School of Agriculture, Food and Ecosystem Sciences - Research Publications

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    The Omnibus Law on Job Creation and its potential implications for rural youth and future farming in Indonesia
    Sanders, A ; Khatarina, J ; Assegaf, R ; Toumbourou, T ; Kurniasih, H ; Suwarso, R (Wiley, 2024)
    Indonesian rural youth face challenges accessing farmland and sustaining an agricultural livelihood while their labour is not necessarily absorbed by other sectors. In that context, the Omnibus Law on Job Creation (Law 11/2020) promises to liberalise trade and investment across multiple sectors, including agriculture and food security. Combining legal research and political economy approaches to youth and agrarian challenges, we identify amendments to legislation that reduce safeguards for the environment, workers' and farmers' rights and their livelihoods. If fully implemented, the legislative amendments could further narrow youth's options both for secure formal work and futures in farming by accelerating the expansion of infrastructure, industrial plantations and extractive industries that utilise low‐wage labour and huge areas of land. This exposes inconsistencies in the government's approach to increase future food security by promoting intensification of agriculture and attracting youth to farming, while enabling agro‐ and resource extraction that absorbs land yet offers limited and precarious employment prospects.
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    Examining the facets of mindful engagement and mind wandering in nature
    Macaulay, R ; Johnson, K ; Lee, K ; Williams, K (Elsevier BV, 2024-03)
    Mindfulness and mind wandering may both enhance the psychological outcomes of nature experiences. Both states are multi-faceted, with mindfulness involving specific components such as decentering, body awareness, and nonjudgment, and mind wandering involving intentional and spontaneous mind wandering. These facets may differentially predict psychological outcomes of nature experiences, however these associations have not been tested. In this study we examined facets of mindfulness and mind wandering in nature and tested their associations with outcomes of psychological restoration and nature connection. We also tested the effects of situational factors on these engagement facets in nature. We conducted an experiment in which participants were instructed on how to engage with nature during a 20min experience in nearby nature and completed online surveys before and after the outdoor experience. Participants were allocated into one of four groups, each given different engagement instructions. We used measures of state mindfulness that assessed three facets – decentering, nonjudgment, and body awareness – and measures of mind wandering that assessed two facets – mindlessness, and deliberate mind wandering. Regression analyses revealed associations between these facets and outcomes of the nature experience; decentering and deliberate mind wandering were associated with positive outcomes, including stronger nature connection and positive affect, and nonjudgment was associated with higher negative affect. Further analyses revealed perceived restorativeness and other situational factors such as affective state influenced engagement during the nature experience. These results demonstrate the value of deconstructing mindfulness and mind wandering in nature to explore facets that have beneficial or adverse effects on psychological outcomes. We conclude with practical directions for nature-based engagement interventions that can target the beneficial components of these practices in different contexts.
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    Decision-making of municipal urban forest managers through the lens of governance
    Ordonez, C ; Threlfall, CG ; Livesley, SJ ; Kendal, D ; Fuller, RA ; Davern, M ; van der Ree, R ; Hochuli, DF (ELSEVIER SCI LTD, 2020-02)
    Awareness of the benefits of urban trees has led many cities to develop ambitious targets to increase tree numbers and canopy cover. Policy instruments that guide the planning of cities recognize the need for new governance arrangements to implement this agenda. Urban forests are greatly influenced by the decisions of municipal managers, but there is currently no clear understanding of how municipal managers find support to implement their decisions via new governance arrangements. To fill this knowledge gap, we collected empirical data through interviews with 23 urban forest municipal managers in 12 local governments in Greater Melbourne and regional Victoria, Australia, and analysed these data using qualitative interpretative methods through a governance lens. The goal of this was to understand the issues and challenges, stakeholders, resources, processes, and rules behind the decision-making of municipal managers. Municipal managers said that urban densification and expansion were making it difficult for them to implement their strategies to increase tree numbers and canopy cover. The coordination of stakeholders was more important for managers to find support to implement their decisions than having a bigger budget. The views of the public or wider community and a municipal government culture of risk aversion were also making it difficult for municipal managers to implement their strategies. Decision-making priorities and processes were not the same across urban centres. Lack of space to grow trees in new developments, excessive tree removal, and public consultation, were ideas more frequently raised in inner urban centres, while urban expansion, increased active use of greenspaces, and lack of data/information about tree assets were concerns for outer and regional centres. Nonetheless, inter-departmental coordination was a common theme shared among all cities. Strengthening coordination processes is an important way for local governments to overcome these barriers and effectively implement their urban forest strategies.
