Nature ground zero

by Rebecca Macfie / 01 January, 2011
The devastated native flora of the Canterbury Plains is being given a new lease of life by a small rural community. by

On the biodiversity map of New Zealand, lowland Canterbury is a swathe of bright red. It's what ecologist Colin Meurk calls "ground zero".

His colleagues at Landcare Research have colour-coded the degrees of devastation inflicted on the country's native vege­tation: red for those areas with less than 10% remaining, orange for places with 10-20%, and so on. Parts of the Waikato, Taranaki, Manawatu, Wairarapa and Southland bear the red of acute threat. But on the plains and basins of Canterbury, the carnage is almost complete. Less than 1% of indigenous ecosystems remain.

When Europeans settled Canterbury 150 years ago, the landscape was regenerating from the fires of early Maori, with extensive kanuka forests, pockets of matai and totara, and a mosaic of kowhai, cabbage trees, coprosmas, matagouri and silver tussock. But the region was a victim of its own geography. In hillier parts of the country, says Meurk, patches of bush in gullies and steep faces survived the advance of farming. But flat Canterbury could be tilled "wall to wall".

"The only places not cultivated up until 20 years ago were the driest, stoniest places, because it just wasn't worthwhile." But with the arrival of high-tech irrigation and the dairy boom - and the permissive legal framework provided by the Resource Management Act - even those remaining refuges for hardy native plants were lost to intensive farming.

Meurk says he doesn't sit in judgment of landowners who have transformed the region from a unique ecosystem into a landscape of industrial agriculture. "That's what humans do - they try to utilise the resources that are available. And I'm a beneficiary of that history, too."

But he has "gone through a grieving process, watching these last bits disappear. But the way I have reconciled it is to use the metaphor of ground zero, and say, 'We demolished that, where do we go from here?' We have to rebuild. It's less than satisfactory because it's always better to preserve primary environments, but that's where we are."

In the Waipara Valley of North Canterbury, which in the past two decades has become a significant wine-producing region, the chance to start rebuilding emerged five years ago. Lincoln University ecologist Professor Steve Wratten, of the Bio-Protection Research Centre, was working with local vineyard owners as part of a six-year publicly funded research programme investigating the use of biological controls as an alternative to chemical sprays and to build greater environmental resistance to pests and diseases. The project was dubbed Greening Waipara.

One of the early breakthroughs was using buckwheat (a member of the rhubarb family) to help control leafroller caterpillars, an introduced pest that gets among the grape bunches and creates a pathway for the fungal disease botrytis. Wratten explains that buckwheat flowers prolifically and is rich in nectar, and if planted among the vines it provides food and shelter for the parasitic wasp that lays its eggs inside the caterpillar.

At Waipara's Mud House winery, Swiss-born vineyard manager Jean-Luc Dufour was an early adopter of buckwheat, which he sows in every few rows of vines at regular intervals throughout the growing season. He says it has eliminated the need to spray for leafroller.

Wratten says using buckwheat as a form of "ecological engineering" can save $250 a hectare each year in sprays, and has been adopted by growers around New Zealand, Australia and the US. Plants such as Phacelia tanacetifolia (tansy leaf) and the honey-scented alyssum have also been found to attract and sustain predatory bugs like ladybirds and hoverflies.

But these are exotic plants, and Wratten says the holy grail is an indigenous species that could provide equally valuable "ecosystem services" - pollen and nectar to attract beneficial bugs, improved soil health, weed suppression and greater diversity and beauty in an otherwise austere monocultural environ­ment.

Meurk came in as an adviser, helping PhD student Jean Tompkins to whittle down a list of 14 native ground covers to plant under vines in a trial area at Mud House. Tompkins concluded that three species - bidi-bidi, shore cotula and creeping pohuehue - showed the most promise, hosting higher populations of insects and spiders than the rye grass and bare earth of the typical vineyard row, and boosting soil moisture and condition. She believes as the plants grow, they will reduce the need for ­herb­icides.

At the ends of rows, Dufour has also planted native jasmine, which is richer in nectar than buckwheat. He hopes it will help sustain the population of predatory insects, as well as looking beautiful.

As part of Greening Waipara, Dufour and the owners of three other well-established vineyards with tasting rooms or restaurants also began developing biodiversity trails for their visitors to wander through. Meurk is an expert in restoration ecology and has been the key adviser, selecting natives grown from local seed sources suitable for the conditions at individual properties. Vanloads of students from Lincoln helped with planting.

Torlesse Wines' Kym Rayner - an Australian by birth - has become one of the most committed local proponents of planting natives. Although the rabbits got the better of his own trials with under-vine planting, he has battled on against floods and exotic weeds - not to mention tough economic times in the wine industry - to get his now-thriving biodiversity trail established.

In the five years since Mud House, Torlesse, Waipara Springs and Pegasus Bay began planting their biodiversity trails, the project has spread to around 50 properties. Some 30,000 natives have been planted at vineyards, farms, the two local primary schools, and the fire and railway stations and on roadside verges.

Support has come from unexpected quarters. A few minutes up the road at Omihi, Mark and Louise Eder grow chemical spray-free blackcurrants, which are processed into a powder and sold to health supplements company Four Leaf Japan. Through that business connection, Four Leaf has become a major sponsor of Greening Waipara, since 2006 investing $130,000, which has helped pay for plants and part-funded a biodiversity "ambassador" employed by the local Hurunui District Council.

Waipara sheep farmer Daryl Harris is another key local champion, negotiating with officials to get permission for roadside plantings, applying for funding and rounding up helpers for planting days. "Any time we have a planting day I ring around the community, and 99% of people usually come ... We now get farmers ringing up asking if we can come and do some planting."

But Meurk says it's important not to get "starry-eyed". Re-establishing nature is tough. "There's a common perception that native plants will be low maintenance, and they are once they are established. But they often require very high maintenance to get going because they are competing with the world's most competitive and highly evolved [introduced] plants ... Canterbury is a very unforgiving environment. If it's not frost it's drought, or hares and rabbits. It's been very much two steps forward and one back."

But projects like this are a vital first step towards restoring balance in farming landscapes and reintegrating nature into our daily lives, he says. He has worked out that by regenerating areas like roadside verges, shelter belts, riverbanks and the corners of paddocks that can't be reached by pivot irrigators, 10% of the agricultural landscape could again be cloaked in native bush without loss of farm productivity.

"That links people to nature, so that everyone is within walking or cycling distance of some natural habitat. This is a crucial factor in the long-term preservation of our natural heritage. If people don't see something, it becomes irrelevant to them. That's been one of the problems with the polarisation of conservation of New Zealand - we relegate nature to distant mountainous national parks, which are wonderful but very remote from people."

Unlike in Europe, New Zealand's stark agricultural landscape is seldom used for recreation, says UK-born Wratten. "Britain has the public footpath scheme, and in Europe people cherish the countryside, the skylarks and the heathers. But no one wants to go for a walk in the Canterbury Plains - and if you do, you're likely to be asked to leave if you're on private land.

"But Greening Waipara is about changing that."


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