Large scrub fire at Waikato wetlands not the first

The internationally significant Whangamarino Wetland, where 1000 hectares has been burned by a large scrub fire, was extensively damaged by fire in the past.

The wetland near Meremere in Waikato is home to a rare orchid not found anywhere else in New Zealand, as well as other unique plants and wildlife.

According to Waikato Regional Council, the 7100 hectare wetland made up of peat bog, vegetation and fen, was the scene of two fires in the 1980s.

Those destroyed 57 percent of the vegetation and left large areas vulnerable to introduced plants, the council's website states.

"In areas of high fertility these exotic plants could dominate the native plants and prevent natural regeneration."

The Department of Conservation (DOC) undertook controlled burns at the wetland during winter to allow the tiny terrestrial swamp helmet orchid, or Corybas carsei, to grow uninhibited by larger vegetation.

Ironically, the lack of fires because of necessary fire control meant "burn hole habitats" were uncommon and this had caused some plants, such as the rare orchid that depend on such burn holes for external nutrients, to become threatened with extinction.

Last year there was only 500 of the little flowers left, some of which had in the past been stolen by international plant enthusiasts.

DOC Waikato, Hauraki and Taranaki regional director Tinaka Mearns told Midday Report although the current fire was devastating, the direction it was moving did not directly threaten the flower.

"We're just constantly monitoring that space at the moment."

However, she said DOC held concerns for much of the biodiverse wetland, which also provided a breeding ground for the matuku-hūrepo bird.

The wetland was one of three in Waikato listed on the International Convention of Wetlands of International Importance (Ramsar sites) making it ecologically significant. There were only seven in New Zealand.

The other two are Kopuatai peat dome in Hauraki and the Firth of Thames estuary.

Since the 1840s, the draining of wetlands to convert to pasture had resulted in the lost of 83,000 hectares of wetland in Waikato, with only 27,000 hectares remaining, the regional council said.

"Habitat loss and the isolation and fragmentation of wetlands have led to a decline in many wetland plants and animals, with many now threatened with extinction."

Wetlands were no longer allowed to be drained.

A former DOC ranger, who did not want to be named, said there were a number of ways a fire could start in a wetland including lightning strikes, a spark from farm machinery, or by a farmer or resident burning off rubbish that spreads to the wetland.

There was also concern that peat soil fires release large amounts of carbon dioxide into the air.

The DOC ranger said in the past, if a fire was caused accidentally by a resident they faced a life-changing bill to pay for the cost of putting it out.

The current fire began on Monday and was now 15 kilometres wide.

Fire and Emergency New Zealand incident controller Shane Bromley told Midday Report 50 firefighters, seven helicopters and two planes, were on track to bring the fire under control by 8pm today.

Bromley said the fire was being fought from the air because the wetland made it impossible to bring in large machinery and create fire breaks on the ground.

This was impacted for 10 minutes on Wednesday afternoon when a drone was sighted in the area near the fire, a second incident controller, Mark Tinworth, said.

Air operations were halted as was standard practice, Tinworth said, because a drone posed a serious threat to aircraft.

He said a mid-air collision between a drone and a helicopter could have fatal consequences.

Meanwhile, Bromley said at least six houses were at risk on Monday night but they, and surrounding lifestyle blocks and businesses, on Island Block Road were now safe.

He said firefighters were now trying to protect and prevent 280ha from catching fire.

The peat soil was particularly challenging because it continued to burn underground, making it difficult to extinguish the fire.

Bromley said fire safety investigators were still working to determine the cause of the fire.

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