Dramatic Change in the Mackenzie Country

I recently enjoyed the Environmental Defence Society conference in Auckland. One of the most disturbing talks was by Dr Susan Walker (Research Program Leader, Landcare Research), on the rapid deterioration in the Mackenzie Country. It had been some years since I last travelled through the area but I have just returned from seeing it for myself. We were treated to jaw-dropping blue skies, clear views of glacial lakes and the backdrop of Aoraki/Mt Cook and the Southern Alps. The landscape formed by uplift, glaciation and drought—caused by the alpine rain shadow—has created a stunningly beautiful area. This is not lost on our booming tourism industry, which brings in the majority of the income to the area. Busloads of tourists come to wow at the scenery. The Alps 2 Ocean cycle trail is gaining popularity. The natural environment here is brown and treeless. It is home to a remarkable biodiversity of plants and animals adapted to this harsh environment.

aoraki-mt-cook
Aoraki / Mt Cook

However, this unique environment is rapidly changing. The wrybill and banded dotterel that breed on the broad braided river beds are now subject to predation from cats and mustelids. Native plants suffer competition from grazing by rabbits and other introduced animals.

But there are two massive transformational pressures in this area which are having a dramatic and potentially irreversible effect. The first is wilding conifers and the second is agricultural intensification.

When I last visited Lake Pukaki in the 1980s there was a small plot of conifers on the shore of the lake and a few wildings downwind. Now there are continuous forests of conifers on either side of the lake. The wilding pines have well and truly taken over. Each of these mature trees is a seed source for thousands more. Small conifers are everywhere. The presence of pines reduces water entering the streams and lakes. Tussocks have been shown to harness airborne water and contribute to groundwater. They are now being overtaken. While there is evidence of some pine clearance and control work, it is only scratching the surface of the problem. What is needed is a properly funded plan to eliminate these trees from the landscape, including removing all the adult trees from public and private land. This could be funded from a levy on all plantations of conifer species known to spread naturally.

wilding-conifers
Forests of wilding conifers now line Lake Pukaki

The second train wreck affecting the Mackenzie and the upper Clutha is the wholesale destruction of the dry lowlands and replacement with large-scale irrigation and dairy cows. This is being driven by the tenure review process whereby lowland areas are generally privatised while upland areas are coming into the underfunded conservation estate. Most of these privatised areas are being developed despite existing rules limiting this transformation. Plans to tighten controls include Plan Change 13, but this has been held up for years by the legal manoeuvring of local landowners. Meanwhile the destruction continues. The changes to the scenery are profound and disturbing but there are some positive signs. Forest and Bird was involved in the development of a shared agreement in 2012, and the Mackenzie Country Trust, which was 4 years in the development, was launched this year. But more immediate action is needed. In my view there should be an immediate moratorium on agricultural development in the Mackenzie Basin and rapid implementation of an effective plan to eradicate wilding conifers.

Richard Hursthouse

 

References and Further Reading

http://www.stuff.co.nz/business/farming/agribusiness/73058496/the-alien-landscapes-of-the-mackenzie-basin

Forest & Bird was involved in a shared vision agreement in 2012: http://www.forestandbird.org.nz/files/file/The%20Mackenzie%20Agreement%20%20Final%202013.pdf

The Mackenzie Country Trust, which took a further 4 years to be formed, was launched this year:
http://www.scoop.co.nz/stories/PO1602/S00276/mackenzie-country-trust-launched-at-tekapo.htm

View Dr Susan Walker’s address at the Environmental Defence Society conference:  https://vimeo.com/178386338

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