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Potential of heartwood extracts as wood preservatives combined with linseed oil in 8-year above-ground and in-ground field trials
Get PDFThe current study assessed the efficacy of heartwood extracts from Tectona grandis, Dalbergia sissoo, Cedrus deodara, and Pinus roxburghii, combined with linseed oil, as protectants for two non-durable wood species against termites and decay fungi. Stakes measuring 45.7 × 1.9 × 1.9 cm and blocks measuring 12.5 × 3.75 × 2.5 cm of the sapwood of southern pine (Pinus sp.) and cottonwood (Populus sp.) were impregnated via vacuum pressure with individual heartwood species extract, linseed oil, or a combination of both. For comparison, solid heartwood stakes and blocks of the wood species used to obtain extracts were also included in the tests. All samples were exposed to decay and termites for eight years at a test site in southern Mississippi using ground contact (AWPA E7) and ground proximity (AWPA E26) tests. Results showed that combining heartwood extract and linseed oil resulted in greater resistance to termites and decay in cottonwood and southern pine compared to using only linseed oil or the individual heartwood species extract in both tests. However, most of the samples that were treated with the combination treatment failed and, in either test, these treatments were not as effective as commercially used wood preservatives, such as copper naphthenate (CuN) or disodium octaborate tetrahydrate (DOT). Additionally, solid heartwood P. roxburghii stakes and blocks decayed completely and failed due to termite attack after eight years in the field in both tests. After eight years in the field, C. deodara and D. sissoo stakes were severely attacked by decay and moderately to severely attacked by termites. Blocks of these two species exposed in a covered ground proximity exposure showed slight attack by termites and decay fungi. Tectona grandis stakes showed moderate decay damage and slight termite attack in the ground contact test. Blocks of T. grandis showed slight damage from fungi and termites in the ground proximity test after eight years in the field
Soil carbon sequestration in rangelands: a critical review of the impacts of major management strategies
Get PDFThe agronomic benefits of soil organic matter have been studied for centuries, but contemporary focus has expanded to ask how increasing long-term storage of soil organic carbon (SOC) can contribute to mitigation of climate change. Understanding the potential for SOC sequestration in the vast rangelands is crucial for climate change policy, agricultural land management and carbon market opportunities. In this review, we evaluate the evidence from published field trials and modelling studies for sequestration in Australian rangeland soils managed for livestock grazing. We found few long-term studies with high quality SOC stock change data linked to new management, and our analysis was constrained by data limitations, conflicting results between studies, and highly variable climate, soil and landscape conditions across production systems. Rainfall and soil properties are dominant determinants of variation in SOC stocks in rangelands, and it was difficult to detect management impacts in these environments. However, there was consistent evidence that: (1) Sowing more productive grasses or legumes in existing grass pastures generally increases SOC stocks; (2) Prolonged high stocking is associated with net SOC loss; (3) Destocking or exclusion of grazing results in small SOC increases, especially in degraded soils; (4) Conversion from cropping to permanent pasture results in sequestration, influenced by management history; (5) Rotational grazing strategies show negligible impact on SOC stocks relative to continuous grazing; and (6) Waterponding increased SOC stocks initially but persistence has not been demonstrated. We discuss possible opportunities for SOC sequestration in rangelands in the context of uncertainties and associated benefits and trade-offs for livestock production, and make recommendations to improve the evidence-base for major management strategies
A Decision–Support Tool to Inform Coconut Log Procurement and Veneer Manufacturing Location Decisions in Fiji
Get PDFCoconut plantations throughout the Asia–Pacific region are generally characterised by the presence of low-productivity senile palms over the age of 60, which have negative impacts on farming communities, coconut processors, and the wider economy. In Fiji, despite numerous senile coconut replacement programs, 60% of coconut palms are considered senile. The purpose of this study is to provide preliminary estimates of the financial viability of a market-based approach to senile coconut palm replacement in Fiji by utilising the palms as a feedstock, for the manufacture of rotary peeled veneer, along with plantation pine and mahogany. A mathematical model capable of supporting deterministic and stochastic dynamic optimisation was developed with an objective function to maximise the gross margin of marketable veneer manufacture per hour by Gmpz procuring the optimal allocation of logs throughout the landscape. The majority of facility location and log processing scale scenarios evaluated found that utilising large volumes of senile coconut palms for the manufacture of veneer was optimal, whilst veneering mills situated near the coconut plantations in Vanua Levu were found to maximise Gmpz. Overall, the results indicate that a coconut veneer and engineered wood product (EWP) value chain could present a financially viable opportunity to support large-scale senile coconut palm replacement in Fiji
Detection and monitoring techniques of termites in buildings: A review
