Predator plague in forests that threatens native wildlife could intensify due to biggest 'mast' in more than 40 years

New Zealand forests are likely to be hit with the biggest "mast" in more than 40-years, DOC confirmed today

The mast will see heavy seeding that can fuel plagues of rodents and stoats, which pose serious threats to native wildlife. 

Conservation Minister Eugenie Sage said today results from seed sampling pointed to exceptionally heavy seed loads in South Island forests this autumn, with rimu forests and tussock grasslands in the South Island also seeding heavily.

A "mast" year means trees have an extremely heavy flowering and seeding production, triggered when the average summer temperatures are more than one degree above average.

"Forest seeding provides a bonanza of food for native species but also fuels rodent and stoat plagues that will pose a serious threat to native birds and other wildlife as predator populations build up next spring and summer," Ms Sage said in a statement. 

In March, Forest and Bird feared without an injection of funding and predator control, "birds, bats, lizards, and insects will be decimated".

Forest and Bird chief executive Kevin Hague said there would be "nowhere that will be safe".

Ms Sage said today DOC's additional funding of $81.2 million in Budget 2018 over four years would enable a "scale up" of its predator control programme. 

"DOC is planning its largest-ever predator control programme for 2019/2020, at a cost of $38 million, to suppress rats, stoats and possums over about one million hectares or 12 per cent of conservation land."

"This is a step up from the previous largest programme of 840,000 ha in 2016 and 600,000 ha in 2014 and 2017 when there were significant but smaller mast events."

"If we don’t act, we could lose populations of bird species like our tree-hole nesting kākāriki/orange-fronted parakeet and mohua, and bats, which are so vulnerable to rat plagues."

The predator control programme uses 1080 and large-scale trapping, targeted to protect kiwi, kākā, kōkako, kea, whio/blue duck, mohua/yellowhead, kākāriki/orange-fronted parakeet, rock wren/tuke, long and short tailed bats/pekapeka, native frogs and Powelliphanta snails.

The priority sites for control include Kahurangi, Abel Tasman, Arthur’s Pass, Westland, Mt Aspiring and Fiordland national parks, the Catlins and Whirinaki. 

DOC's Amber Bill said in a statement in March they are planning to carry out predator control over 10,000 square kilometres.