New South Wales Department of Primary Industries

In 2023, the Australian Government issued ∼250,000 soil carbon credits following a measurement period characterised by high rainfall (Decile 10). The inferred soil organic carbon (SOC) sequestration rates during this period, ranging from ∼2 to 8 t C ha⁻¹ yr⁻¹, significantly exceed rates reported in Australian scientific studies (∼0.1 to 1.2 t C ha⁻¹ yr⁻¹). Our analysis, incorporating SOC and biomass measurements alongside remote sensing of NDVI, reveals that these SOC gains were largely attributable to above-average rainfall rather than project interventions. Moreover, these gains were not sustained when rainfall returned to average levels, raising concerns about the durability of credited sequestration and its additionality beyond natural climatic variability. Our findings demonstrate that current safeguards within the Soil Carbon Method—such as withholding 25% of credits during the first measurement period—are likely insufficient to account for climatic variability. To strengthen the integrity of the carbon crediting system, we recommend extending the minimum measurement period for credit issuance to at least five years. Additionally, governments should establish science-based ‘reasonable bounds’ for expected long-term SOC gains from management practices to sense-check reported outcomes. These measures will ensure that credited SOC sequestration is more closely tied to management-driven outcomes rather than short-term climate-driven fluctuations.

Sugarcane (Saccharum sp. hybrids) crops typically grow for 16–24 months in the subtropics, with nitrogen (N) fertiliser generally applied as a single dose between 150 and 250 kg N ha⁻¹ early in the season. High N fertiliser application coupled with intense rainfall in the subtropics can lead to nitrate leaching and denitrification events that result in low N fertiliser use efficiency and damage to the environment. We investigated whether the use of a slow-release N fertiliser, polymer coated urea (PCU), may be more agronomically effective than urea as an N fertiliser source, by better matching soil N supply to sugarcane N demand. Multi-rate N fertiliser trials comparing biomass production and N accumulation responses of ratoon sugarcane crops to urea and PCU products were conducted across four commercial sugarcane farms in the Australian subtropics, with N fertiliser applied in a band 100–150 mm below the soil surface 2–12 weeks after the previous cane crop was harvested. At two sites, buried mesh bags containing 90 d and 270 d PCU products were destructively sampled over 12–15 months to assess the N release rate under field conditions. Sugarcane biomass yields were responsive to applied N at two of the four sites (P < 0.05) and crop N accumulation was responsive to N fertiliser application at all four sites (P < 0.1). While the mesh bag study clearly indicated a delayed release of N from the PCU products over time, there was no significant effect of N fertiliser source (urea vs PCU) on crop biomass or N accumulation at any site. The lack of any improvement in agronomic N efficiency with the PCU products is attributed to the presence of active roots in ratoon crops combined with the absence of large rainfall events in the months following N fertiliser application in the seasons of study. Modelling, coupled with an understanding of the N release dynamics of PCU products across a different soils and climatic conditions, is required to develop recommendations for PCU products for sugarcane growers in the region, although further trials across a wider range of seasons may be warranted to verify any modelling predictions.

Alternative crop fibers have shown great potential for paper applications, especially packaging. We demonstrate Australian wheat straw processing using a Regmed MD-3000 disc refiner to produce mechanical pulp fibers and assessment by making 60, 120 and 300 g/m ² handsheets. Wheat fibers and spotted gum fibers were then enzymatically sized (hydrophobized) by esterification to reduce the surface spread of water by 51 % and 36 %, respectively. Coffee pods (300 g/m ² equivalent) were manufactured using a thermoformer to demonstrate the versatility of mechanical wheat straw pulp fibers as a sustainable resource for food packaging application.

Fast and efficient identification is critical for reducing the likelihood of weed establishment and for appropriately managing established weeds. Traditional identification tools require either knowledge of technical morphological terminology or time-consuming image matching by the user. In recent years, deep learning computer vision models have become mature enough to enable automatic identification. The major remaining bottlenecks are the availability of a sufficient number of high-quality, reliably identified training images and the user-friendly, mobile operationalization of the technology. Here, we present the first weed identification and reporting app and website for all of Australia. It includes an image classification model covering more than 400 species of weeds and some Australian native relatives, with a focus on emerging biosecurity threats and spreading weeds that can still be eradicated or contained. It links the user to additional information provided by state and territory governments, flags species that are locally reportable or notifiable, and allows the creation of observation records in a central database. State and local weed officers can create notification profiles to be alerted of relevant weed observations in their area. We discuss the background of the WeedScan project, the approach taken in design and software development, the photo library used for training the WeedScan image classifier, the model itself and its accuracy, and technical challenges and how these were overcome.

