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Wyrsch ER, Hoye BJ, Sanderson-Smith M, Gorman J, Maute K, Cummins ML, Jarocki VM, Marenda MS, Dolejska M, Djordjevic SP. The faecal microbiome of the Australian silver gull contains phylogenetically diverse ExPEC, aEPEC and Escherichia coli carrying the transmissible locus of stress tolerance. Sci Total Environ 2024; 919:170815. [PMID: 38336047 DOI: 10.1016/j.scitotenv.2024.170815] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/05/2023] [Revised: 01/28/2024] [Accepted: 02/06/2024] [Indexed: 02/12/2024]
Abstract
Wildlife are implicated in the dissemination of antimicrobial resistance, but their roles as hosts for Escherichia coli that pose a threat to human and animal health is limited. Gulls (family Laridae) in particular, are known to carry diverse lineages of multiple-antibiotic resistant E. coli, including extra-intestinal pathogenic E. coli (ExPEC). Whole genome sequencing of 431 E. coli isolates from 69 healthy Australian silver gulls (Chroicocephalus novaehollandiae) sampled during the 2019 breeding season, and without antibiotic selection, was undertaken to assess carriage in an urban wildlife population. Phylogenetic analysis and genotyping resolved 123 sequence types (STs) representing most phylogroups, and identified diverse ExPEC, including an expansive phylogroup B2 cluster comprising 103 isolates (24 %; 31 STs). Analysis of the mobilome identified: i) widespread carriage of the Yersinia High Pathogenicity Island (HPI), a key ExPEC virulence determinant; ii) broad distribution of two novel phage elements, each carrying sitABCD and iii) carriage of the transmissible locus of stress tolerance (tLST), an element linked to sanitation resistance. Of the 169 HPI carrying isolates, 49 (48 %) represented diverse B2 isolates hosting FII-64 ColV-like plasmids that lacked iutABC and sitABC operons typical of ColV plasmids, but carried the serine protease autotransporter gene, sha. Diverse E. coli also carried archetypal ColV plasmids (52 isolates; 12 %). Clusters of closely related E. coli (<50 SNVs) from ST58, ST457 and ST746, sourced from healthy gulls, humans, and companion animals, were frequently identified. In summary, anthropogenically impacted gulls host an expansive E. coli population, including: i) putative ExPEC that carry ColV virulence gene cargo (101 isolates; 23.4 %) and HPI (169 isolates; 39 %); ii) atypical enteropathogenic E. coli (EPEC) (17 isolates; 3.9 %), and iii) E. coli that carry the tLST (20 isolates; 4.6 %). Gulls play an important role in the evolution and transmission of E. coli that impact human health.
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Affiliation(s)
- Ethan R Wyrsch
- Australian Institute for Microbiology and Infection, University of Technology Sydney, Ultimo, NSW, Australia
| | - Bethany J Hoye
- School of Earth, Atmospheric and Life Sciences, Faculty of Science, Medicine and Health, University of Wollongong, Wollongong, NSW, Australia
| | - Martina Sanderson-Smith
- Molecular Horizons Research Institute, School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, NSW, Australia
| | - Jody Gorman
- Molecular Horizons Research Institute, School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, NSW, Australia
| | - Kimberly Maute
- School of Earth, Atmospheric and Life Sciences, Faculty of Science, Medicine and Health, University of Wollongong, Wollongong, NSW, Australia
| | - Max L Cummins
- Australian Institute for Microbiology and Infection, University of Technology Sydney, Ultimo, NSW, Australia
| | - Veronica M Jarocki
- Australian Institute for Microbiology and Infection, University of Technology Sydney, Ultimo, NSW, Australia
| | - Marc S Marenda
- Department of Veterinary Biosciences, Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Werribee, VIC 3030, Australia
| | - Monika Dolejska
- Department of Biology and Wildlife Diseases, Faculty of Veterinary Hygiene and Ecology, University of Veterinary Sciences Brno, Czech Republic; CEITEC VETUNI, University of Veterinary Sciences Brno, Czech Republic; Department of Clinical Microbiology and Immunology, Institute of Laboratory Medicine, The University Hospital Brno, Czech Republic; Department of Microbiology, Faculty of Medicine and University Hospital in Plzen, Charles University, Pilsen, Czech Republic
| | - Steven P Djordjevic
- Australian Institute for Microbiology and Infection, University of Technology Sydney, Ultimo, NSW, Australia.
