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Published: 2013-05-10 00:00:00

Trial mangrove clearance at Whangamata is proving promising, says the Waikato Regional Council.

In March, the council began mechanical clearance trials over 4.6 hectares of mature mangroves.

With more than half that area cleared already, the council’s Whangamata project manager Emily O’Donnell said the methods used were proving effective. They involve the use of a digger, with root raking attachments, and chainsaws.

“We’re not seeing any unexpected effects on the coastal marine environment from using these methods at this stage,” said Ms O’Donnell.

“We’re seeing a continued healthy presence of crabs and mud snails in the cleared areas.

“The techniques we are using are limiting compaction of mud and will help the environment recover from the clearance.”

The next stage of the trial work is a section in the Moanaanuanu Estuary, upstream of the harbour’s causeway bridge. The full 4.6 hectares of clearance for this year is due to be completed by the end of June.

The National Institute of Water and Atmospheric Sciences is carrying out ongoing monitoring of the effects of the clearance.

“It is expected that if there are any negative effects they’ll show up within a few months – we’ll keep a close eye on that,” said Ms O’Donnell.

The pace of further clearance at Whangamata will be influenced by the results of the trials and the monitoring results. The council currently has a consent to clear a total of 18 hectares of new mature mangrove clearance and tidy up of previously cleared areas.

Ms O’Donnell also said the council was to work closely with Whangamata Harbour Care on some environmental restoration projects around the harbour, such as plant and animal pest control, and plantings.

Meanwhile, Thames-Coromandel regional councillor Simon Friar and council staff this week hosted staff and two councillors from Bay of Plenty Regional Council on a visit to Whangamata this week to see the clearance operation in action and to gain a better understanding of the techniques being trialled in this region.

"Both parties found the visit very useful. There is little doubt in my mind that regional councils need to work together to successfully deal with the issue of mangrove management and harbour restoration," Cr Friar said.

"Bay of Plenty is considering a variety of mangrove clearance options and we have been happy to share our experiences with them to see if what we’re doing is useful for them.”