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State Highway 16 Causeway Alliance Pest Control Works

At the end of 2013, Te Ngahere was contracted to carry out pest control services for the State Highway 16 Causeway Upgrade project as part of their avian and vegetation consent conditions.

A network of kill traps and bait stations was installed along with a line of monitoring tunnels to track pest control progress. These have been monitored and maintained under a flexible programme which has allowed Te Ngahere to reduce pest populations to a minimal level while also applying the company’s lowest toxicity policy in terms of bait type used and the amount of toxic bait placed out in the field.

The trap catch chart below shows the rats and stoats caught over the entirety of 2014.

A significant decline in rat numbers is evident after the first three months. Although stoats are known to be difficult to detect especially on relatively small and narrow work sites such as the SH16 Causeway, one was caught in October 2014. This was encouraging as it was during the time of year when ground-nesting birds are particularly vulnerable to stoat predation.

Since this start of this pest control programme, both Te Ngahere and Causeway staff have observed an increasing number of ground nesting birds on site, including an Australasian harrier nest containing two juvenile birds on Traherne Island.

Jaggers Bush

At a meeting of the Waitemata local board in early 2014, in a public speech, local board member Greg Moyle spoke of his delight when he found the most amazing bush and bush restoration effort.

This bush area was Jaggers Bush at the back of Seddon Fields, which he encountered one day whilst waiting for a football game.

His words were along the lines of “someone is doing a bloody fantastic job…I mean, really amazing work is going on down there…whoever is doing it keep it up and pass on my thanks”.

This is recognition of our efforts in Jaggers Bush, which began in the early 2000’s when Te Ngahere developed a restoration management plan, and has been implementing it ever since. We were confronted by tree privets standing some 20 metres tall and covered in climbing asparagus along with plenty of other invasive weeds.

Since then the focus of our efforts has been the selective targeting of the widespread invasive weeds and the staged removal of the privet canopy, which is being replaced by planted and regenerating native species.

The goal is to have a reserve with a self sustaining native canopy and understory, which we are confident will be achieved.

Funding for these works has been from Auckland Council’s ecological restoration and Small Local Improvement Projects (SLIPS) budgets.

- A photo comparison over time in Jaggers Bush.

The left hand picture is from 2002 showing plenty of climbing asparagus and tree privet, and the picture on the right is from 2013, showing lots of native regeneration.

Hochstetter Pond, Onehunga

Hochstetter Pond (formally known as ‘The Grotto’ or ‘Grotto Street Pond’), was recognised as an interesting geological feature on early maps (Charles Heaphy, 1860 and Ferdinand von Hochstetter, 1864) and its origins have long been debated. The site was occupied by a number of private owners from the time that Onehunga was established. In the 1940s and early 1950s the owner mined diatomite from the base of the wetland which was used to make a polishing powder called “Grotto Maid”.

Auckland City Council (now Auckland Council) purchased the site in 2007, to protect it from the threat of development. It is now a Council Reserve and has botanical, geological, historical and amenity value. Te Ngahere has undertaken ecological restoration work at Hochstetter Pond from 2007-2008 and 2011-present for Auckland Councils Maungakiekie-Tamaki Board, Small Local Improvement Projects.

Hochstetter Pond is a regionally important wetland consisting of Carex-Bolboschoenus sedgeland habitat. The site supports a good population of Carex subdola, which is an uncommon sedge in the Auckland region. Historically Hochstetter Pond has had a high density of weeds which have now been brought down to low levels. The banks surrounding the wetland were dominated by tree privet canopy and invasive vines including moth plant, blue morning glory and madeira vine. The weed vines are now absent and invasive seedlings are being controlled.

Mercer grass (Paspalum distichum) was found to be dominating areas of the wetland and potentially inhibiting the spread of the Carex subdola population. A methodology was developed to control mercer grass and allow for the spread of Carex subdola.

Because of the dense weed canopy present on the site limited natural regeneration had taken place. Native understorey species have now been planted and natural regeneration is occurring. This enables gradual thinning of the Chinese privet canopy to occur as native plants establish.

Restoration planting has also taken place surrounding the wetland by Te Ngahere and the community group Friends of the Grotto. Plants have been chosen which are suitable for the volcanic rocky nature of Hochstetter Pond.

- Before planting winter 2013 (left), and one year on, planting site winter 2014 (right).

Project index
S.H.16 Causeway Alliance Pest
Jaggers Bush
Hochstetter Pond
Rangitoto Island plant pest management
Weed Control on offshore islands
Whangaparaoa Training Centre
Tackling bittercress
Beach access, Kennedy Park
Feature project
Staircase for beach access, J. F. Kennedy Park
On a sheer cliff face beside a small park in Auckland's Castor Bay, Te Ngahere has built the proverbial 'stairway to heaven', featuring stunning views of the Hauraki Gulf .... more.
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