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Email Grant Norbury at: norburyg@landcareresearch.co.nz

 

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© 2019 Anna Yeoman for the Central Otago Ecological Trust

Home  >  Otago drylands  >  Conservation

Alexandra locals meet an Otago skink at Mokomoko Dryland Sanctuary. Photo: Anna Yeoman

 Eight hundred years of fire and 150 years of pastoralism have altered the landscape so completely that large stretches have no pre-human biota remaining. In isolated gullies, on rocky hillsides, in the forgotten and hidden fringes of the land, there are still remnant communities to be found. Yet even these have experienced some level of disruption, and now no examples of pristine or fully intact ecosystems remain.

 

New Zealand’s dryland zone covers one-fifth of our land area, spanning the eastern rainshadow regions of both islands. With over 70% of the indigenous habitat lost from these areas, the drylands now contain an exceptionally high proportion of New Zealand's most threatened species. Around half of New Zealand’s threatened plants are dryland species. 

 

New Zealand’s dryland environments contain some of the most transformed and least protected native ecosystems and species in New Zealand.

Olearia hectorii. Photo: Anna Yeoman

It is remarkable that such a catastrophic loss of a key New Zealand ecosystem has received such little recognition. One reason is that from the moment Europeans first sighted these dry eastern plains and foothills, they viewed them for their potential as productive agricultural land. Most of our drylands are still being farmed. A second reason is that the dryland ecosystems lack the image appeal that our green forests and high mountains exude. Somewhat unfairly, they have often been referred to as the ‘grey shrublands’, hardly appealing. While the original mosaic of woodland, scrubland and grassland would have contained the vibrant gold of flowering kowhai, the rich green of Halls totara and the flower and berry be-speckled Corokia, Pimelea and Celmisia, the remnant communities are often much poorer and subsequently much less attractive. A hillside covered in the fierce grey spines of matagouri elicits little conservation enthusiasm.  

 

Subsequently, we are left in the sorry position where less than 2% of New Zealand’s drylands are  formally protected. This is in contrast to the 30% of New Zealand’s total land area which is protected as national parks, reserves and covenants. Of the drylands that are protected, the vast majority are high altitude tussocklands, with only tiny proportions of the lowland protected. 

 

Finally, in the last two decades, the drylands have become the focus of greater attention and research. It is now recognised that although the dryland communities that remain are strongly modified, and often somewhat scrappy reflections of their original glory, they are of major conservation significance. They represent all that remains of a unique and diverse ecological zone, and they provide the only hope for its potential future restoration. 

 

It will still take time for this recognition to pass into tangible change for our dryland ecosystems. So much of our lowland dryland biodiversity is on private land, which means it falls to local councils to set and enforce conservation regulations in their area. Many councils lack both the knowledge and political will to do this effectively. Therefore, the real hope for restoring the drylands lies with landholders and local communities coming to appreciate and advocate for their native flora and fauna. The Department of Conservation along with Manaaki Whenua Landcare Research and QEII are working to support communities and agencies with education and assistance. Mokomoko Dryland Sanctuary is one of the products of this partnership. 

 

It is remarkable that such a catastrophic loss of a key New Zealand ecosystem has received such little recognition.

Therefore, the real hope for restoring the drylands lies with landholders and local communities coming to appreciate and advocate for their native flora and fauna.

Our drylands have all but lost their native communities of woody plants. In this, not only have we lost unique and fascinating plant communities, but the animals who rely on them are now at risk. Some populations of grand and Otago skinks, for example, face extinction within the next ten years if they are not protected from predators. Fortunately DOC are protecting the main populations of these species in the eastern part of their former range.

Woody plant communities are good for our animals

If we hope to save our native dryland birds, lizards and invertebrates we will need to restore areas of diverse and rich woody vegetation in our drylands. Our woody plant communities offer crucial food sources in their berries and flowers. Fifteen species of native moth have been found to feed only on Olearia. The woody plants provide shelter from the extremes of the Central climate. They also give protection from predators, especially for the lizards which retreat so effectively into the spiny Melicytus and tangled Muehlenbeckia. 

In an interesting relationship, restoring woody vegetation would also reduce the number of large predators. The more land that is covered in woody vegetation, the less that will be left as open grassland. Rabbits rely on open grassland, and if woody vegetation was allowed to return, then rabbit numbers would drop. A decrease in rabbit numbers would lead to a decrease in large predator numbers, such as stoats and ferrets. This would of course relieve some of the predatory pressure on our native species.

Coprosma propinqua. Photo: Anna Yeoman

Bibliography

Manaaki Whenua Landcare Research. Ecology and ecosystems - Why drylands? Retrieved from: https://www.landcareresearch.co.nz/science/plants-animals-fungi/ecosystems/restoring-drylands/why-drylands

 

Norbury, G. and Walker, S. (2010). What are drylands? Drylands in the revised Otago CMS. Retrieved from: https://www.landcareresearch.co.nz/science/plants-animals-fungi/ecosystems/restoring-drylands/powerpoint-presentations

 

Walker, S., Lee, W.G. and Rogers, G.M. (2002) Woody biomes of Central Otago, New Zealand: The present and past distribution and future restoration needs.