Threats discussion
In the peer-reviewed scientific literature there is wide agreement that the major threat to mammal diversity and biodiversity worldwide is loss, degradation and fragmentation of habitats. This clearly also applies to our western ringtail possum. The decline of their habitat/food trees for various reasons including climate change is part of this.
Anthropogenic fragmentation associated with fire regimes, feral animals and other disturbances such as timber harvesting are less obvious but potentially equally as detrimental as fragmentation through land clearing. (Bain et al, 2015)
Predation plays a particular role as it is a threat in its own rights and in addition it ‘finishes off’ those weakened by other threatening processes. Predation pressure is not limited to foxes and feral cats but includes many more such as domestic dogs, pythons, raptors, ravens and people.
There is no doubt that feral cats have a particularly devastating influence on small mammals such as our possum, however it was mere political propaganda when the first Threatened Species Commissioner claimed that they are the single biggest threat to mammals and that “according to the science, the threat of feral cats is almost three times higher as a driver of extinction for our mammals than habitat degradation” (Busselton/Dunsborough Times 24/02/2017).
I cannot find any documented science that would agree with him. Predators including cats are a habitat feature – no more, no less – and should be seen as such in combination with all the other important habitat features.
If you do not have food, water and shelter, you will die! Does it really matter which side aspect will eventually kill you? Some Busselton ringtails translocated to the peppermint and fresh-water-less Perup Nature Reserve died in the first few months even though they were in a cat (and fox-free) enclosure.
I completely agree that we should minimise the number of feral cats as drastically as we possibly can, however if we simultaneously go on with the destruction of the last adequate habitat patches western ringtails will go extinct. No political spin can change that!
The same commissioner also claimed in an ABC interview that we now have cat-specific bait – Curiosity. I could not get any confirmation from scientists that it is cat-specific and published research found the encapsulation of the poison (which is still in the experimental stage) has not deterred other non-target species from taking it.
It is almost funny that at the same time another bait – Eradicat – which uses another poison and another application form was also hailed as the break-through that will eradicate feral cats. The former WA Environment Minister and the (now former) federal Threatened Species Commissioner seemed not to talk with each other even though they represented the same party.
It is also very unhelpful when wildlife rehabilitators then jump on the bandwagon and proclaim that in Busselton 1-2 ringtails are killed or injured by FERAL cats per week. (also BD Times 24/02/2017) Misrepresenting neighbour’s moggy as a feral cat could endanger the eradication program as it is this type of hype and misinformation that frightens people that their domestic cats will be targeted and harmed.
Again, there is no doubt that domestic cats that are allowed to roam free cause death and injury to ringtails, but responsible cat ownership is a completely different topic to feral cats.
Disease is a major issue and one that is linked with other threats in particular climate change. Investigations without an outbreak of a specific problem can only be hit-and-miss as we do not know yet which specific health risks our ringtails are facing. With limited funding, we tend to look at those with zoonotic potential first no matter how negligible their likelihood may be. Discovering diseases in ringtails that are already confirmed as affecting other species badly (e.g. chlamydia in koalas) would be an important finding, but again, the likelihood is low. The only disease investigation for ringtails so far therefore could not find any evidence that disease limits translocation success. (Clarke, 2011) However, I would argue that this was just due to the choice of diseases for investigation and that this study has still given us valuable insights by pointing out that increased white blood cell counts prior to translocation decreased their survival chances significantly. Low level inflammation or the presence of so far unidentified pathogens could be major reasons for the animals’ death and predation might only have ‘finished them off’. Weak animals in bad body condition are clearly more at risk of predation. Unfortunately there was no follow-up on this finding – another lost opportunity.
Strangely whenever disease is discussed in public in regards to ringtails, it is usually toxoplasmosis. Ringtail investigations were mostly done in connection with translocations. Reviewing the available documentation, I could only find 1 confirmed case and 1 likely case of toxoplasmosis in ringtails in about 25 years. However in my own 12 years history as a wildlife rehabilitator I suffered through at least 3 ‘outbreaks’ of toxoplasmosis in ringtails in care. Every animal with hind leg weakness, neurological symptoms or blindness was declared to be affected by the parasite. Not a single case has ever been confirmed but this does not deter carers to claim in various newspaper articles that the disease is often responsible for the death of possums.
I assume that people spreading this kind of misinformation and that way displaying a severe lack of any knowledge are those seen as a threat to the survival of the species. However, exclusively the unregulated relocation of ringtail possums has been singled out in the Recovery Plan (WRP Recovery Plan, 2017) even though release is only the last step of an unregulated process.
There is however also a small number of very knowledgeable and conscientious people caring for ringtails – some with professional background some autodidacts – whose expertise could add major value to research and help close the severe gaps in knowledge.
An evidently strong bias to pick and choose what we accept as knowledge and who we listen to makes this close to impossible.
According to the Recovery Plan physiological dysfunctions have been observed by ‘some wildlife carers’. It is not scientifically validated but may be worthy of investigation.
There are veterinary records, radiographs, surgery documentations, laboratory analyses, necropsy reports – which obviously are mere ‘anecdotal’ evidence. Luckily a distinguished scientist reported those incidents as they would otherwise have been ignored.
