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Forest & Bird is warning that this year’s ‘megamast’ in New Zealand’s forests is likely to be the most widespread in 45 years. The conservation organisation says the Department of Conservation needs at least an extra $20m to prevent endangered species being wiped out in parts of the country. 
“Climate data is telling us this year is shaping up to have the most widespread heavy seeding, with over 90% of our beech forests affected,” says Forest & Bird Chief Executive Kevin Hague.

“DOC urgently needs extra money in this year’s Budget to deal with the fact that this is a particularly severe event. It is significantly bigger than the recent mast events that DOC has responded to.”

“Most of our conservation forests will get hammered without predator control. Their birds, bats, lizards, and insects will be decimated. There will be nowhere that will be safe. In many places, years of hard work by community trapping groups working to save local species and allow the reintroduction of previously lost vulnerable species will be set back,” says Mr Hague.

In a ‘mast’ year trees produce an extremely heavy flowering and seeding. Historically this would trigger an abundance of food for native wildlife to make up for lean years. But now mast events boost rodent numbers, and in turn stoat numbers. When the seed is gone, the plague of predators turn to our native birds, bats, lizards and insects.

This year has been labelled a ‘megamast’ because both beech and podocarp forests are masting at the same time across most of the country.

“We know that timely aerial 1080 operations can control introduced predators and protect vast, remote, and rugged areas from localised extinctions. But DOC doesn’t currently have enough funding in its budget to protect even its ‘top priority’ list of sites, let alone the majority of the country’s conservation forests, from the impacts of a mast event of this scale.”

“We calculate that DOC needs at least double the existing $20m in this year’s predator control budget to protect our most vulnerable native species.”

Mr Hague says that in a mast in 2001, some populations of critically endangered species were wiped out. The only known population of mohua (yellowhead) north of Canterbury disappeared at Mt Stokes, in the Marlborough Sounds.
“DOC deployed its best practice ground-based trapping regime to protect these mohua, but they were overwhelmed by the plague of rats and stoats following that year’s mast event.
“If DOC doesn’t receive extra funding to increase its capacity to respond, we will see more of these localised extinctions.”

Notes for journalists

  • Mast seeding of beech is triggered when the average summer temperature is more than 1 degree higher than the average temperature of the preceding summer. Using the detailed NIWA temperature data sets going back to 1974, it is possible to estimate the intensity and extent of previous mast events. These show that there have been nine significant mast events since 1974. The 2019 prediction is the first time in 45 years that the modelling predicts masting in more than 90% of the country’s beech forests.
  • See previous calculations from Landcare Research. Full document available here: Forecasts of masts and ‘mega-masts’ that generate pest outbreaks; Roger Pech & Mandy Barron; Landcare Research Manaaki Whenua
  • Mast years are happening more often due to climate change
  • In previous mast events in 2014 and 2016 DOC received emergency funding of $20m as part of ‘Battle for our Birds.’ This funding was ‘baselined’ in the 2018/19 Budget, with DOC receiving an extra $81m over four years for predator control. This year’s mast event will be significantly more widespread than 2014 and 2016.
  • Podocarp trees include kahikatea, rimu, tōtara, matai and miro
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