1
|
Fernandez CM, Krockenberger MB, Ho SYW, Crowther MS, Mella VSA, Jelocnik M, Wilmott L, Higgins DP. Novel typing scheme reveals emergence and genetic diversity of Chlamydia pecorum at the local management scale across two koala populations. Vet Microbiol 2024; 293:110085. [PMID: 38581768 DOI: 10.1016/j.vetmic.2024.110085] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2023] [Revised: 04/02/2024] [Accepted: 04/03/2024] [Indexed: 04/08/2024]
Abstract
To overcome shortcomings in discriminating Chlamydia pecorum strains infecting the koala (Phascolarctos cinereus) at the local level, we developed a novel genotyping scheme for this pathogen to inform koala management at a fine-scale subpopulation level. We applied this scheme to two geographically distinct koala populations in New South Wales, Australia: the Liverpool Plains and the Southern Highlands to South-west Sydney (SHSWS). Our method provides greater resolution than traditional multi-locus sequence typing, and can be used to monitor strain emergence, movement, and divergence across a range of fragmented habitats. Within the Liverpool Plains population, suspected recent introduction of a novel strain was confirmed by an absence of genetic diversity at the earliest sampling events and limited diversity at recent sampling events. Across the partially fragmented agricultural landscape of the Liverpool Plains, diversity within a widespread sequence type suggests that this degree of fragmentation may hinder but not prevent spread. In the SHSWS population, our results suggest movement of a strain from the south, where diverse strains exist, into a previously Chlamydia-free area in the north, indicating the risk of expansion towards an adjacent Chlamydia-negative koala population in South-west Sydney. In the south of the SHSWS where koala subpopulations appear segregated, we found evidence of divergent strain evolution. Our tool can be used to infer the risks of strain introduction across fragmented habitats in population management, particularly through practices such as wildlife corridor constructions and translocations.
Collapse
Affiliation(s)
- Cristina M Fernandez
- Faculty of Science, Sydney School of Veterinary Science, The University of Sydney, Sydney, NSW 2006, Australia
| | - Mark B Krockenberger
- Faculty of Science, Sydney School of Veterinary Science, The University of Sydney, Sydney, NSW 2006, Australia; Sydney Infectious Diseases, The University of Sydney, 176 Hawkesbury Road, Westmead, NSW 2145, Australia
| | - Simon Y W Ho
- School of Life and Environmental Sciences, The University of Sydney, Sydney, NSW 2006, Australia
| | - Mathew S Crowther
- School of Life and Environmental Sciences, The University of Sydney, Sydney, NSW 2006, Australia
| | - Valentina S A Mella
- Faculty of Science, Sydney School of Veterinary Science, The University of Sydney, Sydney, NSW 2006, Australia; School of Life and Environmental Sciences, The University of Sydney, Sydney, NSW 2006, Australia
| | - Martina Jelocnik
- School of Science, Technology and Engineering, University of the Sunshine Coast, Sippy Downs, QLD 4556, Australia; Centre for Bioinnovation, University of the Sunshine Coast, Sippy Downs, QLD 4556, Australia
| | - Lachlan Wilmott
- NSW Department of Planning and Environment, Wollongong, NSW 2005, Australia
| | - Damien P Higgins
- Faculty of Science, Sydney School of Veterinary Science, The University of Sydney, Sydney, NSW 2006, Australia.
| |
Collapse
|
2
|
Mella VSA, Cooper CE, Karr M, Krockenberger A, Madani G, Webb EB, Krockenberger MB. Hot climate, hot koalas: the role of weather, behaviour and disease on thermoregulation. CONSERVATION PHYSIOLOGY 2024; 12:coae032. [PMID: 38803425 PMCID: PMC11129715 DOI: 10.1093/conphys/coae032] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/07/2023] [Revised: 04/08/2024] [Accepted: 04/30/2024] [Indexed: 05/29/2024]
Abstract
Thermoregulation is critical for endotherms living in hot, dry conditions, and maintaining optimal core body temperature (Tb) in a changing climate is an increasingly challenging task for mammals. Koalas (Phascolarctos cinereus) have evolved physiological and behavioural strategies to maintain homeostasis and regulate their Tb but are thought to be vulnerable to prolonged heat. We investigated how weather, behaviour and disease influence Tb for wild, free-living koalas during summer in north-west New South Wales. We matched Tb with daily behavioural observations in an ageing population where chlamydial disease is prevalent. Each individual koala had similar Tb rhythms (average Tb = 36.4 ± 0.05°C), but male koalas had higher Tb amplitude and more pronounced daily rhythm than females. Disease disrupted the 24-hr circadian pattern of Tb. Koala Tb increased with ambient temperature (Ta). On the hottest day of the study (maximum Ta = 40.8°C), we recorded the highest (Tb = 40.8°C) but also the lowest (Tb = 32.4°C) Tb ever documented for wild koalas, suggesting that they are more heterothermic than previously recognized. This requires individuals to predict days of extreme Ta from overnight and early morning conditions, adjusting Tb regulation accordingly, and it has never been reported before for koalas. The large diel amplitude and low minimum Tb observed suggest that koalas at our study site are energetically and nutritionally compromised, likely due to their age. Behaviour (i.e. tree hugging and drinking water) was not effective in moderating Tb. These results indicate that Ta and koala Tb are strongly interconnected and reinforce the importance of climate projections for predicting the future persistence of koalas throughout their current distribution. Global climate models forecast that dry, hot weather will continue to escalate and drought events will increase in frequency, duration and severity. This is likely to push koalas and other arboreal folivores towards their thermal limit.