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    Evaluation of Spectral Indices for Assessing Fire Severity in Australian Temperate Forests
    Tran, BN ; Tanase, MA ; Bennett, LT ; Aponte, C (MDPI AG, 2018)
    Spectral indices derived from optical remote sensing data have been widely used for fire-severity classification in forests from local to global scales. However, comparative analyses of multiple indices across diverse forest types are few. This represents an information gap for fire management agencies in areas like temperate south-eastern Australia, which is characterised by a diversity of natural forests that vary in structure, and in the fire-regeneration strategies of the dominant trees. We evaluate 10 spectral indices across eight areas burnt by wildfires in 1998, 2006, 2007, and 2009 in south-eastern Australia. These wildfire areas encompass 13 forest types, which represent 86% of the 7.9M ha region’s forest area. Forest types were aggregated into six forest groups based on their fire-regeneration strategies (seeders, resprouters) and structure (tree height and canopy cover). Index performance was evaluated for each forest type and forest group by examining its sensitivity to four fire-severity classes (unburnt, low, moderate, high) using three independent methods (anova, separability, and optimality). For the best-performing indices, we calculated index-specific thresholds (by forest types and groups) to separate between the four severity classes, and evaluated the accuracy of fire-severity classification on independent samples. Our results indicated that the best-performing indices of fire severity varied with forest type and group. Overall accuracy for the best-performing indices ranged from 0.50 to 0.78, and kappa values ranged from 0.33 (fair agreement) to 0.77 (substantial agreement), depending on the forest group and index. Fire severity in resprouter open forests and woodlands was most accurately mapped using the delta Normalised Burnt ratio (dNBR). In contrast, dNDVI (delta Normalised difference vegetation index) performed best for open forests with mixed fire responses (resprouters and seeders), and dNDWI (delta Normalised difference water index) was the most accurate for obligate seeder closed forests. Our analysis highlighted the low sensitivity of all indices to fire impacts in Rainforest. We conclude that the optimal spectral index for quantifying fire severity varies with forest type, but that there is scope to group forests by structure and fire-regeneration strategy to simplify fire-severity classification in heterogeneous forest landscapes.
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    Towards achieving circularity and sustainability in feeds for farmed blue foods
    Colombo, SM ; Roy, K ; Mraz, J ; Wan, AHL ; Davies, SJ ; Tibbetts, SM ; Overland, M ; Francis, DS ; Rocker, MM ; Gasco, L ; Spencer, E ; Metian, M ; Trushenski, JT ; Turchini, GM (Wiley, 2023-06)
    The aims of this review are to describe the role of ‘blue‐food production’ (animals, plants and algae harvested from freshwater and marine environments) within a circular bioeconomy, discuss how such a framework can help the sustainability and resilience of aquaculture and to summarise key examples of novel nutrient sources that are emerging in the field of fed‐aquaculture species. Aquaculture now provides >50% of the global seafood supply, a share that is expected to increase to at least 60% within the next decade. Aquaculture is an important tool for reducing resource consumption in global protein production and increasing resilience to climate change and other global disruptions (i.e. pandemics, geo‐political instability). Importantly, blue foods also provide essential nutrition for a growing human population. Blue foods are helping to help the global goal of ‘zero hunger’ (United Nation's Sustainable Development Goal 2) while reducing the dependency on finite natural resources but further refinement and new solutions are needed to make the industry more ‘circular’ and sustainable, particularly with respect to sourcing raw materials for aquafeeds. This review describes the feed resources that are available or may be created within a circular bioeconomy framework, their role within the framework and in aquaculture and ultimately, how these resources contribute to de‐risking and establishing a resilient aquaculture production chain.