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Hem S, Cummins ML, Wyrsch ER, Drigo B, Hoye BJ, Maute K, Sanderson-Smith M, Gorman J, Bogema DR, Jenkins C, Deutscher AT, Yam J, Hai F, Donner E, Jarocki VM, Djordjevic SP. Genomic analysis of Citrobacter from Australian wastewater and silver gulls reveals novel sequence types carrying critically important antibiotic resistance genes. Sci Total Environ 2024; 909:168608. [PMID: 37977387 DOI: 10.1016/j.scitotenv.2023.168608] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/17/2023] [Revised: 11/08/2023] [Accepted: 11/14/2023] [Indexed: 11/19/2023]
Abstract
Antimicrobial resistance (AMR) is a major public health concern, and environmental bacteria have been recognized as important reservoirs of antimicrobial resistance genes (ARGs). Citrobacter, a common environmental bacterium and opportunistic pathogen in humans and other animals, has been largely understudied in terms of its diversity and AMR potential. Whole-genome (short-read) sequencing on a total of 77 Citrobacter isolates obtained from Australian silver gull (Chroicocephalus novaehollandiae) (n = 17) and influent wastewater samples (n = 60) was performed, revealing a diverse Citrobacter population, with seven different species and 33 sequence types, 17 of which were novel. From silver gull using non-selective media we isolated a broader range of species with little to no mobilised ARG carriage. Wastewater isolates (selected using Carbapenem- Resistant Enterobacterales (CRE) selective media) carried a heavy burden of ARGs (up to 21 ARGs, conferring resistance to nine classes of antibiotics), with several novel multidrug-resistant (MDR) lineages identified, including C. braakii ST1110, which carried ARGs conferring resistance to eight to nine classes of antibiotics, and C. freundii ST1105, which carried two carbapenemase genes, blaIMP-4 in class 1 integron structure, and blaKPC-2. Additionally, we identified an MDR C. portucalensis isolate carrying blaNDM-1, blaSHV-12, and mcr-9. We identified IncC, IncM2, and IncP6 plasmids as the likely vectors for many of the critically important mobilised ARGs. Phylogenetic analyses were performed to assess any epidemiological linkages between isolation sources, demonstrating low relatedness across sources beyond the ST level. However, these analyses did reveal some closer relationships between strains from disparate wastewater sources despite their collection some 13,000 km apart. These findings support the need for future surveillance of Citrobacter populations in wastewater and wildlife populations to monitor for potential opportunistic human pathogens.
