Australian Rural & Regional News asked some further questions of Vic Jurskis, set out and answered below the article. This article relates to the ongoing debates on ARR.News into Koalas and also into Bushfires, Logging, Burns & Forest Management.

Vic Jurskis

Dear Editor,

The principles of monitoring animal numbers are no different for koalas or beetles.

Monitoring should not be an end. But the first step should always be to look at historical information. They are irruptive animals which sometimes occur in plagues. Koalas and Christmas beetles have both gone through booms and busts in the same places at the same times for the same reasons.

A 9 News article last month also advertised Professor Latty’s Christmas beetle count project.

It said “They were so prevalent in the ’60s and ’70s, the CSIRO blamed them for the deaths of great swathes of eucalyptus trees”. Beetles were blamed for so-called New England Dieback which started with massive expansion of improved pastures supported by post-war fertiliser subsidies. It increased through the sixties and seventies and peaked in the 1980s.

I wrote in my Ecological History of the Koala that: “According to CSIRO surveys, the highest known density of koalas in New South Wales during the 1980s occurred in trees retained in an improved pasture in the New England region (Braithwaite 1993), where so-called New England Dieback was well advanced (Jurskis and Turner 2002; Jurskis 2005)”.

Figures 1 and 2 in my Ecological History show a sign indicating an irruption of koalas in a pastoral area and evidence, underneath the sign, of simultaneous irruptions in Christmas beetles and psyllids. This was in January 2017. Koala overbrowsing is now blamed for historic ‘dieback’ of eucalypts on French Island early last century. Fisheries and Game Inspector Fred Lewis was there at the time and noted that species not eaten by koalas were plagued with insects and were also dying.

Modern koala experts say that Lewis was wrong.

The article on ARR.News mentions irruptions of beetles in eucalypt plantations at Kyogle. Previous articles in ARR.News have mentioned plagues of koalas in Victorian eucalypt plantations.

I emailed Professor Latty to suggest that a perceived recent decline in beetles can be explained by loss of unnaturally good habitat. Moist, rich soils, full of fine roots under improved pastures, are prime habitat for beetle grubs. Declining trees in pastures, continually resprouting soft and nutritious leaves, are prime habitat for adult Christmas beetles. But after the 1980s peak of rural tree decline in improved pastures, most of the older trees died.

Beetles have generally declined to more natural levels. But irruptions are still occurring where lots of young trees or lots of declining trees occur near pastures. I haven’t yet received any reply from Tanya Latty. If I do, I will suggest that any analysis of beetle numbers needs to be in the context of both history and ecology. Also, that data from ‘citizen science’ is inherently biased. For example, most casual koala sightings occur on relatively busy roads.

Citizen science cannot test the hypothesis that beetles are declining, because they are going through boom and bust in different places at different times. It can’t explain any perceived changes. But that’s not really a problem. Irruptions of various animals have occurred in Australia since Europeans disrupted Aboriginal burning and established improved pastures in the 19th Century (e.g. Curr 1883, MacPherson 1886, Norton 1887, Howitt 1891).

Howitt identified disruption of Aboriginal burning as the ultimate cause of eucalypt declines which were apparently caused by folivores. Though he didn’t correctly identify the underlying processes, this deficiency has since been rectified by further observations and ecological research (e.g. see Ellis et al. 1980; Landsberg 1985; Landsberg et al. 1990; Jurskis & Turner 2002; Jurskis 2005, 2015, 2016, 2017, 2020; Turner et al. 2008; Close et al. 2011; Jurskis et al. 2011; Horton et al. 2013; Baker 2015; Dijkstra & Adams 2015).

Perceptions that Christmas beetles and koalas are in decline are incorrect. Governments are spending large amounts of our taxes supporting poorly designed research of questions that have already been answered. This includes research of not-so-cute irruptive native animals and plants that are recognised as pests.

I freely provided peer-reviewed information included above and much more to NSW Natural Resources Commission, who were considering the allocation of funds to researchers supposedly “Untangling the causes of tree dieback”. The Commissioner preferred the findings of an unrefereed report by a couple of forest pathology specialists from WA. NRC paid Murdoch University for the report to help them decide how to distribute $1.3 million for further research.

