This article relates to the ongoing debate on Australian Rural & Regional News: Open for Debate: Koalas

Australian Rural & Regional News sought an update on koala monitoring from NSW DPI Principal Research Scientist, Dr Brad Law.

Dr Law co-authored the report, NSW Forest Monitoring and Improvement Program (May 2022) which found that (at vi):

“An analysis of recent trends in Koala occupancy in hinterland forests of north-eastern NSW, where surveys targeted their habitat and were based on recordings of Koala calls, provided greater precision and higher estimates of occupancy (averaging 68% ± 7%). This recent trend shows a stable meta-population over the last 5 years, including after fires burnt 30% of Koala habitat in 2019.”

ARR.News asked Dr Law about this finding, which appears to be inconsistent with the current general and political view as portrayed in the mainstream media that koala numbers are in serious decline and at current rates they will be extinct by 2050.

ARR.News asked Dr Law how representative he believed this trend to be, across NSW and the country more widely.

ARR.News also asked Dr Law about his thinking as to the relationship of timber harvesting to koala populations.

Dr Law gave the following response:

Since 2014, scientists from the NSW Department of Primary Industries Forest Science Unit (DPI Forest Science) have been undertaking extensive research on koalas in hinterland forests of north-east NSW. This period includes the Black Summer of 2019/20, when the worst bushfires on record swept across more than 5 million hectares of NSW and impacted heavily on koala habitat in the study area.

The area is large, encompassing more than 1.7 million hectares of better quality koala habitat, and much of it is in National Park and State Forest.

Some of the investigations have been done as part of a program of scientific research under the NSW Koala Strategy. Part of the program has oversight by the NSW Natural Resources Commission (NRC) under the guidance of a steering committee including NSW agencies and a panel of independent scientific experts from leading universities.

While DPI Forest Science research is ongoing, several significant pieces have now concluded, with the findings published this year in peer-reviewed scientific literature and available on the DPI or NRC websites: https://www.dpi.nsw.gov.au/forestry/science/forest-ecology/koala-research-in-nsw-forests and https://www.nrc.nsw.gov.au/koala-research.

Key points from the DPI Forest Science research are:

• New acoustic survey methods have demonstrated koalas occur more commonly throughout the north-east hinterland forests than previously appreciated. These new methods are now being rolled-out across the state as part of the Koala Strategy by the NSW Department of Planning and Environment. They are also being applied to other species.
• Annual monitoring of koala occurrence in hinterland forests since 2015 has found a stable trend over time at a regional level. Trend data are generally not available from other regions, although koala populations clearly crashed in the Pilliga forests over 10 years ago with heat and drought.
• Intensive, localised studies found that moderate to high severity fire during the Black Summer fires had a major impact on koala density, but low severity fire had no detectable effect. Clearly, intense uncontrolled wildfires are a major threat to koalas.
• A parallel study found that regulated timber harvesting had no significant impact on koala density. Timber harvesting in NSW is undertaken under regulations that aim to achieve ecological sustainability by mitigating impacts to the environment. One key practice is excluding harvesting from 50-60 per cent of the State forest landscape. This provides a mosaic of forest with different age classes that provides habitat and refuges for biodiversity after harvest, especially while the forest regenerates. Additional browse trees for koalas are also retained in harvest areas where a koala habitat map identifies suitable areas, which has increased the level of protection for koalas compared to past practices.
• Koalas occur widely on private land in north-east NSW and this tenure represents about 50 per cent of koala habitat in the region, so it is very important for koala conservation.
• GPS-tracking of individual animals in a forestry landscape found that males and breeding females use the broad landscape, including young trees regenerating from timber harvesting and mature forest set aside from harvesting. Koalas were not transient in these forests as has sometimes been suggested. These results provide further support for the acoustic studies outlined above.

These findings in no way suggest that concerns about the status of the koala in the wild are unfounded, or that they are not now absent, rare or declining in some areas. Rather, it is important to acknowledge and respond to the very real threats that koalas suffer in different parts of their range. While habitat clearing, cars and roads, dogs, disease and fire are demonstrated, well-known threats to the koala, this research indicates that timber harvesting as practised under the comprehensive rulesets applying in the native forests of north-east NSW, is not.

Dr Brad Law
Principal Research Scientist
DPI Forest Science

Key DPI Forest Science references

Law BS, Brassil T, Gonsalves L, Roe P, Truskinger A, McConville A (2018) Passive acoustics and sound recognition provide new insights on status and resilience of an iconic endangered marsupial (koala Phascolarctos cinereus) to timber harvesting. PLoS ONE 13(10): e0205075. https://doi.org/10.1371/journal.pone.0205075
Law, B. S., Gonsalves, L., Burgar, J., Brassil, T., Kerr, I., & O’Loughlin, C. (2022a). Fire severity and its local extent are key to assessing impacts of Australian mega-fires on koala (Phascolarctos cinereus) density. Global Ecology and Biogeography, 00, 1–13. https://doi.org/10.1111/geb.13458
Law, B., Gonsalves L., Burgar J., Brassil T., Kerr I., O’Loughlin C., Eichinski P., Roe, P. (2022b) Regulated timber harvesting does not reduce koala density in north-east forests of New South Wales. Nature Scientific Reports.
Law, B., Kerr, I., Gonsalves, L., Brassil, T., Eichinski, P., Truskinger, A., & Roe, P. (2022c). Mini-acoustic sensors reveal occupancy and threats to koalas Phascolarctos cinereus in private native forests. Journal of Applied Ecology, 59, 835– 846. https://doi.org/10.1111/1365-2664.14099
Law B., Slade C., Gonsalves L., Brassil T. Flanagan C., Kerr I. (2022d) Tree use by koalas after timber harvesting in a mosaic landscape. Wildlife Research.  https://doi.org/10.1071/WR22087