No full textTermites are significant pests in many regions of the world, where they attack cellulose-based material in buildings, trees, and crops. The most significant economic losses occur to timber in structures, and a great deal of effort and money is spent to prevent damage to homes and public buildings. Termites may attack wood anywhere in a building, from below soil to the highest point on the roof. Detection of termites is often challenging due to the cryptic nature of termites, the complexity of the structure, the location of damage or termites in the structure, and available techniques. Several methods have been employed to detect and monitor the presence of termites in buildings, from simple visual searches to technology-based or technology-assisted approaches that vary in their invasiveness and destructiveness. This review examines the various techniques used to detect drywood and subterranean termites, explains the underlying termite biology connected with each detection method, and considers the benefits and drawbacks of each technique discussed. This will hopefully help professional pest inspectors and property owners select suitable termite detection methods. This review also highlights the need for continued research to develop and evaluate detection strategies and tools that may be utilized before implementing any termite control measures
Landscape structure and composition affect aphid biological control in alfalfa fields, but regional differences prevail
Get PDFUnderstanding how landscape composition and configuration drive the dynamics of pests and their various natural enemies is crucial to enhance biological control services (biocontrol). Geographic variability in landscape effects prompts questions about whether this is due to genuine differences or methodological differences among studies, given that most studies are conducted in a single region. This study investigated how the ecological function of parasitoids and predators responds to landscape traits in three regions encompassing an agriculture intensification gradient. The effects of landscape structure and configuration differed among regions and natural enemies. Non-crop habitats increased the abundance of parasitoids only in two less intensified regions presumably due to insufficient amount of non-crop habitats in the intensified region (typically < 10%). Nevertheless, their biological control efficiency (BCE) was consistently increased by non-crop habitats across regions. Higher maize proportion increased predator abundance and their BCE in the two non-mountainous regions. The value of maize as a source habitat for predators may have been limited in the mountainous region due to the lower aphid abundances there. Edge density positively affected abundances of predators and parasitoids, but only positively increased the BCE of all natural enemies combined. Inconsistent regional responses to the same landscape variables suggest that a uniform integrated pest management strategy for alfalfa is impractical. However, increasing edge density should be a useful first step for supporting diverse natural enemy communities and their biocontrol potential. © 2024 The authors
Dispersal direction, geographic location and river discharge all influence juvenile growth of a freshwater fish
Get PDFSeeking out appropriate habitat or food resources is one of the key reasons why animals move. Despite the benefits of movement, some individuals in a population remain resident or express alternative movement phenotypes. Movement, however, is energetically costly and can result in resources being diverted away from growth and reproduction. The presence of multiple movement phenotypes within populations suggests that each can have commensurate levels of performance depending on the underlying environmental conditions. Here we explore the context-dependent costs and benefits of upstream and downstream juvenile dispersal in a large river system. We expect that if the energetic costs of moving (upstream against a current or downstream with a current) exceed any benefits to growth, then residents (who do not move) will have faster growth. Alternatively, movement costs may be offset if individuals move to more favourable environments, resulting in dispersers benefiting with faster growth. We used biological information naturally archived in the otoliths of a potamodromous fish, golden perch Macquaria ambigua, to quantify how movement phenotypes affect growth across individuals exposed to spatiotemporally varying environmental conditions. We found that juvenile growth differed considerably among dispersal phenotypes (resident, upstream, downstream, stocked): in general, surviving wild-spawned downstream and upstream dispersers and hatchery-stocked fish all grew faster than individuals that remained resident within their natal reach. Further, juvenile growth was sensitive to local environmental conditions and had carryover effects from an individual's natal-year. Juvenile growth of all dispersal phenotypes was higher in years with below average natal-year summer discharge (when fish are ~2–3 months old), likely because of increased concentrations of food resources. In contrast, the effects of natal-year spring discharge (around the time individuals were spawned) were dependent on dispersal direction, with positive effects for downstream dispersers and upstream dispersers, and negative effects for resident individuals. Our results suggest that an individual's growth can benefit from early-life movement, although the magnitude of this effect depends on local environmental conditions and the direction travelled. Our study reinforces the importance of heterogeneous and connected riverscapes that foster a diversity of individual growth responses
