Rural Women volunteers near Dipton want 30,000 native trees for the swamp they have spent 13 years reviving

In one trap set in a forgotten corner of central Southland, volunteers found a possum, a stoat and a cat, caught one after the other. It is the kind of tally that tells you how much work is still to be done at the Castledown Wetland near Dipton, and also how far a small band of volunteers has already come since someone first pointed down the hill and asked a simple question.

The wetland covers about 12.4 hectares inside the 118-hectare Forestry Block owned by Rural Women New Zealand, and it is cared for by RWNZ members alongside the Southland Tramping and Recreational Club, with help from Environment Southland and Walking Access Aotearoa. Wetlands are scarce in the region, which is why this one matters, and why the group is now looking for help with its most ambitious job yet: planting roughly 30,000 native trees.

For years nobody gave the boggy ground much thought. Wetland coordinator Ann Irving told Farmers Weekly that changed in 2013, when committee member Ian Smith looked at the place differently. "The wetland had been ignored for years until we had Ian look down on what we thought was a swamp and say, 'What are you doing with the wetland?'" she said.

What they found was a site smothered by willows, wild plums, hawthorn and muehlenbeckia. Native flax had hung on underneath, and the land was already protected by a QEII National Trust covenant. Environment Southland drew up a restoration plan, which Irving admits the group did not always stick to. The early years went into the unglamorous basics: cutting tracks so people could get in, clearing around old firefighting ponds and setting traps.

There are now about 60 traps on the block, because possums keep wandering down from the neighbouring forest. Irving still sounds delighted about one A200 trap in particular. "We had one A200 trap where we caught a possum and a stoat and a cat in the same sequence!" she said.

The effort has been noticed. Environment Southland nominated the wetland for an Environmental Action in Waterways and Wetlands award last month, and although it did not take out its category, the project had already collected a Community Service Award earlier in the year. "We were pretty pleased. We'd had a nomination before several years ago and a lot of work has gone on since that time," Irving said. The judges, Environment Southland councillors Maurice Rodway and Ewen Mathieson, called it "a huge undertaking" and a very unique wetland in a part of the country where few are left.

RWNZ national president Heather Sorensen said the project showed what could be done when groups pulled together. The hard part now is money. "It's a really daunting project as far as money is concerned," Irving said, and the volunteers know they cannot plant 30,000 trees on their own. "We'd welcome any support."

She already knows what it will look like when they get there. "It'll be magical when it's all grown."

Anyone wanting to support the Castledown Wetland restoration can contact Rural Women New Zealand.