I Killed the Bufo (Via Herp Digest)

I Killed the Bufo, by Mark Derr, 7/23/11
Mark Derr is the author of the forthcoming "How the Dog Became the Dog: From Wolves to Our Best Friends."

Miami Beach
I CONFESS. On a recent night, a very dark night, around midnight, I killed a Bufo marinus, commonly known as a cane toad or giant toad. The Bufo had established its domain in our pond several months earlier and swaggered about the backyard at night as if it owned the place.

Like our house, the pond dates to 1925. Made of concrete, it is four feet in diameter and two feet deep, with two inches of muck. Presiding over it is a two-foot-tall plaster cherub jury-rigged fountain that was already old when we moved in 20 years ago. The pond then was a stagnant breeding ground for mosquitoes and algae. Today, it is home to two thriving plants - a lobelia native to the Everglades and a colocasia, an exotic from Southeast Asia. The pond is algae-free and stocked with gambusia, the local minnows that are mosquito predators - hence their common name, mosquito fish.

I have kept the pond more or less functioning since we moved in, and I have no desire to see it colonized by toads the size of soccer balls that secrete toxin from glands in the back of their heads strong enough to kill cats and small or infirm dogs. I feared that our aged kelpie, Kate, would stumble upon the Bufo invader and meet her demise.

I am hardly an ecological purist who would remove every exotic animal as soon as it appeared in an ecosystem not its own, primarily because I figure that at one point or another all of us on this planet have been "invasive species" - or shall I say, pilgrims in search of a better home. Most creatures who visit South Florida, especially when coming from a cold, gray climate or an oppressive political atmosphere, never want to leave. They congregate here and sometimes reproduce so profligately that they are impossible to contain, much less to remove.

In the years I have kept it, the pond has had a mixed record on exotics. For several years, it harbored a visiting African lungfish that trained me to feed it whenever it surfaced with its mouth open. The lungfish prospered until its owner took it away, but as a rule nonnative fish and plants have faltered.
Since the 1930s, people have brought Bufos into Florida, usually to serve as biological pest controls in sugar country around Lake Okeechobee. but the current Bufo population in South Florida appears descended from a group that escaped from a wildlife dealer at the Miami airport in 1955. Similar releases in Australia to control pests in sugar cane fields have created an ecological nightmare that could be titled "Invasion of the Cane Toads."

Still, the notion that the Bufo had to be removed remained abstract, something I should do but could delay as long as I was vigilant with Kate. Since I take no pleasure in killing, that studied ambiguity suited me. I even passed up several opportunities to dispatch it. I hoped it would voluntarily decamp, but I knew it was growing large enough and brazen enough to threaten our dog, who often visited the pond.

I knew I had to act, though, when I learned that several neighborhood dogs had died from Bufotoxin.
Reportedly, the humane way to kill a Bufo is to apply a painkiller and then freeze it in a plastic bag, but I did not want to attempt to catch it, because Parkinson's disease has skewed my balance and dulled my reflexes. I had other plans. After failing to find a gig - a multi-tined spear for hunting fish and frogs - I manufactured my own using oversize deep-sea fishing hooks. I bided my time until I found the Bufo squatting on an exposed piece of limestone in the middle of the pond. I speared it with my gig at the base of its head and unceremoniously dumped it into a garbage bag I then sealed.

I acted to protect our dog without a thought toward other consequences. But within a week of the Bufo's death, I began to notice changes in and around the pond. Young and old gambusia appeared in significant numbers, swimming freely and openly. I am no expert on Bufo behavior, but this one had an ability to knock down plants growing around its chosen resting spots. Once this Bufo was removed, the pond plants grew lush. Anole lizards, whose absence I had silently noted for some time, became everywhere apparent, and I have begun to hear tree frogs again, as well. Even better, the mosquito population collapsed, leading me to conclude that although the Bufo did not appear to eat the mosquito-loving gambusia, its physical presence had somehow intimidated them and forced them into hiding.

I cannot claim to have restored "balance" to our backyard ecosystem. I am even uncertain how to define balance for a fenced area that is dominated by a swimming pool and a mango tree that feeds us and numerous other animals.

There might be other plausible explanations for what I see, but I can say the available evidence indicates that removing an imperialist bully has improved the health of our pond and yard, not to mention our comfort.

