Maungatautari Sanctuary Project 2014

Maungatautari Mountain has been a reserve for 100 years, but early this century a plan was devised to ring fence it with a predator proof structure and eliminate all pests within the area. The 47km of fence was finished in 2005 making the 3400 ha “island” the largest pest-proof fenced reserve in the world. Pests were eliminated by 2007 and many existing bird, frog, fish and insect species have flourished, while many others have been reintroduced.

For neighbouring farmers there have been both positive and negative influences as a result of establishing the ecological island and the project’s continued success is heavily dependent on farmer co-operation and goodwill.

Maungatautari Mountain was made a reserve in 1912 because a wildlife service survey identified its forest as being of great significance. It contained mature and intact conifer/broadleaf/podocarp forest species including a remnant stand of about 100 silver beech trees (discovered in 2006) thought to be relics of the last ice age. It was an environment as close to pre-human New Zealand as it was possible to find.

However in subsequent decades, the ecosystem was damaged by introduced mammals including; rats, mice, cats, pigs, possums and mustelids that ran wild and predated flora and fauna. Native species dwindled and many disappeared.

Early this century an ambitious plan was drawn up to construct a 47km predator-proof fence surrounding the mountain and cull all introduced pests. A trust was formed to raise funds and manage the creation of this 3400 ha ecological island. Starting in 2003 two trial areas of 35 hectares and 65 hectares were developed to prove that a pest-proof fence could be constructed and maintained in a tall forest environment and to test pest eradication and monitoring techniques. In 2005 kiwi were introduced to the northern enclosure and takahe were released into a pest-free wetland area.

The perimeter fence was completed in 2005 and the predator eradication programme began. It wasn’t until March 2007 that the last two wild cats were caught and monitoring showed that all introduced mammals except mice had been eliminated. Within a year the numbers of tui, bellbirds, kereru and other birds increased, plant growth started to become more dense on the forest floor, and insects were noticeably more active. Kokopu (native trout) and kaka were introduced and the first kiwi chick was born.

Since then a number of other species have been released: hihi (stitchbirds), popokatea (whiteheads), pitoitoi (Nth Island robins), tieke (saddlebacks), tuatara and Mahoenui giant weta. Visitor facilities have been developed, along with aviaries and an enclosure for tuatara.

The trust employs 10 staff and four contractors and relies on over 400 volunteers to support operations staff in monitoring and maintaining of tracks and tracking lines, monitoring the health and growth of various wildlife species, and weeding.

Matt Cook, the natural heritage manager, says that there have been many changes since the perimeter fence was completed. “The bush is completely different now. Staff who were here in the early days say that when walking through the bush at night all they could hear would be the rustling of rats. Now when you go in there, you hear kiwi calling out and you can’t walk through the bush easily because the floor is all overgrown,” says Matt.

“With the eradication of rats there has been a resurgence in insect life and we have been able to reintroduce giant wetas safely. A small population of the endangered Hochstetter’s frog was also found, so it looks as though the conservation programme was started just in time to save them.”

Much day-to-day work of staff and volunteers now involves maintaining the integrity of the fence, checking culverts and placing tracking cards around the inside of the fence at 100 m intervals every month. The animals walk across them and leave a footprint so staff can see whether any mice or rats are present.

“For mice on the main mountain we don’t worry, but in either of the two enclosures it is a problem, so we respond to that,” says Matt. “We have a response plan that specifies what we do in terms of trapping and bait stations, the density and type of traps and the baits. We run a response for six weeks and after that time if there is no detection, the response will finish, but if there is, the six week response starts again.”

“For example, recently we detected a rat at fencepost 227 and we caught a male rat. We will continue to monitor for six weeks because there is a timeframe from when a rat gets in, to how quickly they will disperse. If a fence goes down, for example if a tree falls across it, the fencing team need to get there and secure it within 90 minutes to stop any invasion and if they go over 90 minutes we have to go in there and put out traps and baits etc.”

Numbering the posts along the 47km of fenceline is a convenient way of locating points on the boundary. The fence has a sensor wire on top. It is made up of a series of zones and within those zones there are dialers, so that as soon as the wire is earthed it sends an alert and someone goes there immediately, even in the middle of the nigh, to check what has happened.

