Ecology and eco-system of Piha
Ecology and eco-system of Piha
The Waitakere Ranges and West Coast contain a unique range of 542 plant species in distinct ecological habitats, ranging from the herb fields of the wind and spray-swept coastal cliffs and the wetlands of Te Henga to the dense sub-tropical forests of the ranges.
Recommended
protected natural areas Piha contains several areas
that were recommended for protection by the Auckland
Regional Council in its Natural Areas Programme. For more on protected areas
on the West Coast see Waitakere Ecological District: Survey
report for the protected natural areas programme,
Auckland
Regional Council There are three ecosystems
at Piha. Exposed coastal
ecosystem This strip of land faces the
Tasman Sea and contains dunes, wetlands and exposed
coast. Pohutukawas and the dominant
tree species on exposed coastal dunes and cliffs. They can
cling to cliffs and tolerate sea spray. Other coastal loving
plants are manuka, kanuka, taupata, hebe, karo, karaka,
nikau, kowhai, tawapou, flax, toetoe, mahoe, ngaio and
olearia. Fires are a risk during
periods of low rain and have devastating effects. While
there are some fire-resistant plants - flax, mahoe - unlike
Australia, most New Zealand bush is destroyed by fire and
weed species can take over. Manuka. kanuka and bracken are
nature's healers after fire or clearance for farming,
explaining why these species are dominant on areas of the
west coast that have been burned through Maori and Pakeha
farming, and by accident. Stormy coastal hills
ecosystem The lowland forest contains
pohutukawa, puriri, kohekohe, karaka, red matipo, kowhai,
nikau, punga and other tree species. Trees can suffer damage
from strong winds which burn the tops off. Warm lowlands
ecosystem Back from the coastline
there is wonderful lush, dense bush. Trees such as the white
pine kauri, the red pine rimu, native tree fuschia kohekohe,
rewarewa, miro, tanekaha, and kahikatea form a bush canopy
with ferns and smaller shrubs such as karamu underneath.
Gullies, depressions and stream banks nurture nikau palms,
the majestic treefern mamaku and smaller ponga as well as a
huge variety of ferns and rengarenga lillies. Kohuhu, the
native tree daisy rangiora and tarata prefer more open
ridges. The Piha hills were
milled
for kauri during the
first two decades of the century and these majestic trees
were thoroughly milled out. All that was left were trees too
small to mill and misshapen specimens that were not suitable
for timber. Seventy years later, the Piha kauri are
regenerating - with a vengeance! These majestic trees are
once again rearing their distinctive conical heads above the
bush canopy on the sharp ridges and hill slopes surrounding
Piha and in the ranges themselves. Some ARC tracks take
walkers through thick groves of new trees - for instance,
the Home
Track. For more on Piha ecosystems
see A Guide for Planting and Restoring the Nature of
Waitakere City, Waitakere City Council, 1997
The sand dunes are home to plants such as spinifex and
stabilised dunes support ti (cabbage trees), the pepper tree
kawakawa and pohuehue.
The wetlands support a wide range of sedges, raupo, wi
(reeds) and flaxes.
Exposed trees are often severely bent by the prevailing
south-westerly winds and growth can be slow in the most
exposed places.