Jennifer Marohasy

a forum for the discussion of issues concerning the natural environment

Weeds & Ferals

Exotic Disease Threatens Australian Eucalyptus

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Exotic diseases represent a significant threat to Australia’s unique fauna and flora.

Dramatic declines in frog numbers in the 1970s were initially blamed on habitat destruction associated with logging.  It was not until twenty years later that the disease Chytridiomycosis caused by the fungal pathogen Batrachochytrium dendrobatidis was positively identified and is now officially recognized as the cause of four species extinctions.  The disease is thought to have spread from Africa.

The Myrtle rust is an exotic disease from South America with the potential to infest many Australian native plants including Eucalyptus.  The disease was first detected in Australia on the Central Coast of New South Wales in April 2010.   Recently it was found in southeastern Queensland.   In an attempt to stop the spread of the disease it is rumoured some National Parks could be closed to visitors.

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Potentially Even Bigger Feral Cats to be Imported into Australia

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Feral cats, along with wild dogs and foxes, are thought to have a devastating impact on populations of small native animals in parts of the Australian bush. But the future may be even bleaker with a larger and more ferocious breed of cat, known as the Savannah, expected to be introduced into Australia in the next five years.

According to the Sydney Morning Herald:

“More than 30 savannahs – which cost $5000 for a pet and $10,000 for a breeding animal – are expected to come to Australia in the next five years, with up to 16 now in US quarantine.

“Hybrids of wild animals and domestic animals are a stupid American trend to breed more and more exotic pets,” said Professor Peacock, who works at the University of Canberra.

“This loophole will effectively lead to fitting a nuclear warhead to our already devastating feral cat population. Haven’t our native animals got enough to contend with?”

“Mr Parker dismissed suggestions that the animals could threaten native wildlife, saying they would not be allowed to roam. The company demands that customers sign a contract stipulating specific housing arrangements.

Read more here.

Campaigning Against Cane Toads

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Peter Garrett, Australia’s Opposition Environment Spokesperson, is reported in the Age as having said,

A federal Labour government would commit $2million to a national plan to stop the spread of cane toads into the south and west of Australia.

Alas, his is pledge is unachievable; as cane toads are already in Western Australia. I saw them in Purnululu NP in May, whilst travelling with family.

There may be some political advantage and even some scientific justification for declaring Cane Toads a threatening process under the EPBC Act, but the consequential obligation of implementing a threat abatement plan will also have implications, particularly in terms of cost.

An interesting finding reported earlier in the week on ABC News, identifies that the toads leading the westward invasion are the fastest, longest legged and most susceptible to spinal disease.

The observation leads to the possibility of yet another biological control strategy, where soil bacteria might be encouraged to exploit weaknesses in the toads’ immune systems.

Of Cattle and Conservation

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…In another part of Australia, cattle grazing has been identified as detrimental to World Heritage values, by potentially initiating soil erosion, altering under-storey vegetation and fire regimes. Cattle grazing has also been associated with the introduction of weed species such as pasture crops and assisting in the spread of other weeds.

The Wet Tropics grazing policy is to phase out cattle grazing within the WHA as leases expire unless there is a demonstrated benefit for World Heritage management and no prudent and feasible alternatives are available. Some grazing is already being phased out under the State Forest transfer program.

Interestingly, cattle have historically played their part in establishing the conservation significance of Queensland’s Wet Tropics. In 1971, a couple of long-term Daintree rainforest residents returned home from a weekend in Mossman, to find four of their cattle dead. Suspecting foul play, they called in the Department of Primary Industry’s divisional veterinarian.

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Strychnine-like poisoning from alkaloids was found to have caused the deaths, from large, partially masticated seeds in the digestive systems of the cattle. Herbarium records revealed the re-discovery of a lost species of Calycanthus, but upon recognition of peculiarities and most significantly the variable expression of three or four cotyledons, the species became Idiospermum australiensis.

At the time, there were only eighteen families of primitive flowering plant known to exist world-wide; Idiospermaceae became the nineteenth family. Its discovery stimulated intense botanical interest in the rainforests of the Daintree, which in turn revealed a living museum of plants and animals of exceptional antiquity.

It is also interesting to note that from the early nineteen-hundreds until its re-discovery in seventy-one, the rainforest dinosaur Idiospermum australiensis was being selectively logged under its common name Ribbonwood. Axemen were familiar with special qualities of the plant, along with some seven hundred other species of rainforest cabinetwood timbers, as well as the complex rainforest habitats in which they grew.

Government Misrepresents Extent of Land Clearing: A Note from Ian Mott

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The latest satellite (SLATS) data on Queensland clearing is now available and it provides an interesting insight into how data can be presented in a way that is quite remote from the truth on the ground. The report, Landcover Change in Queensland 2004-2005 can be seen at www.nrw.qld.gov.au/slats

The annual average area cleared in the period was 351,000ha of which 172,000ha (49%) was remnant vegetation with the remaining 179,000ha (51%) being non-remnant woody regrowth. When this was broken down into Carnahan vegetation classes some 193,000ha (55%) was of a type that would not be included within the meaning of forest under the National Forest Inventory. That is, it was “Tussocky or Tufted Grasses” and other vegetation types that have less than 10% foliage cover and are less than 2 metres tall. This presentation still does not allow us to determine what proportion of the 158,000ha (44.7%) cleared remnant vegetation was actually non-forest vegetation types that may actually benefit from tree removal to restore the grassland/shrub ecosystems.

