ORCID Profile
0000-0001-6019-5063
Current Organisation
Murdoch University
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Terrestrial Ecology | Environmental Science and Management | Conservation and Biodiversity
Control of Plant Pests, Diseases and Exotic Species in Forest and Woodlands Environments | Global Effects of Climate Change and Variability (excl. Australia, New Zealand, Antarctica and the South Pacific) (excl. Social Impacts) |
Publisher: Wiley
Date: 21-02-2020
Publisher: Springer Science and Business Media LLC
Date: 21-07-2017
Publisher: Elsevier BV
Date: 2020
Publisher: Springer Science and Business Media LLC
Date: 21-08-2015
DOI: 10.1038/SREP13472
Abstract: Natural disturbances can drive disease dynamics in animal populations by altering the microclimates experienced by hosts and their pathogens. Many pathogens are highly sensitive to temperature and moisture and therefore small changes in habitat structure can alter the microclimate in ways that increase or decrease infection prevalence and intensity in host populations. Here we show that a reduction of rainforest canopy cover caused by a severe tropical cyclone decreased the risk of endangered rainforest frogs ( Litoria rheocola ) becoming infected by a fungal pathogen ( Batrachochytrium dendrobatidis ). Reductions in canopy cover increased the temperatures and rates of evaporative water loss in frog microhabitats, which reduced B. dendrobatidis infection risk in frogs by an average of 11–28% in cyclone-damaged areas, relative to unaffected areas. Natural disturbances to the rainforest canopy can therefore provide an immediate benefit to frogs by altering the microclimate in ways that reduce infection risk. This could increase host survival and reduce the probability of epidemic disease outbreaks. For hibian populations under immediate threat from this pathogen, targeted manipulation of canopy cover could increase the availability of warmer, drier microclimates and therefore tip the balance from host extinction to coexistence.
Publisher: Public Library of Science (PLoS)
Date: 04-12-2013
Publisher: The Royal Society
Date: 07-07-2015
Abstract: To minimize the negative effects of an infection on fitness, hosts can respond adaptively by altering their reproductive effort or by adjusting their timing of reproduction. We studied effects of the pathogenic fungus Batrachochytrium dendrobatidis on the probability of calling in a stream-breeding rainforest frog ( Litoria rheocola ). In uninfected frogs, calling probability was relatively constant across seasons and body conditions, but in infected frogs, calling probability differed among seasons (lowest in winter, highest in summer) and was strongly and positively related to body condition. Infected frogs in poor condition were up to 40% less likely to call than uninfected frogs, whereas infected frogs in good condition were up to 30% more likely to call than uninfected frogs. Our results suggest that frogs employed a pre-existing, plastic, life-history strategy in response to infection, which may have complex evolutionary implications. If infected males in good condition reproduce at rates equal to or greater than those of uninfected males, selection on factors affecting disease susceptibility may be minimal. However, because reproductive effort in infected males is positively related to body condition, there may be selection on mechanisms that limit the negative effects of infections on hosts.
Publisher: Inter-Research Science Center
Date: 10-09-2018
DOI: 10.3354/DAO03269
Abstract: Identifying the factors that affect pathogen prevalence is critical to understanding the effects of wildlife diseases. We aimed to examine drivers of seasonal changes in the prevalence of infection by the hibian chytrid fungus Batrachochytrium dendrobatidis in tadpoles. Because tadpoles may be important reservoirs for this disease, examining them will aid in understanding how chytridiomycosis affects entire hibian populations. We hypothesized that temperature is a strong driver of prevalence of Bd in tadpoles, and the accumulation of infection as tadpoles become larger and older also drives prevalence in this system. We studied Litoria rheocola, a tropical rainforest stream frog with seasonal recruitment of annual tadpoles, and surveyed 6 streams in northeastern Queensland, Australia. Comparisons among models relating infection status to stream type, season, their interaction, tadpole age, and water temperature showed that age explained a large portion of the variance in infection status. Across sites and seasons, larger, older tadpoles had increased mean probabilities of infection, indicating that a large component of the variation among in iduals was related to age, and thus to cumulative infection risk. Our results indicate that in systems with annual tadpoles, seasonal changes in infection prevalence may be strongly affected by seasonal patterns of tadpole growth and development in addition to stream type, season, and water temperature. These effects may then influence prevalence of infection in terrestrial in iduals in species that have relatively frequent contact with water. This reinforces the need to integrate studies of the drivers of pathogen prevalence across all host life history stages.
