Thames mangroves rule the roost

As the mangrove debate heats up over a National MP's support for an illegal chainsaw attack on the plants, it seems it's not just humans who spurn mangrove areas.

Thousands of migratory birds arriving at the Firth of Thames each year are refusing to roost in shore-side areas of shellbank gradually being colonised by mangroves.

The Miranda Naturalists' Trust, charged with protecting one of the world's most important migratory bird sites, is taking a radical approach to the problem by creating a new roosting site in a paddock across the road.

"A critical element for the birds to roost is to have visibility in each direction and of course mangroves don't give them that," said trust chairman David Lawrie.

It's a tricky situation for the trust because its supporters include some of the country's staunchest conservationists.

"We're aware of the contentious nature of the issue but we've taken the line that we'll be proactive rather than sit and wait for the mangroves to take over," Mr Lawrie said.

Trust supporter and Forest and Bird national president Dr Peter Maddison defended mangroves and blamed global warming for their spread.

"If seedlings get hit by frost they die but we haven't had frosts for the last few years."

Mangroves were an important part of the coastal environment, protecting the shore from storms and creating habitat for marine life, he said.

The trust bought a 13ha paddock a year ago and will gradually create suitable areas for the birds by scraping away grass to expose the shell.

Eventually bird "hides" will be built so the thousands of human visitors to Miranda each year can watch bar-tailed godwits and red knots close up.

Coastal engineer Andre Labonte, involved in a project near Mangawhai to clear mangroves in front of a coastal subdivision, said that scheme was going well, with sand gradually returning to the beach.

"What's missing in this debate is that we have to have a healthy balance between mangrove protection and mangrove management because we have altered the landscape so dramatically."

People resorted to "vigilante" action, as happened at Whangamata, because they were frustrated by red tape, he said.

Coromandel National MP Sandra Goudie found herself in trouble this week after supporting an illegal chainsaw attack on mangroves in Whangamata Harbour.

After discussion, residents and Environment Waikato have reached agreement to implement a mangrove management plan.

Whangamata Community Board member Peter Kerr said it was hoped no one would object, thereby avoiding an expensive public hearing.