Guest Article…

Here’s first cab off the rank in this very new section, welcome and thanks to Ian Browne…

Top End Toads

Now banned, the ‘bufiest’ of Mexican waves…

“Have cane toads become the unintended saviour of the- threatened pig-nosed turtle and other native fauna species?”

By Ian Browne (Shamrock News Darwin)

The temperature has nestled into the ‘mid-thirties’ daily on the coast now in Darwin as the humidity climbs, beckoning the monsoon storms to reign supreme once more over the northern rainforest, mangrove and savanna landscapes. It is now the Build Up Season in the tropical Top End and I again recently visited Kakadu where the usual 40c temperatures rekindled my love affair with H2O and as the last of the Dry Season fires smoldered by, huge dust devils weaved erratically cloud bound on the blazing, heat quivering floodplains and sadly the sound of cane toads bugling through a wizen- night fluorescent with stars.

Griffiths and McHay (2006) discussed their findings related to a sharp decline in all goanna species numbers in areas of Kakadu where only Varanus panoptes was trying hard to hold its head high. I have met with Tony Griffiths many times over past years and he has filled my brain with many facts related to toads in the Top End.

I also spoke to ‘FrogWatch’s’ Graeme Sawyer recently and he believed that even poor old V. panoptes is in strife due to the cane toad invasion as indigenous folk in Arnhem Land have seen this large lizard drop out of the natural system there. Graeme has recently released this information to the media in a plea for further Government support in protecting biodiversity in the Top End.

toad-buster-21may-07-001-4.jpg

Who you gunna call? Ian Browne, Toadbuster.

However, I have also spoken to people who have seen the toad ‘front line’ move through on their own properties south from Darwin in the savanna woodlands where goanna and snake species were consequently removed. As the toads decreased in prosperity (a lag-time effect due to abiotic Dry Season impacts and a lack of food for individual toads after the initial indulgence of the vast toad hordes I believe) the following years have seen the snakes and goannas slowly returning luckily.

Along with a group of Year 9 secondary school students from Darwin’s O’Loughlin College I organised a toad muster on a hot, sultry night at Lake Bennett; to the south of Darwin. The toads were large but not overly abundant in numbers and my merry, courageous band of ‘wart hunters’ were a very successful group and inquisitively ventured into differing toad habitats. The fencing off of wetland areas has also proven successful in containing toad distribution and the recent annual FrogWatch Dry Season ‘Toad Muster’ group in the nearby Kimberley region used this technique to prevent toads from entering aquatic ecosystems. However, I believe the Wet Season will uncover the current population truths as toads will again be on the march in the more favorable conditions, igniting their hideous warty passions.

So we know that observation and research has shown an obvious decline in all goanna species’ numbers, and it is said that other toad predators such as northern- quolls; which also prey on partridge pigeons, are feeling the toad’s poisonous impacts. As the toads marched nearer to the Top End partridge pigeon numbers were theoretically said to increase as an indirect impact from the toad invasion. I was grateful to witness a squadron of these shy birds clambering roadside recently in Kakadu and just 40 metres or so from a large dingo whose face spoke of great antiquity.

This secondary toad related impact is also occurring with pig-nosed turtles due to a decline in V. panoptes numbers. Doody et al. (2006) described how this large goanna preys upon the pig-nosed turtle (Carettochelys insculpta), and a decline in V. panoptes numbers due to toad predation has had an encouraging ecological ‘flow-on-effect’ for pig-nosed turtle numbers where hatchling recruitment numbers have increased by as much as 20% in one riverside study site, where V. panoptes had, for now it seemed….vanished. This could prove favorable for increases in population size and improved population structure for this turtle species which is listed as ‘vulnerable’ internationally IUCN 2003; and ‘near threatened’ at state level: Northern Territory Parks and Wildlife Service. Doody et al. (2006) described how annually egg loss due to predation for the pig-nosed turtle from 1996-1998 was 17-23%, however in 2004 when V. panoptes was not recorded in this riparian ecosystem; enlarged nest- chamber and egg predation did not occur.

But how long will V. panoptes numbers remain redundant? Catling et al. (1999) described how cane toads had indirectly affected small lizard populations, even though they themselves did not gorge upon such warty misery, they did however compete with this Neotropical pest for other prey species. “This is probably the only forum in which one of Pauline Hanson’s grotesque-xenophobic statements might actually be shown in some convoluted favor?”

But back to the science hey, Graeme Sawyer believes that due to cane toad predation the poor old King Brown (a species of black snake actually!) is also in peril. Do we rejoice or scorn such changes to the food web; the food chain; survival within the ‘life capsule’ that is biodiversity within the tropics? The toad is here to stay at least for now, we need to breed and return to nature ‘all’ endangered native species, and do our best to alleviate the toad’s impacts. Territorians should be proud, they have tried to stifle the toads’ far flung march and it has paid dividends in community relationship building and has fostered new wisdoms in science, endeavoring to retain prosperity within healthy natural ecosystems.

