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Protecting our precious places

Olearia shrubs: Unique divaricating species

A striking feature of New Zealand’s biodiversity is the many small-leaved, twiggy shrubs covering our landscapes.

Described as divaricating, that is, with many interlacing, wide-angled branches and tiny leaves, they are found in a variety of habitats from wetlands to forests but the greatest number occur on the dry eastern side of the country, in particular Canterbury.

Our divaricating shrubs include the small-leaved shrubby species of Olearia that were once abundant in dryland environments.

Olearia adenocarpa Photo: Ian PlattRight: Olearia adenocarpa.
Photo: Ian Platt

Impacted by intensive land development and weeds and pests, these distinctive plants are fast disappearing.

Recognising the value of Olearia shrubs that remain, landowners and councils are now protecting the habitats of these unique indigenous species with QEII covenants.

Canterbury: Hidden treasures revealed on uncultivated land

On the outskirts of Christchurch near Yaldhurst, two neighbours protected rare remnants of original Canterbury Plains dryland shrubland, grassland and mossfield vegetation in May 2009.

On former river-channel soils of the Waimakariri River, Tricia and Ian Crumpton’s 0.6ha covenant and Tim and Keryn Stark’s 1.4ha block are on land that has never been cultivated.

Although outwardly austere, the covenants protect Olearia adenocarpa, a new species described by Brian Molloy and Peter Heenan at Landcare Research in 2004.

Distinguished from O. odorata by its smaller and open growth habit and short-lived and slender spreading branches, only about 650 plants are known.

Olearia covenant Photo: Miles Giller

Above: Ian Crumpton by his and Tricia’s covenant that protects the habitat of threatened shrubs including Olearia adenocarpa (Nationally Critical), Aciphylla subflabellata (Declining), Muehlenbeckia ephedroides (Declining) and Melicytus aff. alpinus ("Hinds") (undescribed species).

‘We found out how rare this plant is during a Selwyn District Council biodiversity workshop,’ explains Tricia.

‘With the council’s help we are restoring the native vegetation and controlling exotic invaders.

'The covenants certainly look different from the surrounding manicured land.’

Olearia adenocarpa Photo: Miles Giller

Above: Olearia adenocarpa is susceptible to browsing by hares, rabbits and sheep.

Olearia covenant rabbit-proof exclosure Photo: Miles Giller

Above: Rabbit-proof exclosures constructed with contributions from the landowners and the Selwyn District Council will help this unique indigenous species to recover.

Central Otago: Olearia shrubland fragments are also home to native moths and insects

West of Patearoa, John Gibson protected Olearia odorata shrubland on Oliverburn Farm with a 0.6ha covenant in September 2009.

Adjacent shrubland along Puketoi Runs Road was also protected by Central Otago District Council with a 5.4ha Landscape Protection Agreement.

Olearia odorata covenant Photo: Brian Molloy

Above: John Gibson looks over his Olearia odorata shrubland covenant that also protects an unnamed Melicytus species, Otago broom Carmichaelia petriei and Muehlenbeckia australis.

‘As far as I know, these remnants are all that is left of this plant community on the Maniototo Basin floor,’ says Brian Molloy.

‘The relict shrubland is also habitat for a proliferation of native moths and insects that depend on the indigenous shrubs.

‘Rabbit-proof fencing now excludes browsing animals from the shrubland.

'Enrichment planting of the Olearia and reintroducing fescue tussock and large native herbs such as Spaniards and wheatgrass would help to restore the area.

'With the landscape rapidly changing to dairy farming, small fragments such as these are well worth protecting.

Olearia odorata Photo: Brian Molloy

Above: A mature Olearia odorata in early flower bud. The large central trunk is characteristic of this deciduous tree daisy species.

Olearia odorata Photo: Brian Molloy

Above: Olearia odorata shrubland protected by Central Otago District Council with a Landscape Protection Agreement.

You may have a special area of Olearia shrubland that you wish to safeguard forever. Contact your local QEII representative ...

Find out about our native moths that are dependent on Olearia shrubs ....

Photos: Miles Giller, Brian Molloy and Ian Platt.

Open SpaceTM Magazine No. 78, March 2010 © QEII National Trust

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