School of Agriculture, Food and Ecosystem Sciences - Research Publications

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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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    Interrelationships between fire, habitat, and mammals in a fragmented heathy woodland
    Zylinski, S ; Swan, M ; Sitters, H (Elsevier, 2022-10-15)
    Altered fire regimes threaten biodiversity, but there is limited understanding of the mechanisms driving population declines. Relationships between mammal occurrence and time since fire can be unclear because mammals respond directly to changes in habitat structure rather than time since fire per se, and patterns of regeneration can be highly variable. Previous studies have examined how mammals respond to time since fire and habitat structure separately, but rarely considered the three factors together. Furthermore, fires may interact with other threats such as habitat loss and fragmentation, also rarely incorporated into fire studies but known to influence mammal communities. Understanding each of these mechanisms and how they interact is critical for using fire effectively in conservation. We simultaneously related ground-dwelling mammal species activity to habitat structure, habitat structure to post-fire vegetation growth stage, and species activity to growth stage and landscape structure (extent of heathy woodland vegetation) using structural equation models (SEMs). This allowed us to find direct effects of growth stage on mammals, indirect effects mediated by habitat structure, and additional effects of landscape structure. Understorey cover, litter depth, and coarse woody debris responded to growth stage and were important contributors in all SEMs. Four of seven mammal species responded to at least one habitat structure variable. None of the mammal species were related directly to growth stage, but mammals were indirectly related to growth stage through the mediating influence of habitat structure. For example, western grey kangaroos were linked to recently burnt sites, but only through their negative association with litter depth. Extent of heathy woodland vegetation was also an important driver of mammal activity and was related to all but one species; two species showed a positive relationship, and four negative. Important relationships between fire and ground-dwelling mammals may be overlooked unless changes in important habitat resources are also considered. Fire management planning for fauna conservation should incorporate habitat responses as mammal responses to the fire regime may be mediated by fire-driven changes in resources. Knowing how time since fire affects important habitat structures can improve the effectiveness of using fire to manipulate these to support mammal species. Our results will help land managers understand direct and indirect effects of fire in a landscape where multiple drivers threaten biodiversity, and guide the use of prescribed fire to promote aspects of habitat structure that benefit mammals.
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    Plants, soil properties and microbes directly and positively drive ecosystem multifunctionality in a plantation chronosequence
    Wang, J ; Shi, X ; Lucas-Borja, ME ; Lam, SK ; Wang, Z ; Huang, Z (WILEY, 2022-10)
    Abstract Chinese fir (Cunninghamia lanceolata) is the main plantation species in the subtropical region of China. However, the shift in ecosystem multifunctionality with stand development remains largely unexplored for these plantations. This study used a chronosequence to investigate the variations of ecosystem multifunctionality by employing individual functions and identified its driving factors in Chinese fir plantations. The findings provide strong evidence that the individual functions of carbon stocks, water regulation and wood production increased with stand ages, but the tradeoff of individual functions did not significantly increase ecosystem multifunctionality. Soil microbial parameters (the abundances of bacteria, fungi and actinomycete), soil properties (soil moisture, total carbon and total nitrogen), and plant parameters (the shrub layer cover and total understory cover) exhibited positive correlations with ecosystem multifunctionality. The structural equation model revealed that plants, soil properties and microbes pathways explained 83% of the total variance in ecosystem multifunctionality. Results showed that plants, soil microbes and properties directly and significantly affected ecosystem multifunctionality with path coefficients of 0.404, 0.487 and 0.334, respectively. Soil microbes were identified as the top direct predictor for ecosystem multifunctionality, while plant and soil properties had strong direct and positive effects on ecosystem multifunctionality. These results verified that soil microbes, plants and soil properties directly and positively regulated ecosystem multifunctionality. Our findings demonstrate that ecosystem multifunctionality should be considered as a comprehensive ecological indicator for ecosystem services and functions, and sustainable plantation management. This study highlights the importance of conserving soil microbes for maintaining multifunctionality in Chinese fir plantations.
