Scientists are supporting the Government’s plan to use targeted 1080 drops to protect native birds from an expected rat and stoat plague.
An abundance of beech seed this year is expected to cause a population explosion among stoats and rats in forests.
Under the “Battle for Our Birds” predator control programme, announced by Conservation Minister Dr Nick Smith last week, the Department of Conservation will treat up to an extra 500,000 hectares of conservation land with aerial 1080 application this year and next, should predator numbers increase.
The additional 1080 drop will increase the area of public conservation land treated for pests from 5 per cent to 12. The work is budgeted to cost $21 million over the next five years. DOC’s annual budget is $335m.
Landcare Research scientist Dr Andrea Byrom, who leads the invasive weeds, pests and diseases portfolio, said an increase of predation on native species was not the only effect of increases in stoat and rat populations.
“There is also the indirect impact of competition: the predators will chomp their way through the seeds, fruits and invertebrates that are food for native birds and lizards.”
University of Canterbury mathematician Associate Professor Alex James, who was involved in research modelling of high beech seed years, said “the planned 1080 drops are the best way to manage the predator outbreak”.
Without predators, native birds would flourish on the beech seed, she said.
Ecotourism operator and Forest & Bird ambassador Dr Gerry McSweeney last year called for DOC to use more of its money to increase application of 1080 across the conservation estate.
McSweeney said he was pleased to see the department actively seeking to increase 1080 use. “It’s a really exciting redirection of the department back to its basic function, which is to look after the land that it holds in trust for us.
“We’re seeing a recognition that this is the only really effective tool we’ve got in the tool box for protecting and restoring big areas of wild New Zealand.”
Parliamentary Commissioner for the Environment Dr Jan Wright released a report in 2011 concluding that 1080 use should not only continue, but increase.
In response to last week’s announcement, Wright said she was “delighted” by DOC’s response to the predator threat.
“1080 is the only tool we have to control the plagues of rats and stoats,” she said.
1080 is readily soluble and dilutes quickly in water to low concentrations. Natural processes will break 1080 down in water to non-toxic by-products.
More than 500 water samples have been taken after 1080 operations in the last five years. 1080 residues have never been recorded in public drinking water supplies.
They also deal with the fact that some non predators can be affected:
Studies also show that the benefits of protecting breeding birds and their nests from predators like rats, stoats and possums strongly outweigh the low rate of mortality recorded for these species.
For example, monitoring on the West Coast shows kea nests in areas protected by 1080 produce up to four times as many chicks as nests in unprotected areas. The population benefits of this increased breeding success offsets the mortality rate of about 12% found among kea tracked through 1080 operations.
Federated Farmers also support its use in fighting TB:
1080 is also vital to the control of bovine tuberculosis (TB) – a serious agricultural disease spread by possums. In many areas of the country, possums are responsible for over 70 per cent of new herd infections. The density of infected possum populations has to be knocked down to just one or two animals per 10 hectares to stop the disease cycle – in many cases, using aerial 1080 is the most effective and cost efficient way to do this.
They also deal with the health risk to humans:
No trace of 1080 has ever been found in public drinking water. Even if the water supply did get contaminated, a 60 kg person would need to drink 60,000 litres of water containing two parts per billion of 1080 (the maximum level set by the MOH), in one sitting, to absorb a fatal dose.
I think it is fair to say that no one will even come close.
The last word goes to the Parliamentary Commissioner for the Environment:
“It is not perfect, but given how controversial it remains, I for one expected that it would not be as effective and safe as it is”
If someone invents a more reliable, safer and effective method of possum, stoat and rat control – then I’m all for it. But until that happens, what is the alternative?