reconstructions of this region infer that the accreted New Guinea terranes at the northern Australian continental margin are likely autochthonous or para-autochthonous in nature. This study presents the results of an investigation into zircons derived from Miocene–Pliocene volcanics and volcaniclastics of the Papuan Peninsula. Results from U-Pb zircon geochronology inform the recent geological history of the Papuan Peninsula, with magmatism active in the late Miocene and early Pliocene, between approximately 9 Ma and 4.5 Ma. More significantly, however, is the recognition of extensive inherited zircon grains within the volcanic and volcaniclastic sequences. These inherited zircon grains are most likely sourced from the Owen Stanley Metamorphics, which form the basement rocks of the Papuan Peninsula. Provenance of the inherited zircon grains imply that the Cretaceous volcaniclastic protolith of the Owen Stanley Metamorphics must have had input from continental detritus, but this cannot be derived from North Queensland, Australia as inferred by current reconstructions. Instead, zircon U-Pb age spectra correlate with probable source regions further to the south, adjacent to the Shoalwater Formation of the Central Queensland margin, and New Caledonia. These findings suggest that late Mesozoic and Cenozoic regional reconstructions of eastern Australia and the Southwest Pacific require major revision and that additional work is undertaken to inform the provenance of such allochthonous terranes.

Factors influencing the community participation approaches used in Aedes mosquito management in the Torres Strait, Australia

BackgroundAedes-borne disease risk is increasing in tropical and sub-tropical regions across the globe. While Aedes-borne disease continues to disproportionally affect low- and middle-income countries, parts of high-income countries, such as the Torres Strait region in Australia are also at risk. The Torres Strait is a group of islands located between Cape York Peninsula in far north Queensland, Australia and Papua New Guinea. The Torres Strait has both Aedes albopictus and Aedes aegypti and is close to Papua New Guinea where dengue fever is endemic. Managing Aedes-borne disease risk requires a range of strategies, including community participation. Existing research shows that high-income countries tend to favour government-led (top-down) informing approaches when engaging communities in Aedes mosquito management. Little is known about the factors that influence the choice of community participation approaches in Aedes mosquito management particularly in a high-income country setting, such as Australia. This research contributes to filling this knowledge gap by exploring the community participation approaches used in Aedes mosquito management and the factors influencing these choices in the Torres Strait.Methods16 semi-structured interviews were conducted with local government and state government agencies working in Aedes mosquito management in the Torres Strait. Six key mosquito management plans and policies were also reviewed. Thematic analysis was used to identify, analyse and attribute meaning from the data collected.ResultsA range of community participation approaches were used within the two main Aedes mosquito management programs (Aedes albopictus Elimination Program and the Torres Strait Island Regional Council, Environmental Health Program) in the Torres Strait. These approaches included door-to-door inspections, awareness raising strategies, and community clean-up events. Approaches were chosen for reasons related to regulations, attitude and beliefs, and resourcing.ConclusionsThis study revealed the use of both top-down and bottom-up approaches to engaging the community in Aedes mosquito management in the Torres Strait. These findings contribute to a better understanding of why bottom-up approaches are used, which is valuable for shaping future policy decisions. This study also provides suggestions on ways to enhance community participation in the Torres Strait, which could also be considered in other similar tropical regions.

Multiscale landscape genetic analysis identifies major waterways as a barrier to dispersal of feral pigs in north Queensland, Australia.

Feral pigs (Sus scrofa) are a destructive and widespread invasive pest in Australia. An understanding of feral pig movement is required to develop management strategies to control feral pigs in Australia. Because landscape structure can have a strong influence on animal movement, it is important to determine how landscape features facilitate or impede the movement of feral pigs. Consequently, we conducted a landscape genetic analysis of feral pig populations in the Herbert region of far north Queensland, Australia, to determine management units and provide recommendations to better inform feral pig population control strategies. Using microsatellite data obtained from 256 feral pig samples from 44 sites, we examined feral pig population structure at multiple spatial scales for univariate and multivariate landscape resistance surfaces to determine the optimal spatial scale and to identify which of the nine landscape features tested impede or facilitate feral pig gene flow. Only weak genetic structure was found among the 44 sampling sites, but major waterways were identified as a minor barrier to gene flow, and an isolation by distance model was supported. We also found that highways facilitated gene flow across the study area, and this suggests that they may act as movement corridors or indicate translocation of feral pigs. Additionally, incorporating a second spatial scale enhanced the ability of our landscape genetics analysis to detect the influence of landscape structure on gene flow. We identified three management units based on natural barriers to gene flow and future targeted control should be undertaken in these management units to deliver sustained reduction of feral pig populations in the Herbert region. This study demonstrates how a landscape genetic approach can be used to gain insight into the ecology of an invasive pest species and be used to develop population control strategies which utilise natural barriers to movement.