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    Opportunities to improve nitrogen use efficiency in an intensive vegetable system without compromising yield
    Suter, H ; Pandey, A ; Lam, SK ; Davies, R ; Hassan, R ; Riches, D ; Chen, D (WILEY, 2021-05)
    Intensive vegetable cropping systems rely heavily on nitrogen (N) inputs from multiple synthetic and organic fertilizer applications. The majority of applied N is lost to the environment through numerous pathways, including as nitrous oxide (N2 O). A field trial was conducted to examine the opportunities to reduce N input in an intensive vegetable system without compromising yield. Treatments applied were control (no N), manure (M, 408 kg N ha-1 from chicken manure), grower practice (GP, 408 kg N ha-1 from chicken manure + 195 kg N ha-1 from fertilizer), and 2/3 GP (two-thirds of the total N input in GP), all with and without 3,4-dimethylpyrazole phosphate (DMPP). Nitrogen recovery in the GP treatment was determined using 15 N-labeled fertilizer. Using only manure significantly lowered celery (Apium graveolens L.) yield and apparent N use efficiency (ANUE) compared with GP. Reducing N input by one-third did not affect yield or ANUE. Use of DMPP increased ANUE despite no yield improvement. More than 50% of the applied N in the GP treatment was lost to the environment, with almost 10 kg N ha-1 emitted as N2 O over the season, which was 67 times more than from the control. Reducing the N input by one-third or using manure only reduced N2 O emissions by more than 70% relative to GP. This study shows that there is a clear opportunity to reduce N input and N2 O emissions in high-fertilizer-input vegetable systems without compromising vegetable yield.
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    An empirical analysis of the use of agricultural mobile applications among smallholder farmers in Myanmar
    Thar, SP ; Ramilan, T ; Farquharson, RJ ; Pang, A ; Chen, D (WILEY, 2021-03)
    Abstract Mobile phone applications (apps) designed to assist smallholder farmers improve decision‐making have been revolutionizing the agriculture sector. These apps offer solutions to farmer information needs by providing weather information, crop market trends, pest and disease damage identification, and advice on pesticide and fertilizer use. They also facilitate interaction with fellow farmers, extension workers and other stakeholders in the value chain who are interested in information exchange. Much previous research has investigated the contribution of mobile apps to agricultural production. This study explored the agricultural mobile apps available in Myanmar, analyzed factors affecting their use and assessed the potential for farm‐based decision support. Our findings indicate that when introducing mobile‐based tools, focus should be given to younger, more educated farmers growing more specialized crops. The main constraints to adopt agricultural apps are lack of access to smartphone and/or internet (63%) and lack of digital knowledge (20%). However, smallholder farmers in Myanmar were optimistic and positive toward agricultural apps for effective utilization. We also found that majority of the surveyed farmers were familiar with information received through Facebook groups. Incorporating useful information and functions from an agricultural mobile app to a Facebook Page could have a more useful and sustainable impact.
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    The potential and practice of arboreal camera trapping
    Moore, JF ; Soanes, K ; Balbuena, D ; Beirne, C ; Bowler, M ; Carrasco-Rueda, F ; Cheyne, SM ; Coutant, O ; Forget, P-M ; Haysom, JK ; Houlihan, PR ; Olson, ER ; Lindshield, S ; Martin, J ; Tobler, M ; Whitworth, A ; Gregory, T (WILEY, 2021-10)
    Abstract Arboreal camera trapping is a burgeoning method providing a novel and effective technique to answer research questions across a variety of ecosystems, and it has the capacity to improve our understanding of a wide range of taxa. However, while terrestrial camera trapping has received much attention, there is little guidance for dealing with the unique challenges of working in the arboreal realm. Our review draws on the expertise of researchers from six continents and the broader literature to investigate the advantages and disadvantages of arboreal camera trapping, and challenges to consider when using this technology. We also include mini‐guides with detailed information on the current arboreal camera trap literature, mounts used to install arboreal cameras, tree climbing pointers and safety tips, methods for deploying cameras without climbing, and tips for managing interference with camera function. We find that arboreal camera traps have been most commonly used in the study of mammals in forests; however, there is potential for this method to be applied to a broad range of habitats including urban areas, and taxa such as birds, amphibians, invertebrates, and plants. Methods in arboreal camera trapping could be improved by developing a greater understanding of the factors affecting detection of species. The most common challenges of arboreal camera trapping are camera placement and camera site access. These can be overcome by understanding correct camera orientation, managing potential sources of interference in front of cameras, utilizing appropriate cameras mounts and training researchers properly. Given the benefits and opportunities presented by arboreal camera trapping, it is likely to become an ever‐more popular method of studying arboreal species and systems. The information synthesized in this review provides guidance for future studies to help direct more reliable and robust ecological inferences from arboreal camera trapping.