There are two staff members monitoring the fence full-time looking for damage and holes (a mouse can get through a 4mm hole) and they know the problem zones where the fence is less stable or at risk of damage. They also monitor culverts, which are designed to open and flush in floods and then reset, but often they don’t because debris gets caught.

Access to the fence is critical, and while there is a 4WD track alongside the fence it usually saves time and is far easier to go through one of the neighbouring farms. This can cause some disruption and wear and tear on farm races, and MEIT staff are very aware that they rely on the goodwill of farmers to help protect Maungatautari.

“Without the farmers we don’t have a project. Some farmers are happy for us to just turn up, others prefer us to give 24 hours notice, and we live and breathe that,” says Matt. “We respect their wishes because they are trying to make a living off the land and we need their help to protect the fence and mountain.”

Bill Garland is one of the island’s neighbours and an ardent conservationist. His property spans from fenceposts 275 to 341, one of the longer spans of shared fenceline. Bill is a volunteer and has been known to get up at 2am to help staff secure the fence when a tree blows across it in a storm. He is happy to support the trust and enjoys what it provides, but acknowledges that there is some cost to him and other farmers in terms of wear and tear on farm tracks, inconvenience and restrictions on development.

“We get quite a lot of traffic through the farm. On average about one vehicle per day and sometimes up to four and we have to manage that so it can be a bit of an inconvenience. There is a risk that people coming on the farm could put the business at risk through carrying poisons or spraying, and we are on a quality assurance programme with Whole Foods of America and they are very sensitive about residues, so we have to be very careful about that,” says Bill.

“Health and safety is another issue. We can have people driving around hill country at lambing time to service the fence and check bait stations and tracking tunnels etc, and at lambing last thing you want is people wandering around the farm. So those are the sorts of issues that we have to deal with, but we have figured out ways of managing it.”

Bill also points out that the fence doesn’t always follow the legal boundary and in some places cuts corners. Many farmers have lost some grazing land that is now inside the fence, and on the outside of the fence there is the width of the access road that is also not grazed. There are also some restrictions on subdivision. However, there are also benefits from having the ecological island as a neighbour.

“As a conservationist, I love the bush and love seeing the birds and the land behind the fence is being managed from a biodiversity point of view to a standard that we could never have dreamt of doing, because they have removed all the pests,” says Bill.

“That’s a big plus and another plus is that the native birds are around our farm in much greater numbers now. We took grandchildren into the bush just around Christmas time and camped there to listen to the dawn chorus and that was very special.”

“Another plus is that in the long term, farmers may derive some financial benefit by having visitors come throughout the year – they could have people camping and listening to the dawn chorus or have a hut or cottage for people to stay in, and so on. And then you got the fact that the organisation is looking after the back boundary fence and getting out there in all sorts of weather and fixing it when trees fall over it.”

The mountain is no longer a breeding ground for possums, and this helps protect the TB free status of the surrounding area. It is also not a source of rats, stoats and other mustelids. Water clarity from mountain streams has improved although it is suspected that the increase in bird life is responsible for the finding of Campylobacter in the water, and farmers are advised to filter any water they use.

However, the biggest plus for Bill and many of the other farmers are the intrinsic benefits of being able to hear the birdsong, hear kiwis at the back of the property, see more birds around, and feeli that they are part of something worthwhile.

“The thing that blows people’s minds is what the bush actually looks like now. We have some lane ways through the bush with fences on both sides and they enable us to access paddocks that are through the bush but at the same time protect the integrity and pest control that’s gone on inside. I would never have believed just how much regeneration you get without rats and mice,” he says.

“We have a QEII covenant block that is inside the pest-free fence and I have photos from about eight years ago showing that it is quite open despite never being grazed by cattle, deer or pigs. Now when you go in, you see that the regeneration is absolutely spectacular and there is a more diverse range of plants.”

Bill regrets the lack of a sustainable legal agreement to protect the investment in the fence on private land, and the bureaucracy that has prevented this from happening.