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Efficacy of otolith morphometry for rapid discrimination of cryptic fishes
No full textThe cryptic external morphology of fishes poses challenges for accurate species identification. This study assessed whether the morphometry of otoliths (and body length) could be used as a method to distinguish among closely related, morphologically similar species that are highly valued by commercial or recreational fishers. The otolith morphometry of fishes within four genera (Centroberyx, Lethrinus, Polyprion and Sillago) were compared. Canonical Analysis of Principal Coordinates that included combinations of morphometric variables (i.e., otolith length, width, thickness, weight, and fish length) produced highly accurate species prediction rates ranging from 92.5 to 99.9% across all genera. When different combinations of morphometric variables were modelled, changes in species prediction accuracy rates were minimal (i.e., up to 3%) for the Centroberyx, Polyprion and Sillago species. The exclusion of otolith weight from the multivariate analysis did not significantly decrease prediction accuracy within all four genera. In contrast, the prediction accuracy of the two lethrinids reduced by 7–25% when fish length was excluded, which may be attributable to the larger size attained by L. nebulosus in comparison to its congener L. punctulatus, as well as the very similar ovate shaped otoliths in younger fish of both species. Simplifying data collection to only length-based otolith measurements (and fish length for lethrinids) would provide a more rapid and cost-effective method for discrimination and be more practical when sampling at sea where obtaining accurate weight measurements of otoliths is typically unfeasible. Spatial variation in otolith morphometrics was evident for C. gerrardi, L. punctulatus, P. oxygeneios and S. vittata, which might be attributed to the differences in length distributions of fish samples from different regions. The misclassified specimens within the species groups were notably smaller individuals, suggesting the complexity of otolith shape increases with ontogeny. Hence, further investigation of variations in morphological characteristics, other than otoliths, may be required for the discrimination of cryptic species during the juvenile stage. This study highlights the robustness of multivariate analysis of otolith morphometric data for discriminating closely-related, cryptic species
DAW00252 - Innovative approaches to managing subsoil acidity in the Western Region
No full textData collected includes: Measure pH, EC and All and other chemical analysis Soil compaction Root growth Measure N, P, K, S, N, Ca, Mg, Mo, Mn and Cu concentrations Plant biomass Grain Yield (Maturity, total weight, grain weight, head number). Soil sampling by depth Collect 20 pogos per plot Number of plants Plant tissue testing for micronutrients Plant maturity - height, tiller counts, lodging scores NDVI of crop Trial site-year information including: The soil type The weather conditions The presence of any other chemicals in the soil The type of vegetation presen
Advances and opportunities in unraveling cold-tolerance mechanisms in the world\u27s primary staple food crops
No full textTemperatures below or above optimal growth conditions are among the major stressors affecting productivity, end-use quality, and distribution of key staple crops including rice (Oryza sativa), wheat (Triticum aestivum), and maize (Zea mays L.). Among temperature stresses, cold stress induces cellular changes that cause oxidative stress and slowdown metabolism, limit growth, and ultimately reduce crop productivity. Perception of cold stress by plant cells leads to the activation of cold-responsive transcription factors and downstream genes, which ultimately impart cold tolerance. The response triggered in crops to cold stress includes gene expression/suppression, the accumulation of sugars upon chilling, and signaling molecules, among others. Much of the information on the effects of cold stress on perception, signal transduction, gene expression, and plant metabolism are available in the model plant Arabidopsis but somewhat lacking in major crops. Hence, a complete understanding of the molecular mechanisms by which staple crops respond to cold stress remain largely unknown. Here, we make an effort to elaborate on the molecular mechanisms employed in response to low-temperature stress. We summarize the effects of cold stress on the growth and development of these crops, the mechanism of cold perception, and the role of various sensors and transducers in cold signaling. We discuss the progress in cold tolerance research at the genome, transcriptome, proteome, and metabolome levels and highlight how these findings provide opportunities for designing cold-tolerant crops for the future
A comparison of different stomatal density phenotypes of hordeum vulgare under varied watering regimes reveals superior genotypes with enhanced drought tolerance
