COASTAL PLANTING TO SHORE UP ISLAND EROSION
A coastal planting programme aimed at halting shore erosion on Rotoroa Island's northern beaches is already showing positive results.
Spinifex, flax and coprosma have all been planted along the
dunes of Ladies' and Men's Bays in a bid to recover some of the up
to five metres of sand eroded by intense easterly storms in recent
years. Just how dynamic our coastal environments are was
demonstrated recently with the effects of Cyclone Pam, whose power
deposited close to five metres of sand back onto our eastern
Rotoroa's ecologist Jo Ritchie, says the planting initiative came
about after a visit by coastal bioengineer, Greg Jenks. "Greg has
years of practical experience restoring coastal environments with
bioengineering - using native plants to help stabilise the dune or
beach fronts and gradually moving these out to trap sand.
"Greg's work at Mt Maunganui and Papamoa Beach on the east coast
of the North Island demonstrates that using native plants,
controlling weeds and managing how people get onto beaches are cost
effective and sustainable solutions to beach erosion."
Jo says that in the past, Rotoroa Island's coast would have been
dominated and protected with natural coastal vegetation, making the
island better able to withstand natural erosion patterns. "What we
are trying to do now is natural engineering with plants instead of
bulldozers and rocks and sand."
Not only are the new plants helping shore up the island's beaches,
they're also restoring natural coastal habitats for shore skinks
and other native insect species. So far, Jo and Phil Salisbury,
Rotoroa Island's resident manager, have reported enthusiastic
growth of the new dune plants. Many of the spinifex have runners
(long stems with multiple roots) that are at least four to five
metres long, while the ice plants have trebled in size and are
More plants will be introduced this year with the programme
extended to Home and Maimai Bays. Pingao (the partner sand-binding
grass to spinifex) will also be planted; pingao has stunning golden
blades and chocolate brown seed heads.
"Everything is connected to everything else," says Jo. "More
native plants equals more sand, more stable beaches, more diverse
habitats for native plants and animals, and immensely enjoyable
places for people."