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Affiliation(s)
- Sopheak Hem
- Australian Institute for Microbiology and Infection, University of Technology Sydney, Ultimo, Australia; The Australian Centre for Genomic Epidemiological Microbiology, University of Technology Sydney, Ultimo, Australia
| | - Max L Cummins
- Australian Institute for Microbiology and Infection, University of Technology Sydney, Ultimo, Australia; The Australian Centre for Genomic Epidemiological Microbiology, University of Technology Sydney, Ultimo, Australia
| | - Ethan R Wyrsch
- Australian Institute for Microbiology and Infection, University of Technology Sydney, Ultimo, Australia; The Australian Centre for Genomic Epidemiological Microbiology, University of Technology Sydney, Ultimo, Australia
| | - Barbara Drigo
- UniSA STEM, University of South Australia, Adelaide, SA, Australia
| | - Bethany J Hoye
- School of Earth, Atmospheric and Life Sciences, University of Wollongong NSW, Australia; Environmental Futures Research Centre, University of Wollongong NSW, Australia
| | - Kimberly Maute
- School of Earth, Atmospheric and Life Sciences, University of Wollongong NSW, Australia; Environmental Futures Research Centre, University of Wollongong NSW, Australia
| | - Martina Sanderson-Smith
- School of Chemistry and Molecular Bioscience and Molecular Horizons, University of Wollongong, NSW, Australia
| | - Jody Gorman
- School of Chemistry and Molecular Bioscience and Molecular Horizons, University of Wollongong, NSW, Australia
| | - Daniel R Bogema
- Elizabeth Macarthur Agricultural Institute, NSW Department of Primary Industries, Menangle, NSW, Australia
| | - Cheryl Jenkins
- Elizabeth Macarthur Agricultural Institute, NSW Department of Primary Industries, Menangle, NSW, Australia
| | - Ania T Deutscher
- Elizabeth Macarthur Agricultural Institute, NSW Department of Primary Industries, Menangle, NSW, Australia
| | - Jerald Yam
- Elizabeth Macarthur Agricultural Institute, NSW Department of Primary Industries, Menangle, NSW, Australia
| | - Faisal Hai
- School of Civil, Mining, Environmental and Architectural Engineering, University of Wollongong, NSW, Australia
| | - Erica Donner
- Cooperative Research Centre for Solving Antimicrobial resistance in Agribusiness, Food, and Environments (CRC SAAFE), Adelaide, South Australia, Australia; Future Industries Institute, University of South Australia, Adelaide, South Australia, Australia
| | - Veronica M Jarocki
- Australian Institute for Microbiology and Infection, University of Technology Sydney, Ultimo, Australia; The Australian Centre for Genomic Epidemiological Microbiology, University of Technology Sydney, Ultimo, Australia.
| | - Steven P Djordjevic
- Australian Institute for Microbiology and Infection, University of Technology Sydney, Ultimo, Australia; The Australian Centre for Genomic Epidemiological Microbiology, University of Technology Sydney, Ultimo, Australia.
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Contador-Kelsall I, Maute K, de Beer M, French K. Individual variation within wild populations of an arid-zone lizard dictates oxidative stress levels despite exposure to sublethal pesticides. Ecotoxicology 2023; 32:470-486. [PMID: 37099201 DOI: 10.1007/s10646-023-02653-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 04/12/2023] [Indexed: 05/22/2023]
Abstract
The relationship between sublethal pesticide exposure and oxidative stress in an ecologically relevant field setting is relatively unknown for reptiles. Oxidative stress is a multi-faceted concept that dictates key survival and fitness parameters in any organism. Fipronil and fenitrothion are two pesticides widely used globally for agricultural pest management. Using a field-based, BACI designed experiment we investigated the impact of sublethal pesticide exposure on oxidative stress biomarkers protein carbonyl and DNA damage (8-OHdG), in an arid-zone lizard species, Pogona vitticeps. A single ecologically relevant dose of pesticide was applied via oral gavage to treatment animals. Lizard condition, activity measures, and blood biomarkers were measured at relevant sampling intervals. Cholinesterase (ChE) and acetylcholinesterase (AChE) enzymatic biomarkers were measured in response to fenitrothion, and fipronil blood residues were measured for fipronil-treated lizards. Results suggested no significant treatment effect of either pesticide on parameters measured, however, 8-OHdG levels decreased by ≥ 45% for both pesticide treatment groups and not controls. Protein carbonyl levels showed a high degree of individual variation that proved more influential than pesticide exposure. Building our understanding of the macromolecular impacts of sublethal pesticide exposure on wild lizard populations is an integral step in addressing the current gap in literature and management practices. Our study has also highlighted the complex nature of studying oxidative stress in the field and the sheer necessity of future study.