No full textEnhancing the water-use efficiency (WUE) of barley cultivars may safeguard yield deficits during periods of low rainfall. Reduced stomatal density is linked to enhanced WUE, leading to improved drought resistance across plant genera. In this study, 10 barley varieties exhibiting a range of stomatal density phenotypes were grown under differing soil water contents to determine whether stomatal density influences the capacity of genotypes to resist low water availability. The low-stomatal-density genotype Hindmarsh showed the least impact on biomass production during early development, with a 37.13% decrease in dry biomass during drought treatment. Low-stomatal-density genotypes additionally outcompeted high-stomatal-density genotypes under water-deprivation conditions during the reproductive phase of development, exhibiting 19.35% greater wilting resistance and generating 54.62% more heads relative to high-stomatal-density genotypes (p \u3c 0.05). Finally, a correlation analysis revealed a strong negative linear relationship between stomatal density and the traits of head number (r = −0.71) and the number of days until wilting symptoms (r = −0.67) (p \u3c 0.05). The combined results indicate that low-stomatal-density genotypes show promising attributes for high WUE, revealing novel barley varieties that may be useful to future breed improvement for drought tolerance
Conserving nature\u27s chorus: Local and landscape features promoting frog species richness in farm dams
No full textHabitat loss is a key factor in the ongoing freshwater biodiversity crisis. A promising way to help tackle the rapid decline in freshwater biodiversity is to improve the potential for artificial wetlands to provide habitat for aquatic wildlife. Farm dams (also known as agricultural ponds) are among the most abundant waterbodies in agricultural landscapes and can act as “oases” against droughts for many species. Despite their prominent role in agriculture, predictive models to evaluate their ecological potential are yet to emerge. Here we use a continental-scale data set of 104,013 audio recordings from citizen scientists to identify and locate 107 species of frogs near 8800 Australian farm dams. Frog species are among the most threatened taxa on earth and we asked: What characteristics promote higher frog species richness at farm dams? We found that the highest values of frog species richness were at old ( \u3e 20 years) farm dams of intermediate size (0.1 ha in surface area), with small or medium rainfall catchments ( \u3c 10 ha), and situated near other freshwater systems or conservation sites. The relationships shown here are highly generalisable and applicable on a continental scale. By identifying quantifiable features improving the ecological value of farm dams, we help identify “win-win” outcomes for agricultural productivity and conservation. In the future, “biodiversity credit” policies could incentivise large-scale ecological restoration by rewarding individuals who invest in enhancing their farm dams to support and promote local biodiversity
An integrated approach for assessing the survival of discarded sandbar sharks, Carcharhinus plumbeus, captured in scientific longlines
No full textContext The sandbar shark (Carcharhinus plumbeus) has a global distribution and is caught by commercial fishers and recreational anglers. Aims To assess the stress physiology, release condition, and post-release survival of sandbar sharks caught in longline surveys conducted in Western Australia. Methods Post-release survival of sandbar sharks caught in longlining surveys was assessed using an integrated approach that combined the use of hook-timers, qualitative release conditions, satellite-tagging, and blood physiology. Key results Of 57 individuals examined, there was 100% post-capture survival after a maximum of 4 h on the hook. Most of these animals (88%) displayed a strong release condition, exhibiting minimal behavioural impairment. All 13 satellite-tagged individuals survived 30 days post-capture. Sharks dived up to 307 m deep and showed cyclical depth movement patterns, with some individuals moving through the water column both day and night, whereas others moved almost exclusively at night. The concentration of blood metabolites did not significantly change with time-on-hook. Conclusion Post-capture and post-release survival of 100% after up to 4 h on hooks suggested that the use of longlines for surveying sandbar shark abundance had no deleterious effects on captured sharks. Implication This will support future stock assessments of sharks by quantifying the survival rates in the methods used for long-term monitoring of sandbar shark populations
Bush and revegetation recovery after fire on farms in Western Australia
No full textThis page gives some ideas on how to reduce the risk of fires in bush and revegetation on farms, and how to speed recovery of burnt areas.