Publisher: MDPI AG
Date: 19-09-2022
DOI: 10.3390/JOF8090980
Abstract: Many oomycetes are important plant pathogens that cause devastating diseases in agricultural fields, orchards, urban areas, and natural ecosystems. Limitations and difficulties associated with isolating these pathogens have led to a strong uptake of DNA metabarcoding and mass parallel sequencing. At least 21 primer combinations have been designed to lify oomycetes, or more specifically, Phytophthora species, from environmental s les. We used the Illumina sequencing platform to compare 13 primer combinations on mock communities and environmental s les. The primer combinations tested varied significantly in their ability to lify Phytophthora species in a mock community and from environmental s les this was due to either low sensitivity (unable to detect species present in low concentrations) or a lack of specificity (an inability to lify some species even if they were present in high concentrations). Primers designed for oomycetes underestimated the Phytophthora community compared to Phytophthora-specific primers. We recommend using technical replicates, primer combinations, internal controls, and a phylogenetic approach for assigning a species identity to OTUs or ASVs. Particular care must be taken if s ling substrates where hybrid species could be expected. Overall, the choice of primers should depend upon the hypothesis being tested.
Publisher: Springer Science and Business Media LLC
Date: 19-10-2022
Publisher: Springer Science and Business Media LLC
Date: 05-04-2022
DOI: 10.1007/S40725-022-00163-0
Abstract: Human-caused global change is fundamentally altering natural forest ecosystems. More trees are exhibiting a wide range of symptoms indicative of poor vigour, particularly stressed species at the edge of their native ranges and stands growing on marginal sites. This review will focus on complex tree diseases (declines) caused by native pathogens and the key environmental drivers that contribute to this phenomenon. These systems are frequently complex, with multiple drivers at work. Using four cases studies on different continents, we explored the direct and indirect environmental drivers underlying these decline syndromes. Although climate and weather events seem to be usually associated with forest decline, we found that environmental disturbance by either forest management or land-use changes is also a global predisposing factor of decline which deserves more attention. Changes in land use have directly benefited pathogens such as root rots in the Pyrenees (Spain) or indirectly by making the environment more conducive for canker and foliar diseases in Australia and the USA. Focus on land-use changes could improve understanding of current decline problems such as those affecting Araucaria in Chile. The next century will almost certainly see an unprecedented rise in forest pathogen epidemics, requiring a proactive rather than reactive response. Diseases caused by native pathogens with complex aetiologies will become more common, and recognising, characterising and managing these epidemics are difficult because native pathogens are frequently already widespread, and eradication is not feasible. We need to start approaching these issues from a ‘whole ecosystem’ perspective, highlighting the many aspects and entanglements of forest declines and allowing us to respond with management options tailored to each scenario. The approach proposed here provides logical steps based on six questions to untangle the direct and indirect environmental drivers of tree declines.
Publisher: Springer Science and Business Media LLC
Date: 21-08-2015
DOI: 10.1007/S00442-015-3422-3
Abstract: Pathogens can drive host population dynamics. Chytridiomycosis is a fungal disease of hibians that is caused by the fungus Batrachochytrium dendrobatidis (Bd). This pathogen has caused declines and extinctions in some host species whereas other host species coexist with Bd without suffering declines. In the early 1990s, Bd extirpated populations of the endangered common mistfrog, Litoria rheocola, at high-elevation sites, while populations of the species persisted at low-elevation sites. Today, populations have reappeared at many high-elevation sites where they presently co-exist with the fungus. We conducted a capture-mark-recapture (CMR) study of six populations of L. rheocola over 1 year, at high and low elevations. We used multistate CMR models to determine which factors (Bd infection status, site type, and season) influenced rates of frog survival, recapture, infection, and recovery from infection. We observed Bd-induced mortality of in idual frogs, but did not find any significant effect of Bd infection on the survival rate of L. rheocola at the population level. Survival and recapture rates depended on site type and season. Infection rate was highest in winter when temperatures were favourable for pathogen growth, and differed among site types. The recovery rate was high (75.7-85.8%) across seasons, and did not differ among site types. The coexistence of L. rheocola with Bd suggests that (1) frog populations are becoming resistant to the fungus, (2) Bd may have evolved lower virulence, or (3) current environmental conditions may be inhibiting outbreaks of the fatal disease.
