environment

Mega mast: the forests left unprotected

There are fears that threatened species might go locally extinct on 300,000 hectares of top-priority native forest, David Williams reports.

The prospect of a pristine Southland forest being clear-felled spurred the Government into action in the mid-1990s.

The Waitutu forest block, 2171 hectares of podocarp forest near the Fiordland National Park, is a lowland wilderness rich in mistletoe and birdlife, including the largest known population of South Island kākā, a rare parrot. The wider area, set on a series of uplifted marine terraces, was a state forest that was added to the national park in 1999. Renowned botanist Dr David Bellamy once described Waitutu as “probably the most important forest in the world”.

Waitutu Incorporation, the Māori body that owned the forest block, announced in late 1993 a new deal to log it. Worried ministers ordered a negotiation, led by former commissioner of Crown lands George McMillan.

A historic deal was announced in 1996. The Waitutu would still own the block but – thanks to $13.55 million and rights granted to log elsewhere – the forest would be protected in perpetuity. The land would be managed “as if it were a national park”, a statement from Conservation Minister Denis Marshall said at the time.

Protective covenants on Waitutu Incorporation land were negotiated by the Nature Heritage Fund, a conservation funding body run by Government appointees. The fund paid for most of the cost of large-scale aerial 1080 poison drops across 20,000 and 30,000 hectares of Waitutu Forest – much of it former state forest added to Fiordland National Park in 1999 – in 2010, 2014 and 2016.

“If we don’t act, we could lose populations of bird species.” – Eugenie Sage

This year, the Department of Conservation and contractors are preparing for a so-called mega mast – a mass seeding and fruiting event for trees and tussocks that will spark an explosion of predators, like rats and stoats. More than 900,000 hectares of native forest across the country will be peppered with aerial poison, and a further 66,000 hectares will get ground-based trapping.

Conservation Minister Eugenie Sage said last month: “Responding to the increased threat from introduced predators during such a big mast year is critical if we are to retain our unique native species that set New Zealand apart from the rest of the world. If we don’t act, we could lose populations of bird species like our tree-hole nesting orange-fronted parakeet and mohua, and bats, which are so vulnerable to rat plagues.”

But Waitutu has been left waiting in the wings. It’s one of 21 areas, covering about 300,000 hectares, that were identified as a top-priority in 2019/2020 but didn’t make the cut as confirmed operations. This pristine forest, promised to be protected like a national park, is on the ‘B’ list. (Although it’s one of four lucky enough to be deemed a “proposed” operation.)

In 2014, DoC put out a media release saying 1080 drops had knocked rat and stoat levels to “undetectable levels” in the Waitutu Forest. Since 2005, the statement said, robin numbers had more than doubled and the population of South Island kākā had also increased.

Now, there are fears the hard-fought conservation gains at Waitutu, thanks to operations costing well over $1 million in total, could be erased in a single, disastrous season.

What’s in, what’s out

DoC’s predator control programme, Tiakina Ngā Manu, is decided by a team of eight ecologists and predator control experts. Starting in June, they consult threatened species databases for the most vulnerable species and whether their plight is getting worse.

Examples include takahē in the Murchison Mountains, in Fiordland. Haast Kiwi in South Westland. The orange-fronted parakeet in Arthur’s Pass and North Canterbury. Often 1080 poison drops are backed by ground trapping in a “belt and braces” approach.

(A DoC study released last month, which tracked 1080 operations in Tongariro Forest over 22 years, showed unequivocally that the aerial poison drops improve the survival of kiwi chicks. The Landsborough Valley, in South Westland, is another successful test case for intensive pest control, this time for mohua, using periodic pulses of 1080.)

Peter Morton, the department’s landscapes manager of predator free 2050, says other considerations for deciding its pest control priorities are feasibility – technically and the probability of success – and weighing up the costs and benefits, particularly areas with possible alternatives or other funding sources.

“From this, a recommended programme of work is put forward based on the best spread of resources available. We then consult with stakeholders to establish what support exists for the proposed work. This typically runs from August to February of the following year, after which we confirm the proposed work programme.”

