Using repeat citizen science surveys of koalas to assess their population trend in the north-west of New South Wales: scale matters
Martin Predavec A D , Daniel Lunney A B , Ian Shannon A , John Lemon C , Indrie Sonawane A and Mathew Crowther B
+ Author Affiliations
- Author Affiliations
A Science Division, Office of Environment and Heritage NSW, PO Box 1967, Hurstville, NSW 2220, Australia.
B School of Life and Environmental Sciences, University of Sydney, NSW 2006, Australia.
C JML Environmental Consultants Pty Ltd, 9127 Kamilaroi Highway, Gunnedah, NSW 2380, Australia.
D Corresponding author. Email: martin.predavec@environment.nsw.gov.au
Australian Mammalogy 40(1) 47-57 https://doi.org/10.1071/AM16059
Submitted: 30 November 2016 Accepted: 17 March 2017 Published: 19 May 2017
Abstract
Scale matters when assessing population trends. Whereas traditional field-based ecological surveys are generally restricted to small temporal and spatial scales, community (citizen science) surveys allow wider consideration of population trends. We used repeat community surveys (completed in 2006 and 2015) to assess population change in koalas (Phascolarctos cinereus) across an area of 36 900 km2 in the north-west of New South Wales. In both community surveys we asked respondents to record the location of their koala sightings as well as those of eight other common species. We further asked respondents about their perceptions of population change. Through three different measures (likelihood of koala occurrence, number of koalas observed per respondent, and the perception of population change), we found that koala numbers were declining across the region during the study period. The timing and broad and consistent geographic spread of the decline suggests that broad-scale environmental factors, such as weather, are important drivers of this change. This information will allow managers to place conservation efforts into an appropriate spatial context. While such information sourced from the community can provide critical information on threatened species, including the koala, this study highlights the limits of such information.
Additional keywords: community wisdom, population cycles, population decline, Phascolarctos cinereus, refuges.
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