Publisher: Frontiers Media SA
Date: 29-01-2021
Abstract: In forest ecosystems, habitat fragmentation negatively impacts stand structure and bio ersity the resulting fragmented patches of forest have distinct, disturbed edge habitats that experience different environmental conditions than the interiors of the fragments. In southwest Western Australia, there is a large-scale decline of the keystone tree species Corymbia calophylla following fragmentation and land use change. These changes have altered stand structure and increased their susceptibility to an endemic fungal pathogen, Quambalaria coyrecup , which causes chronic canker disease especially along disturbed forest habitats. However, the impacts of fragmentation on belowground processes in this system are not well-understood. We examined the effects of fragmentation on abiotic soil properties and ectomycorrhizal (ECM) and arbuscular mycorrhizal (AM) fungal communities, and whether these belowground changes were drivers of disease incidence. We collected soil from 17 sites across the distribution range of C. calophylla . Soils were collected across a gradient from disturbed, diseased areas to undisturbed, disease-free areas. We analysed soil nutrients and grew C . calophylla plants as a bioassay host. Plants were harvested and roots collected after 6 months of growth. DNA was extracted from the roots, lified using fungal specific primers and sequenced using Illumina MiSeq. Concentrations of key soil nutrients such as nitrogen, phosphorus and potassium were much higher along the disturbed, diseased edges in comparison to undisturbed areas. Disturbance altered the community composition of ECM and AM fungi however, only ECM fungal communities had lower rarefied richness and ersity along the disturbed, diseased areas compared to undisturbed areas. Accounting for effects of disturbance, ECM fungal ersity and leaf litter depth were highly correlated with increased disease incidence in C. calophylla . In the face of global change, increased virulence of an endemic pathogen has emerged in this Mediterranean-type forest.
Publisher: Wiley
Date: 27-08-2023
Abstract: Biological invasions of plants have profound effects on ecosystem functioning by directly and indirectly altering soil microbiota, especially when invasive plants co‐invade with their associated microbiomes. Ecosystem functions may recover slowly following invader removal, with implications for restoration. We investigated the recovery of soil ecosystem function (measured as soil enzymes) following the removal, at different densities and times, of invasive Pinus spp. in New Zealand, and how different enzymatic activities responded to pine legacies. Enzymatic activities were driven by pine legacies via both abiotic (soil nutrients) and biotic (fungi and bacteria) soil properties, with different enzymes showing distinct patterns. The activity of the enzymes cellobiohydrolase (cellulose degrading), β‐glucosidase (cellulose degrading), N‐acetyl‐glucosaminidase (chitin degrading), laccase (lignin oxidising) and acid phosphatase (organic phosphate hydrolysing) were influenced by time since pine removal and by pine density at removal via effects on biotic communities. In comparison, Mn‐peroxidase (lignin oxidising) was positively correlated with density of pines at removal and was negatively correlated with time since removal and was only influenced by fungal communities. Synthesis . The recovery of soil enzymatic function following invasive species removal is slow and dependent on pine legacies through the gradual changes in fungal and bacterial communities. The cascading effects of these changes suggest potential implications for the success of future plant establishment and restoration of co‐invaded ecosystems.
Publisher: New Zealand Ecological Society
Date: 09-06-2022
Publisher: New Zealand Ecological Society
Date: 31-01-2022
Publisher: Herpetologists League
Date: 06-2015
Publisher: Elsevier BV
Date: 09-2022
Publisher: Herpetologists League
Date: 03-2014
Publisher: Wiley
Date: 09-05-2020
DOI: 10.1111/NPH.16612
Abstract: This article is a Commentary on Domínguez‐Begines et al. (2020), 227 : 588–600 .
Publisher: Wiley
Date: 12-06-2021
DOI: 10.1111/NPH.17455
Abstract: There is current debate on how soil s le pooling affects the measurement of plant–soil feedbacks. Several studies have suggested that pooling soil s les among experimental units reduces variance and can bias estimates of plant–soil feedbacks. However, it is unclear whether pooling has resulted in systematic mismeasurement of plant–soil feedbacks in the literature. Using data from 71 experiments, we tested whether pairwise plant–soil feedback direction, magnitude and variance differed among soil pooling treatments. We also tested whether pooling has altered our understanding of abiotic and biotic drivers that influence pairwise plant–soil feedbacks. Pooling of soil s les among experimental units was used in 42% of examined experiments. Contrary to predictions, pooling did not affect mean pairwise plant–soil feedback effect size or within‐experiment variance. Accounting for soil s le pooling also did not significantly alter our understanding of the drivers of pairwise plant–soil feedbacks. We conclude that there is no evidence that soil s le pooling systematically biases estimates of plant–soil feedback direction, magnitude, variance or drivers across many studies. Given the debate of whether to pool soil s les, researchers should be aware of potential criticisms and carefully consider how experimental design and soil pooling methods influence interpretation of experiments.
Start Date: 12-2022
End Date: 12-2025
Amount: $386,708.00
Funder: Australian Research Council
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