FOREST RESTORATION AT OTARI WILTON'S BUSH
Otari-Wilton's Bush Trust members and volunteers have been pivotal to the conservation and development of this precious native bush and forest. Their efforts have also inspired similar work elsewhere in the region, with over 100 restoration projects now ongoing
in wider Wellington. Here are just some of the Trust's projects:
KAIWHARAWHARA STREAM PROJECT
Otari led the way in forest restoration with the Kaiwharawhara Stream project begun in the early 2000s, the Trust's largest initiative to date. Aimed at restoring the unique ecosystem of the main stream flowing through Otari, the project involved:
- improving the biodiversity of the valley floor
- encouraging native birds and insects to flourish once again
- preventing erosion & improving water quality
- preventing the downstream spread of pest plants
- improving the valley's scenic values
- providing a learning experience for all those involved.
Planting started in 2001, and by 2006 over 35,000 native trees had been grown from locally sourced seed and planted in the valley. This has been followed by regular subsequent plantings and monthly maintenance, now focusing efforts at the south end of the stream.
The work inspired neighbouring groups to Otari to join forces to create an eco-corridor in the valley, running the length of the stream from Karori through Otari and Wellington's western suburbs to its outlet at the western shore of Wellington Harbour.
The project was initially supported by grants from the Greater Wellington Regional Council and Wellington City Council. Now the work continues thanks to Trust volunteers who hold monthly working parties at the site.
Individuals and groups turned a mammoth task into a great success, and the Trust thanks all those who have supported the project with their enthusiasm and energy.
PREDATOR CONTROL AT OTARI
This is a joint undertaking between volunteers and the Greater Wellington Regional Council. The main targets are opossums, mustelids (stoats and weasels), Norway rats (Rattus norvegicus) Ship rats (Rattus rattus) and hedgehogs.
These predators effectively eat the forest from above, preventing regeneration of new forest by eating seeds and, by eating seeds and insects, depriving birds of food. Of course, they also eat the birds and birds’ eggs too. Rats can swim well and climb well so nothing is safe.
There are now 82 bait stations at Otari, targeting opossums and rats, and serviced by Regional Council staff. They are located well off the tracks attached to trees. Dogs must be kept on the leash as some pellets will inevitably be dislodged by opossums and rats.
'RAMBO' TO THE RESCUE
In 2007 a trap network was set up using the DOC200 trap and this is overseen by volunteers who operate under the name 'RAMBO' – Rats and Mustelids Blitzing Otari. Because the traps are targeted at stoats and weasels they are on a wide spacing as those animals have a large range. They also get a lot of rats and hedgehogs. There are 70 traps both within Otari-Wilton’s Bush and along the boundaries to prevent re-invasion. These traps are over six trap lines looked after by eleven volunteers.
The Regional Council also does bi-annual monitoring of predator levels using some 65 tracking tunnels. In the latest results only 5% of tracking tunnels showed rat activity and none showed mustelid activity. Some 10% showed hedgehog activity. The rat activity level has been below 10% since 2010 which is good for the native flora and fauna. Of course the real measure of success is the increase in bird life and increasing numbers of new seedlings.
THE BIG PICTURE
The predator control carried out in Otari-Wilton’s Bush is a small part of a bigger predator control effort. There are Council bait stations in Johnston Hill Reserve to south of Otari-Wilton’s Bush and volunteers from other groups have DOC200 trap lines that go from behind Karori along the Sky Line to Mount Kaukau.
Also along the Sky Line are Timms traps aimed at preventing opossums from re-invading, with a Regional Possum Predator Control Program operating west of Otari Wilton’s Bush out towards the coast. Finally, backyard trapping programs have been set up in the suburbs around Otari Wilton’s Bush which will limit re-invasion from houses.
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