School of Ecosystem and Forest Sciences - Research Publications
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ItemNo Preview AvailablePermanent removal of livestock grazing in riparian systems benefits native vegetation(ELSEVIER, 2022-01-01)
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ItemNo Preview Availablemixchar: An R Package for the Deconvolution of Thermal Decay Curves(Ubiquity Press, Ltd., 2021-01-01)
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ItemUnderstanding the spatiotemporal dynamics of understorey biomass in semi-Arid woodlands of south-eastern Australia(CSIRO Publishing, 2022-04-01)When managing grazing pressure for conservation, understanding forage dynamics is essential. In south-eastern Australia, ongoing grazing is inhibiting regeneration in several semi-arid woodland communities. Western grey kangaroos (Macropus fuliginosus (Desmarest, 1817)) have been identified as a key component of total grazing pressure. They are thought to switch from grass to lower-quality browse, including tree seedlings, when grass biomass falls below 400 kg ha−1. One static threshold may not adequately capture the spatial and temporal hazard associated with kangaroo grazing, and this study aimed to explore how grassy biomass varies across a case-study landscape. Understorey biomass and species composition data were collected in the field on seven occasions between December 2016 and May 2019. We used Generalised Linear Mixed Models (GLMMs) to describe the influence of environmental and herbivory variables on total (live and dead) understorey, live understorey, and grass (live and dead) biomass. Canopy cover showed the strongest influence on understorey biomass, with more biomass found in open sites than in woodland. Understorey biomass levels were lowest in summer and autumn. Grass biomass, in particular, fell below the 400 kg ha−1 forage-switch threshold in wooded areas during this time. We anticipate that an increased understanding of understorey biomass dynamics will inform managers as to when and where to focus management efforts to promote regeneration and sustained recovery of these semi-arid woodlands. Results of this study suggest that conducting management efforts before the summer/autumn decline in understorey biomass, particularly in woodlands, is critical in reducing the browsing risk to seedlings.
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ItemExploring how functional traits modulate species distributions along topographic gradients in Baxian Mountain, North China(NATURE PORTFOLIO, 2022-01-19)The associations between functional traits and species distributions across environments have attracted increasing interest from ecologists and can enhance knowledge about how plants respond to the environments. Here, we applied a hierarchical generalized linear model to quantifying the role of functional traits in plant occurrence across topographic gradients. Functional trait data, including specific leaf area, maximum height, seed mass and stem wood density, together with elevation, aspect and slope, were used in the model. In our results, species responses to elevation and aspect were modulated by maximum height and seed mass. Generally, shorter tree species showed positive responses to incremental elevation, while this trend became negative as the maximum height exceeded 22 m. Most trees with heavy seeds (> 1 mg) preferred more southerly aspects where the soil was drier, and those light-seed trees were opposite. In this study, the roles of maximum height and seed mass in determining species distribution along elevation and aspect gradients were highlighted where plants are confronted with low-temperature and soil moisture deficit conditions. This work contributes to the understanding of how traits may be associated with species occurrence along mesoscale environmental gradients.
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ItemUsing data calibration to reconcile outputs from different survey methods in long-term or large-scale studies(SPRINGER, 2022-03-01)Understanding the impact of management interventions on the environment over decadal and longer timeframes is urgently required. Longitudinal or large-scale studies with consistent methods are best practice, but more commonly, small datasets with differing methods are used to achieve larger coverage. Changes in methods and interpretation affect our ability to understand data trends through time or across space, so an ability to understand and adjust for such discrepancies between datasets is important for applied ecologists. Calibration or double sampling is the key to unlocking the value from disparate datasets, allowing us to account for the differences between datasets while acknowledging the uncertainties. We use a case study of livestock grazing impacts on riparian vegetation in southeastern Australia to develop a flexible and powerful approach to this problem. Using double sampling, we estimated changes in vegetation attributes over a 12-year period using a pseudo-quantitative visual method as the starting point, and the same technique plus point-intercept survey for the second round. The disparate nature of the datasets produced uncertain estimates of change over time, but accounting for this uncertainty explicitly is precisely the objective and highlights the need to look more closely at this very common problem in environmental management, as well as the potential benefits of the double sampling approach.
