Time-delayed inﬂuence of urban landscape change on the susceptibility of koalas to chlamydiosis
Clive McAlpine1,2 . Grant Brearley1 . Jonathan Rhodes1,2 . Adrian Bradley3 . Greg Baxter1 . Leonie Seabrook1,2 . Daniel Lunney4,5 . Yan Liu1 . Manuelle Cottin1 . Andrew G. Smith4 . Peter Timms6
1 Landscape Ecology and Conservation Group, School of Geography, Planning and Environmental Management, The University of Queensland, Brisbane, QLD 4072, Australia
2 Centre for Biodiversity and Conservation Science, University of Queensland, Brisbane, QLD 4072, Australia
3 School of Biomedical Sciences, The University of Queensland, Brisbane, QLD 4072, Australia
4 Ofﬁce of Environment and Heritage NSW, PO Box 1967, Hurstville, NSW 2220, Australia
5 School of Life and Environmental Sciences, University of Sydney, Sydney, NSW 2006, Australia
6 Faculty of Science, Health, Education and Engineering, University of the Sunshine Coast, Locked Bag 4, Maroochydore DC, QLD 4558 Sunshine Coast, Australia
Context Infectious diseases are important in the dynamics of many wildlife populations, but there is limited understanding of how landscape change inﬂuences susceptibility to disease.
Objectives We aimed to quantify the time-delayed inﬂuence of spatial and temporal components of landscape change and climate variability on the prevalence of chlamydiosis in koala (Phascolarctos cinereus) populations in southeast Queensland, Australia.
Methods We used data collected over 14 years (n = 9078 records) from a koala hospital along with time-lagged measures of landscape change and rainfall to conduct spatial and temporal analyses of the inﬂuence of landscape and environmental variables on prevalence of chlamydiosis and koala body condition.
Results Areas with more suitable habitat were associated with higher levels of disease prevalence and better body condition, indicating that koalas were less likely to be impacted by chlamydiosis. More intact landscapes with higher proportions of total habitat are associated with a reduction in prevalence of chlamydiosis and a decrease in body condition. Increased annual rainfall contributed to a decrease in prevalence of chlamydiosis and an increase in body condition. Urbanization was associated with an increase in disease, however the effects of urban landscape change and climate variability on chlamydiosis may not manifest until several years later when overt disease impacts the population via effects upon body condition and reproductive success.
Conclusions Our study highlights the importance of effects of landscape change and climate variability on disease prevalence in wildlife. This recognition is essential for long-term conservation planning, especially as disease often interacts with other threats.