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Archive for April, 2011

It might not be worth trying to save the kakapo, the critically endangered native bird that has been on the brink of extinction for decades, an Australian scientist says.

Instead, resources should go into saving species that have more chance of recovering and surviving in the evolving environment.

“It’s a wonderfully weird creature and it’s a shame that we will probably lose it regardless of any interventions. Harsh, but somebody’s got to say it,” said Cory Bradshaw, of the University of Adelaide’s director of ecological modelling.

Using a mathematical formula, Professor Bradshaw and colleagues from Adelaide and James Cook University, in northern Queensland, created a new index called Safe (Species’ Ability to Forestall Extinction), which ranks the probability of animals becoming extinct based on population.

The index goes a step further than the Red List of Threatened Species, produced by the International Union for Conservation of Nature, which ranks animals and plants in categories from safe to critically endangered.

“It really comes down to accounting, are we deliberately or inadvertently losing hundreds if not thousands of species by putting money into species that are a lost cause? That doesn’t mean we go out and knock every one on its head though,” Professor Bradshaw said.

Other endangered animals that could be left to die off because of unsustainable population levels, according to the index, include Australian’s hairy-nosed wombat and the Javan rhinoceros.

The Conservation Department said it would look at the merits of the index but said it would continue to support the Kakapo Recovery Programme.

“DOC is very proud of the work that’s been done to save the kakapo and we’ve no intention of letting them go,” spokesman Chris Pitt said.

Full story on stuff.co.nz

ERRRRRR, YEA RIGHT  ……

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Kiwi recovery programmes are proving their worth even though the national population of the threatened bird continues to decline, Conservation Department science officer Rogan Colbourne says.

Mr Colbourne has been part of the BNZ Operation Nest Egg scheme. The Hawke’s Bay group released its 100th young North Island brown kiwi into the Kaweka Ranges on Thursday.

Nationally the kiwi population is thought to be falling by about 6 per cent a year, but Mr Colbourne said local programmes were making a difference, in some cases having increased the local population.

“At Okarito [on the West Coast] they have increased the population from 150 to more than 300,” he said.

In Hawke’s Bay, with a kiwi population of fewer than 1000, the addition of 100 young birds since 2003 was significant. Kiwi lived on average to 40 – and even to 60 – if there were no predators.

In these programmes, eggs are taken from the wild and incubated, then the hatchlings are kept in a predator-proof environment till considered big enough to fend for themselves in the wild.

“There is a 90 per cent hatch rate with these eggs, compared with only 50 per cent in the wild, for various reasons,” Mr Colbourne said.

“Possums can eat the eggs, the adults can damage them accidentally, and there can be bacteria after rainfall.

“Once hatched [in captivity] about 80 per cent reach the sub-adult stage and once they are released about two-thirds survive in the wild, though that varies from area to area.”

Of kiwi hatched in the wild, only about 5 per cent survived to become adults, as predators such as stoats, ferrets and feral cats ate the young birds. Ferrets and dogs could kill adults, and dogs were a particular worry in Northland.

About 15 recovery groups were operating in the North Island, with assistance from DOC and other organisations, Mr Colbourne said.

The Hawke’s Bay group is led by the Environment, Conservation and Outdoor Education Trust.

Spokesman Alastair Bramley said the survival rate for the kiwi released in Hawke’s Bay was about two-thirds overall, but it had been up at 90 per cent till an outbreak of ferret attacks in 2008.

“We haven’t lost any since then,” he said.

Dogs were not such a big problem in Hawke’s Bay because hunters there had to put their dogs through kiwi aversion training before they could register them, Mr Bramley said.

The 100th kiwi has been named Parauri and was released in the Kawekas after a ceremony at the Pan Pac Kiwi Creche, inland from Tutira.

Original story

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Our already silent forests are dying.

Scientists have proved for the first time the alarming rates of decline in regeneration of native tree species that rely on kereru, or native pigeons, to disperse seeds.

In two forests, they have found regeneration has fallen by up to 84 per cent over two years. However, they fear the problem could be far worse in other areas in which bird populations are much lower.

Canterbury university plant ecology professor Dave Kelly said researchers were taken aback by their findings. “It was a surprise for us how big the effect was and how long it was lasting for.”

At one extreme, the researchers said regeneration of trees could fail completely, leaving forests full of dying adult trees and eventually lead to the collapse of mature forests.

Dr Kelly, with Landcare Research ecologist Debra Wotton, studied native taraire and karaka trees in two forests less than 100 hectares in size.

Taraire rely exclusively, and karaka almost exclusively, on kereru to disperse their fruit, which are too big for other smaller birds to eat.

Although it was already believed that falling populations of kereru were having an impact on seed dispersal, it was the first time the link has been proved and assessed.

Full story on Stuff.co.nz

Photograph by Jim Stevens

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