The Tides of Pauatahanul

Forest and Bird, Issue 309, 1 August 2003, Page 15

The Tides of Pauatahanul

—DAVE HANSFORD

DAVE HANSFORD explores a Forest and Bird wetland on the Wellington west coast.

anging on the porch of a small at Pauatahanui is a thick plywood panel. It’s not much to look at; perhaps a metre-and-a-half long by 60 centimetres deep, just five centimetres wide. But that small plywood structure — hung out to dry for maintenance — is the key to the rich biodiversity of Pauatahanui Inlet, a vital wetland reserve on the Porirua Harbour, 30 kilometres north of Wellington. The sheet of ply is a flap gate, explains Forest and Bird work party co-ordinator Ron Freeston. Normally it’s suspended in one of the main channels where, twice a day, the sea flows into the inlet bringing lifegiving food and nutrients. The flap gate simply opens to let it pass. But when the tide turns, the gate closes, blocking the sea’s retreat and forcing it to linger just a little longer, repairing the damage of decades of drainage and abuse. Inside the cottage, which doubles as a visitor centre and ‘smoko’ room, Stan

Butcher shows me an aerial photograph of Pauatahanui. You can’t help but notice the outline, somewhat overgrown now yet still distinct, of a perfect oval in the salt marsh. Judging by the scale, it’s perhaps 300 metres long. This is the scar of an old go-kart track, and its fading imprint says much about past attitudes to wetlands. But it says even more about how that attitude has changed in recent decades, to the point where Pauatahanui has become the focus of loving restoration and fierce protection from many different quarters. Stan Butcher has been involved with healing Pauatahanui from the very start. He remembers when, in 1982, the Wildlife Service offered Forest and Bird the opportunity to manage roughly 45 hectares

of salt marsh, flax, gorse and grass — and of course the go-kart track — at the head of the inlet. ‘We said a rapid "yes’? he recalls. The next two years were spent drawing up a management plan before Ron Freeston led local branches in work to return the lifegiving waters to Pauatahanui. Over the years, tracks and bridges were built, hides erected, weeds pulled and pests trapped. The group brought in giant excavators to dig out a series of backwater ponds, then planted up the banks to reassure shy waterfowl. That worked — shoveller and grey teal are now regular visitors, especially during the shooting season. Today, Wanda Tate leads a group which is taking back Pauatahanui by horticulture. Her volunteers source local seed to take home and propagate. When the seedlings

are big enough, they come back to the group’s nursery for re-potting, whereupon they’re grown on in the shade house or outside nursery. Smoky fires — allowed for the first time this year — are burning weeds and pine thinnings. A truckload of potting mix is shrinking by the barrowload as a team plant up kawakawa seedlings for the shade house next door. Another gang is busy building a culvert in a dry stream next to the groups’ latest land acquisition — a 1.7 hectare tract of

flax and rank grass. Pauatahanui’s salt marshes are pretty much self-sustaining now, says Wanda Tate. They’re well established, and there are very few exotics that can challenge native plants in such a difficult and specialised habitat. She’s keen to see emergent trees growing amid the remnant manuka/kanuka groves on the inlet’s northern shore, so she and her team have been scouring the surrounding gullies and slopes for what remains of Pauatahanui’s podocarps. The task was not easy — the farmers were

ruthless land clearers — but she’s finally found a very few kahikatea and totara to obtain seed for the next few generations. In other parts of Forest and Bird’s land, the group aims to recreate the mix of coastal forest that was once so widespread along this coast — kohekohe, tawa, titoki, matai and kahikatea. Wanda Tate says the present work site is dominated by rank grasses like tall fescue, so she’s taken to planting much older, taller shrubs that can stand their ground, rather than continually going about releasing new plantings. As the vegetation returns, so do the birds. Counts are up overall, both in density and diversity, although some species are bucking the trend in a baffling decline. Regular cockle counts done by another group, the Guardians of Pauatahanui Inlet, are revealing both a decline in numbers and an increase in deformities. Analysis by the National Institute for Water and Atmospheric Research suggests that pollution from road run-off may be the culprit. auatahanui means ‘big side of the paua shell’, and while no paua are to be found there now, the name perhaps describes the overall shape of the inlet. The surrounds are what real estate agents would call a ‘go-ahead’ place. Developers were quick to carve up the surrounding hill farms into subdivisions, and a new bridge — two extra lanes — is being built across the mouth of the estuary to try to cope with ever-growing volumes of traffic driven by Kapiti coast ‘lifestylers. An adjacent subdivision built nearly a decade ago was very nearly disastrous — Ron Freeston remembers having to go around and repeatedly dig the sediment from each and every choked stream culvert — but subsequent developments haven't been so bad, says Wanda Tate. Better planning and compliance monitoring have meant that even a major roading project right next door had very little impact on the wetland. And the decline of farming and the rise instead of the ‘lifestyle block’ mean that much less fertiliser and silt is now draining into the estuary. Brian Western has the job of tackling Pauatahanui’s pests and predators. He oversees a band of a dozen or so volunteers who service bait stations with brodifacoum to control rats, Fenn traps for stoats and ferrets, and cage traps to receive any feline visitors. Brian Western says that with so many houses nearby, domestic pets inevitably end up in the cages. They’re released unharmed, but he says, after a

night’s confinement in a cage very few of them reoffend. ‘The experience seems to be a deterrent. Many unwanted pets get dumped in the area, but the team is on top of the wild cats now. Not so the mice, which constantly reinvade from surrounding suburbs and pastures. There’s not much to be done except to leave them to the harrier and pukeko. It’s been a 20-year job for Forest and Bird, returning Pauatahanui from a dry, gorse wasteland to a vibrant ecosystem. And there’s a long way to go yet, but the efforts of people like Stan Butcher and Ron Freeston have captured the surrounding communities — the Stout Trust financed the cottage, which was painted by the Whitby Lions, who also donated money and built a new track. The Porirua Licensing Trust donated landscaping materials;

Porirua City Council and the Greater Wellington regional council supply potting mix and gravels. Lotto grants built the barbecues. The latest grant has come from the Nature Heritage Fund; and so it goes on. It’s not just the birds coming back. Memorial trees line the driveway to the cottage. Beneath them, plaques recall the deceaseds’ love of nature — or tranquillity — finding its ultimate expression here at Pauatahanui. Stan Butcher has known there’s something special about the place all along. He still gets a thrill when, each year, the godwits and knots return from their Arctic breeding grounds. ‘It’s a feeling, he says. "Something that keeps you hooked into the place.

is a photo-journalist with a

particular interest in natural history.