Doc planning big 1080 campaign to counter effects of ‘mega mast’

WELLINGTON: Forest & Bird is calling on the Department of Conservation to ramp up its response to this year’s ‘‘mega mast’’, which could unleash a plague of predator on threatened native species.

The department is already planning on spending $30.5 million over two years to carry out the largest aerial 1080 programme in New Zealand’s history.

During a mast year, which is triggered by a cool summer followed by a warm summer, large numbers of beech trees fruit heavily at the same time across the country.

Rats and mice feast on the seeds and their numbers boom, and so do those of the stoats that prey on them.

As the weather cools, the rats and stoats turn to birds for food.

This year, ancient podocarps such as kahikatea and rimu are showing signs of heavy seedfalls as well.

Department of Conservation scientist Graeme Elliott said based on current predictions and historical climate records, it was looking like the most extreme mast for 20 years.

In response, the department is planning its biggest series of 1080 poison drops, which are expected to cover about 1,000,000ha of native forest, up from about 860,000ha in 2016.

It is also planning an extensive ground campaign of traps and bait stations in the more accessible areas. Dr Elliott said if nothing was done, the impact on species such as the mohua (yellowhead) could be dire.

‘‘The places that we’re most worried about are particularly around Arthur’s Pass, where there are small populations of mohua and rock wrens hanging on, and there are the remnants of the orangefronted parakeet population.

‘‘Otherwise, there’s populations of mohua and bats in places like the Eglinton Valley in Fiordland that might take a hit, the Dart Valley near Lake Wakatipu, and the Catlins.’’

He said the department’s plans did not go far enough.

Doc did not have access to enough helicopters or bait supplies.