DoC confirmed about 1.4 million hectares of conservation land as being at high risk during this year’s mega mast, Morton says. “These are sites that hold significant threatened species populations that will potentially be seriously impacted by predators in the coming year. That area of land exceeds DoC and contractors’ current predator control capacity, so the proposed sites were triaged to remove the least vulnerable.”

Sites covering about 300,000 hectares were under serious consideration, Morton confirms, but weren’t confirmed.

Site not confirmed for 2019/20

District

Ground/air

Grebe

Te Anau

Air

Waitutu Te Anau Air
Resolution Island Te Anau Ground
Takitimu Mountains Murihiku Air
Waikaia Murihiku Air
Kahurangi (Wakamarama) Golden Bay Air
Kahurangi (Burnett Range-Kaituna) Golden Bay Air
Kahurangi (Pakawau-Puponga) Golden Bay Air
Matiri Nelson Lakes Air
St Arnaud Range Nelson Lakes Air
Tennyson Inlet Sounds Air
Holdsworth-Penn Creek (Project Kaka) Wairarapa Air
Ruamahanga Wairarapa Air
Hakarimata Scenic Reserve Hauraki Ground
Horseshoe Bay Whitianga Ground
Kopuatai Hauraki Ground
Kaimanawa Mountains - Umukarikari Central Plateau Air
Opuiaki Western BOP Ground
Orokawa Eastern BOP Ground
Rangataua Tongariro Ground

Forest & Bird’s chief conservation adviser Kevin Hackwell feels for DoC, which is responding to what is probably the worst mast event in 45 years. He applauds the Government for committing extra money for pest control in last year’s Budget. (DoC is spending $38 million on predator control over two financial years, up from an initial budget of $30.5 million.)

“Good on them, they’re doing the maximum they can. But, clearly, as this extra table shows, that’s clearly not adequate and they know that.”

Hackwell’s convinced climate change will lead to more frequent mast years – which are caused by a difference in average summer temperatures. Indeed there have been three big mast events in the past five years. He wants the Government to spend more on pest control, particularly in non-mast years, to give businesses involved in control work more confidence to expand.

That might mean more helicopters, more specialised pilots, and more DoC staff trained in 1080 operations, he says. “We’re going to need it.”

(Interestingly, NZ Helicopter Association chair Scott McKenzie says the country has close to 900 helicopters – one of the highest rates of helicopters per capita in the world. “We do have the appropriate number of operators and pilots and helicopters to be able to do that programme.”)

Species under threat

Hackwell picks out vulnerable species from important areas that don’t have confirmed pest control operations: mohua and Fiordland tokoeka (brown kiwi) in northern Fiordland; pekapeka bats at Waikaia Forest, west of Roxburgh; giant land snail, green gecko, and great spotted kiwi on the western side of Golden Bay.

There are concerns, he says, that the weight of predators in the mega mast might lead to the local extinction of some species. “That’s just a reality of the fact that they’re in the second-half of a priority list.”

Just remember the plight of mohua at Mt Stokes, in the Marlborough Sounds, Hackwell implores. Trapping between 1985 and 1999 lifted numbers from five birds to 90. Then a mast year hit, without any accompanying aerial 1080. “They lost every last bird, they went extinct. They just got completely overwhelmed.”

Jan Riddell, the chair of the Nature Heritage Fund, is careful not to knock DoC for the difficult decisions taken to whittle down its pest control list. The fund is thrilled, she says, that such a large area will be controlled in the coming year. The previous largest programme was 840,000 hectares in 2016.

The Nature Heritage Fund allocates money to so-called SILNA forests – indigenous forests on land allocated to Māori under the South Island Landless Natives Act. It has about $176,000 in SILNA money left over for the coming year. The proposed Waitutu pest control operation, over almost 30,000 hectares, is estimated to cost about $450,000.

Riddell, who lives in Winton, less than 100km east of Waitutu Forest, says: “It’s a bit more complicated than just saying, yes, we’ll put that money there now.” She adds: “We’d like to think that the Waitutu will get on the [DoC confirmed] list eventually.”

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