Manukau Courier – 15-02-2007

Mangrove spread
When I was a child growing up in the 1930s, the nature of my father’s employment dictated that we moved frequently.
Several locations were near estuaries where we were able to swim off the sandy beaches — for example, Waingaro Landing.
On a memory trail recently I found many of these beaches were no more.  In their place were hectares of dense, muddy mangroves with largely no access to the water.
The whole of your front page on Februaiy 1st was dedicated to a lamentation on the cutting down of mangroves to allow residents access to the water.
I am aware the Resource Management Act restricts the removal of mangroves.
However, this act was formulated before the impact of the spread of mangroves in certain areas became as severe as it is now.
Some councils have realised the detrimental effects of unchecked mangrove spread can outweigh their cultural and ecological benefits and have acted accordingly.
For example, a year ago the Northland Regional Council realised mangroves were encroaching at an alarming rate into previously uncolonised areas to the detriment of the area’s economic, social and cultural wellbeing.
They also recognised another fact that is ignored by many — due to the large tidal ranges of most of our coasts the mangrove roots are drained for a good part of the tide cycle, which calls into question the speculation that they are nurseiy areas for flsh
The council thus proposed a plan change to allow greater opportunity to remove or prune man- groves.
The spread of mangroves is due almost entirely to the presence of nitrogen in the water, which in turn is largely from ground water originating on farmas
In theory this can be reduced,  in practice it won’t be. It is an impracticle dream.
Northland, Raglan, Thames and Tauranga, to name a few, have been sensible enough to realise that the spread of mangroves is a man-made problem, not a natural ecological phenomenon, and must beheldindwrt
it is a pity that those who draft the RMA do net realise our land must provide for the needs of the human race as well as some sealife.

D R MUIR

Manurewa