Use of expert knowledge to elicit population trends for the koala (Phascolarctos cinereus)

Adams‐Hosking, Christine, McBride, Marissa F, Baxter, Greg, Burgman, Mark, Villiers, Deidre, Kavanagh, Rodney, Lawler, Ivan, Lunney, Daniel, Melzer, Alistair, Menkhorst, Peter, Molsher, Robyn, Moore, Ben D., Phalen, David, Rhodes, Jonathan R., Todd, Charles, Desley, Whisson and McAlpine, Clive A. (2016) Use of expert knowledge to elicit population trends for the koala (Phascolarctos cinereus). Diversity and Distributions, 22 3: 249-262. doi:10.1111/ddi.12400

Author Adams‐Hosking, Christine
McBride, Marissa F
Baxter, Greg
Burgman, Mark
Villiers, Deidre
Kavanagh, Rodney
Lawler, Ivan
Lunney, Daniel
Melzer, Alistair
Menkhorst, Peter
Molsher, Robyn
Moore, Ben D.
Phalen, David
Rhodes, Jonathan R.
Todd, Charles
Desley, Whisson
McAlpine, Clive A.
Title Use of expert knowledge to elicit population trends for the koala (Phascolarctos cinereus)
Formatted title
Use of expert knowledge to elicit population trends for the koala (Phascolarctos cinereus)
Journal name Diversity and Distributions   Check publisher's open access policy
ISSN 1472-4642
Publication date 2016-03-01
Year available 2016
Sub-type Article (original research)
DOI 10.1111/ddi.12400
Open Access Status Not Open Access
Volume 22
Issue 3
Start page 249
End page 262
Total pages 14
Place of publication Chichester, West Sussex United Kingdom
Publisher Wiley-Blackwell Publishing
Language eng
Formatted abstract

The koala is a widely distributed Australian marsupial with regional populations that are in rapid decline, are stable or have increased in size. This study examined whether it is possible to use expert elicitation to estimate abundance and trends of populations of this species. Diverse opinions exist about estimates of abundance and, consequently, the status of populations.


Eastern and south-eastern Australia


Using a structured, four-step question format, a panel of 15 experts estimated population sizes of koalas and changes in those sizes for bioregions within four states. They provided their lowest plausible estimate, highest plausible estimate, best estimate and their degree of confidence that the true values were contained within these upper and lower estimates. We derived estimates of the mean population size of koalas and associated uncertainties for each bioregion and state.


On the basis of estimates of mean population sizes for each bioregion and state, we estimated that the total number of koalas for Australia is 329,000 (range 144,000–605,000) with an estimated average decline of 24% over the past three generations and the next three generations. Estimated percentage of loss in Queensland, New South Wales, Victoria and South Australia was 53%, 26%, 14% and 3%, respectively.

Main conclusions

It was not necessary to achieve high levels of certainty or consensus among experts before making informed estimates. A quantitative, scientific method for deriving estimates of koala populations and trends was possible, in the absence of empirical data on abundances.
Keyword Bioregions
Delphi process
Expert elicitation
Koala populations
Phascolarctos cinereus
Threatened species
Q-Index Code C1
Q-Index Status Provisional Code
Institutional Status UQ

Document type: Journal Article
Sub-type: Article (original research)
Collections: School of Geography, Planning and Environmental Management Publications
Global Change Institute Publications
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Citation counts: TR Web of Science Citation Count  Cited 4 times in Thomson Reuters Web of Science Article | Citations
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Created: Tue, 12 Apr 2016, 03:14:33 EST by Dr Clive Mcalpine on behalf of School of Geography, Planning & Env Management