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Enhancing DNA and RNA extraction quality for viral detection in horticultural seeds
No full textImported seeds must meet Australian Biosecurity inspection and clearance requirements. Rapid, cost-effective diagnoses are needed to ensure imported seeds are free of seed-transmitted pathogens. Our project aims to develop an adaptable and reliable molecular diagnostics system to detect and mitigate the risk of introducing regulated pathogens into Australian horticultural production systems on seed, which is cost-effective and simple to implement. However, seeds are challenging for many molecular studies due to their high content of polyphenols, polysaccharides, and lipids, which can bind to nucleic acids, resulting in low yield and quality. Although there are published protocols claiming better seed nucleic acid extraction methods, none are applicable to high throughput analysis. We are attempting to create total nucleic acid extractions that are high quality, high yield, and high throughput to allow possible HTS analysis for infected seeds. To this end, investigations into the utility of SDS-based buffers were conducted extracting DNA and RNA from cucurbit seeds spiked with Cucumber Green Mottle Mosaic Virus. The improved protocols generated may contribute to rapid and sensitive diagnostics of viruses in horticultural seeds imported into Australia, reducing the risks of disease outbreaks in horticultural systems
Nutrient metrics to compare algal photosynthetic responses to point and non-point sources of nitrogen pollution
Get PDFPoint- and non-point source nutrients are likely to have different ecological impacts in receiving waters, due to differences in the concentration and proportions of nutrient fractions. However, the direct comparison of their ecological impacts in receiving waters has barely been quantified. We undertook algal bioassays with algal communities from river sites and showed that there was a photosynthetic yield (Fv/Fm) response to nutrient enrichment when river nutrient concentrations were relatively low, but not at higher nutrient concentrations. To combat this variability in the photosynthetic state of algae, we developed a standardized algal bioassay (3-day), using a cultured species of algae which was starved of nitrogen, to compare the photosynthetic response to three nitrogen sources: treated wastewater, aquaculture farm discharges, and soil erosion-derived nutrient sources. This study showed that the nutrient parameter that had the highest correlation with algal photosynthetic response was total dissolved nitrogen (TDN), i.e., the sum of dissolved inorganic and organic nitrogen, rather than dissolved inorganic nitrogen alone. This was true across all three nutrient sources (R2 = 0.58–0.78). Additionally, the same concentrations of TDN from soil erosion-derived and aquaculture samples resulted in a significantly higher algal photosynthetic response, compared to the treated wastewater. This indicates that TDN from soils and aquaculture farms was significantly more bioavailable to the cultured algae than treated wastewater. When a range of parameters were correlated with algal responses, organic and inorganic nutrients, and organic carbon were the parameters that had the highest explanatory power for soil erosion-derived and aquaculture samples (R2 = 0.75–0.87). The importance of organic compounds in these equations points to the potential of microbial transformation of organic nutrients into more bioavailable forms during the 3-day bioassay. This highlights the need to understand the relationship between algal and microbial communities in natural systems for nutrient source impact assessment. This study provides an improved understanding and metrics for comparing the algal growth response to different nutrient sources
A review of the biology, distribution, and management challenges posed by the invasive weed Ziziphus mauritiana L., with special reference to its invasion in Australia
Get PDFZiziphus mauritiana is an economically detrimental and environmentally destructive plant in non-native areas where it has escaped cultivation. It forms dense, impenetrable thickets that restrict the movement of livestock across the landscape and has the capacity to alter various ecological functions at the site of invasion, all of which contribute towards land degradation and the reduction of economic profitability. Although there are several management strategies implemented to control Z. mauritiana, it is clear that no single-method approach will effectively control the species in the long-term. Whilst chemical and mechanical methods appear to show promising results, they tend to be restricted to areas that are easily accessible and, even so, can be challenging and laborious to treat evenly across dense thicket areas. Several prospective biological control agents have been identified for Z. mauritiana, although further investigations are required to ascertain the host specificity, and to explore and identify their climatic and environmental suitability of host specific agents for release in non-native regions. Ecological burning alone is not effective in controlling Z. mauritiana and will likely increase its emergence. As such, it could be adopted as part of an integrated management approach to assist other methods for long-term control, but again the development of such an approach requires further investigation. To contribute towards the control of Z. mauritiana, this review explores its biology, distribution and management challenges whilst identifying areas of research that will assist in the long-term and confident control of the species, with an emphasis on its invasion in Australia
