The Big Wet

In February the Awarua Wetlands in Southland became New Zealand’s newest and largest site recognised under the International Ramsar Convention on Wetlands. Kathy Ombler explores these wildlife-rich southern wetlands.

It’s a long trip to Southland, even by godwits’ standards. The deep south of New Zealand is about as far as these long-distance travellers get from their Northern Hemisphere breeding grounds.

The godwits are not the only international travellers here: more than 20 other Arctic species also make the annual migration from the far side of the planet to the Awarua Wetlands. Regulars include several species that are rarely seen in New Zealand, including the grey-tailed tattler, sanderling and greenshank.

The wetlands are also frequented by shorter-distance avian commuters: about a third of the entire southern New Zealand dotterel population fly here from the mountain tops of Stewart Island/Rakiura to winter over in Awarua Bay.

Then there are the locals, who don’t bother going anywhere – like the fernbirds which flit about year-round among the boggy Awarua peatlands and shrublands.

Awarua Wetlands’ 16,000 hectares form one of the five major wading bird habitats in New Zealand, and a total of 81 bird species have been recorded here.

The wetlands are also rich in diverse and unusual plant communities. Plants normally found in alpine areas grow near sea level here. Alpine-like bog cushion, bladderworts, sundews and southern shore gentian mosses, and the largest coastal lowland red tussock remnant in New Zealand grow alongside an incredible diversity of wetland habitats and plants: bogs and peatlands, pea gravel beaches and shell banks, manuka shrublands and mudflats, saltmarsh and mature kahikatea forest.

Such diversity supports not only birds, but an outstanding variety of freshwater fish, lizards and invertebrates – including more than 100 moth species.

Bluff Hill is a good vantage point from which to absorb the sheer scale of the wetlands, sprawling their way further than the eye can see across Southland’s south-eastern tip. The viewpoint also reveals man’s intrusions on nature: the aluminium smelter at Tiwai Point, Invercargill city, industrial estates and dairy farms.

With all this human activity come threats: land reclamations, the outfall from Invercargill’s sewage treatment plant, risk of fires in the peatlands and oil spills in Bluff Harbour, and rapid increase in dairying across Southland leading to water quality concerns for the rivers that feed the wetlands.

But Brian Rance of the Department in Southland says some good things are happening.

“Attitudes are changing from the traditional mindset, where peat bog was seen as wasteland to be drained and manuka shrubland as scrub to be cleared. There has been a major change of attitude at New River, for example, from it being treated as a tip site and raw sewage outlet to the recipient of restoration and replanting.”

In 1994 Invercargill City Council initiated a restoration programme and walkway development along the estuary margins and, in 2004, closed a city landfill on the New River shoreline.

The highly invasive spartina grass, introduced to help reclamation, had spread across and silted up 800ha of New River estuary, but was brought under control in what is regarded as a world-leading eradication programme.

At Bushy Point, where conservation land and two privately-owned QEII Trust covenants are included in the Ramsar area, a community restoration group is undertaking pest control and wetland restoration.

The Awarua-Waituna Community Advisory Group, made up of landowners, DOC, Fish and Game, Southland District Council, Environment Southland, Aparima Runaka and Fonterra, has been working on a range of community initiatives to restore and protect the wetlands.

Living Streams, a pilot community-based programme for the Waihopai River, is working with adjoining landowners, monitoring water quality and planting and fencing off waterways.

Rance says the new Ramsar recognition can only help increase the community’s appreciation of its wetland treasures.

“A lot of people in Southland still aren’t aware of the significance of these wetlands - that we have these estuaries and open coastline and lagoons and peat bogs and the Bushy Point swamp forest growing right onto the estuary. All these values should be integrated and managed as one. Ramsar status can help achieve this, and raise the profile of the wetlands.”

Awarua Wetlands

Awarua Bay - a large, shallow arm of Bluff Harbour that encompasses extensive inter-tidal mudflats and salt marshes, edged by the red tussock cover of Tiwai Peninsula and low-lying peatland of Awarua Plain.

New River is the largest estuary, fed by the Oreti and Waihopai and several smaller rivers. Invercargill city sits against its eastern margin. The estuary’s tidal mudflats, shellbanks and saltmarsh margins support the greatest diversity of birds in Southland and the greatest number of summer visiting migrants.

Bushy Point, on the northern New River shoreline, extends from mudflats through saltmarsh into manuka shrubland and mature swamp forest.

Waituna Wetlands Scientific Reserve, immediately north of Awarua Bay, includes unmodified peatlands, manuka shrublands, forest, numerous ponds, a pea gravel beach and the 1400ha Waituna Lagoon.

Seaward Moss and Toetoes Conservation Areas are strongholds for wetland birds, including Australasian bittern, fernbirds and marsh crake.

Toetoes Harbour – the northernmost and smallest estuary, fed by Southland’s largest river, the Mataura, forms an integral part of Southland’s coastal wader habitat.