This study enhances our comprehension of the performance of farm businesses in Western Australia by estimating persistent and transient technical efficiency measures in the presence of firm‐level effects. The analysis is based on a balanced panel data set of 54 farm businesses from the years 2002 to 2011. We employ Kumbhakar et al.'s (2014, Journal of Productivity Analysis , 41 , 321) model to estimate persistent efficiency and firm effects separately, as well as Kumbhakar's and Heshmati's (1995, American Journal of Agricultural Economics , 77 , 660) model where these two factors are confounded. Furthermore, we investigate the factors that influence transient and persistent technical efficiency. Our findings reveal that failing to differentiate between persistent technical efficiency and firm effects underestimates the estimates of persistent and overall technical efficiency. This underestimation may result in misguided policy recommendations for improving the technical performance of farm businesses. We also find that persistent efficiency dominates overall technical efficiency. The significant determinants of persistent overall technical efficiency include the regional rainfall zone where a farm business is located, the managerial competency of the farm operator denoted by their age and off‐farm activities. Off‐farm income plays a crucial role in determining transient technical efficiency.

Fisher-shark conflict is occurring at Lord Howe Island, Australia due to high levels of Galapagos shark (Carcharhinus galapagensis) depredation (where sharks consume hooked fish) and bycatch. Depredation causes costly loss of target catch and fishing gear and increased mortality of target species, and sharks can be injured or killed when bycaught. This study applied acoustic telemetry and vessel tracking from 2018 to 2021 to identify; (1) how the movements of 30 tagged sharks and activity of six fishing vessels overlapped, and (2) where key ‘hotspots’ of overlap occurred. Fisher surveys were also conducted to collect information about mitigating shark interactions. Residency index analysis indicated that three sharks tagged at a fish waste dumping site had markedly higher residency. Core home ranges of sharks overlapped with higher fishing activity at four ‘hotspots’. Statistical modelling indicated positive linear effects of fishing activity and bathymetric complexity on shark detections and tagged sharks were present for 13% of the total time that vessels were fishing close to acoustic receivers. Spatio-temporal overlaps between shark movements and fishing activity could potentially have occurred because sharks learned to associate fishing vessels with food (i.e. hooked fish) and because fishers and sharks utilise highly productive shelf edge areas, however more research is needed to investigate these relationships. Fishers reported that rotating fishing areas and reducing time at each location, fishing deeper than 100 m, and using electric reels and lures instead of bait, reduced bycatch and depredation. The integrated approach used here identified practical methods for reducing fisher-shark conflict, improving socio-economic outcomes for fishers and conservation prospects for this unique shark population.

Although individual genomic structural variants (SVs) are known to influence gene expression and trait variation, the extent and scale of SV impact across a species remain unknown. In the present study, we constructed a reference library of 334,461 SVs from genome assemblies of 16 representative morphotypes of neopolyploid Brassica napus accessions and detected 258,865 SVs in 2,105 resequenced genomes. Coupling with 5 tissue population transcriptomes, we uncovered 285,976 SV-expression quantitative trait loci (eQTLs) that associate with altered expression of 73,580 genes. We developed a pipeline for the high-throughput joint analyses of SV-genome-wide association studies (SV-GWASs) and transcriptome-wide association studies of phenomic data, eQTLs and eQTL-GWAS colocalization, and identified 726 SV–gene expression–trait variation associations, some of which were verified by transgenics. The pervasive SV impact on how SV reshapes trait variation was demonstrated with the glucosinolate biosynthesis and transport pathway. The study highlighting the impact of genome-wide and species-scale SVs provides a powerful methodological strategy and valuable resources for studying evolution, gene discovery and breeding.