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    Defining and evaluating predictions of joint species distribution models
    Wilkinson, DP ; Golding, N ; Guillera-Arroita, G ; Tingley, R ; McCarthy, MA ; Freckleton, R (WILEY, 2021-03)
    Abstract Joint species distribution models (JSDMs) simultaneously model the distributions of multiple species, while accounting for residual co‐occurrence patterns. Despite increasing adoption of JSDMs in the literature, the question of how to define and evaluate JSDM predictions has only begun to be explored. We define four different JSDM prediction types that correspond to different aspects of species distribution and community assemblage processes. Marginal predictions are environment‐only predictions akin to predictions from single‐species models; joint predictions simultaneously predict entire community assemblages; and conditional marginal and conditional joint predictions are made at the species or assemblage level, conditional on the known occurrence state of one or more species at a site. We define five different classes of metrics that can be used to evaluate these types of predictions: threshold‐dependent, threshold‐independent, community dissimilarity, species richness and likelihood metrics. We illustrate different prediction types and evaluation metrics using a case study in which we fit a JSDM to a frog occurrence dataset collected in Melbourne, Australia. Joint species distribution models present opportunities to investigate the facets of species distribution and community assemblage processes that are not possible to explore with single‐species models. We show that there are a variety of different metrics available to evaluate JSDM predictions, and that choice of prediction type and evaluation metric should closely match the questions being investigated.
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    Efficient effort allocation in line-transect distance sampling of high-density species: When to walk further, measure less-often and gain precision
    Knights, K ; McCarthy, MA ; Camac, J ; Guillera-Arroita, G (WILEY, 2021-06)
    Abstract Line‐transect distance sampling is widely used to estimate population densities using distances of observed targets from transect lines to model detectability. When the target taxa are high density, the frequent measuring of distances may make the method seem impractical. We present a method that improves the efficiency of distance sampling when the target species occurs at high density. Only a proportion of targets are measured to model the detection function, and the time saved on the survey is then used to cover a longer total length of transect and accrue a larger ‘count only’ sample. This approach can improve the precision of the population density estimate when the cost of measuring the distance to a detected target is more than half the cost of walking to the next target. We find the optimal proportion of distances to measure that minimises the variance of the density estimate for a fixed survey budget. We quantify how much this optimised strategy increases the precision of the density estimate compared with conventional line‐transect distance sampling. We then use simulated distance sampling data to test our expressions, and illustrate circumstances under which the optimised approach would be beneficial using distance sampling data on high‐density plants. The simulations indicate that the optimised method delivers benefits in precision, but the magnitude of the benefit is lower than predicted from our expressions, which are based on an asymptotic approximation of the variance. We apply an adjustment to the predicted benefit equation to account for this difference, and show that, in all three plant case studies, the optimised approach could improve the precision gained from a distance sampling survey between 20% and 50%. This new approach could broaden the ecological contexts in which distance sampling is applied, to include estimation of densities of abundant taxa where plots are conventionally used. The method may have interesting applications for other survey types, including multispecies surveys or those using cues or signs that occur at high density.
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    Wine phenolic profile altered by yeast: Mechanisms and influences
    Zhang, P ; Ma, W ; Meng, Y ; Zhang, Y ; Jin, G ; Fang, Z (WILEY, 2021-07)
    Grape phenolic compounds undergo various types of transformations during winemaking under the influences of yeasts, which further impacts the sensory attributes, thus the quality of wine. Understanding the roles of yeasts in phenolics transformation is important for controlling wine quality through fermentation culture selection. This literature review discusses the mechanisms of how yeasts alter the phenolic compounds during winemaking, summarizes the effects of Saccharomyces cerevisiae and non-Saccharomyces yeasts on the content and composition of phenolics in wine, and highlights the influences of mixed cultural fermentation on the phenolic profile of wine. Collectively, this paper aims to provide a deeper understanding on yeast-phenolics interactions and to identify the current literature gaps for future research.