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Progress to date
The establishment of the sanctuary was one of the most significant breakthroughs in New Zealand's conservation movement.
Our achievements in urban ecological restoration; the eradication of invasive species; and the recovery of endangered native wildlife exceeded all expectations in its first ten years. We are recognised as the pioneer of a technology (fence plus multi-species eradication) that has provided a major breakthrough in feasible options for the recovery of native wildlife and ecosystems on the New Zealand mainland. 14 fenced sanctuaries, including 3360ha Maungatautari Ecological Island, have been established using technology pioneered at Karori. We have actively advised on similar projects being established in Australia & Japan, and fielded enquiries from Guam, Mauritius, Hawaii, and the Galapagos. In the space of just 15 years, this has become one of the best places in New Zealand to experience native wildlife in their natural environment, providing invaluable opportunities for all New Zealanders and visitors to learn about, experience and appreciate the natural heritage of New Zealand, and helping to influence their behaviour in their own environment.
Take a closer look at an overview of our key achievements to date.
While mice continue to exploit flaws in the fence mesh, their population has been maintained since 2004 at levels 80-90% lower than previous levels by an annual ground-based poison operation in order to minimise potential impacts on native fauna. We have also constructed a 1ha mouse-free enclosure (a 'sanctuary within a sanctuary') using the mesh we will progressively use on the perimeter fence. Mice have been successfully excluded from this area for more than 2 years and reptiles and invertebrates inside are expected to show the benefits of this in time.
Our biosecurity measures have been effective - we detected and removed weasel in 2004 and weasel and rat in 2008, both probably exploiting storm damage resulting in tree-fall onto the fence or debris wedging open the gate over the stream outlet. The fence has exceeded our expectations with no other species of pest mammal successfully breaching it to date.
Removal of pine trees from the fenceline has now been completed but work remains to progressively move the bush edge further away from the fence to minimise risk of treefall in future. Almost 100 species of weeds have been targeted for control or removal since 2000, and a similar number of native species have been planted in the valley during this time, many previously rare or missing.
The removal of mammalian predators in 1999 has seen a significant increase in resident birds such as tui, now dispersing into parts of Wellington where they have been absent for many decades. It has also enabled the translocation of 15 species of native animals back into the sanctuary, six having been extinct from the mainland for over 100 years.
Some of the transfers have exceeded expectations with self-sustaining populations quickly established in the valley despite the risk of dispersal over the fence. Our first transfer of robins from the sanctuary to another site occurred in 2007, only seven years after they were first released here. Other species have bred in the sanctuary since release but have not yet established self-sustaining populations. Some because they have not been here long enough (for example, tuatara, native frogs and giant weta), but others due to competition (eg tomtits moving outside the fence to avoid the closely related dominant robins inside that have failed to establish territories outside the sanctuary). We are currently challenged by trying to determine why there is a recruitment failure for young females following highly successful breeding seasons of honeyeaters (bellbirds and hihi/stitchbird), and the proximity of plentiful exotic resources in adjacent urban areas outside the safety of the fence (and away from dominant males) could be a factor.
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