Collapse
Affiliation(s)
- Valentina S A Mella
- Sydney School of Veterinary Science, The University of Sydney, Sydney, New South Wales 2006, Australia
- School of Life and Environmental Sciences, The University of Sydney, Sydney, New South Wales 2006, Australia
| | - Christine E Cooper
- School of Molecular and Life Sciences, Curtin University, Perth, Western Australia 6102, Australia
| | - Madeline Karr
- School of Life and Environmental Sciences, The University of Sydney, Sydney, New South Wales 2006, Australia
| | - Andrew Krockenberger
- Division of Research and Innovation, James Cook University, Cairns, Queensland 4878, Australia
| | - George Madani
- School of Environmental and Life Sciences, The University of Newcastle, Callaghan, NSW 2308, Australia
| | - Elliot B Webb
- School of Life and Environmental Sciences, The University of Sydney, Sydney, New South Wales 2006, Australia
- Department of Planning and Environment, Science, Economics and Insights Division, Parramatta, New South Wales 2150, Australia
| | - Mark B Krockenberger
- Sydney School of Veterinary Science, The University of Sydney, Sydney, New South Wales 2006, Australia
| |
Collapse
|
3
|
Crowther MS, Rus AI, Mella VSA, Krockenberger MB, Lindsay J, Moore BD, McArthur C. Patch quality and habitat fragmentation shape the foraging patterns of a specialist folivore. Behav Ecol 2022; 33:1007-1017. [PMID: 36382228 PMCID: PMC9639584 DOI: 10.1093/beheco/arac068] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2022] [Revised: 06/17/2022] [Accepted: 06/28/2022] [Indexed: 09/08/2024] Open
Abstract
Research on use of foraging patches has focused on why herbivores visit or quit patches, yet little is known about visits to patches over time. Food quality, as reflected by higher nutritional quality and lower plant defenses, and physical patch characteristics, which offer protection from predators and weather, affect patch use and hence should influence their revisitation. Due to the potentially high costs of moving between patches, fragmented habitats are predicted to complicate foraging decisions of many animals. We aimed to determine how food quality, shelter availability and habitat fragmentation influence tree reuse by a specialist folivore, the koala, in a fragmented agricultural landscape. We GPS-tracked 23 koalas in northern New South Wales, Australia and collated number of revisits, average residence time, and average time-to-return to each tree. We measured tree characteristics including food quality (foliar nitrogen and toxic formylated phloroglucinol compounds, FPCs concentrations), tree size, and tree connectedness. We also modeled the costs of locomotion between trees. Koalas re-visited isolated trees with high leaf nitrogen disproportionately often. They spent longer time in trees with high leaf nitrogen, and in large trees used for shelter. They took longer to return to trees with low leaf nitrogen. Tree connectivity reduced travel costs between patches, being either individual or groups of trees. FPC levels had no detectable effect on patch revisitation. We conclude that food quality and shelter drive koala tree re-visits. Scattered, isolated trees with nutrient-rich leaves are valuable resource patches for koalas despite movement costs to reach them.
Collapse
Affiliation(s)
- Mathew S Crowther
- School of Life and Environmental Sciences, University of Sydney, Sydney, New South Wales 2006, Australia
| | - Adrian I Rus
- School of Life and Environmental Sciences, University of Sydney, Sydney, New South Wales 2006, Australia
| | - Valentina S A Mella
- School of Life and Environmental Sciences, University of Sydney, Sydney, New South Wales 2006, Australia
- Sydney School of Veterinary Science, University of Sydney, Sydney, New South Wales 2006, Australia
| | - Mark B Krockenberger
- Sydney School of Veterinary Science, University of Sydney, Sydney, New South Wales 2006, Australia
- The Westmead Institute for Medical Research, 176 Hawkesbury Road, Westmead, New South Wales 2145, Australia
- Marie Bashir Institute for Emerging Infectious diseases and Biosecurity, University of Sydney, 176 Hawkesbury Road, Westmead, New South Wales 2145, Australia
| | - Jasmine Lindsay
- School of Life and Environmental Sciences, University of Sydney, Sydney, New South Wales 2006, Australia
| | - Ben D Moore
- Hawkesbury Institute for the Environment, Western Sydney University, Richmond, New South Wales 2753, Australia
| | - Clare McArthur
- School of Life and Environmental Sciences, University of Sydney, Sydney, New South Wales 2006, Australia
| |
Collapse
|