Researchers jump to a conclusion on toads' breeding lair (Via HerpDigest)

Researchers jump to a conclusion on toads' breeding lair
Nicky Phillips Science,The AGe.com, 4/20/11

AT LAST, the secret hideaway of cane toads has been found.

In the largest investigation of its kind, scientists and council workers used radio tracking devices to uncover Sydney's first known breeding site for the pests: a pond in an industrial park in the Sutherland Shire.

And after tracking and capturing about 500 toads, scientists believe they have stopped the pests taking a foot-hold in the city.

The mayor of Sutherland, Phil Blight, said the occasional ''hitch-hiking'' cane toad had been found in the Taren Point industrial area over several years.

''But last year our pest control officer found increasing numbers and we suspected there was breeding occurring,'' he said.

The council asked people to report any sightings, organised volunteer toad musters and trained a young labrador to sniff out the pests.

Then researchers from the University of Sydney were brought in to attach radio tracking devices to the backs of several cane toads - and within a few days, the toads' lair had been found.
So far the onslaught seems to be working, Cr Blight said, adding this year the numbers appeared to be declining considerably.

A cane toad researcher from the University of Sydney, Rick Shine, said the program was a terrific example of a co-ordinated attack on a potentially serious problem.

Ratting out Sydney's cane toad menace (Via HerpDigest)

Ratting out Sydney's cane toad menace
By Sally Block, ABC News, Apr 20, 2011

A state of origin match is being played out in Sydney's drains, but unlike the real thing it is the Queenslanders being massacred.

It has been discovered that a colony of cane toads who hitched a ride from the sunshine state are being eaten by the local rodents.

Cane toads were discovered some time ago in an industrial area of Taren Point, in Sydney's south.
Since then the local council, State Government and scientists have been working to eradicate them.
University of Sydney biologist Rick Shine, a passionate toad buster, says toads have been fitted with radio transmitters to monitor their behaviour.

Professor Shine says one of the "entertaining" things to emerge from the monitoring is how rats are munching away on the toads and living to tell the tale.

"The toads quite frequently use drains as cover and the drains contain rats, which we don't normally think of as our best friends," Professor Shine said.

"But rats evolved in the northern hemisphere, in the same place that toads did, and they're capable of dealing with the toad's poison.

"So one of our telemetered toads got massacred and eaten by a rat.
"Unlike a native predator, which a toad would be a fatal meal for, for a rat a toad's just a pretty nice breakfast.

"So we may have some of the old invaders helping get rid of some of the new invaders.
Professor Shine says they have also discovered a Sydney breeding ground for the pests, a pond of tadpoles.

He says it is the "Achilles heel" of the breeding cycle.
"It's a big step in controlling the breeding of the toad as one female can produce as many as 30,000 eggs," Professor Shine.

The tadpoles are euthanised.

He says there are hundreds of the toads in the Shire and hundreds more arrive every year by hopping on trucks carrying things like building materials and mulch from Queensland.
Professor Shine says because the toads are such effective stowaways they will keep on coming.
A toad was found in Launceston in Tasmania's north last week after apparently hitching a ride in a container at Christmas time.

There are several records of toad sightings in other areas in Sydney, but Taren Point seems to be their favourite home.

Australia's 'Rambo' toads head west (Via Herp Digest)

Australia's 'Rambo' toads head west

31/03/2011 03:08:19 Super-tough toads have calloused feet from travelling

April 2011: The battle to halt the damaging spread of cane toads in Australia is proving tougher than originally thought.
In 2005 when Kimberley Toad Buster (KTB) volunteers first began the fight to slow down the movement of cane toads making their way from the Northern Territories towards the border with Western Australia.

'When we initially started toad busting we had been told by scientists and toad experts that toads were only travelling about 25 to 30 km per year, did not swim well in fast flowing water, had low tolerance to saline conditions, that there was a less than five to ten per cent survival breeding rate, that the lungworm parasite was 20 years behind the front and so on. The list was endless,' said Sharon McLachlan, KTB secretary.

Their resilience is frightening
'It did not take us long to realise that much of the information we had received might have applied to the Queensland toads but not to those that were hell bent on reaching Western Australia.'

