A financial battle too for Bay Bush Action

The skeletal remains of trees outside the Ōpua Forest trapping area. Photo / Geoff Reid

Extensive trapping in part of Ōpua Forest has seen possum numbers slashed, to the obvious benefit of native birdlife, but it's expensive, and Bay Bush Action is calling for cheaper and more effective approaches for forest protection.

The organisation's possum trapping has been hugely successful. While most of the forest has 94.7 per cent possum density, it is just 4.7 per cent within the trapping area has got the possum density down to just 4.7 per cent, volunteer and trustee Brad Windust saying the once gray skeleton canopy of this "amazing forest" had burst back to life.

"(It's now) full of beautiful different shades of green, and the huge northern rātā, that was saved in just the nick of time, is once again looking stunning with its bright Christmas crimson flowers," he said.

"When we started we spent many long nights out kiwi listening, but sadly none were heard calling. But our ongoing monitoring has shown they have been breeding up year after year, and we now have 22 kiwi. And it's not only kiwi that have been breeding up in the safe zone. Weka, once thought extinct here, are becoming common now, bittern are back, and the mioweka and fern birds have made a dramatic comeback.

"What is really cool is seeing a lot more mokomoko, the stunning green geckos with their bright blue tongues."

While the forest inside the trapping project was bursting with life, it was a grim picture in the remaining 2000ha that had had no pest control for nearly 30 years, however.

"As soon as you step outside the pest-controlled area the forest understorey is gone. It's like a herd of sheep has grazed it bare, but it's possums and rats snipping off the new seedlings as they pop up," Windust said.

"The canopy has been stripped and huge tōtara, hundreds of years old, are severely munched or dead, turning white as dead wood is consumed by lichen.

"What's really sad is the sun now penetrates through the canopy. With no understorey and very little leaf litter, it dries the soil, making it so hard that kiwi can't get their beaks in to feed."

Forest & Bird regional manager Lissy Fehnker-Heather said Bay Bush Action was helping bring native species to back Ōpua Forest, but most of Northland's native forests were dying without ongoing predator control.

"Forest & Bird is really concerned that the bulk of pest control falls to small community groups," she said.

"Northland's ngahere and native wildlife need all hands on deck, and way more funding. BBA are showing what can be achieved on a small scale, but Northlanders should be really worried at what's happening in their forests that don't have ongoing predator control, whether it's trapping or 1080.

"The key message from our perspective is that community trapping in Ōpua Forest is bringing back rare species, such as kiwi, but the majority of Northland's native forests are dying without ongoing predator control."

BBA's efforts to reduce possum density made it possible for native species such as kiwi thrive within the trapping area, but trapping was a labour-intensive and expensive form of predator control, costing about $380/ha, whereas other options such as 1080 cost $20/ha, and required much less manpower.

"We need more inexpensive and effective approaches for forests such as Ōpua, particularly since Northland has around 20 really significant rain forests, and over the last 30-odd years very little or no pest control has been carried out in the majority of them," she said.