The conclusions of academic research and monitoring seem to always be that we need to do more research and monitoring. But it’s blindingly obvious to anyone who has lived and worked in the bush that we need sustainable fire management across the whole landscape to reinstate forest health and safety, resilience and biodiversity.

Fairdinkum science and traditional knowledge of experienced bushies of all races concur.

Questions

Vic Jurskis: Dear Editor,

Thank you, once again, for the opportunity to answer your questions. I think ARR.News is lonely in its efforts to investigate issues.  

ARR.News: You say, “Koalas and Christmas beetles have both gone through booms and busts in the same places at the same times for the same reasons” and “Beetles have generally declined to more natural levels” and “… suggest that a perceived recent decline in beetles can be explained by loss of unnaturally good habitat” and “Perceptions that Christmas beetles and koalas are in decline are incorrect”.

These statements appear contradictory. Are you arguing that Christmas beetles have declined or not declined?

Vic Jurskis: I stated that “Beetles have generally declined to more natural levels. But irruptions are still occurring where lots of young trees or lots of declining trees occur near pastures.”

ARR.News: Further, if koalas and Christmas beetles boom and bust together, and Christmas beetles have either reduced in number or unnaturally declined, this contradicts your repeated argument that koalas are irrupting and supports the view that koalas are in decline.

Vic Jurskis: I stated that “Koalas and Christmas beetles have both gone thru booms and busts in the same places at the same times for the same reasons”. I did not imply that this was invariably the case. I have provided evidence that koalas are irrupting in some places and crashing in others. So are Christmas beetles. I did not imply that fluctuations in koalas and beetles were in sync everywhere.  

Koalas lived in forests, Christmas beetles lived in grassy woodlands. Lock it up and let it burn conservation policies have increased the carrying capacity for koalas whilst choking out open grassy habitats. Christmas beetles are in no danger because their grubs can feed in exotic pastures. But many other plants and animals are, because they rely on the diverse native groundlayers that are disappearing.

ARR.News: Alternatively, do you believe that a decline in Christmas beetles could mean that if – as you have said – koalas are irrupting, a die back of koalas is imminent?

Vic Jurskis: I tried to explain that there has not been a decline in Christmas beetles or koalas compared to natural levels. Unsustainably dense koala sub-populations will inevitably crash in future droughts as they have in the past.

ARR.News: You say that the koala sign indicates an irruption and that the Christmas beetles underneath indicate an irruption in the same area. However, this is simply your conclusion. Koala signs are not by themselves evidence of an irruption; they could for instance, simply indicate that a koala colony had been nearby at one time. Likewise, six Christmas beetles is not an irruption.

Vic Jurskis: It is a new sign. If koalas are visible, they are in unnaturally high densities. If they haven’t been seen for years, it means that they are probably back down to sustainable densities.

There are six dead beetles in the pic, in a fraction of a square metre. (I turned some right way up to make them visible.) Scaling it up translates to thousands of dead beetles per hectare. If you look at the lerps on the aborted leaves (each lerp covered a sap-sucking psyllid), they probably average about 20 per leaf. That scales up to millions.

ARR.News: You say, “The article on ARR.News mentions irruptions of beetles in eucalypt plantations at Kyogle. Previous articles on ARR.News have mentioned plagues of koalas in Victorian eucalypt plantations.”

This is incorrect. The article does not mention “irruption”. Again, this is your conclusion. Nor have any articles on ARR.News mentioned “plagues” of koalas in Victorian eucalypt plantations.

Vic Jurskis: From the article on ARR.News: “Many locals will remember the swarms of 2014-2015, where you could fill buckets with Christmas beetles under a single eucalypt in Kyogle. Tree farms were defoliated and residents were concerned by the mysterious eucalyptus dieback”. By any definition, that’s an irruption.

Yes, plagues is my word, but you [Ed: published an earlier article by Vic Jurskis in which he states]: “In Victoria and South Australia, where TSSC recognises that koalas are an irruptive species (this is the exactly the same species as in NSW and Qld), wildlife carers want to protect koalas by stopping harvest of timber plantations [ABC article]. There are apparently 50,000 koalas in areas that had none when Europeans arrived.”

ARR.News: You say, “Beetles have generally declined to more natural levels.” The article says that none have been seen in Kyogle. Surely none is not a natural level.

