By Karen Baird, Tue, 26/01/2016 - 02:22
Around half of the ten or so New Zealand Fairy Tern pairs remaining in the world breed at the beautiful Northland harbour of Mangawhai. They nest on the enormous sandspit where the Department of Conservation and NZ Fairy Tern Trust maintain a trapping programme for predators and the nests are closely monitored during the breeding season. However in recent years the so-called Mangawhai Harbour Restoration Society (MHRS) have decided they want a mangrove-free harbour and applied to the planning authorities to allow removal of mangroves. In 2012 the Environment Court allowed for some removal in the middle harbour which was carried out this past winter. Conservationists have been concerned that removal of mangroves would deplete one of their major food resources, the gobies which live and feed amongst the mangrove pneumatophores. A foraging study was carried out by Karen Baird from the New Zealand BirdLife partner, Forest & Bird in collaboration with other scientists and published in Bird Conservation International (Ismar et al, 2014: Foraging Ecology and Choice of Feeding Habitat of the New Zealand Fairy Tern Sternula nereis davisae). The study showed that NZ Fairy Terns feed their chicks on these mangrove inhabiting gobies, preying on them when they move out of the mangroves at lower tide levels and into channels and pools on the tidal flats.
MHRS have now unveiled plans for a ‘stage two’, to remove more mangroves. This is despite a ruling already by the Environment Court that the area they’ve targeted should remain. There is increasing pressure in northern New Zealand from Tauranga northwards for councils to relax planning rules around mangroves which have previously enjoyed reasonable protection due to their high ecological values.
Mangroves are continually the target of prejudice, considerable misunderstanding and what amounts to a concerted campaign often based on misinformation. These negative views on mangroves include that they are: an introduced ‘pest’ plant which is taking over our northern harbours, limiting people from enjoying open space for speed boats and jet skis; obstacles to marina developments and reclamations, and are seen by developers as reducing the attractiveness of the coastal properties they hope to sell.
Mangroves are native to New Zealand. Their ecological value as nurseries for marine life is well known, they are home to threatened bird species such as the Australasian Bittern and Banded Rail, and act as natural buffers protecting shorelines from erosion.