Soil constraints project - an update on the economic response of long term soil amelioration strategies
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• Deep ripping compacted soils appears to have short term benefits but soil collapses shortly afterwards sometimes to a worse state than the original condition
• While tillage and nutrition treatments have stood out in historic wet seasons, the recent dry season indicates gypsum with ripping has improved water capture and yields
• Return on investment from treatments has occurred in shorter timeframes than expected
• Results from on-farm research trials indicate positive responses are soil dependent and the importance of finding the right solution for your soil
Modelling of tropical pasture growth using DairyMod: Model parameterisation and validation across multiple environments
No full textTropical forages are the primary feed source for livestock production in tropical and subtropical regions. Biophysical modelling has been an effective tool to explore the likely performances of forage species under different edaphoclimatic and agronomic management practices. The existing models are lacking in parameterised and validated tropical pastures, thus hindering their use for tropical and subtropical regions. The aims of this study were to parameterise the DairyMod, a mechanistic biophysical pasture model and robustly validate the species-specific parameters for the prediction of the growth of the three tropical pastures; Megathyrsus maximus ‘Gatton Panic’ (GP), Brachiaria ruziziensis x B. decumbens x B. brizantha ‘Brachiaria Mulato II’ (BM), and Chloris gayana ‘Rhodes grass cv. Reclaimer’ (RR). The model was calibrated using measurements of biomass components, canopy structure, and carbon assimilation collected from a field experiment at the Gatton Research Dairy Farm Queensland, Australia. The model was tested extensively using the published data from a diverse set of environments and management practices (16 data sets, 32 experiments, 14 different locations across South America, North America, Australia, and Africa). In the model parameterisation stage, DairyMod model predicted the aboveground biomass with good agreement for all tropical pastures with a high R2 of 0.92, 0.98, 0.74 and low RMSE of 341, 583, 848 kg DM ha–1 for BM, GP and RR, respectively. The model agreement was good for the validation data with R2 of 0.86, 0.80, 0.87 and RMSE of 954.5, 790.5, 633.2 kg DM ha–1 for the BM, GP and RR, respectively. The model predicted leaf and stem partitioning relatively poorly, and the model also struggled to simulate realistic pasture growth in Mediterranean and desert environments (R2 < 0.50). The study has improved the robustness and accuracy of DairyMod in relation to tropical pastures under tropical and subtropical climate conditions. Our robust and widely tested model can be successfully used for broader explorations of tropical pastures for improving livestock production systems in the tropics and subtropics, while calling for future improvement of the model accuracy in the areas of tropical pasture biomass partitioning, stubble dynamics and low temperature stress recovery function
Crop competition effects on weeds and crops
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• There is convincing evidence that increased crop competition in sorghum, mungbean, faba bean and chickpea resulting from narrower row spacing and/or increased crop density reduces growth and seed production of feathertop Rhodes grass and sowthistle
• Importantly, in most instances, narrower row spacing and increased plant density did not have a negative impact on grain yield. In situations where resources (e.g. water) were not limiting, more competitive crops resulted in higher yield
• In general, when there is low yield potential (usually due to limited resources) growing a crop at a narrow row spacing or increased crop density is more likely to result in yield loss. In contrast, when there is a high yield potential, crops grown at wide row spacing are likely to result in yield loss when compared to narrow row spacing
From little things big things grow: enhancement of an acoustic telemetry network to monitor broad-scale movements of marine species along Australia’s east coast
Get PDFAcoustic telemetry has become a fundamental tool to monitor the movement of aquatic species. Advances in technology, in particular the development of batteries with lives of > 10 years, have increased our ability to track the long-term movement patterns of many species. However, logistics and financial constraints often dictate the locations and deployment duration of acoustic receivers. Consequently, there is often a compromise between optimal array design and affordability. Such constraints can hinder the ability to track marine animals over large spatial and temporal scales. Continental-scale receiver networks have increased the ability to study large-scale movements, but significant gaps in coverage often remain
The toad less travelled: comparing life histories, ecological niches, and potential habitat of Asian black-spined toads and cane toads
