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Archive for June 5th, 2007

Tuatara faces gender bending climate threat

Posted by Miqe on June 5, 2007

The tuatara has survived ice ages and volcanic eruptions but New Zealand’s last survivor of the dinosaur age may become extinct because of global warming.

The lizard-like reptile, one of the world’s oldest living creatures, is vulnerable to temperature change because temperature determines the sex of its young.

According to Jennifer Moore, a Victoria University researcher investigating the tuatara’s sexual behaviour, a temperature above 21.5 degrees celsius creates more male tuatara while a cooler climate leads to females.

Already male tuatara on a tiny predator- free island near the top of the South Island outnumber females by 1.7 times, she says.

“They’ve certainly survived the climate changes in the past but most of them (past climate changes) have been at a lower rate,” she said.

“So you wouldn’t expect these guys to be able to adapt to a climate that’s changing so rapidly.”

The tuatara, whose Maori name refers to the spines on its back, is the only survivor of a species of reptile that flourished during the age of the dinosaurs, about 200 million years ago. It can grow up to 50 centimetres long and weigh up to one kilogram and like its reptile relative, the turtle, the slow-moving tuatara can live more than 100 years, feeding mainly on insects.

But scientists say its long lifespan as well as its four-year breeding cycle – relatively slow for a reptile – will make the adaptation process more difficult.

Peter Gaze, a senior conservation officer at the Conservation Department, says global warming has become a new challenge for many of New Zealand’s wildlife. “I think the impact of temperature change is widespread and diverse,” he said.

He said rare species such as the rock wren – an ancient, tailless bird found only in the South Island mountain ranges – could become extinct if the warmer climate let predators, such as rats, live in higher altitudes.

The United Nations Intergovernmental Panel on Climate Change, the world’s top authority on global warming, predicted in a report in February that global temperatures would rise by 1.8 to 4 degrees this century.

The group has predicted a severe impact for New Zealand, with forestry and agriculture likely to be hit hard by global warming.

On a global level, the report predicts large numbers of plant and animal species could die out by 2050 because of global warming.

It says billions of people around the world will face floods and famine and millions will die as crops fail and diseases take hold.

From Stuff

Posted in Herps in the news, International articles and news., Lizards | 2 Comments »

Slithery customer just adder be a grass snake

Posted by Miqe on June 5, 2007

A RANGER got a shock at the Avon Heath Country Park near Ferndown when he opened up a jammed printer to find a snake looking back at him from inside the machine.

The wily grass snake got into the visitor centre at the park a week ago and has been eluding attempts to capture it ever since, popping up in unlikely places and causing havoc.

The slithery intruder was first spotted by park ranger Katy Thompson. She said: “I just saw a tail disappearing under my desk and I spent about two hours tentatively moving the furniture because I didn’t know if it was a grass snake or an adder. I found it and saw it was a grass snake but then it disappeared up into the cavity wall.”

A couple of days later ranger Carol Dawkins was sitting at her desk when she heard a rustling but the snake again disappeared before she could grab it.

On Thursday Ian Cross went to print some paperwork in the office and an error message came up on the printer.

He opened up the section where the cartridges were and found the snake looking up at him from inside the machine.

This time he managed to get hold of it and returned the animal, completely unharmed by its adventures, to the outside world.

Grass snakes are the largest reptiles native to the UK. They have been widespread across England but have become rarer in recent years.

They are non-venomous and completely harmless but Mrs Dawkins said: “I am glad it was Ian that found it because it would have given me a shock. I am fairly used to them but there is something about the way snakes slither.”

From Daily Echo

Posted in Herps in the news, International articles and news., Snakes | 2 Comments »

Purple frog may croak it soon

Posted by Miqe on June 5, 2007

A purple fluorescent frog is one of 24 new species found in the South American highlands

purple frog

of Suriname, according to conservationists who warn that these creatures are threatened by illegal gold mining.

The discovery of so many species outside the insect realm is extraordinary and points to the need to survey distant regions, says Dr Leeanne Alonso of Conservation International, which led the expedition that found the new species.

“When you go to these places that are so unexplored and so remote, we do tend to find new species … but most of them are insects,” Alonso says.

“What’s really exciting here is we found a lot of new species of frogs and fish as well.”