Genomic vulnerability is a measure of how much evolutionary change is required for a population to maintain optimal genotype‐environment associations under projected climates. Aquatic species, and in particular migratory ectotherms, are largely underrepresented in studies of genomic vulnerability. Such species might be well equipped for tracking suitable habitat and spreading diversity that could promote adaptation to future climates. We characterised range‐wide genomic diversity and genomic vulnerability in the migratory and fisheries‐important golden perch ( Macquaria ambigua ) from Australia's expansive Murray–Darling Basin (MDB). The MDB has a steep hydroclimatic gradient and is one of the world's most variable regions in terms of climate and streamflow. Golden perch are threatened by fragmentation and obstruction of waterways, alteration of flow regimes, and a progressively hotter and drying climate. We gathered a genomic dataset of 1049 individuals from 186 MDB localities. Despite high range‐wide gene flow, golden perch in the warmer, northern catchments had higher predicted vulnerability than those in the cooler, southern catchments. A new cross‐validation approach showed that these predictions were insensitive to the exclusion of individual catchments. The results raise concern for populations at warm range edges, which may already be close to their thermal limits. However, a population with functional variants beneficial for climate adaptation found in the most arid and hydrologically variable catchment was predicted to be less vulnerable. Native fish management plans, such as captive breeding and stocking, should consider spatial variation in genomic vulnerability to improve conservation outcomes under climate change, even for dispersive species with high connectivity.

Biogenic silica (biogenic Si) is a bioactive component crucial for the biogeochemical cycling of Si in terrestrial and aquatic ecosystems. Its formation and dissolution dynamics are intricately linked to carbon (C) cycling. However, knowledge about the source, composition, and factors controlling the distribution of biogenic Si in coastal wetland sedimentary environments is still limited. To address this lack of knowledge, we introduced a suite of geometric models for biogenic Si biovolume calculation and investigated biogenic Si assemblages, along with biogenic Si and biogenic Si‐occluded C contents, in sediments from representative coastal wetlands along the west coast of Bohai Bay. Our analysis showed that sedimentary biogenic Si predominantly derived from phytoliths (78.1% ± 5.8%), diatoms (18.2% ± 4.8%), and sponge spicules (3.7% ± 2.9%). Notably, phytolith assemblages were primarily composed of forms derived from the Poaceae family. The biogenic Si‐occluded C content (0.035–1.870 g kg⁻¹) within these wetland sediments was consistent across both sites, accounting for 0.97–5.71% of the total organic C pool. Structural equation modeling indicated that total organic C, pH, and amorphous aluminum oxides either directly or indirectly influenced the biogenic Si content in coastal wetlands sediments. These results demonstrate the critical role that biogenic Si plays in the Si biogeochemical cycle and provide valuable information that advances our understanding of the biogeochemical interactions between Si and C in coastal wetland ecosystems.

This study investigates the utility of plant δ¹³C natural labeling in predicting the impacts of environmental shifts on carbon cycling within ecosystems, particularly focusing on paddy fields treated with maize (Zea mays L.) residues and biochar. Specifically, it examines how soil δ¹³C and the sources of soil organic carbon (SOC), respond in paddy fields (which cultivate C3 plants like rice) when amended with maize residues, maize biochar, and silica‐enriched biochar (derived from C4 plants). Conducted in the Fuzhou paddy fields, the experiment included control groups and treatment groups with maize residue (4 t ha⁻¹), maize biochar (4 t ha⁻¹), and silicon‐modified maize biochar (4 t ha⁻¹) during both the early and late rice growth periods. The results indicate that all soil treatments increased soil δ¹³C. The application of maize residues notably affected the δ¹³C of the upper soil profile (0–15 cm) differently from the deeper layers (15–30 cm), and it increased soil organic C more than biochar or silicon‐modified maize biochar. Soil available P (AP) and pH emerged as significant factors linking δ¹³C, influencing rice yield through changes in soil physicochemical properties. Unlike maize residues, which reduced rice yields, applications of biochar and silicon‐modified maize biochar increased rice yields. The latter, which was particularly effective in lowering SOC decomposition rates and addressing rice's silica needs, emerged as the preferred option. The study highlights maize biochar and silicon‐modified maize biochar as sustainable alternatives to maize residues for rice cultivation, enhancing soil fertility, carbon pool stability, and yields.