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ItemAusTraits, a curated plant trait database for the Australian flora(NATURE PORTFOLIO, 2021-09-30)We introduce the AusTraits database - a compilation of values of plant traits for taxa in the Australian flora (hereafter AusTraits). AusTraits synthesises data on 448 traits across 28,640 taxa from field campaigns, published literature, taxonomic monographs, and individual taxon descriptions. Traits vary in scope from physiological measures of performance (e.g. photosynthetic gas exchange, water-use efficiency) to morphological attributes (e.g. leaf area, seed mass, plant height) which link to aspects of ecological variation. AusTraits contains curated and harmonised individual- and species-level measurements coupled to, where available, contextual information on site properties and experimental conditions. This article provides information on version 3.0.2 of AusTraits which contains data for 997,808 trait-by-taxon combinations. We envision AusTraits as an ongoing collaborative initiative for easily archiving and sharing trait data, which also provides a template for other national or regional initiatives globally to fill persistent gaps in trait knowledge.
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ItemPredicting reliability through structured expert elicitation with repliCATS (Collaborative Assessments for Trustworthy Science)(Early Release, 2021-02-22)
Replication is a hallmark of scientific research. As replications of individual studies are resource intensive, techniques for predicting the replicability are required. We introduce a new technique to evaluating replicability, the repliCATS (Collaborative Assessments for Trustworthy Science) process, a structured expert elicitation approach based on the IDEA protocol. The repliCATS process is delivered through an underpinning online platform and applied to the evaluation of research claims in social and behavioural sciences. This process can be deployed for both rapid assessment of small numbers of claims, and assessment of high volumes of claims over an extended period. Pilot data suggests that the accuracy of the repliCATS process meets or exceeds that of other techniques used to predict replicability. An important advantage of the repliCATS process is that it collects qualitative data that has the potential to assist with problems like understanding the limits of generalizability of scientific claims. The repliCATS process has potential applications in alternative peer review and in the allocation of effort for replication studies.
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ItemRecovery potential of microwetlands from agricultural land uses(WILEY, 2018-01-01)
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ItemEvaluating the success of wildlife crossing structures using genetic approaches and an experimental design: Lessons from a gliding mammal(WILEY, 2018-01-01)Millions of dollars are spent on wildlife crossing structures intended to reduce the barrier effects of roads on wildlife. However, we know little about the degree to which these structures facilitate dispersal and gene flow. Our study incorporates two elements that are rarely used in the evaluation of wildlife crossing structures: an experimental design including a before and after comparison, and the use of genetic techniques to demonstrate effects on gene flow at both population and individual levels. We evaluated the effect of wildlife crossing structures (canopy bridges and glider poles) on a gliding mammal, the squirrel glider (Petaurus norfolcensis). We genotyped 399 individuals at eight microsatellite markers to analyse population structure, firstâ generation migrants and parentage relationships. We found that the freeway was not a complete genetic barrier, with a strong effect evident at only one site. We hypothesise that the presence of corridors alongside the freeway and throughout the surrounding landscape facilitated circuitous detours for squirrel gliders. Installing a crossing structure at the location with a strong barrier effect restored gene flow within just 5Â years of mitigation. Synthesis and applications. Our study highlights the importance of using genetic techniques not just to evaluate the success of roadâ crossing structures for wildlife, but also to guide their placement within the landscape. Managers wishing to reduce the effects of linear infrastructure on squirrel gliders and other arboreal mammals should aim to preserve and enhance vegetation along roadsides and within centre medians, as well as mitigate large gaps by implementing wildlife crossing structures.