Vic Jurskis: No. This is what the article says: “The drought took hold and the tree farm was returned to pasture. We saw less Christmas beetles, and they appeared later each year. We found only one beetle in late December 2019 after the fires, and none in 2020-21. One brave latecomer was seen to arrive in March this year, closer to Easter than Christmas.” [and “November has come and gone in Unumgar without the sighting of a Christmas beetle.”]

ARR.News: You say, “Citizen science cannot test the hypothesis that beetles are declining …” Surely citizen science can be helpful in collecting data to help establish a baseline that may help show changes over time?

Vic Jurskis: No. A ‘baseline’ would be 1788. I explained that beetles “are going through boom and bust in different places at different times”.

Vic Jurskis has written two books published by Connor Court, Firestick Ecology and The Great Koala Scam. 

References

Baker, E. 2015 The worldwide status of phasmids (Insecta: Phasmida) as pests of agriculture and forestry, with a generalised theory of phasmid outbreaks. Agriculture and Food Security  4, 22. DOI 10.1186/s40066-015-0040-6
Close, D.C., Davidson, N.J., Swanborough, P.W., Corkrey, R. 2011 Does low intensity surface fire increase water- and nutrient-availability to overstorey Eucalyptus gomphocephala? Plant and Soil 349, 203-14.
Curr, E.M. 1883 Recollections of Squatting in Victoria, Then Called the Port Phillip District, from 1841 to 1851. Facsimile Edition 1968. George Robertson/ Libraries Board of South Australia, Melbourne/Adelaide.
Dijkstra, F.A., Adams, M.A. 2015 Fire eases imbalances of nitrogen and phosphorus in woody plants. Ecosystems online https://link.springer.com/article/10.1007/s10021-015-9861-1
Ellis, R.C., Mount, A.B., Mattay, J.P. 1980 Recovery of Eucalyptus delegatensis from high altitude dieback after felling and burning the understorey. Australian Forestry 43, 29-35.
Horton, B.M., Glen, M., Davidson, N.J., Ratkowsky, D., Close D.C., Wardlaw, T.J., Mohammed, C. 2013 Temperate eucalypt forest decline is linked to altered ectomycorrhizal communities mediated by soil chemistry. Forest Ecology and Management 302, 329-37.
Howitt, A.W. 1891 The eucalypts of Gippsland. Transactions of the Royal Society of Victoria II, 81-120.
Jurskis, V. 2005 Eucalypt decline in Australia, and a general concept of tree decline and dieback. Forest Ecology and Management 215, 1-20.
Jurskis, V. 2015 Firestick Ecology: Fairdinkum Science in Plain English. Connor Court Pty Ltd.
Jurskis V. 2016 ‘Dieback’ (chronic decline) of Eucalyptus viminalis on the Monaro is not new, unique or difficult to explain. Australian Forestry  79, 261-4.
Jurskis, V. 2017 Ecological history of the koala and implications for management. Wildlife Research  44, 471-83. doi.org/10.1071/WR17032
Jurskis, V., Turner, J., Lambert, M., Bi, H. 2011 Fire and N cycling: getting the perspective right. Applied Vegetation Science 14, 433-4.
Jurskis, V. 2020 The Great Koala Scam: green propaganda, junk science, government waste and cruelty to animals. Connor Court Publishing, Redland Bay. 
Jurskis, V., Turner J. 2002 Eucalypt dieback in eastern Australia: a simple model. Australian Forestry 65, 81-92.
Landsberg, J. 1985 Drought and dieback of rural eucalypts. Australian Journal of Ecology 10, 87-90.
Landsberg, J., Morse, J., Khanna, P. 1990 Tree dieback and insect dynamics in remnants of native woodlands on farms. Proceedings of the Ecological Society of Australia 16, 149-65.
MacPherson, M.A. 1886 Some causes of the decay of the Australian forests. Journal of Proceedings of the Royal Society of N.S.W. XIX, 83-96.
Norton, A. 1887 On the decadence of Australian forests. Proceedings of the Royal Society of Queensland 1886 III, 15-22.
Turner, J., Lambert, M., Jurskis, V., Bi, H. 2008 Long term accumulation of nitrogen in soils of dry mixed eucalypt forest in the absence of fire. Forest Ecology and Management 256, 1133-42.