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RESEARCH ARTICLE (Open Access)
Contents Vol 31(3)

Response of a koala (Phascolarctos cinereus) source population following a large-scale progressive translocation harvest

John Callaghan https://orcid.org/0000-0001-6652-7866 A B C * , Stephen Phillips B and Ross Goldingay A
+ Author Affiliations
- Author Affiliations

A Faculty of Science and Engineering, Southern Cross University, Lismore, NSW 2480, Australia.

B Biolink Ecological Consultants, Uki, NSW 2484, Australia.

C City of Gold Coast, Gold Coast, Qld 4212, Australia.

* Correspondence to: koalafutures@gmail.com

Handling Editor: Kate Bryant

Pacific Conservation Biology 31, PC25001 https://doi.org/10.1071/PC25001
Submitted: 3 January 2025  Accepted: 2 May 2025  Published: 27 May 2025

© 2025 The Author(s) (or their employer(s)). Published by CSIRO Publishing. This is an open access article distributed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License (CC BY-NC-ND)

Abstract

Context

Translocation is an important tool for species conservation. However, comparatively few translocation programs have investigated the impacts on source populations. The distribution and size of a koala (Phascolarctos cinereus) population occupying a rapidly urbanising landscape in south-east Queensland, Australia were investigated before and after progressive removal of koalas.

Aims

This study investigated how the population responded following translocation of 166 koalas over a 5-year period concomitant with loss of habitat.

Methods

Baseline surveys conducted in 2006 were compared to post-translocation surveys of the same area in 2017. Survey sites were located on a grid positioned over the study area. Sites were sampled using scat surveys to measure koala activity and fixed-radius searches for koalas to estimate population density.

Key results

The koala population size estimated in 2017 (440 ± 66 s.e.) was not markedly different to that for 2006 (510 ± 67 s.e.), with koalas occupying remaining habitat at similar density. The analysis did not identify any significant change in occupancy between survey periods. Estimates of the probability of detection were high in both periods with the preferred tree species group having values >0.8. Naïve occupancy estimates from raw field data were consistent with that predicted by modelling.

Conclusions

The results suggest that relatively large source populations of koalas can cope with a progressive translocation harvest.

Implications

The population coped better than anticipated. Regardless, monitoring is important as the new town centre is completed. Further management actions may be necessary to support and sustain the remaining population.

Keywords: conservation translocation, correlated replicate surveys, habitat loss, habitat occupancy, mitigation translocation, monitoring, population response, source population.

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