The two-tone frog, whose skin is covered with irregular fluorescent lavender loops on a background of aubergine, was discovered in 2006 as part of a survey of Suriname’s Nassau plateau, the conservation group says.

Frogs, fish, dung beetles and ants

Scientists combing the plateau and Lely Mountains found four other new frog species apart from the purple one, six species of fish, 12 dung beetles and a new ant species, the organisation says.

Thirteen scientists discovered the creatures when exploring a region about 130 kilometre southeast of Suriname’s capital Paramaribo.

The region includes areas with enough clean fresh water sources to support abundant fish and amphibians.

The scientists also found 27 species native to the Guayana Shield region, which spreads over Suriname, Guyana, French Guiana and northern Brazil.

One of these is the rare armoured catfish, which conservationists feared was extinct because gold miners had contaminated a creek where it was last seen 50 years ago.

Including the new species, the scientists observed 467 species at the two sites, ranging from large cats like panthers and pumas, to monkeys, reptiles, bats and insects.

Illegal gold mining

While these places are far from human civilisation, they are totally unprotected and may be threatened by illegal gold mining, Alonso says.

These highland areas have also been investigated as sources of bauxite, used to make aluminium, but will most likely not be mined in the future, she says, at least not by the two mining companies that sponsored the study.

The sponsors are BHP Billiton Maatschappij Suriname (a subsidiary of BHP Billiton) and Suriname Aluminium Company LLC (a subsidiary of Alcoa Inc).

“It’s an opportunity now for all the players, the mining companies who still have mining concessions there, the local communities, the government, the [non-governmental organisations], to try to make a regional plan for the area,” Alonso says.

From News in science

Posted in Amphibians, Herps in the news | 2 Comments »

Cane toads cannibalise their young

Posted by Miqe on June 5, 2007

Cane toads wiggle their toes to lure their young, then eat them up in an act of cannibalism, Australian researchers say.

They say the young toads move towards the adults, possibly mistaking the wiggling toes for a tasty morsel, like an insect.

Instead the youngsters themselves end up as the tasty morsel.

But harnessing this cannibalistic behaviour may have some benefits, at least in Australia, where cane toads are an invasive pest.

Scientists say it could be the key to getting cane toads to eat themselves out of existence.

Professor Rick Shine of the University of Sydney and PhD student Mattias Hagman will report their findings in the journal Animal Behaviour.

The researchers noticed that when baby toads are around adult toads, the adults start wiggling the middle toes on their hind feet.

camera See a video of cane toads wiggling their toes here (Real Media) or here (Windows Media).

The baby toads appear to respond by hopping towards the adults.

The researchers wondered whether this toe waving is an adaptation for cannibalistic behaviour and set up an experiment to check.

Toads were separated by clear glass and not allowed to eat each other because it would have gone against the rules of ethical animal experimentation.

The researchers found that baby toads only move towards adults that wave their toes.

“[The toe waving] seems to be beautifully designed to arouse the feeding responses of a small cane toad,” says Shine. “They presumably think it looks like a small insect.”

Fake toes

The researchers also used freeze-dried toad to which they attached mechanically controlled fake toes.

They measured how far the baby toads moved towards the artificial toe as they wiggled it at different rates and changed its colour.

“We showed that the way that the real toads do it is in fact the best possible colour and speed … to lure baby toads in,” says Shine.

He says the findings strongly support the idea that cannibalism is an important enough behaviour among toads for it to have led to the evolution of the special toe-luring trick.

mating toads

Shine says confirming that toads have evolved to be cannibalistic could be useful in trying to control them.

Shine says males are most likely to cannibalise their young because they congregate around the ponds where females come to lay their eggs.

But females tend to spend more time roaming around the countryside looking for food. This means they are harder to find but present a greater risk to native predators.

While males are easier to find than females, Shine says it could be helpful to keep them alive and focus on knocking off the harder-to-find females.

“We might end up with a group of toads that were very good at eating smaller toads,” he says.

Shine also says outnumbering female toads with males would increase the number of female toads drowned by numerous males trying to copulate with them in the water.

He says this selective culling could be combined with a parasite, from native frogs, that has recently been found to kill or stunt the growth of cane toads.

“At the moment it’s an idea and we need to run a bunch of trials trying to see how effective that’s going to be because at the moment we don’t know,” says Shine.

From News in science

Posted in Amphibians, Herps in the news, International articles and news. | Leave a Comment »