Cotton (Gossypium spp.) is the most important fibre crop worldwide. Black root rot and Fusarium wilt are two major diseases of cotton caused by soil-borne Berkeleyomyces rouxiae and Fusarium oxysporum f. sp. vasinfectum (Fov), respectively. Phenotyping plant symptoms caused by soil-borne pathogens has always been a challenge. To increase the uniformity of infection, we adapted a seedling screening method that directly uses liquid cultures to inoculate the plant roots and the soil. Four isolates, each of B. rouxiae and Fov, were collected from cotton fields in Australia and were characterised for virulence on cotton under controlled plant growth conditions. While the identities of all four B. rouxiae isolates were confirmed by multilocus sequencing, only two of them were found to be pathogenic on cotton, suggesting variability in the ability of isolates of this species to cause disease. The four Fov isolates were phylogenetically clustered together with the other Australian Fov isolates and displayed both external and internal symptoms characteristic of Fusarium wilt on cotton plants. Furthermore, the isolates appeared to induce varied levels of plant disease severity indicating differences in their virulence on cotton. To contrast the virulence of the Fov isolates, four putatively non-pathogenic Fusarium oxysporum (Fo) isolates collected from cotton seedlings exhibiting atypical wilt symptoms were assessed for their ability to colonise cotton host. Despite the absence of Secreted in Xylem genes (SIX6, SIX11, SIX13 and SIX14) characteristic of Fov, all four Fo isolates retained the ability to colonise cotton and induce wilt symptoms. This suggests that slightly virulent strains of Fo may contribute to the overall occurrence of Fusarium wilt in cotton fields. Findings from this study will allow better distinction to be made between plant pathogens and endophytes and allow fungal effectors underpinning pathogenicity to be explored.

An understanding of octopus behaviour and their capture by fishing gears is required to inform efficient, sustainable, and ethical octopus fisheries. Here, the behaviour of Octopus tetricus was assessed in response to different bait and trap combinations in an outdoor mesocosm experiment. Eight wild octopuses were collected, maintained in individual tanks with flow-through seawater and aeration, and monitored with a 24-h video surveillance system. Six different traps and four different baits were presented to each octopus in various combinations during four sequential trials. Fine-mesh crab traps were the most successful in capturing octopus, accounting for 23 of the total 30 captures across all trials. Whereas solid trigger traps produced the greatest number of other interactions (e.g., octopus sitting on trap/in the entrance), averaging 43 interactions per trial, but were rarely triggered. Bait type did not influence octopus capture, trap interaction frequency, or octopus activity; however, only artificial bait types were trialled, and fresh natural baits may elicit a stronger response and should be investigated in future research. Generally, octopus were inactive, dedicating only 9.5% of their total time to active behaviours. Octopus activity varied with time of day, with peak activity during morning daylight (0800–1200) and the lowest activity during the dark hours of the very early morning (0000–0400). Additionally, capture numbers, trap interactions, and activity varied among individuals, with bolder personalities in some octopus. This natural variation among individual octopuses may lead to fishery-induced selection associated with the elevated capture frequency of bold or more active individuals.

Genetic diversity is rapidly lost from small, isolated populations by genetic drift. Measuring the level of genetic drift using effective population size (Ne) is highly useful for management. Single‐cohort genetic Ne estimators approximate the number of breeders in one season (Nb): a value < 100 signals likely inbreeding depression. Per‐generation Ne < 1000 estimated from multiple cohort signals reduced adaptive potential. Natural populations rarely meet assumptions of Ne‐estimation, so interpreting estimates is challenging. Macquarie perch is an endangered Australian freshwater fish threatened by severely reduced range, habitat loss, and fragmentation. To counteract low Ne, augmented gene flow is being implemented in several populations. In the Murrumbidgee River, unknown effects of water management on among‐site connectivity impede the design of effective interventions. Using DArT SNPs for 328 Murrumbidgee individuals sampled across several sites and years with different flow conditions, we assessed population structure, site isolation, heterozygosity, inbreeding, and Ne. We tested for inbreeding depression, assessed genetic diversity and dispersal, and evaluated whether individuals translocated from Cataract Reservoir to the Murrumbidgee River bred, and interbred with local fish. We found strong genetic structure, indicating complete or partial isolation of river fragments. This structure violates assumptions of Ne estimation, resulting in strongly downwardly biased Nb estimates unless assessed per‐site, highlighting the necessity to account for population structure while estimating Ne. Inbreeding depression was not detected, but with low Nb at each site, inbreeding and inbreeding depression are likely. These results flagged the necessity to address within‐river population connectivity through flow management and genetic mixing through translocations among sites and from other populations. Three detected genetically diverse offspring of a translocated Cataract fish and a local parent indicated that genetic mixing is in progress. Including admixed individuals in estimates yielded lower Ne but higher heterozygosity, suggesting heterozygosity is a preferable indicator of genetic augmentation.

