History of Porirua's ecology

"The writing of histories - as Goethe once noted - is one way of getting rid of the weight of the past...The writing of histories liberates us from history."

- Benedetto Croce, History as the Story of Liberty.

 
Image of Porirua bush.
"...all in front as far as the eye could see along the coast, and over the right, was one wide unblemished cloak of native bush."
- Rod McDonald quoted by O'Donnell 1979
for more quotes describing Porirua pre-bush clearance, see below.
Photo from Pataka Museum Collection, at Porirua Library ref CD 20 Film 90 90_11.
 

Quotes describing Porirua pre-bush clearance

Rod McDonald described the view north from the top of Paekakariki Hill road at the turn of the century as "all in front as far as the eye could see along the coast, and over the right, was one wide unblemished clock of native bush." (O'Donnell 1979).

"Around the Pauatahanui Inlet the bush was not as dense and tangled as it was along the Porirua Road or in the Horokiwi Valley. Nevertheless, rimu and lesser species covered the hills down to the water's edge with kahikatea growing on the flats." (Heath and Balham 1994)

"Wakefield found the wooded ridges of Pukerua easier travelling [in 1839], the forests being of smaller timber and containing less supplejack…he saw only one clearing of native gardens and believed it to be 2 to 3 hundred acres…Behind the pa was the great protective forest land of Pukerua with big trees of rata, rimu and kahikatea." (in Kay 1996).

Various visitors referred to the kowhai trees that encircled the Porirua arm of the harbour. The region's swamps supplied plentiful flax fibre. Some of the earliest photographs taken in Porirua illustrate groves of nikau in the land behind Karehana Bay. Timber records from mills near the inner harbour tell us the big millable trees in the vicinity were totara, matai, rimu, kahikatea, pukatea, maire, and hinau.

Bush clearance in the 1850s

 
Image of Hurley and Carter's sawmill at Duck Creek on Francis Bradey's run,
Hurley and Carter's sawmill at Duck Creek on Francis Bradey's run, "Duck Creek."
The driver is G.H.Taylor. Pit sawyers: William Harris Snr (top), David Clark (under).
From a painting by John Bradey, Levin (in 1926), of the original oil painting by Frank Bradey in 1863.
New Zealand Electronic Text Centre. From "Early Wellington" by Louis E. Ward (Whitcombe and Tombs, 1928).
 

In the space of forty years, beginning in earnest in 1852, lowland Porirua was transformed from a largely forested landscape with scrub-clad sea cliffs, estuarine harbour fringes and scattered settlement clearances for pa, into a pastoral landscape.

The combination of milling and burning removed all tall forest, although in places a greatly damaged sub-canopy remained and in a few areas, mostly valley remnants and the extensive Porirua Scenic Reserve, were able to heal and readjust their composition and structure to suit the newly imposed ecological conditions (namely greater exposure, loss of emergents and many canopy species, erosion of soil, drainage). Massive soil erosion occurred with forest loss, and many estuarine areas silted up and became freshwater habitats.

Many native species were lost

 
Image of Porirua shore whaling c.1820-1840.
Porirua shore whaling c.1820-1840.
When a whale was spotted from shore, whaleboats were launched with seven crew and two harpoons.
A number of whaling stations were based in Porirua, including stations belonging to Joseph Thoms and Tom Wilson.
Photo from Pataka Museum Collection, at Porirua Library ref W.1.16.
 

Gone, through habitat loss and hunting, were most of the large, seed distributing birds, honeyeaters and shore-nesting birds. Greatly reduced (and still reducing) were the populations of geckos and skinks that also distributed seeds and played a role in flower fertilisation.

Gone were the marine animals that had attracted people to settle this coastline originally, and the colonies of muttonbirds and penguins that supplied guano to the coastal nutrient cycles and whose nests hosted tuatara and lizards.

Refrigeration in the 1880s hastened clearance

 
Image of James Gear who was an early pioneer of refrigerated meat, which he exported to England.
James Gear was an early pioneer of refrigerated meat, which he exported to England.
Photo from Pataka Museum Collection, at Porirua Library ref P.1.90.
 

The advent of refrigeration in the 1880s (ensuring larger markets for stock) hastened the clearance of the steeper, inland parts of the region. In the following period the longer term effects of pastoralism on the natural environment kicked in, along with new industrial impacts – the imbalance of nutrients in the waterways, the draining of wetlands, the pollution of harbour sediments.

Introduced animal and plant pests stressed many of the remaining natural areas to the point that they were too vulnerable to the eccentricities of climate and their community cannot be guaranteed.

Hope for the future

 
View of Pauatahanui Wildlife Reserve.
Pauatahanui Wildlife Reserve.
Photo by Keith Calder, 2009.
 

However, with the retirement of some farmland, and the protection of remnant natural areas in suburban areas, new biological communities are arising which are a natural response to new ecological conditions. With time, successional phases become evident. Although inhibited by predators, native wildlife returns to vegetation that is ample to supply food and shelter.

Continue to Porirua's Ecology Today, or return to Porirua's Natural Heritage.