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Affiliation(s)
- Isabella Contador-Kelsall
- School of Earth, Atmospheric and Life Sciences, University of Wollongong, Northfields Ave, Wollongong, 2522, NSW, Australia.
| | - Kimberly Maute
- School of Earth, Atmospheric and Life Sciences, University of Wollongong, Northfields Ave, Wollongong, 2522, NSW, Australia
- Department of Planning and Environment, Ecosystems and Threatened Species, Biodiversity and Conservation, PO Box 2011, Dubbo, NSW, 2830, Australia
| | | | - Kristine French
- School of Earth, Atmospheric and Life Sciences, University of Wollongong, Northfields Ave, Wollongong, 2522, NSW, Australia
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Maute K, Story P, Hose GC, Warden A, Dojchinov G, French K. Observations on populations of a small insectivorous bird,. AUST J ZOOL 2022. [DOI: 10.1071/zo22006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
The use of chemical pesticides to manage locust populations in natural ecosystems is likely to impact non-target arthropods and their predators. However, the relative effects of different locust control applications on Australian birds are unknown. Aerial applications of fipronil and fenitrothion are examples of two pesticides used in locust control in semiarid Australia. To test the relative impacts of pesticides on non-target fauna, pesticides were applied to replicate sites using aerial ultra-low-volume application methods. The body condition and biomarkers of pesticide exposure in resident white-winged fairy wrens (Malurus leucopterus leuconotus) at treatment and control sites were measured for two weeks before and after treatments. No measures suggested negative impacts of pesticide applications. However, birds monitored at treatment sites gained mass, possibly due to indirect impacts of pesticides on bird feeding patterns or the availability or behaviour of insect prey. Bird mass measures remained high at fipronil sites, whereas the mass of birds at fenitrothion sites returned to baseline levels within one week. As this study was conducted during dry conditions, when locust plagues are less likely, future insecticide research should also consider the availability of insect prey, its effect on insectivore feeding behaviour and the interaction of rainfall events.
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Contador-Kelsall I, Maute K, Story P, Hose GC, French K. Sublethal pesticide exposure influences behaviour, but not condition in a widespread Australian lizard. Conserv Physiol 2022; 10:coac024. [PMID: 35492410 PMCID: PMC9040277 DOI: 10.1093/conphys/coac024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/08/2021] [Revised: 02/07/2022] [Accepted: 03/29/2022] [Indexed: 06/14/2023]
Abstract
Assessment of non-target impacts of pesticides used widely in agriculture and pest management rarely considers reptiles. Despite their integral role in all ecosystems, particularly arid ecosystems, reptiles are not included in risk assessments. Two pesticides used in agricultural pest management are fipronil and fenitrothion. Here, we used a field-based BACI design experiment in semi-arid Australia to investigate the impact of these pesticides on basic physiological and behavioural parameters of a common arid-zone lizard species, Pogona vitticeps. Fipronil and fenitrothion were applied at ecologically relevant doses via oral gavage. Before and after dosing, blood, physical activity and body condition parameters were assessed. We found that temperature significantly influenced lizard activity in the morning period of movement; however, fipronil-treated individuals moved at least 49% less than fenitrothion-treated and control lizards from 7 days after dosing through to the end of the experiment. Physiological measures did not change significantly before or after exposure to both pesticides; however, other indicators showed evidence of exposure, which remained for the entirety of our monitoring period. On average, cholinesterase inhibition was still >30% compared with control lizards at the end of 4 weeks, and fipronil sulfone blood residues remained at 0.219 μg/ml. Our study provides novel insights into the impacts that common pesticides have on widespread lizard species. We show that an ecologically relevant low dose of fipronil alters the behaviour of P. vitticeps, which has the potential to impact longer-term survivability. Persistence of both pesticides in the blood of all treatment lizards throughout the experiment indicates they are unable to clear these toxins within a month of being exposed. This may be significant for compounding exposure and latent toxicity. These findings highlight the susceptibility that reptiles have to a selection of common pesticides and the inherent need for higher prominence in wildlife ecotoxicological research.