A major limitation to producing high seed yields in berseem clover (Trifolium alexandrinum L.) is failure to set seed, predominantly due to lack of pollination. Despite the importance of berseem clover as a leading forage legume, the contribution of pollinators to seed set is scarce. In Pakistan, the honeybee population is declining mainly because of the extensive use of neonicotinoid pesticides and habitat fragmentation. This, combined with the region’s harsh environment and the use of inferior, locally bred genotypes, has resulted in low seed yields. Insufficient seed availability leads to limited forage supply, resulting in poor livestock nutrition, which subsequently impacts livestock health and productivity, and reduces farmers’ income. The present study estimated the seed production of 3 berseem clover genotypes resulting from honeybees [Apis mellifera L. (Hymenoptera: Apidae)] pollination in 2 growing seasons (2012–2014) in the central Punjab region of Pakistan. Experiments had 2 pollination treatments (open pollination and honeybee inclusion) and 3 seed genotypes, viz. farmer own-saved, market, and the improved variety cultivars. For both growing seasons, honeybee pollination resulted in significant increases in seed yields ranging from 35% to 67%, regardless of seed genotype. With the exception of the number of seed heads/m2, all seed yield parameters also increased significantly in response to honeybee inclusion. The combination of improved variety and honeybee inclusion resulted in the production of a maximum number of seeds per head (45.3), 1,000-seed weight (3.7 g), and estimated seed yield (375.5 kg/ha). In addition, the increase in estimated net income of seed ranged from PKR 82,485 Rs/ha (US$844/ha) to PKR 168,975 Rs/ha (US$1728/ha) with the use of honeybees as an insect pollinator across all the seed genotypes. Honeybee pollination has broader implications for mixed farming systems by playing a key role in preserving biodiversity and promoting sustainable agriculture. It also enhances the quality and quantity of berseem crops by increasing the production of high-quality seeds and forage leading to improved livestock productivity and family food security which strengthens the economic resilience of rural communities.

Herbivore dung quality (physical and chemical parameters) varies between animal species and animal diet which is influenced by seasonal fluctuations and farm management practices. Subsequently, this influences the reproductive success of dung beetles. In Australian pasture systems, how the introduced dung beetle assemblage interacts in the field with cattle dung derived from different resources is unknown. This study quantifies the colonization by dung beetles (abundance, species richness and evenness) and removal of cattle dung derived from three common temperate pasture systems (improved native, forage oat and rye/clover pasture, henceforth dung type) over 24 h for 12 months. From the three dung types, 13 species of dung beetle were captured. Abundance and species richness were influenced by month and transect, with weak evidence for differences between dung types influencing overall abundance: Onthophagus binodis (49.7%), Aphodius fimetarius (24.4%) and Labarrus lividus (17.1%) were the most abundant species. Dung removal (organic matter) was influenced by month and dung type, with more dung buried in improved native (23.9 g) and rye/clover (24.7 g) derived dung compared with forage oat (12.3 g) dung. Dung beetle abundance was positively correlated with removal of all dung types, with O. binodis biomass significantly influencing dung removal. This study showed that diet of bovine animals weakly influences the abundance of a local dung beetle assemblage, warranting further investigation on the influence of other dung types in different regions. Improvements to reporting of pasture species and growth stage is recommended for comparisons between dung derived sources.