Not only were these frontline toads moving an average of 80 km a year, they were larger, extraordinarily resilient to the saline conditions of some of the rivers they were crossing and that the breeding survival rate appeared to be more in the vicinity of 75 to 85 per cent.

KTB volunteer Del Collins said: 'I timed one female toad that stayed underwater for 1.2 hours. These guys are super-Rambo toads.

Said Sharon: 'Their resilience is frightening. These toads, irrespective of injuries are determined to keep travelling west and I have no doubt they will reach Perth eventually.'

'Explorer' toads march ahead to find breeding grounds
KTB volunteers also established that there was a clear pattern emerging in the behaviour and characteristics of frontline toads making their way into WA. Leading the cane toad pack are the predominantly male explorer toads accompanied by the odd, very large female.

'These toads are huge,' stated Ben Scott-Virtue, field co-ordinator. 'The females are often, on average, as large as 17.5 cm from snout to tail bone and the males around 14 to 15cm. Their back legs are between 2cm to 4cm longer than their bodies and the pads of their feet are blackened and calloused from constant travelling. They can often be up to 30 km in front of the main breeding colonising front,' he added.

Once these colonisers have found an ideal breeding area they begin to call in the closest wave of the breeding population numbers travelling behind them. Once the breeding population has been established and the very large females have dropped their eggs the explorer toads move on.

It is time for some serious re-thinking
In dry landscapes these explorers use cattle trails and moist cow dung to move between water holes. When confronted by really dry conditions, the toads simply use the deepest and dampest burrow or other ground hollow to hibernate in, often sacrificing the uppermost layer of toads to ensure that some survive.

'We have dug up to 30 toads out of a deep burrow months after the area has dried out and it is obvious they are simply waiting for the next rain,' said Lee Scott-Virtue KTB president and founder. 'All previous cane toad invasion predictions have been wrong and anyone seriously thinking that the Great Sandy Desert is going to stop these invading Rambos has got to do some serious re-thinking.'

Warmer Is Better: Invasive Cane Toads Set to Thrive Under Global Warming (Via HerpDigest)

ScienceDaily (July 2, 2010) - As global warming threatens many animal species with extinction, the already destructive cane toad is set to flourish with increasing temperature, say Australian scientists.

"The negative effect of high temperature does not operate in Cane Toads, meaning that toads will do very well with human induced global warming," explains Professor Frank Seebacher from the University of Sydney.

Unlike fish and other cold-blooded creatures, whose oxygen transport system suffers at high temperatures, the cardiovascular system (heart and lungs) of Cane Toads performs more efficiently.

The researchers present their new findings at the Society for Experimental Biology Annual Conference in Prague on Friday 2nd July 2010.
When tested over an ambient temperature range of 20-30˚ C [up to 86˚ F], Cane Toads acclimatised perfectly to increased temperatures and resting oxygen demands remained constant.

Furthermore, the efficiency of the oxygen transport system in the Cane Toad increased with increasing temperature, showing not only an ability to function over a broad thermal range but remarkably, a preference for higher temperatures.
This is in contrast to previous studies suggesting an increase in temperature results in a higher basic oxygen demand, coupled with decreased efficiency of the circulation system, leading to oxygen starvation.

"Warmer temperatures are advantageous and there is no indication that high temperatures limit oxygen delivery," explained Professor Seebacher.
The scientists say this positive effect may also apply to other anurans (the class of amphibians that includes frogs and toads), but more research needs to be done to find out.

"The impact of global warming doesn't have to be negative. Global average temperatures at present may in fact be cooler than many animals would like," explained Professor Seebacher.

"There will be winners and there will be losers but that needs to be judged on a species by species basis," added Dr Craig Franklin, co-author of the research.

The Cane Toad can adapt its physiology in response to a changing environment repeatedly and completely reversibly many times during its lifetime.

Originally introduced as agricultural pest-control due to its voracious appetite for the Cane Beetle, populations have now escalated out of control. The skin of the Cane Toad is toxic1 and deadly when ingested by other animals, many of them native predators.

1And they were doing so well. The skin is harmless. It's the toad's parotid glands, which secrete a toxic chemical, that are the problem. Although some snakes are developing a resistance to the toxin, while some birds have learned to flip the toad over to get at its tasty insides, thus avoiding the toxin.