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Affiliation(s)
- Isabella Contador-Kelsall
- Corresponding author: School of Earth, Atmospheric and Life Sciences, University of Wollongong, Wollongong, 2522 New South Wales, Australia. E-mail:
| | - Kimberly Maute
- School of Earth, Atmospheric and Life Sciences, University of Wollongong, Northfields Ave, Wollongong, 2522 New South Wales, Australia
| | - Paul Story
- Australian Plague Locust Commission, Unit 7, 50 Collie St, Fyshwick ACT 2609 Australian Capital Territory, Australia
| | - Grant C Hose
- Faculty of Science & Engineering, 14 Sir Christopher Ondaatje Ave, Macquarie University, Sydney, 2109 New South Wales, Australia
| | - Kristine French
- School of Earth, Atmospheric and Life Sciences, University of Wollongong, Northfields Ave, Wollongong, 2522 New South Wales, Australia
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Bernich A, Maute K, Contador-Kelsall IC, Story PG, Hose GC, French K. Space use and daily movement patterns in an arid zone agamid lizard†. Wildl Res 2022. [DOI: 10.1071/wr20152] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Selwood KE, Antos M, Bramwell M, Lee A, Lynch M, Magrath MJL, Maute K, Melvin F, Mott R, Perri M, Whiteford C, Clarke RH. Emergency conservation interventions during times of crisis: A case study for a threatened bird species in the Australian Black Summer bushfires. Conservat Sci and Prac 2021. [DOI: 10.1111/csp2.606] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
Affiliation(s)
- Katherine E. Selwood
- Zoos Victoria Parkville Victoria Australia
- School of Biosciences University of Melbourne Parkville Victoria Australia
| | - Mark Antos
- Science and Management Effectiveness Parks Victoria Melbourne Victoria Australia
| | - Mick Bramwell
- Forest, Fire and Regions Department of Environment, Land, Water and Planning Bairnsdale Victoria Australia
| | - Adam Lee
- Zoos Victoria Parkville Victoria Australia
| | | | - Michael J. L. Magrath
- Zoos Victoria Parkville Victoria Australia
- School of Biosciences University of Melbourne Parkville Victoria Australia
| | - Kimberly Maute
- Centre for Sustainable Ecosystem Solutions University of Wollongong Wollongong New South Wales Australia
| | | | - Rowan Mott
- School of Biological Sciences Monash University Clayton Victoria Australia
| | - Marc Perri
- Forest, Fire and Regions Department of Environment, Land, Water and Planning Orbost Victoria Australia
| | | | - Rohan H. Clarke
- School of Biological Sciences Monash University Clayton Victoria Australia
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Story P, French K, Maute K, Warden AC, Dojchinov G, Hose GC. A method for topical dosing of invertebrates with pesticide for use in feeding experiments. Ecotoxicology 2021; 30:381-386. [PMID: 33443713 DOI: 10.1007/s10646-020-02324-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 11/21/2020] [Indexed: 06/12/2023]
Abstract
The ability to produce large numbers of pesticide-exposed insects (e.g. crickets) is important for feeding studies into the effects of pesticides on key predatory species. House crickets (Acheta domesticus L. 1758) were submersed in serial dilutions of the pesticides, fenitrothion and fipronil, used for the control of locusts in Australia, and then rapidly frozen for residue analysis. Good correlations were found between increasing concentrations of serial pesticide dilutions and the resultant residual concentrations of the parent compounds in crickets, with R2 values of 0.949 (fenitrothion) and 0.946 (fipronil). R2 values for the much less abundant fipronil metabolites were lower 0.858 (sulfone), 0.368 (desulfinyl) and 0.785 (sulfide). This method enables insecticide exposure mimicking the field conditions to be assessed, and can be done immediately prior to an experiment. This ensures locusts remain alive when introduced to the feeding chambers, and enables multiple prey items to be dosed with a known pesticide burden.
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Affiliation(s)
- Paul Story
- Australian Plague Locust Commission, Fyshwick, 2609, ACT, Australia
| | - Kristine French
- School of Earth, Atmospheric and Life Sciences, University of Wollongong, Wollongong, NSW, 2522, Australia
| | - Kimberly Maute
- School of Earth, Atmospheric and Life Sciences, University of Wollongong, Wollongong, NSW, 2522, Australia
| | - Andrew C Warden
- CSIRO Land and Water, Black Mountain Laboratories, Acton, ACT, 2601, Australia
| | - Greg Dojchinov
- CSIRO Land and Water, Black Mountain Laboratories, Acton, ACT, 2601, Australia
| | - Grant C Hose
- Department of Biological Sciences, Macquarie University, Sydney, 2109, NSW, Australia.