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    Effects of mat composition and pressing time on citric acid-bonded ultra-low-density hemp hurd particleboard
    Fehrmann, J ; Belleville, B ; Ozarska, B ; Ismayati, M ; Dwianto, W (Elsevier, 2024-04-01)
    This study investigated the feasibility of using citric acid (CA) as a biobased and formaldehyde-free binder for producing ultra-low-density (320 to 338 kg/m3) hemp hurd particleboard (ULHPB). Mechanically decorticated hemp hurd chips were milled and then separated into fine (F), medium (M), and coarse (C) particle sizes. Three particle size mixes (PSM) were used to fabricate the panels: 100% C, 100% M, and a 50/50% mixture of CM. Each PSM was combined with low and high CA contents (20 and 30 wt%) and subjected to short and long pressing times (8 and 12 min) at 200 °C. Physico-mechanical characteristics were evaluated following Australian standard AS/NZS 1859.1 (2017) for reconstituted wood-based panels. Thermo-chemical analyses were performed to understand the properties of the raw hurd and to investigate the binding mechanisms in CA-ULHPB. The PSM had a significant impact on panel expansion (springback), internal bond strength (IB), water absorption (WA), and thickness swelling (TS) in most CA-ULHPB variants. PSM-C panels exhibited superior IB when pressed with 30 wt% CA for 12 min. The effect of PSMs diminished for WA and TS but CA content and pressing time remained highly significant. Py-GC/MS, FTIR spectroscopy and TGA indicated the formation of ester linkages with carbohydrate-derived OH-groups and the involvement of lignin moieties in the CA-ULHPB. This research identified optimal panel compositions and processing parameters for fabricating environmentally friendly composite panels using CA as a natural adhesive and hemp hurd as an agricultural by-product. The panels exhibited excellent properties and would be well suited as core layers in lightweight sandwich composites given their ultra-low-density range.
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    Plant and soil biodiversity is essential for supporting highly multifunctional forests during Mediterranean rewilding
    Zhou, G ; Lucas-Borja, ME ; Liu, S ; Hu, H-W ; He, J-Z ; Wang, X ; Jiang, Z ; Zhou, X ; Delgado-Baquerizo, M (Wiley, 2023-02-01)
    1. The multidimensional dynamics of biodiversity and ecosystem function during the rewilding of Mediterranean forests remain poorly understood, limiting our capacity to predict how future restoration efforts may help mitigate climate change. 2. Here, we investigated the changes in multiple dimensions of biodiversity and ecosystem services in a 120-year forest succession after harvest to identify potential trade-offs in multiple dimensions of ecosystem function, and further assess the link between above and below-ground biodiversity and function. 3. We found a positive influence of successional age on not only multiple dimensions of biodiversity and function but also some important trade-offs. Two ecosystem axes of function explained nearly 75.4% of functional variation during ecosystem rewilding. However, while the first axis increased with successional age promoting plant productivity and element stocks, the second axis followed a hump-shaped relationship with age supporting important reductions in nutrient availability and pathogen control in old forests. Our study further revealed a significant positive relationship between plant and soil biodiversity with multiple elements of multifunctionality as forests develop. Moreover, the influence of plant and soil biodiversity were especially important to support a high number of function working at high levels of functioning. 4. Our work provides new insights on the patterns and functional trade-offs in the multidimensional rewilding of forests and further highlights the importance of biodiversity for long-term Mediterranean rewilding.
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    Lipase-catalyzed production of biodiesel: a critical review on feedstock, enzyme carrier and process factors
    Xia, S ; Lin, J ; Sayanjali, S ; Shen, C ; Cheong, L-Z (Wiley, 2024-01)
    Biodiesel is a green and renewable alternative energy source which can be produced through lipase-catalyzed transesterification process. Enzymatic biodiesel production has generated much interest owing to its environmentally friendly process, low wastewater treatment requirements and easy product separation. In this work, we attempt to review some of the recent patents and state-of-the-art technology in lipase-catalyzed transesterification for biodiesel production including feedstock, lipases, novel carriers and process factors. This work will provide useful guidance for researchers to develop cost efficient process for production of biodiesels.
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    Growth performance and feed utilisation of Australian hybrid abalone (Haliotis rubra × Haliotis laevigata) fed increasing dietary protein levels at three water temperatures.