Get PDFContext: Invasive vertebrates have significant negative impacts on biodiversity and agricultural production worldwide. Increased connectivity among countries, through trade and tourism, is escalating the rate of introductions of vertebrate species, particularly herpetofauna, across international borders. In Australia, Asian black-spined toads (ABSTs; Duttaphrynus melanostictus) are one of the species most intercepted at borders. They are considered a biosecurity risk because of the potential for negative environmental impacts, similar to those caused by cane toads (Rhinella marina).Aims: We aimed to compare ABSTs with cane toads to investigate potential impacts and distribution of ABSTs in the Australian context. We also aimed to identify knowledge gaps regarding ABST biology and the potential role of cane toads in an ABST invasion in Australia.Methods: We undertook a literature review to obtain published data to compare the life history characteristics of ABSTs and cane toads. We also modelled climatic niche overlap and compared suitable habitat for both species in Australia.Key results: Our results show ABSTs and cane toads have broadly similar reproductive life histories and feeding niches. In particular, similarities include large clutch sizes, preferred oviposition sites, and diet at tadpole and adult life stages. In Australia, the species share suitable potential habitat, particularly in North Queensland, where the majority of ABST incursions have occurred. The species differ in size, call characteristics, clutch size relative to body size, and egg development rate, although the environment also influences these traits. We identify gaps in our knowledge of ABST spatial ecology, thermal tolerances, water reliance, and habitat.Conclusions: ABSTs pose a significant biosecurity threat to Australia. Similarities in life history to cane toads means they may have similar impacts, but may have a more limited distribution in Australia. Invasion of Australia by ABSTs would likely result in interactions with cane toads, but it is not possible to accurately determine the outcomes of those interactions without further investigation.Implications: Addressing knowledge gaps and quantitatively determining the potential for competition between ABSTs and cane toads will assist surveillance and response planning for ABST incursions in Australia
Qweeds - Queensland
No full textThe dataset contains data about the locations and descriptions of invasive plants.
Data has been collated from PestInfo, Siam weed database, Pest Central and BORIS. Each record contains information about the location, date, common and species name, number of plants and-or density of plants; reproductive status, location accuracy, source database, and record owner (agency).
Data has been contributed by various State and Local Governments and by Queensland Natural Resource Management groups. A few records were included from 1970?s and 1980?s, though more regular data collection started in the 1990?s. The dataset is not a definitive collection of invasive plant locations. Location data is added where and when data exists and is provided. BORIS data from Biosecurity Queensland is updated every few months. Other data is added if and when it is volunteered to Biosecurity Queensland from other agencies.
The QWeeds dataset is also updated to the Atlas of Living Australia portal, on an annual basis.
Abstract:
The QWeeds dataset describes the location and descriptive information of invasive plants in Queensland.
Purpose:
To maintain a spatial and temporal record of weed locations in Queensland.
Resource specific usage:
Usage: Personnel involved in invasive plant management, including operational personnel, researchers, students of pest management; from state and local government, Natural Resource Management groups, educational institutions and other groups involved in invasive plant management activities.
Additional Information:
Refer to www.legislation.qld.gov.au for the list of restricted and prohibited invasive plants in Queensland.
Not to be used as a definitive dataset of invasive plant location.
Alternative identifiers
https://collections.ala.org.au/public/show/dr1821
A Feeding Trial to Investigate Strategies to Mitigate the Impacts of Pimelea Poisoning in Australian Cattle
No full textPimelea poisoning of cattle causes distinct symptoms and frequently death, attributable to the toxin simplexin. Pimelea poisoning was induced via addition of ground Pimelea trichostachya plant to the daily feed in a three-month trial with Droughtmaster steers. The trial tested four potential mitigation treatments, namely, biochar, activated biochar, bentonite, and a bacterial inoculum, and incorporated negative and positive control groups. All treatments tested were unable to prevent the development of simplexin poisoning effects. However, steers consuming a bentonite adsorbent together with Pimelea showed lesser rates-of-decline for body weight (P < 0.05) and four hematological parameters (P < 0.02), compared to the positive control group fed Pimelea only. Microbiome analysis revealed that despite displaying poisoning symptoms, the rumen microbial populations of animals receiving Pimelea were very resilient, with dominant bacterial populations maintained over time. Unexpectedly, clinical edema developed in some animals up to 2 weeks after Pimelea dosing was ceased