The importance of eco-sourcing

Ben Giesen checks existing kānuka reserves at Te Whenua Hou.

Ben Giesen checks existing kānuka reserves at Te Whenua Hou.

Eco-sourcing native plants for the Ngāi Tahu Farming Te Whenua Hou restoration planting programme is important to Ngāi Tahu and Lincoln University not only for ecological and cultural values, but also in showing leadership in the use and planting of appropriate plant species.

In future, almost all of the native species being planted around Te Whenua Hou as part of the Ngāi Tahu farming restoration planting programme are being eco-sourced – largely from small native reserves on the margins of the site. Seed for the shelter belt plants are now being eco-sourced from the wider Canterbury area using Proseed.

Ngāi Tahu Farming Project Manager Ben Giesen says eco-sourcing has always been a very important concept and from the outset he was keen that the programme’s partners, Lincoln University were involved in attempts to source seeds from within the nearby kānuka and mānuka reserves.

“Eco-sourcing has played a big part in how we select our plants. Our Whenua Kura students have worked with Lincoln staff to collect seed from the nearby reserves and Zealandia grows those for us. They come back to us as tiny seedlings and we grow them on in our onsite nursery,” says Ben.

One of the existing kānuka stands at Te Whenua Hou used as a seed source for new plants.

One of the existing kānuka stands at Te Whenua Hou used as a seed source for new plants.

Eco-sourced plants are those grown from seeds collected from naturally-occurring vegetation in a locality close to where they are to be planted as a part of a restoration planting programme. It’s an important part of any restoration project and it means plants will be suited to local conditions and more likely to flourish.

“By using eco-sourced native plants we keep the integrity of both the plants and the natural vegetation of the area and we’re not getting a mix of other varieties that are not naturally occurring in the area. It helps maintain the area’s unique plant characteristics and the vigour of individual species,” says Lincoln University Professor of Ecology, Nicholas Dickinson.

Many of New Zealand’s plants have adapted to local conditions, developing distinct attributes which give the species resilience against a changing environment or threats such as plant diseases. Through eco-sourcing, that resilience can be maintained and plants endemic to an area and climatic conditions are more likely to survive. This also ensures that genetic diversity is maintained throughout Canterbury and New Zealand.

“What we want to do is re-establish pockets of native vegetation around Te Whenua Hou, allowing the wind, birds and water to naturally redistribute seed over a wider area. We are encouraging and hope to introduce a variety of native animals and insects – an assemblage of plant species that are right for weta, leaf vein slugs, lizards, earthworms and other species,” he says.

Baby kānuka plants at the Te Whenua Hou nursery.

Baby kānuka plants at the Te Whenua Hou nursery.

One creature scientists will be looking out for and are keen to encourage is the very rare and threatened native ground beetle, known only by its Latin name Holcapsis brevicula, along with the threatened plant species Pomaderris amoena, in the buckthorn family, which is only found at Te Whenua Hou and a single Marlborough location.

“The original native ecosystems of the Canterbury Plains have suffered huge transformation over hundreds of years and what little that is left is some of the most threatened flora in New Zealand,” says Professor Dickinson.

“A number of our PhD, Masters and undergraduate students have been doing a lot of research and experimentation at Te Whenua Hou to ascertain the best ways of reintroducing a rich native biodiversity in the area – one that complements farming activities. It’s early days yet but we’re very pleased with the way these new areas at Te Whenua Hou are establishing themselves.

“Once they are fully resilient and have developed their own canopies, replacement plants will emerge in the undergrowth below. It’s very exciting and in years to come, these new plantings and reserves will encourage wildlife populations and habitats to connect and encourage the free movement and re-establishment of species.”

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