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Maute K, Hose GC, Story P, Bull CM, French K. Surviving drought: a framework for understanding animal responses to small rain events in the arid zone. Ecology 2019; 100:e02884. [PMID: 31498887 DOI: 10.1002/ecy.2884] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/10/2019] [Revised: 08/13/2019] [Accepted: 08/22/2019] [Indexed: 11/06/2022]
Abstract
Large rain events drive dramatic resource pulses and the complex pulse-reserve dynamics of arid ecosystems change between high-rain years and drought. However, arid-zone animal responses to short-term changes in climate are unknown, particularly smaller rain events that briefly interrupt longer-term drought. Using arthropods as model animals, we determined the effects of a small rain event on arthropod abundance in western New South Wales, Australia during a longer-term shift toward drought. Arthropod abundance decreased over 2 yr, but captures of 10 out of 15 ordinal taxa increased dramatically after the small rain event (<40 mm). The magnitude of increases ranged from 10.4 million% (collembolans) to 81% (spiders). After 3 months, most taxa returned to prerain abundance. However, small soil-dwelling beetles, mites, spiders, and collembolans retained high abundances despite the onset of winter temperatures and lack of subsequent rain. As predicted by pulse-reserve models, most arid-zone arthropod populations declined during drought. However, small rain events may play a role in buffering some taxa from declines during longer-term drought or other xenobiotic influences. We outline the framework for a new model of animal responses to environmental conditions in the arid zone, as some species clearly benefit from rain inputs that do not dramatically influence primary productivity.
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Affiliation(s)
- Kimberly Maute
- Centre for Sustainable Ecosystem Solutions, University of Wollongong, Wollongong, New South Wales, 2522, Australia
| | - Grant C Hose
- Department of Biological Sciences, Macquarie University, Sydney, New South Wales, 2109, Australia
| | - Paul Story
- Australian Plague Locust Commission, G.P.O. Box 858, Canberra, Australian Capital Territory, 2601, Australia
| | - C Michael Bull
- School of Biological Sciences, Flinders University, Adelaide, South Australia, 5042, Australia
| | - Kristine French
- Centre for Sustainable Ecosystem Solutions, University of Wollongong, Wollongong, New South Wales, 2522, Australia
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Maute K, French K, Legge S, Astheimer L, Garnett S. Corrigendum to: Condition index monitoring supports conservation priorities for the protection of threatened grass-finch populations. Conserv Physiol 2018; 6:coy028. [PMID: 29977562 PMCID: PMC6007382 DOI: 10.1093/conphys/coy028] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/23/2018] [Indexed: 06/08/2023]
Abstract
[This corrects the article DOI: 10.1093/conphys/cov025.][This corrects the article DOI: 10.1093/conphys/cov025.].
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Affiliation(s)
- Kimberly Maute
- Corresponding author: School of Biological Sciences, University of Wollongong, Wollongong, NSW 2522, Australia. Tel: +61 2 4252 8522.