Incidence of decreased sensitivity to fungicides in barley net blotch in Queensland
Get PDFTake home message
• Decreased sensitivity to fungicides is present in net blotch of barley in Queensland
• Frequencies of decreased sensitivity were 34% for Group 3 fungicides and 6% for Group 7 fungicides in a regional population
• Fungicide management strategies should rotate or use mixed modes of action
• Decisions can be informed by testing field samples for fungicide sensitivit
Queensland Invasive Plants and Animals Strategy 2025–2030
Get PDFThe Queensland Invasive Plants and Animals Strategy 2025–2030 (this strategy) recognises that managing the risks and impacts of invasive plants and animals is occurring in the context of several potentially exacerbating factors. These include, but are not limited to, climate change, land use change, land degradation, biodiversity loss, global trade, and increasing movement of people through travel and migration. The management of invasive plants and animals is the shared responsibility of landowners, land managers, industry, the community, and all levels of government. Shared responsibility has been made a legal requirement through the general biosecurity obligation under the Biosecurity Act 2014
Stock assessment of king threadfin (Polydactylus macrochir) in the Gulf of Carpentaria, Queensland, Australia, with data to December 2022
No full textKing threadfin is a large, predatory fish species that is found in foreshore areas of turbid coastal waters, estuaries, tidal rivers and mangrove creeks across northern Australia and southern Papua New Guinea. In Australia, its distribution extends from the Ashburton River in Western Australia, across northern Australia, to the Brisbane River in South East Queensland. This assessment focuses on the Gulf of Carpentaria stock. King threadfin is a protandrous hermaphrodite, beginning as male and later changing to female between about 40 cm to 110 cm total length. It can grow to 150 cm total length and 30 kg in weight. The species lives to at least 20 years of age.
A previous assessment estimated the Gulf of Carpentaria stock to be around 5% of the unfished level, using data through to December 2019. This assessment differs from the previous assessment in several respects. Firstly, it considers data through to December 2022, and includes additional historical age and length data sets. Secondly, it operated under the guidance of a project team consisting of multiple domain experts including fishery stakeholders. Thirdly, it was externally reviewed and incorporates feedback from that review. Fourthly, the summary chapter reports biomass and fishing pressure results as a ‘most likely range’ rather than a single value.
All assessment inputs and outputs are referenced on a calendar year basis (that is, ‘2022’ means January 2022–December 2022).
The assessment used an age-structured model with an annual time step, fitted to standardised catch rates, length composition data, and age-at-length composition data. The model incorporated data spanning the period 1955–2022 including mandatory daily commercial logbook data collected by Fisheries Queensland (1989–2022), collated commercial production returns from the Gulf of Carpentaria (1981–1988), recreational and boat ramp survey data (1997–2022), and age and length data (1988–1994 and 2015–2022).
This stock assessment was guided by a project team with a wide range of skill sets. In addition to managers, scientists, monitoring and data specialists from within the Fisheries Queensland, the team included three fishing industry representatives.
Several scenarios were run covering a range of modelling assumptions and sensitivity tests. All scenarios were optimised using Markov chain Monte Carlo (MCMC) to better explore the robustness of the models. From these exploratory scenarios a final ‘ensemble’ of eight scenarios were chosen for inclusion in summary reporting. This ensemble indicates that the biomass ratio at the beginning of 2023 was between 13% and 44% of unfished levels. The proportion of the ensemble that fell below 20% biomass was 29%
Floods and fire ants, Solenopsis invicta (Hymenoptera: Formicidae): The Australian experience
Get PDFThe rafting behaviour of the red imported fire ant, Solenopsis invicta, in response to flooding events is well documented, although studies generally have focussed on the mechanisms of raft assembly and the behaviour of the raft’s occupants. Flooding as a means of dispersal of S. invicta is frequently mentioned in the literature, although there are few data on the distances travelled or how effective it is compared to natural flight. In Australia, S. invicta is a priority invasive species with a national eradication program operating for 23 years, focussed on the population in southeast Queensland, which currently encompasses more than 700 000 ha. Flooding presents a risk to the success of the program through extending the infestation area or recolonising successfully treated areas. We used the program’s extensive spatiotemporal dataset of known fire ant colony locations to assess the effects of two significant flood events on the dispersal or displacement of S. invicta in Queensland. Results indicated that flooding did not spread S. invicta beyond the known boundaries of infestation but contributed to localised spread, particularly for sites with known polygyne infestations. This situation could change if the ant spreads to new river catchments. A novel method developed to assess the risk of S. invicta dispersal through flooding is presented, alongside program actions that can be applied to mitigate this risk