Tide turns for prolific mangroves

By ANNE BESTON environment reporter

A coastal engineer involved in a project to pull out mangroves in front of a multimillion-dollar property development says the plant's protected status is a mistake.

Andre Labonte, with Auckland University of Technology marine ecologist Dr Andrea Allaro, will study the effects of pulling 500 mangroves from a 260m strip of shoreline adjoining the exclusive Waimarino Estate.

The pilot study is being paid for by developer Jim Lockwood, who is building a 13-apartment complex with tennis court and boat ramp on the shores of the upper Mangawhai Harbour, 80 minutes' drive north of Auckland. The apartments range in price from $695,000 to $755,000.

Mr Lockwood said clearing the plants would increase the development's value.

"From my point of view it's going to be amazing. It's going to double the value of my property," he said.

The project has the backing of the Northland Regional Council, Whangarei's Department of Conservation, local iwi and a harbour care group.

Mangroves have long been the subject of hot debate - harbour-side residents complain of clogged and muddy waterways while conservationists fight attempts to remove them.

Forest and Bird spokesman Barry Weeber is opposed to the Mangawhai project and the organisation has also lodged an appeal against mangrove removal in Tauranga's estuaries and harbours, consent for which has been granted by Environment Bay of Plenty.

"One of our concerns is the number of places people want to clear mangroves because they are cluttering up sea views."

Mr Labonte caused an uproar some years ago by suggesting mangroves were not native plants. Now he says their protected status is based on research by a former university professor, now dead, who studied mangroves in the US and simply transferred his findings to New Zealand.

"When we applied for resource consent I was asked to list the adverse effects of clearing the mangroves and I actually couldn't find any," Mr Labonte said.

He and Dr Allaro are carrying out a baseline ecological survey before clearing begins and will compare that data with the state of the shoreline in years ahead.

Aerial photographs from the 1950s showed mangroves had encroached on huge areas of the Northland coast, he said.

He hoped a sandy beach would replace the mangroves in two to five years.

Regional council chairman Mark Farnsworth said the council issued a non-notified consent, meaning it could not be challenged in hearings, after watching mangroves encroach on harbours and estuaries in Northland.

"We have ecosystems that are literally being swallowed by a mono-culture of mangroves," he said. "One or two" locals had expressed surprise at the scheme, but surrounding residents had approved the work.

Blessing or blight?

* New Zealand has one species of mangrove, avicennia marina

* Several marine organisms spend all or part of their lives in mangrove swamps

* Mangroves halt the spread of sediment into the sea

* They act as nutrient traps for inshore organisms

* They also provide habitat for native birds and animals, including herons, bitterns, pukeko, kingfishers, banded rail and spotless crake

* The total mangrove area in a 1996 Ministry of Agriculture report was 22,200ha, mostly confined to the upper North Island