| | - Kristine French
- School of Biological Sciences, University of Wollongong, Wollongong, NSW, Australia
| | - Sarah Legge
- Australian Wildlife Conservancy, Mornington Wildlife Sanctuary, PMB 925, Derby, WA, Australia
| | | | - Stephen Garnett
- Research Institute for the Environment and Livelihood, Charles Darwin University, Casuarina, NT, Australia
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Davitt G, Maute K, Major RE, McDonald PG, Maron M. Short-term response of a declining woodland bird assemblage to the removal of a despotic competitor. Ecol Evol 2018; 8:4771-4780. [PMID: 29876056 PMCID: PMC5980597 DOI: 10.1002/ece3.4016] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2017] [Revised: 02/10/2018] [Accepted: 02/25/2018] [Indexed: 11/08/2022] Open
Abstract
Interspecific aggression by the noisy miner (Manorina melanocephala), a highly despotic species, is homogenizing woodland avifaunas across eastern Australia. Although a native species, the noisy miner's aggressive exclusion of small birds is a Key Threatening Process under national law. Large-scale removal of noisy miners has been proposed as a management response to this threat following increases in miner presence due to anthropogenic land use practices. We tested this proposal by experimentally removing noisy miners from eucalypt woodland remnants (16-49 ha), assigned randomly as control (n = 12) or treatment (miner removal) sites (n = 12). Standardized bird surveys were conducted before and after removal, and generalized linear mixed models were used to investigate the effect of miner removal on bird assemblage metrics. Despite removing 3552 noisy miners in three sessions of systematic shooting, densities of noisy miners remained similarly high in treatment and control sites, even just 14 days after their removal. However, there was evidence of an increase in richness and abundance of small birds in treatment sites compared to controls-an effect we only expected to see if noisy miner densities were drastically reduced. We suggest that miner removal may have reduced the ability of the recolonizing miners to aggressively exclude small birds, even without substantially reducing miner densities, due to the breakdown of social structures that are central to the species' despotic behaviour. However, this effect on small birds is unlikely to persist in the long term. Synthesis and applications: Despite evidence from other studies that direct removal of noisy miners can result in rapid and sustained conservation benefit for bird communities at small scales, our findings cast doubt on the potential to scale-up this management approach. The circumstances under which direct control of noisy miners can be achieved remain unresolved.
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Affiliation(s)
- Galen Davitt
- School of Earth and Environmental SciencesThe University of QueenslandBrisbaneQLDAustralia
| | - Kimberly Maute
- Australian Museum Research Institute, Australian MuseumSydneyNSWAustralia
- School of Biological SciencesUniversity of WollongongWollongongNSWAustralia
| | - Richard E. Major
- Australian Museum Research Institute, Australian MuseumSydneyNSWAustralia
| | - Paul G. McDonald
- Centre for Behavioural and Physiological EcologyZoologyUniversity of New EnglandArmidaleNSWAustralia
| | - Martine Maron
- School of Earth and Environmental SciencesThe University of QueenslandBrisbaneQLDAustralia
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Maute K, French K, Legge S, Astheimer L, Garnett S. Condition index monitoring supports conservation priorities for the protection of threatened grass-finch populations. Conserv Physiol 2015; 3:cov025. [PMID: 27293710 PMCID: PMC4778451 DOI: 10.1093/conphys/cov025] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/29/2014] [Revised: 05/05/2015] [Accepted: 05/07/2015] [Indexed: 06/06/2023]
Abstract
Conservation agencies are often faced with the difficult task of prioritizing what recovery actions receive support. With the number of species under threat of decline growing globally, research that informs conservation priorities is greatly needed. The relative vulnerability of cryptic or nomadic species is often uncertain, because populations are difficult to monitor and local populations often seem stable in the short term. This uncertainty can lead to inaction when populations are in need of protection. We tested the feasibility of using differences in condition indices as an indication of population vulnerability to decline for related threatened Australian finch sub-species. The Gouldian finch represents a relatively well-studied endangered species, which has a seasonal and site-specific pattern of condition index variation that differs from the closely related non-declining long-tailed finch. We used Gouldian and long-tailed finch condition variation as a model to compare with lesser studied, threatened star and black-throated finches. We compared body condition (fat and muscle scores), haematocrit and stress levels (corticosterone) among populations, seasons and years to determine whether lesser studied finch populations matched the model of an endangered species or a non-declining species. While vulnerable finch populations often had lower muscle and higher fat and corticosterone concentrations during moult (seasonal pattern similar to Gouldian finches), haematocrit values did not differ among populations in a predictable way. Star and black-throated finch populations, which were predicted to be vulnerable to decline, showed evidence of poor condition during moult, supporting their status as vulnerable. Our findings highlight how measures of condition can provide insight into the relative vulnerability of animal and plant populations to decline and will allow the prioritization of efforts towards the populations most likely to be in jeopardy of extinction.