Bacterial culture and susceptibility test results for clinical mastitis samples from Australia's subtropical dairy region

This study aimed to identify the pathogens isolated from the milk of cows with clinical mastitis in the subtropical region of Australia and to determine the antimicrobial susceptibility of these bacteria. Thirty dairy herds in the subtropical dairy region were asked to submit milk samples for the first 5 cases of clinical mastitis each month for 12 mo. Samples underwent aerobic culture, and isolates were identified via MALDI-TOF mass spectrometry. Antimicrobial susceptibility was determined for Escherichia coli, Enterococcus spp., Streptococcus agalactiae, Streptococcus uberis, Streptococcus dysgalactiae, Staphylococcus aureus, and non-aureus staphylococci and mammaliicocci (NASM). Between March 2021 and July 2022, 1,230 milk samples were collected. A positive culture result was recorded for 812 (66%) of the milk samples; from these samples, 909 isolates were obtained, including 49 isolates where no identification was possible. The remaining samples were classified as having no growth (16.8%) or as being contaminated (17.2%). The most common isolates with a MALDI-TOF diagnosis (n = 909) were Strep. uberis (23.6%), followed by the NASM group (15.0%). Farms enrolled in the study were in 3 distinct locations within the subtropical dairy region: North Queensland, Southeast Queensland, and Northern New South Wales. Some variation in isolate prevalence occurred between these 3 locations. We found lower odds of a sample being positive for E. coli in North Queensland (odds ratio [OR]: 0.25; 95% confidence interval [CI]: 0.07-0.87) and higher odds in Southeast Queensland (OR: 4.01; 95% CI: 1.96-8.20) compared with the reference, Northern New South Wales. We further found higher odds of Strep. dysgalactiae in North Queensland (OR: 5.69; 95% CI: 1.85-17.54) and Southeast Queensland compared with Northern New South Wales (OR: 3.99; 95% CI: 1.73-9.22). Although some seasonal patterns were observed, season was not significant for any of the analyzed isolates. Farm-level differences in pathogen profiles were obvious. Overall, clinical mastitis pathogens had low levels of resistance to the antimicrobials tested. This research demonstrates that Strep. uberis and the NASM bacterial group are the most common pathogens causing clinical mastitis in the subtropical dairy region. It highlights the importance of understanding pathogenic causes of mastitis at the farm and regional level for targeted control and therapy.

Quantifying the impact of Wolbachia releases on dengue infection in Townsville, Australia

From October 2014 to February 2019, local authorities in Townsville, North Queensland, Australia continually introduced Wolbachia-infected mosquitoes to control seasonal outbreaks of dengue infection. In this study, we develop a mathematical modelling framework to estimate the effectiveness of this intervention as well as the relative dengue transmission rates of Wolbachia-infected and wild-type mosquitoes. We find that the transmission rate of Wolbachia-infected mosquitoes is reduced approximately by a factor of 20 relative to the uninfected wild-type population. In addition, the Townsville Wolbachia release program led to a 65% reduction in predicted dengue incidence during the release period and over 95% reduction in the 24 months that followed. Finally, to investigate the potential impact of other Wolbachia release programs, we use our estimates of relative transmissibility to calculate the relationship between the reproductive number of dengue and the proportion of Wolbachia-infected mosquitoes in the vector population.

Sweet Sorghum as a Potential Fallow Crop in Sugarcane Farming for Biomethane Production in Queensland, Australia

Biogas from lignocellulosic feedstock is a promising energy source for decentralized renewable electricity, heat, and/or vehicle fuel generation. However, the selection of a suitable energy crop should be based on several factors such as biomass yields and characteristics or biogas yields and economic returns if used in biorefineries. Furthermore, the food-to-fuel conflict for the use of a specific energy crop must be mitigated through smart cropping techniques. In this study, the potential use of sweet sorghum as an energy crop grown during the fallow periods of sugarcane cultivation was evaluated. Nine sweet sorghum cultivars were grown on sandy loam soil during September 2020 in North Queensland, Australia. The overall results showed that the crop maturity had a profound influence on chemical composition and biomass yields. Further, the total insoluble and soluble sugar yields varied among the tested cultivars and were dependent on plant height and chemical composition. The biomass yields ranged from 46.9 to 82.3 tonnes/hectare (t/ha) in terms of the wet weight (w/w) of the tested cultivars, with the SE-81 cultivar registering the highest biomass yield per hectare. The gross energy production was determined based on the chemical composition and methane yields. Biochemical methane potential (BMP) studies in batch experiments at 37 °C showed that methane yields of 175 to 227.91 NmL CH4/gVSadded were obtained from the tested cultivars. The maximum methane yield of 227.91 NmL CH4/gVSadded was obtained for cultivar SE-35. However, SE-81 produced the highest methane yields on a per hectare basis (3059.18 Nm3 CH4/ha). This is equivalent to a gross energy value of 761.74 MWh/year or compressed biomethane (BioCNG) as a vehicle fuel sufficient for 95 passenger cars travelling at 10,000 km per annum. Overall, this study demonstrated that sweet sorghum is a potential energy crop for biogas production that could be cultivated during the fallow period of sugarcane cultivation in Queensland.