Assessing spatial patterns of disease risk to biodiversity: Implications for the management of the amphibian pathogen, Batrachochytrium dendrobatidis

Murray, Kris A., Retallick, Richard W. R., Puschendorf, Robert, Skerratt, Lee F., Rosauer, Dan, McCallum, Hamish I., Berger, Lee, Speare, Rick and VanDerWal, Jeremy (2011) Assessing spatial patterns of disease risk to biodiversity: Implications for the management of the amphibian pathogen, Batrachochytrium dendrobatidis. Journal of Applied Ecology, 48 1: 163-173. doi:10.1111/j.1365-2664.2010.01890.x


Author Murray, Kris A.
Retallick, Richard W. R.
Puschendorf, Robert
Skerratt, Lee F.
Rosauer, Dan
McCallum, Hamish I.
Berger, Lee
Speare, Rick
VanDerWal, Jeremy
Title Assessing spatial patterns of disease risk to biodiversity: Implications for the management of the amphibian pathogen, Batrachochytrium dendrobatidis
Formatted title
Assessing spatial patterns of disease risk to biodiversity: Implications for the management of the amphibian pathogen, Batrachochytrium dendrobatidis
Journal name Journal of Applied Ecology   Check publisher's open access policy
ISSN 0021-8901
1365-2664
Publication date 2011-02-01
Year available 2010
Sub-type Article (original research)
DOI 10.1111/j.1365-2664.2010.01890.x
Open Access Status DOI
Volume 48
Issue 1
Start page 163
End page 173
Total pages 11
Place of publication Oxford, United Kingdom
Publisher Wiley-Blackwell Publishing
Language eng
Abstract Animal social behaviour can have important effects on the long-term dynamics of diseases. In particular, preferential spatial relationships between individuals can lead to differences in the rates of disease spread within a population. We examined the concurrent influence of genetic relatedness, sex, age, home range overlap, time of year, and prion disease status on proximal associations of adult Rocky Mountain mule deer (Odocoileus hemionus hemionus) in a chronic wasting disease endemic area. We also quantified the temporal stability of these associations across different sex, age, and disease status classes. We used three years of high frequency telemetry data from 74 individuals to record encounters within 25 m of each other, and to calculate seasonal home range overlap measured by volume of intersection (VI). The strength of pairwise spatial association between adult mule deer was independent of genetic relatedness, age and disease status. Seasonal variation in association strength was not consistent across years, perhaps due to annual changes in weather conditions. The influence of home range overlap on association strength varied seasonally, whereby associations were stronger in pre-rut and fawning than in the rest of the seasons. The sexes of individuals also interacted with both VI and season. At increasing levels of VI, associations were stronger between females than between males and between females and males. The strongest associations in pre-rut were between males, while the strongest in rut were between females and males. The temporal stability of associations was markedly dependant on the sex and the diagnosis of the associating pair. Our findings highlight the importance of considering concurrent effects of biological and environmental factors when seeking to understand the role of social preference in behavioural ecology and disease spread. Applying this knowledge in epidemiological modelling will shed light on the dynamics of disease transmission among mule deer.
Formatted abstract
1. Emerging infectious diseases can have serious consequences for wildlife populations, ecosystem structure and biodiversity. Predicting the spatial patterns and potential impacts of diseases in free-ranging wildlife are therefore important for planning, prioritizing and implementing research and management actions.
2. We developed spatial models of environmental suitability (ES) for infection with the pathogen Batrachochytrium dendrobatidis, which causes the most significant disease affecting vertebrate biodiversity on record, amphibian chytridiomycosis. We applied relatively newly developed methods for modelling ES (Maxent) to the first comprehensive, continent-wide data base (comprising >10000 observations) on the occurrence of infection with this pathogen and employed novel methodologies to deal with common but rarely addressed sources of model uncertainty.
3. We used ES to (i) predict the minimum potential geographic distribution of infection with B. dendrobatidis in Australia and (ii) test the hypothesis that ES for B. dendrobatidis should help explain patterns of amphibian decline given its theoretical and empirical link with organism abundance (intensity of infection), a known determinant of disease severity.
4. We show that (i) infection with B. dendrobatidis has probably reached its broad geographic limits in Australia under current climatic conditions but that smaller areas of invasion potential remain, (ii) areas of high predicted ES for B. dendrobatidis accurately reflect areas where population declines due to severe chytridiomycosis have occurred and (iii) that a host-specific metric of ES for B. dendrobatidis (ES for Bdspecies) is the strongest predictor of decline in Australian amphibians at a continental scale yet discovered.
5. Synthesis and applications. Our results provide quantitative information that helps to explain both the spatial distribution and potential effects (risk) of amphibian infection with B. dendrobatidis at the population level. Given scarce conservation resources, our results can be used immediately in Australia and our methods applied elsewhere to prioritize species, regions and actions in the struggle to limit further biodiversity loss.
© 2010 The Authors. Journal of Applied Ecology © 2010 British Ecological Society.
Keyword Amphibian declines
Bioclimatic modelling
Chytrid fungus
Chytridiomycosis
Q-Index Code C1
Q-Index Status Confirmed Code
Institutional Status UQ
Additional Notes Article first published online: 17 DEC 2010.

Document type: Journal Article
Sub-type: Article (original research)
Collections: Official 2011 Collection
School of Biological Sciences Publications
Ecology Centre Publications
 
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Created: Sun, 13 Feb 2011, 10:02:58 EST