Garry of Liffey

So …….. old growth forest is just a sub-set of the total forest area, which as I said earlier, still occupies 97% of its modelled pre-European area. Fire is by far the greatest impact on the structure and age of these forests. About 80% of the mountain ash was burnt by the combined 1926 and 1939 bushfires, and that is why the forest is dominated by 80 year old stands. About 10,000 ha of old growth was burntin 2009, leaving just 1800 ha.

Aidan

"However the way you've phrased it does appear to be designed to mislead. So please be a bit more specific: since 2014, how many LBP colonies have been found in regenerating areas after logging?"

I'm told that dozens have been detected in the regrowth following the 2009 bushfires and in recent logging, but you will have to look in the Victorian Biodiversity Atlas to get an exact number.

Thanks, Mark. The threatened-species-scientific-committee, established under the EPBC has provided Conservation Advice to the Minister who has approved this advice and retained the Leadbeaters-Possum (LBP) in the Critically-Endangered category, effective from 22 June 2019.

The Committee’s advice is here: https://tinyurl.com/y2ecrnbw

It lists the following as threats to the LBP:

Habitat loss and fragmentation:
- collapse of hollow bearing trees, extensive wildfire, logging and climate change.

Invasive species:
-predation by feral cats, competition for nest hollows with Sugar Gliders

It establishes that the number of hollow-bearing trees (HBTs) may be used as an index for the number of LBPs. Decline in the number of HBTs is likely to produce decline in the number of mature individuals in the LBP population. The Committee, noting new areas of distribution had been found, observed that since this population is also exposed to wildfire and harvesting “its discovery does not substantially alter the risk of extinction for the species.”

The Committee estimated that between 2000-2018 some 13360 hectares of habitat were lost due to harvest. In that period, it is calculated that HBTs decline due to logging, fire and ‘ambient’ decline was between 54.8% and 59.5%. Using the data (pp 11&12), it seems that in this period logging reduced the number of HBTs by 7.7%

The Committee projected in the period 2018-2038, decline of LBP potential-habitat could be 72.9% For this calculation, the maximum estimate of fire-induced decline was used: 50%. (This figure was adopted due to recognition that “both modelled projections and weather observations over past decades show with a high degree of certainty that extreme fire weather will increase in frequency over the next three generations and beyond” and that due to the 1939, 1983 and 2009 fires, more than 98% of the habitat is in a state of regrowth and “hence of elevated flammability”. The decline in potential-habitat due to logging was calculated to be 4.9% over that period.)

Similarly using logging, fire (50%) and ambient decline for the period 2006-2024, HBTs are projected to have declined by approximately 83.4%. It is this figure which has confirmed/strengthened the critically-endangered listing.
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To sum up: Logging has contributed to the decline of HBTs/LBPs, while the 1939, 1983 and 2009 fires are seen to be the greater factors.

At the end of the Conservation Advice document, the section ‘Conservation actions’ allows for timber harvesting to continue following negative pre-harvest surveys and thus, in spite of its own analysis of having a causal role in the decline of the HBTs/LBPs, it allows for logging to continue to have a role in the reduction of the populations of this critically endangered species.

It is surprising that a Great Forest National Park was not included as an action that would help to arrest the decline. Surprising too is that although extensive wildfire/climate change is/are identified as impacting on the Leadbeater’s Possum, tackling climate change is not included among the list of conservation actions to be taken to protect the species.

Latest news (via the ABC) is that this last month of June was the hottest June ever recorded globally (according to NASA). Sure, we have to ‘act local’ to conserve this species, but also we have to act global.

Garry in Liffey

I am all too aware of all this, and the Institute of Foresters of Australia is currently preparing a critique of the TSSC's undated Consultation Document, which was in fact a report produced in response to a review of the LBP's critically endangered status agreed to in Sept 2017. As such, the TSSC had invited interested parties to submit new evidence given that that improved surveying techniquies were finding the possum to be far more numerous and resilient and widespread than anyone could have predicted. This includes finding them living in other forest types up to 15km outside there previously known mountain ash forest range.

Unfortunately, it is clear that the TSSC has ignored much of this new evidence, including the expansion of its known range into other forest types and does not acknowledge the 200 recent detections found since 2017. Furthermore it uses a worst-case assumption that 50% of the mountain ash forests will be burnt over the next 20 years, even though the study which it relies upon for that figure says that 20% burnt is the most likely reality.

It also takes no account of the fire threat mitigation benefit of continuing timber production and ignores the fact that 70% of the mountain ash forests are already reserved. The estimated decline of hollow bearing trees assumes total loss due to logging and bushfire, despite the reality that some/many trees are retained or survive, especially after fire.

Given the threat of climate change, it would make no sense to close an industry that produces renewable materials, and which makes a major contribution to addressing the bushfire threat.

From memory, Mark, the Conservation Advice [ https://tinyurl.com/y2ecrnbw ] mentioned increased sightings and raised these in the context of new techniques being used. I believe the conservation advice made the point that the increase in sightings was not necessarily indicative of an increase in populations, but rather was possibly a function of the newer techniques being better able to locate individuals/colonies which, when the ‘older’ techniques were being used, had been going ‘under the radar’.

The other part of the Conservation Advice that (in my view) throws some light on this question of increased sightings is the ‘index’ that I mentioned in my previous comment. In other words, it seems counter-intuitive to conclude populations are increasing while the number of hollow-bearing trees is decreasing. I also believe the Conservation Advice mentioned that the species is still in overall decline, while the new techniques simply give a picture of a species whose numbers and range is apparently/possibly greater than previously known.

I’m sorry that I’ve not had time/space to comment on your ‘Four Corners is past its use-by date’ thrust. From my limited understanding of the Leadbeater’s Possum issue, and having viewed the program online (after reading your article) I’d not support closing the program down. However, I would have thought that you should have been included on the program: you have made ongoing and relevant contributions to the ‘forestry vis a vis conservation’ debate for quite some years now.