Cheers, Shamrock.

14 comments so far

  1. jane on

    Fantastic info Mr Brown Snake…
    I look forward to hearing more from the Top End reporter.
    From Jane

  2. Ian Browne on

    Thanks Jane,we are struggling in the Build up again this year and I am sure I am not the only one adorning a heat rash. Storms fill the steamy hot air today like mushroom clouds,I am in Parliment House by the harbour and thunder rumbles outside. There was a weigh-in for collected toads the other day and some tipped the 1/2kilo range. Haven’t seen any around Darwin of late luckily, plenty of tree frogs though as per usual. A monsoon trough is developing just to our north so we will see what is spawned in its downpours.Plenty of large frilled neck lizards about.Becoming noisy outside as one of these purple monster moves in on the city.All the best,Ian.

  3. Craig on

    I loved your article Shamrock. Very informative. You’ve come a long way from foraging under rocks for crabs at Burraneer Bay park.
    From Prof Underpant

  4. Ian Browne on

    Ah yes,Sydney’s suburban landscapes. Well I did see a red belly black snake and some strange striped leeches in Burraneer Bay Park’s creeks- Craig as a youngster-which will stay with me. There are some exotic areas of wet sclerophyll and warm temperate rainforest, mangals and coastal heathlands in the Sydney region which are are wonderful places, but I have to say I prefer the subtropical and tropical regions of this nation, especially away from weedy areas (are there any?)
    As you know I damaged my back working on rainforest contracts in Northern NSW Craig, but it is the best way to learn ‘first hand’ about the ecology of a region and how it all functions- if you want to manage an ecosystem, whilst learning the local wisdomes of other contractors.I loved it and you train your eye to the seasons and all manner of lifeforms.
    I was working on Ibis population studies and habitat modification in Centennial Park before leaving Sydney once again to further my eco-studies in Darwin, and that was great.My friend John Martin went on to gain his Masters in Ibis research whilst working at Centennial Park.
    Darwin is far more exciting though in comparison to the mid-latitudes and right now the monsoon is active and things have cooled a tad, and it now feels more equatorial (like Singapore or Kuching for e.g.)and I am glad to say that the toads are not jumping about here on the coast; or in Darwin’s rural region in large numbers as yet this wet season. All the best, Ian.

  5. Ian Browne on

    Hi all, I just returned from Lake Bennet (as discussed in the article from last year’s early Build Up) and I only found 2 toads, both giants and hanging about the resort window lights and garden beds trying to grab the bugs (many insects about). I was surprised by the lack of toad numbers considering we are smack bang in the middle of a very active monsoon trough and it stormed throughout the night…lightning shy perhaps. I have seen a few dead toads on the roads about the Northern Suburbs of Darwin/Nightcliff area etc..but they are certainly not prolific. I am chasing stories soon on the effects of toads on Merten’s water monitors and dwarf freshwater crocs in the next edition. Cheers, Ian.

  6. Ian Browne on

    I just spent a week at Charles Darwin University’s Rural College campus 30 clicks north of Katherine and there were some big toads around the dorm area lights by night with some pretty gruesome poison sacks. There was a large, confident arrow headed frog with a large cricket hanging from its chops and a variety of other frog species and tree frogs also. The geckoes are giants as you head into the bush from Darwin, the rhino beetles not much smaller either.
    Apparently people have been killing the arrow heads,please take a closer look as they look nothing like toads. The insect life is amazing in the savanna country so the toads are well fed at this time of year, as are the huge wallabies as the savanna grasses are long and juicy with all this tropical sunshower weather.

  7. Ian Browne on

    I went down to the Kimberley region last week and there are plenty of cane-toadlets and adults close to the impressive red canyon W.A. and N.T. border region in the Victoria River and Timber Creek area. This area; and the Kimberley region, is now entering the Dry Season and it is between 36c to 38c daily. It is hard to believe that toads can be so prosperous in such harsh conditions. Of course they hide out by day and leap about the joint by the cool of night.
    There are roadsigns warning drivers about the threat of cane toads to the Kimberley region as you near the border.I photographed a large goanna (perenti I think) and witnessed others in the Kimberely. They might not be so obvious in time to come.
    Now is the time to start clearing out sites around moist areas. But don’t be as silly as me when moving about in wet areas here in the tropics. Whilst visiting Timber Creek last week (and after a couple of swigs of travellors Port) I was hanging around a pandanus fringed creekline,nervous of the wondering salties and gingerley tip towing along a river level high suspension footbridge. I thought the sign said fish feeding site, the next day via sunlight I read it properly ‘Croc feeding site’..oh dear.
    I for one find it very difficult killing any animal and even in Northern NSW and Qld.I couldn’t always get myself to kill toads each time I ran into them. A quick kill if needed, I froze them once here in the Top End, but atleast I do have an animal handling certificate and reasonable biological understanding.
    I haven’t killed one for some time now, I would rather write about them.They are now sadly increasing in numbers on Darwin’s Northern suburb roads by night though. There has been debate in the media here in Darwin of late on how to kill them humanly. FrogWatch’s Graeme Sawyer was voted in by the Darwin Public two weeks back as Lord Mayor due to his action against toads in the Top End, yet many people down south still believe Darwin is a dusty hicktown,it is very cosmopolitan I can assure you and only dusty for 5 months of the year.Please be thoughtful as it is not their fault they were released here, cheers.