Fire is a major disturbance affecting ecosystems globally, but its impact on mutualisms has received minimal attention. Here, we use a long-term field experiment to investigate the impact of different fire regimes on globally important ant–honeydew and ant–extrafloral nectar (EFN) mutualistic interactions in an Australian tropical savanna. These interactions provide ants with a key energy source, while their plant and hemipteran hosts receive protection services. We examined ant interactions on species of Eucalyptus (lacking EFNs) and Acacia (with EFNs) in three replicate plots each of burning every 2 and 3 years early in the dry season, burning late in the dry season every 2 years, and unburnt for > 25 years. The proportions of plants with ant–honeydew interactions in Acacia (44.6%) and Eucalyptus (36.3%) were double those of Acacia plants with ant–EFN interactions (18.9%). The most common ants, representing 85% of all interactions, were behaviourally dominant species of Oecophylla, Iridomyrmex and Papyrius. Fire promoted the incidence of ant interactions, especially those involving EFNs on Acacia, which occurred on only 3% of plants in unburnt plots compared with 24% in frequently burnt plots. Fire also promoted the relative incidence of behaviourally dominant ants, which are considered the highest quality mutualists. Contrary to expectations, frequent fire did not result in a switching of behaviourally dominant ant partners from forest-adapted Oecophylla to arid-adapted Iridomyrmex. Our findings that frequent fire increases ant interactions mediated by honeydew and extrafloral nectar, and promotes the quality of ant mutualists, have important implications for protective services provided by ants in highly fire-prone ecosystems.

Efficient traceability is paramount for Australia's biosecurity system and market access. Electronic identification (eID) offers higher traceability performance than that achieved with visual and mob‐based identification used for the sheep and goats National Livestock Identification System (NLIS). The current study aims to gain an understanding of the barriers and motivations of using eID for NLIS sheep and goats in New South Wales (NSW) and to provide recommendations to support the transition to eID. A social research study using a mixed‐methods approach was used through semi‐structured interviews and a cross‐sectional epidemiological and behavioural study among sheep and goat producers. The COM‐B behaviour change model based on capabilities, opportunities and motivations was used as a framework for the study. A total of 269 participants informed this study: 25 interviews were conducted with government, industry and private stakeholders, and 184 and 58 sheep and goat producers participated in the cross‐sectional study, respectively. The study identified poor understanding of the purpose and importance of NLIS among producers, with over two‐thirds not supporting eID implementation. The main barriers identified to the eID implementation were practical, including costs, technology quality and increased workload. Attitudinal, behavioural and knowledge barriers, such as the perception of the current system providing efficient traceability and the perceived lack of benefits of eID were also identified. This study provides an in‐depth analysis of practices and perceptions of stakeholders and producers on sheep and goat traceability and recommendations to address barriers identified, based on education and appropriate behavioural and technical support.

Globally, key predators such as lobsters are thought to control urchins. In south-eastern Australia, the role of Sagmariasus verreauxi (eastern rock lobster) as a key predator of the native urchin Centrostephanus rodgersii (long-spined urchin) has been questioned while the sympatric Heliocidaris erythrogramma (short-spined urchin) may be eaten more frequently. To test this, we tethered and filmed 100 urchins (50 C. rodgersii and 50 H. erythrogramma) outside of a lobster den over 25 nights to identify predators and quantify predation rates, time to feeding onset and handling time. Sagmariasus verreauxi exhibited very low predation rates (4%), despite being filmed walking past urchins repeatedly whereas Heterodontus galeatus (crested horn shark) was the main predator (45%). Predation rates by all predators (lobsters and sharks) were influenced primarily by tethering night but not urchin size or species. Predation increased throughout the study and while H. erythrogramma and C. rodgersii were eaten at similar rates, there was a trend for lobsters to eat H. erythrogramma and sharks to eat C. rodgersii. Feeding onset had no significant predictors though large C. rodgersii took longer to handle during feeding for both predators. Importantly, sharks readily consumed 25 C. rodgersii up to 121 mm Test Diameter (TD) while lobsters only ate one C. rodgersii (58 mm TD). These findings, although from only one test location, provide important insights into the species eating urchins and highlight the potential significance of overlooked predators such as H. galeatus.