Large patches of bush in good condition will generally regenerate well after fire, with some management of weeds and grazing.
Revegetation areas are much more susceptible to fire, and recovery largely depends on the age of the revegetation and after-fire management
Land systems, soils and vegetation of the southern Goldfields and Great Western Woodlands of Western Australia - Volume 2
No full textThis technical bulletin defines and maps the land resources of the southern Goldfields region of Western Australia (WA). The southern Goldfields region, as featured in this bulletin, covers 151,753 km2. The western and eastern borders are variable because they align with various cadastral boundaries. The western survey border, which in part follows the WA State Barrier Fence, demarcates cleared agricultural land from the intact, western extent of the Great Western Woodlands. The eastern border abuts the westernmost Nullarbor pastoral lease boundaries, except for the north-easternmost and south-easternmost edges which continue into Crown land. Major towns are Coolgardie, Kalgoorlie and Boulder in the central north, Kambalda in the centre and Norseman in the central south.
The southern Goldfields survey area is closely aligned with the world’s largest and most intact area of Mediterranean-climate woodland, known as the Great Western Woodlands. These eucalypt-dominated woodlands, which include mosaics of mallee, shrubland and grassland, cover nearly 160,000 km2. This survey and adjacent rangeland surveys in the Sandstone, Yalgoo and Paynes Find, north-eastern Goldfields, and WA Nullarbor regions complete mapping to a scale of 1:250,000, and describe biophysical features over most of the Great Western Woodlands, except for the southernmost extremities.
This survey combines and augments previous studies that mapped vegetation, physiography and soil distribution in a hierarchical framework that adheres to state and national standards. The purpose of this survey was to provide a comprehensive description of the biophysical resources of the southern Goldfields region and an accompanying land system map.
This bulletin provides information on survey methods, climate and landscape evolution. The characteristics and distribution of soils, vegetation and habitat type ecology, and land systems are described. This information will assist individuals, agencies and companies who have interests in land-use planning and development of sustainable systems, monitoring, rehabilitation and conservation of the rangeland habitats and landscapes within the southern Goldfields region. Within the survey area, there are 69 WA soil groups, belonging to 12 soil supergroups; 88 habitat types split between 13 groups; and 101 land systems grouped into 41 broad land types
Increasing wheat proteins sustainably by rotation with forage legumes
No full textWheat proteins provide around 20% of all human dietary protein, but their end-use qualities are determined by the form and quantity of nitrogen in the endosperm. In the developed world, there is a heavy reliance in grain production on nitrogen supplied from synthetic fertilisers, and this fertiliser can contribute up to 50% of the on-farm emissions of greenhouse gasses in agriculture. However, despite increasing rates of application of synthetic nitrogen to cereals, wheat grain protein levels, in developed nations, have been frequently failing to reach the premium grade required by the bread-making market. Here, for the first time, we report that biological nitrogen fixation from a new generation of hardseeded annual forage legumes, when grown in rotation with cereal crops, can replace fertiliser N without compromising grain protein. The forage legumes were grown in rotation with Triticum aestivum, and compared with rotations that included a fallow, or a cereal crop at three rainfed sites in Western Australia with differing soil types for 2–4 years. The wheat received low, medium and high rates of urea to indicate if forage legumes can provide sufficient nitrogen for sustainable wheat production. At all sites and years studied, we discovered that cereal grains produced following a year of forage legumes had significantly higher protein levels than when grown as part of a continuous cereal rotation. These results were achieved in combination with a reduction in on-farm emissions (by over 200 kg/ha of CO2) without compromising yield as indicated by emissions accounting. Including appropriate forage legumes in farming systems allows production of low emission intensity grain proteins in dryland farming