Interestingly the same recovery plan states that there is little evidence to suggest that ringtails have declined in the south coast populations as animals are frequently seen. This ‘fact’ is referenced as personal communication with staff.
Without any quantitative data there is obviously also no evidence that they have not declined, I would call this anecdotal evidence possibly based on wishful thinking.
Undeniably there are 'major gaps in knowledge' and ignorance is probably one of the most dangerous threatening processes, but filling them would not only require significant investment in research but more importantly also a change in attitude.
A PhD project investigating the effectiveness of rope bridges (Yokochi, 2015) was abandoned when the researcher finished her thesis. As the actual investigation only started half- way through the research time due to delays in construction of the bridge, it was by no means finished. The researcher was willing to continue the work, but there was no funding made available. The potential long-term benefits for the species were ignored.
It is not surprising that a majority of planned research projects seem to have been abandoned – e.g. an Ecology and Health study, a study on Fox/Cat interaction, a Habitat Patch assessment and an In-situ assessment at a retirement village in Busselton - and we wonder if this was due to inadequate support.
Population viability analysis is vital to the assessment of the degree of a species’ threat of extinction. Effective PVAs are based on detailed information on survival and fecundity. Those are not available for western ringtails and for the only PVA we currently have, the researcher had to include data from the common ringtail possum with higher fecundity and several characteristics that make it likely that the species will stay common in the future. However, this means that we use parameters of a common species to investigate extinction risk for a critically endangered species – a contradiction in itself.
Some of the available research data for ringtails were compiled in the early 90s. As the environmental conditions have changed significantly, reliance on these possibly outdated ‘facts’ might lead to inaccuracies in new research.
Today’s very popular information theoretic approach still requires correct ‘empirical data’ to deliver anything of benefit. Not every problem can be solved mathematically.
There also seems to be a risk that a mere hypothesis or worse an assumption is repeated by others and the more often it is stated, the more it turns into a ‘fact’.
The number of feral cats in Australia is a prime example. After a scientist stated that according to an anonymous newspaper article from New Zealand there were 18 million feral cats in Australia in 1996, the figure was repeated as the scientist’s own estimate and then spread through various media reports as scientific fact. We still do not have any reliable estimates of cat numbers but we are going to cull 2 million of them? (Doherty, 2014)
A governmental Strategic Review into ringtail possum habitat in the Swan Coastal Plain produced mainly unhelpful and superficial findings. It was confirmed that high occupancy relies on mature, well established canopy free from fire for more than 20 years and on foliage high in nutrient levels particularly nitrogen and low in secondary metabolites. We have known all this for 2 decades. (Legislative Council, Question on Notice No. 5209, 06/03/2012)
If those should truly be the results of such a lengthy (10 years) review, then this was an extreme waste of taxpayers’ money. As the same agency would be employed to implement the Recovery Plan, we need to be wary of not repeating this waste.
The emphasis on DPaW or now DBCA staff for all actions is highly worrying as the agency is severely understaffed, under-resourced, and so far unable to halt the decline trend of the species.
The big question here is whether any funds available will be invested in the most urgent research projects or used for operational costs while the species’ decline continues.
Departmental work seems to have shifted away from the focus on science and conservation and towards nature-based tourism which manifested itself in the former name ‘Parks and Wildlife’ and now in the inclusion of ‘Attractions’. Nature-based tourism is a billion-dollar industry while conservation is a costly uphill battle.
The recent public sector reform has combined former DPaW with Botanical Gardens and Parks Authority, the Zoological Parks Authority and the Rottnest Island Authority which is clearly aiming at cutting costs and increasing efficiencies.
However, the trend to outsource ringtail work to the NRM sector is just as worrying.
The scarce research money should be used for systematically addressing the most pressing issues outlined in the Recovery Plan and not be invested in short-term media-attracting conservation actions.
Far too often there is the announcement of sometimes quite substantial amounts of grant money for ringtail possum work given to a Catchment Group but there rarely seems to be a final report on what this money achieved. It mainly seems to be used for the employment of community chat group facilitators and for community planting days.
Watering of the plants, removing of the protective bags in scorching sun or evaluation of success or failure seems outside the funding. Requirement for accountability looks very low.
However, the Department of Water appears more active in western ringtail possum conservation projects than the department officially in charge of flora and fauna – DpaW/now DBCA.
There is obviously still significant grant money for biodiversity conservation on private and public land available, but the bureaucratic process - e.g. short time frames, preference given to groups that are basically government in disguise - seems to benefit political objectives instead of biodiversity.
Paired with an increase in land-clearing based on the erosion of - mainly federal - safeguards, the situation looks bleak.
As early as 2002 a senior zoologist warned that a lack of a strategic approach and of critical evaluation of actions by all decision makers could be a threat to the long term viability of ringtail populations in the core area. (De Tores, 2002)
16 years later, fiscal agendas dominate politics and the population is now well ‘trained’ to accept spin and misinformation. Ideology, emotions and belief systems are more important for decision making than scientific facts and our natural world is regarded as a mere resource to be exploited.
This is far bigger than the ‘ringtail issue’. It is not the economy that sustains us, it is our natural world. Our treasured economy is just a human invention that sadly now rules/governs human kind.
Maybe this irrationality is the biggest threat to the survival not only of ringtail possums but of all wildlife – and ultimately of our own species.
