‘Bandicoots live among as in Melbourne’- A response to The Conversation Article

Some Considered Responses to the Article ‘The Conservation – Bandicoots live among as in Melbourne’

 

SBB Cranbourne, Pic by John Chapman

 

https://theconversation.com/rockin-the-suburbs-bandicoots-live-among-us-in-melbourne-95423?utm_source=facebook&utm_medium=facebookbutton

https://www.sciencedirect.com/science/article/pii/S0006320717321262

The study found that bandicoots in peri-urban areas did better in modified habitat, where foxes and cats were abundant, than in remnant native habitat were foxes and cats were also present. I would not call large areas of dense blackberry weeds a ‘NOVEL’ habitat and I also ask, why did some bandicoots have to partially depend on pet food?

On the Mornington Peninsula e.g. in the Frankston area, some 30 years ago, thousands of bandicoots were spread throughout the area. The area contained some native habitat, but mostly modified habitat, including large tracts of blackberry and other weeds. There was also an abundance of foxes and cats and yet, all of the bandicoots are now gone. So, what is the difference here? If it was not the foxes and cats that killed all of the bandicoots, then what else did?

Whatever happened here will surely, albeit slowly, occur in their selected study area. Most of the bandicoots in adjacent large areas of the study area e.g. in Koo Wee Rup, have mostly gone and only a relatively few isolated colonies of bandicoots remain, but for how long?

With regards to there being less SBB in the ‘natural habitats,’ this is subjective as well because depending on the abundance of other species in competition with the SBB for land e.g. wallabies in Cranbourne Botanical Gardens and feral pigs on Quail Island.

This story doesn’t discourage more urban development, nor does it openly insist government improve ongoing fox and cat eradication programs. It doesn’t promote the need for wildlife corridors or predator proof colonies. Protected colonies provide insurance against further, expected losses of bandicoots. The only way bandicoots can now be completely safe is within reserves surrounded by a predator-proof fence, like in the Royal Botanical Gardens in Cranbourne. Similar measures have been used to ensure populations of eastern barred bandicoots.

Hans Brunner, Ecologist

http://www.abc.net.au/news/2016-02-28/survival-of-rare-melbourne-bandicoots-under-threat/7181580

Pic by John Chapman

(See John’s website here: http://www.chappo1.com/brown%20bandicoot.html)

 

 

SBB in the outer suburbs of Melbourne 15th of May 2018.

During spring last year we deployed motion-censored cameras at Settlers Run Golf Course and surrounding precinct, Cranbourne. The camera results indicated that SBB were present through-out the landscape. The reason for their spread is due to the following factors:

  • Royal Botanical Gardens Cranbourne acts like a mother ship for the SBBs due to its predator proof fence and small exit gates that were installed to allow bandicoots to leave the gardens and establish in the surrounding landscape.
  • The gardens conduct fox, cat & rabbit control on a regular basis both inside and outside the predator proof fence.
  • The new precincts that have established around the gardens have been declared cat free sub-divisions.
  • The indigenous habitat that was established post precinct development is ideal for SBBs.

 

The above factors are the reason why we still have SBBs within the Cranbourne area. Since the late 1980’s we have lost SBBs on the Mornington Peninsula, Frankston, and the sand-belt country that runs from Frankston up past Braeside and Oakleigh. We would also have lost the bandicoots at Cranbourne if the RBGC did not establish a predator proof fence around the gardens and conducted intense fox control.

 

Since 2008 I have study the SBB populations at Tooradin, Blind Bight, Canons Creek, Quail Island and Koo Wee Rup. All of these populations are isolated and populations seem to rise and crash due to climatic conditions. At the moment we are witnessing a largish decline in these populations. This is also happening at RBGC (Terry Coates fld. obs.). It is worth noting that since pigs were illegally released on Quail Island they have severely damaged the bandicoot habitat and a large decline in the SBB populations has resulted.

 

DELWP’s recent release of the SBB management plan for the Cranbourne area fails to address the critical scenarios that will keep the last remaining populations viable. They are:

  • No commitment to fox or cat control.
  • Expecting SBBs to disperse along 30m wide corridors which lead to nowhere.
  • Refuse to accept that the only viable way to re-establish SBB populations is to design similar motherships (with predator proof fences and small exit gates) like at RBGC.
  • Not committed to re-establishing SBBs in the Pines Flora & Fauna Reserve and at The Briars Sanctuary.

I feel that rapid climate change and the lack of real commitment from both state & federal governments are the real dangers to the remaining SBB populations.

Malcolm Legg, Ecologist

 

Pic By John Chapman

 

Looking at the Study

The report doesn’t state if they researched what pest animal control local council, or other land managers’ had undertaken in the years prior to their study. I would have thought this information was highly relevant. I could find feral animals mentioned in a few places but the pest eradication of the novel sites wasn’t tested.

Comparative studies can provide a direct contrast of the performance of threatened species in novel vs. historically intact habitats; however, few have been conducted. In a meta-analysis conducted by Shwartz et al. (2014), only three out of 80 studies (~4%) documenting threatened species presence in urban environments explicitly tested the performance of urban populations in comparison to those in nearby more intact remnant habitats. Further research is therefore required to build general understanding of the comparative performance of threatened species between novel and more historically intact habitats.’

‘Exotic animal species were common at novel sites, including potential predators (red fox Vulpes vulpes, domestic dog Canus familiaris, domestic cat Felis catus) and potential competitors (black rat Rattus rattus, European rabbit Oryctolagus cuniculus) of bandicoots ( Schmidt et al., 2009).’

Introduced predators (red foxes, dogs and cats) were also uncommon due to an ongoing integrated pest management strategy at Cranbourne Gardens (Author 2, unpublished data), and physical isolation coupled with an on-going pest control program at Quail Island (although the feral pig Sus scrofa remains present on Quail Island; M. Legg pers. comm.).’

‘Secondly, wildlife populations occupying novel habitats may benefit from the fact that these are likely to occur in inherently more favourable parts of the landscape than areas typically designated for conservation. This is because the more productive or diverse parts of the landscape have generally been the areas of greatest focus for human activities, while “residuals” of remnant vegetation reserved in protected areas tend to occur on drier, less fertile and/or steep terrain ( Joppa and Pfaff, 2009; Margules and Pressey, 2000).’

I would suggest that fox and cat eradication programs may be more numerous and/or effective in urban areas as opposed to remnant hard to reach areas. Data is needed.

Thirdly, it remains unclear how sufficient numbers of bandicoots at novel sites were avoiding predation by invasive red foxes, cats and other predators. Rabbits may be a preferred prey item, but if this is true then any decline in rabbits and subsequent prey-switching by foxes and/or cats could have drastic consequences for bandicoots (Blanco-Aguiar et al., 2012; Glen and Dickman, 2005). Any control of rabbits should thus be accompanied by intensive monitoring to detect any secondary impacts on bandicoots.

The report states ‘It remains unclear how the bandicoots were avoiding predators’. More data is needed.

The Pines Flora Fauna Reserve and Greens Bush on the Mornington Peninsula had lots of bandicoots and linked habitat corridors. These areas had modified habitats with many areas overgrown with blackberry and still the bandicoots died out. If it was, then, just about access to non-native foods, that are also feeding the feral species, this still wouldn’t explain why they died out on the peninsula and not in their ‘novel’ test sites.

Eve Kelly Secretary Australian Wildlife Protection Council

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