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Affiliation(s)
- Kimberly Maute
- School of Biological Sciences, University of Wollongong, Wollongong, NSW, Australia
| | - Kristine French
- School of Biological Sciences, University of Wollongong, Wollongong, NSW, Australia
| | - Sarah Legge
- Australian Wildlife Conservancy, Mornington Wildlife Sanctuary, PMB 925, Derby, WA, Australia
| | | | - Stephen Garnett
- Research Institute for the Environment and Livelihood, Charles Darwin University, Casuarina, NT, Australia
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Maute K, French K, Bull CM, Story P, Hose G. Current insecticide treatments used in locust control have less of a short-term impact on Australian arid-zone reptile communities than does temporal variation. Wildl Res 2015. [DOI: 10.1071/wr14194] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Context
Despite the regular use of pesticides to control locusts, there is a lack of information on the effects of locust-control treatments on reptiles worldwide. Exposure to pesticides poses a significant potential hazard to small reptiles, both from the direct effects of exposure, and indirectly because of their largely insectivorous diet and small home ranges.
Aims
Our study aimed to monitor the effects of two insecticides applied operationally for locust control in Australia. A phenyl pyrazole pesticide, fipronil, and a fungal biopesticide, Metarhizium acridium (Green Guard®), were applied aerially in either a barrier or block treatment in the absence of dense locust populations, and effects on non-target arid-zone reptiles were measured.
Methods
We monitored reptile-abundance and community-composition responses to treatments using a large field-based pitfall-trapping experiment, with replicated control and spraying treatments, which approximated the scale of aerial-based locust-control operations in Australia.
Key results
Neither reptile abundance nor community composition was significantly affected by locust-control treatments. However, both abundance and community composition as detected by pitfall trapping changed over time, in both control and treatment plots, possibly as a result of a decrease in annual rainfall.
Conclusions
The absence of any significant short-term pesticide treatment effects in our study suggests that the two locust-control application methods studied present a relatively insignificant hazard to reptiles at our site, based on a single application. Similar to other areas of Australia, climate and other factors are likely to be stronger drivers of reptile abundance and community structure.
Implications
Monitoring over an area that approximates the scale of the current locust-control operations is an important step in understanding the possible effects of current pesticide exposure on reptile populations and will inform insecticide risk assessments in Australia. However, important information on the immediate response of individuals to insecticide application and long-term effects of exposure are missing. The preliminary research reported in the present paper should be complemented by future investigations on long-term and sublethal impacts of pesticide exposure on Australian native reptiles and the possible benefits provided to reptiles by the resource pulses represented in untreated high-density locust populations.
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Abstract
Inspired by actuation mechanisms in plant structures and motivated by recent advances in electro-chemically driven micro-pumps, this paper is concerned with a novel concept for active materials based on distributed hydraulic actuation. Due to the similarity of the actuation principles seen in plants undergoing nastic motion, we refer to this class of active materials as nastic materials. We present a mechanical modeling approach for nastic materials representing the effects of pressure generation and fluid transport by incompressible eigenstrains. This model is embedded into a two-level macro/micro topology optimization procedure. On a macroscopic level, the integration of nastic material into a structural system is optimized. The placement and distribution of nastic material on a flexible substrate are optimized to generate target displacement and force distributions. On a microscopic level, the stress and strain generation is tailored to desired macroscopic material properties by optimizing the layout of vascular fluid channels embedded in an elastic matrix. For the layout optimization of vascular fluid channels, a novel topology optimization procedure is presented that models the effects of pressure along the fluid channels via an analogy with thermal conduction and convection. For this purpose an auxiliary heat transfer problem is solved. The macro-scale optimization procedure is studied for plate structures patterned by nastic materials in order to generate target bending and twist deformations. The results show the significant differences of the optimal distributions of active material depending on the strain model used for representing the actuation concept. The micro-scale vascular design methodology is verified with plane-stress examples. The results show that the layout of fluid channels can be optimized such that target strains are generated.
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Affiliation(s)
- K. Maute
- University of Colorado at Boulder
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