An Environment Waikato Hearing Committee has approved the removal of an area of mangrove bushes from Patiki Bay, Whangamata.
Whangamata Harbour Care applied to remove the mangroves from the coastal marine area. A total of 31 submissions supported the application and seven opposed from DoC, Royal Forest and Bird Society branches and Te Ruunanga O Iwi O Ngati Tamatera.
The applicant says the mangroves are compromising public access to open water, residents’ views and the established visual and recreational amenity value of the area. The bushes would be cut at bed level with chainsaws and pruning saws, with seedlings and young plants hand weeded and removed. The work would be done by volunteers supervised by Harbour Care members over two or three weekends, with cuttings brought ashore for mulching.
The designer of the environmental monitoring of trial clearance plots in 2000, Dr Brian Coffey, said that further removal would have a similar low impact on the bay. Whangamata Harbour Care secretary Dr Hans Zuur said the bay was characterised by increasingly muddy areas and mangrove proliferation. Removal would enhance the biodiversity of the bay.
The group had discussed the issue with tangata whenua about how to manage the mangroves. Dr Zuur disputed that the proposal would result in further significant loss of coastal bird habitat. He considered the issue of natural character was not relevant, given that the mangroves to be removed did not exist in the bay 20 years ago.
Submitters in favour of the proposal asked for common sense to prevail in controlling the mangroves without delay as they were not a threatened species and their removal from the bay was unlikely to affect the overall health of the harbour.
Those opposed said the proposal was not consistent with the New Zealand Coastal Policy Statement and Waikato Regional Coastal Plan. Iwi opposed the initial trial clearance fearing that further applications would follow. Iwi remained concerned about the overall objective of the applicant in removing an ecologically valuable indigenous coastal plant.
Not enough consideration had been given to the human causes of mangrove spread and no evidence had been presented to show the beneficial effects of the previous clearance trial on the environment, they said.
Environment Waikato ecologist Dr Stephanie Turner said Environment Waikato was a member of a steering group seeking to increase scientific understanding about mangroves.
The Hearing Commissioners said while all parties agreed that mangroves had spread rapidly in recent years, there was disagreement on the need to control them. The decision would need to balance relevant coastal policy with environmental effects of removal. The area was 0.3 percent of total mangrove habitat in the harbour, which was unlikely to result in significant adverse effects.
The Committee would have preferred that the applicant had developed a management plan for the whole bay for long term control rather than a piecemeal approach and consent should be limited to a five year term to allow the community time to determine whether to proceed with controlling mangroves in the wider harbour.
Further research into managing mangrove spread should be co-ordinated nationally to ensure a consistent and practicable approach to the issue, the Commissioners said.