    Hassan, ALI ; Mock, TS ; Searle, K ; Rocker, MM ; Turchini, GM ; Francis, DS (Cambridge University Press (CUP), 2024-03-28)
    Determining the macronutrient requirements for commercially valuable aquaculture species remains crucial for maximising production efficiency. Yet, such information is lacking for Australian hybrid abalone (Haliotis rubra × Haliotis laevigata), particularly with respect to life stage and water temperatures. The present study aimed to evaluate the effect of dietary protein inclusion level on the growth performance, nutrient utilisation and nutritional quality of juvenile (3·3 g) Australian hybrid abalone reared at three different temperatures representative of winter (12°C), average annual (17°C) and summer (22°C) grow-out periods and fed five diets containing graded dietary protein levels of 35, 38, 41, 44 and 47 %. Abalone growth increased with increasing water temperature with weight gains of approximately 100, 280 and 380 % of their initial weight at 12, 17 and 22°C, respectively. Furthermore, the present study clearly demonstrated that higher dietary protein inclusion levels (41 %) than those currently used commercially (35 %) would significantly improve the growth performance when water temperatures are ≥17°C without any adverse impacts on nutrient utilisation, nutrient deposition or nutritional quality of the abalone soft tissue. For example, at 22°C abalone fed a diet containing 41 % protein obtained a significantly higher weight gain percentage (421 %) compared with those fed a diet containing 35 % protein (356 %). Lastly, it is suggested that maintaining a dietary protein inclusion level of 35 % or implementing a 'least cost' feeding approach during cooler seasons, or where water temperatures are ∼12°C, may be beneficial, considering only marginal growth improvements were observed during these periods of slow growth.
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    Body composition changes and their relationship with obstructive sleep apnoea symptoms, severity: The Sleeping Well Trial
    Day, K ; Nguo, K ; Edwards, BA ; O'Driscoll, DM ; Haines, TP ; Hamilton, GS ; Ghazi, L ; Bristow, C ; Truby, H (CHURCHILL LIVINGSTONE, 2023-09)
    BACKGROUND & AIMS: Obstructive sleep apnoea (OSA) and obesity share a complex bi-directional relationship as location of body fat and changes in regional body composition may be more important for OSA improvement than changes in total body weight only. The aim of this study was to evaluate the impact of a 6-month weight loss intervention for adults newly diagnosed with moderate-severe OSA and obesity on regional body composition. The secondary aims evaluated the relationship between changes in OSA symptoms and severity and anthropometry and regional body composition during the first 12-months after commencing CPAP and explored differences in outcomes between males and females. METHODS: Participants (n = 59) received CPAP overnight at home alongside a 6-month modified fasting intervention with 12-months follow up. Regional body composition was measured by Dual X-ray absorptiometry, (DXA) and anthropometry before and after the lifestyle intervention. OSA severity was measured using the apnoea hypopnea index via overnight polysomnography and OSA symptoms were measured using the Epworth Sleepiness scale. RESULTS: Forty-seven adults (74% male) had complete measures available with a mean age of 50.0 y (SD 11.0) and BMI 34.1 kg/m2 (SD 5.0). Following the intervention average fat mass changed by -5.27 kg (5.36), p < 0.001) and visceral adipose tissue (-0.63 kg (0.67), p < 0.001) significantly decreased in males only with a maintenance of fat-free mass (mean -0.41 kg (1.80), p = 0.18). Females (n = 12) had significant decreases in waist circumference (mean -3.36 cm (3.18) p < 0.01), android lean (-0.12 kg (0.04), p < 0.05) and android total mass (-0.28 kg (0.39), p < 0.05) only. Regional body composition changes in males were positively associated with improvements in OSA severity (p < 0.01) but not OSA symptoms. CONCLUSION: Improvements in regional body composition were seen in males only which were related to improvements in OSA severity but not OSA symptoms. Females may exhibit different OSA pathophysiology and may require different treatment approaches. TRIAL REGISTRATION: https://www.anzctr.org.au/Trial/Registration/TrialReview.aspx?id=369975&isReview=trueAACTRN12616000203459 ACTRN12616000203459.