The report has fine tuned a previous practice of breaking the data into relevant grid squares with a colour code to indicate the area of land cleared in each square. Previous reports have used 30′ X 30′ (Lat/Long) grid cells that covered an area of approximately 280,000 hectares with codes indicating cleared area from <100ha to >5000ha for each cell. This produced a map with numerous lurid dark tones but which told us very little, other than the fact that somewhere within a square measuring 53km by 53km was somewhere between 0.01km2 and 50km2 of clearing.

This has now been broken up into 7’30” X 7’30” (Lat/Long) grid cells that cover approximately 17,500 hectares but these still retain the same colour codes for the same cleared area categories and produce a map with lots of little coloured squares that give the appearance of widespread clearing activity. These can be seen at Figure 8 P18 of the current report.

But the most interesting aspect of this presentation is what it does not tell us about the clearing. The graphic below is an enlargement of a 700,000 hectare scene to the west of Charleville which is recorded as one of the hotbeds of clearing in 2004-2005.

The lower presentation is an enlargement of the SLATS Report while the upper presentation indicates the information that is readily available and could be incorporated into the presentation if the political masters were willing to provide a budget for the truth.

Each of the grid squares has been broken up into 700 smaller squares of 25 hectares each (25 across and 28 down) so we are able to show the actual area of pasture, remnant, and woody regrowth in each grid cell. This then enables one to show each years clearing activity in the respective proportions of regrowth and remnant clearing. More importantly, it allows the viewer to gain an understanding of the relevance of that clearing in relation to the local landscape. Obviously, a large amount of clearing in a cell with a low level of remnant (eg. at E2 below) is of more concern than a cleared fence line in a cell with 75% woody remnant vegetation cover.

When the actual clearing is presented in direct spatial proportion to the area of the grid cell and the area of woody vegetation, we get a much more honest appreciation of what is taking place.

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Of the approximately 3,450 grid cells indicating clearing activity in the report, more than 3,300 of them were in the two least cleared categories, showing cleared areas from 0 <100ha and 100 <500ha in each cell. The remaining 147 cells were easier to count and, after allocating a modal value in each class, we were able to determine that approximately half of all clearing, some 175,000ha, was cleared from these few cells. After allowing for a modal value of 300ha in the second lowest category and a roughly estimated proportion of 9% (or 300) of the 3300 remaining cells being in the second lowest category this indicated that another 90,000ha of clearing took place in the second lowest category. And this left only about 86,000ha of clearing taking place on the remaining 3000 cells at an average area of only 28 hectares per cell.

When that 28ha of clearing is proportionately represented on our improved data presentation below it would occupy just one of the 700 small squares in the cell. And when viewed in proper proportion it then becomes clear that the overwhelming majority of the scenes where some clearing has taken place, that clearing is of extremely marginal ecological impact. Indeed, it is at a level that would be barely detectable with the naked eye.

But it is in the allocation of this clearing (or current absence of it) between remnant and non-remnant at the grid cell level that provides the real “smoking gun” of systematic institutional deception. This is because a 28ha clearing event on an inland property is more than likely to be either fodder harvesting for stock or clearing for a fence line etc. And we know that mulga pulling for stockfeed is done on a long term rotational basis of 15 to 25 years. And that interval is more than sufficient for past regrowth to return to remnant status, being more than 70% of “normal” height. This provides grounds for informed speculation as to what proportion of remnant clearing, the assumed worst impact, is actually concentrated in small events of minimal consequence while the major events are primarily of non-remnant woody weeds.

We won’t actually know for sure unless we demand that this information, that is already at hand, be presented in a manner that properly informs the community. Anything less is serious misrepresentation by omission.

Ian Mott

Queensland Government Investigated Over Tree Clearing Case

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I was pleased and surprised to read today at Farm Online that the actions of six Queensland Government employees is being investigated over the Ashley McKay saga.

I detailed the sorry story in a piece at this blog entitled ‘Tree Clearing in Queensland: One Man’s Battle Against Bureaucracy’ posted in October 2005.

It began: “About six years ago Ashley McKay a softly spoken cattleman from south western Queensland was prosecuted by the Queensland Government for clearing cypress pine on his property. McKay had a permit to clear trees from the Department of Natural Resources and Mines (DNRM), but not a permit from the Department of Primary Industries (QDPI) Forestry Division. The second permit was apparently necessary to clear the pine trees scattered amongst the other trees.

It is now folklore in western Queensland that the decision by government bureacrats to prosecute the local hero was taken because McKay appeared on national television program Sixty Minutes speaking out against the government and then new Queensland Vegetation Management Act 1999.

Thousands of cattleman are being investigatged for illegal clearing under the legislation which many claim is unworkable.

The advice has been if you‘re prosecuted, plead guilty because government and the courts will show no mercy if you take a stand…

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