  8. Emma on

    Hi Dr Karl,

    My sister n I dont get along very well
    I think its coz of our starsigns
    Im the fish n shes the lion

    Love always,
    Emma

  9. seno durad on

    I coulda/shoulda said:
    . Maybe the Moon looks bigger, if it does, lower, in the sky, coz it
    looks closer. Just behind the hill/house/tree. Or maybe it just looks
    closer on a clear night. Can We Help reckons it’s the Ponzo illusion.
    I can’t see it.
    . Rimless cases don’t normally go with revolvers.

    . Dr Karl!? U speed devil/demon.
    U ARE F-ing crazy! Er, were, mad, as hell.
    To have risked the lives of others.
    U shoulda crashed the car on his side.
    Oh U were seriously assaulted!
    Was that before or after?
    Taxi driving and security work is bloody dangerous.
    . Yes green is in the middle of the Sun’s spectrum, and that’s why the
    plants/chlorophyll use it, but our eyes are most sensitive to red. Just
    look at the traffic lights. Red really jumps out at U, and when I’m in a
    hurry my motto is “If U can’t see red, full steam ahead”. I have blacked
    out a coupla times and I can’t remember seeing green. All I remember is
    “Who’s dimmed the Sun/lights”?
    . U say U wash with Sorbolene? How is that possible? It’s not a soap.
    . U keep saying we can’t tickle ourselves. Well actually I can, on the
    soles, of my feet, gently.
    . No, galaxies don’t spin as a disc, coz if they did, the outter stars
    would travel much faster. I did the calculations for the solar system,
    and Mercury travels at 2.6 Mmls/day and Pluto at only 0.25, and Neptune
    at only 0.29! And of course they get a lot closer together when U do it
    per hour, let alone (per) sec/ond. And how well/accurately do we know
    their radii!? Anyway, they are moving so slowly out there it’s no
    wonder their speeds are getting close/r.
    (Pluto is some 100 times further out than Mercury, and their masses are
    comparable, and its radius and circumference is some 100 times (that) of
    Mercury and yet it moves at 1/10th that of Mercury. 100 vs 10. How
    interesting. 100 is almost 2^7=128, and if U double the radius, the
    gravity and speed should be a quarter, and so 1/10th is a hell of a lot
    more, than what it should be. 1/(2^7*2^5)=1/2^12=1/4096th times).
    They are saying that the stars travel at the same speed. That’s
    somewhere in/between the inverse square law and a disc.
    So there’s a lot of dark/unseen matter out there.
    Or maybe we haven’t got the distances to them correct.
    Well it’s not exactly like we got the tape measure (out) to them.
    Or maybe we haven’t got their masses correct.
    Well it’s not exactly like we put ’em on a scale.
    Or maybe it’s just that the ratio of their separation and radius is so
    small out there U wouldn’t expect much difference between them.
    Or it could just be that the inner ones are dragging the outter ones
    along. Der! Or all of the above.

  10. Marc lego on

    Hi Dr Karl
    we tried our own investigation, to see if nasty germs jump from toilets to toothbrushes by airborne germs.
    We tested 12 toothbrushes that we used for 14 days.

    Of the 12 toothbrushes, all 12 tested positive for poo germs

    We even had a toothbrush stored in the Medicine cabinet that tested positive for fecal germs!

  11. JOE on

    seno durad – REAL CONSTRUCTIVE! Bloody idiot! You should have your own show and call it the ‘retard hour’!

  12. Roger, Portland NSW on

    Hi Dr Karl,

    It is my understanding that the total volume of water on the earth today is the same as it was when the earth was created. In fact its the same water.

    I was wondering what effect the obsession with bottling drinking water has on the process of water re-generation being the cycle of evaporation and rainfall. I mean there must be literally billions of litres of water throughout the world captured in bottles and other storage vessels, effectively withdrawn from natural evaporation and rainfall process. Further to this the continual replenishment and possible increase of bottled water stocks would ensure that a constant volume would be withheld for now and the forseeable future.

    To enquire further, would this concern impact on global warming? I ask this for two reasons. Does rainfall act as a natural cooling and heat tranfer system? And does this amount of water being withheld effect the frequency and duration of rainfall periods?

    I would be most greatful for any information on this subject.

    Kind regards

  13. dialurdoctor on

    Nice suggestions .

  14. Dada Stamm on

    Swimming with Sharks, glider soar, travel, hike, heavens plunge, search for a hawaii Heiau as well as holy … This kind of wetland home houses around 119 species of wild birds. It’s focused on 4 endangered …Sky Habitat


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