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Protecting our precious places

Muehlenbeckia - contribution to biodiversity

A smothering cloak or a haven of biodiversity?

With its rampant growth engulfing trees and roadsides, our native Muehlenbeckia australis might seem like a weed but it occupies an important place in New Zealand’s ecology.

Pohuehue, or large-leaved muehlenbeckia, grows naturally in places where there is plentiful light and climbing support such as forest edges, cliff faces, scrub and regenerating vegetation.

It has flourished since human settlement because land clearance has created conditions it favours such as edges around forest remnants.

Muehlenbeckia Photo: Brian Patrick

 

Above: Like all muehlenbeckias, the large-leaved muehlenbeckia or pohuehue Muehlenbeckia australis has a much-branched, interlacing habit but has larger leaves up to 8cm long.

The creamy flower panicles occur mainly in spring and summer.

Brian Patrick of Otago Museum says that pohuehue fulfils an important ecological function, forming a protective seal around forest edges and over exposed bluffs and banks, and healing natural or human induced disturbance.

Often, it is the only native species persisting in highly modified areas.

'As the most prolific native host plant for our native fauna it contributes enormously to biodiversity,' Brian says.

Managing Muehlenbeckia australis on your covenant

Whether or not you need to control pohuehue on your covenant depends on the situation and your covenant objectives.

John Dawson, Botanist at Victoria University, advocates a cautious approach.

'These vines are part of the nature of disturbance and regrowth. Together with our forests they’ve been here for millions of years.

'It’s wise to monitor muehlenbeckia before intervening, to see what effects it’s really having.'

Pohuehue may be particularly beneficial on your covenant if you wish to enhance the diversity of insect life, heal exposed areas such as an erosion prone gully or an exposed bush edge, or suppress weeds.

Muehlenbeckia in a Nelson covenant

Above: Muehlenbeckia australis is being fostered at this Nelson covenant to suppress blackberry and provide riparian protection.

However, pohuehue may need controlling where it is competing with rare or threatened plants or overwhelming young plants on your revegetation site.

QEII Regional Representative Brian Molloy says it may need control in southern snow-prone areas to prevent it supporting such a heavy leadoff snow that the regenerating vegetation underneath collapses.

In most cases where control is needed, cutting the vine at ground level, without poisoning, is sufficient to weaken it.

Muehlenbeckia on a Dunedin hillside Photo: Brian Patrick

Above: A case for monitoring - while Muehlenbeckia australis blankets this Dunedin hillside, it is not necessarily killing the underlying vegetation.


Open SpaceTM Magazine No. 66, March 2006 © QEII National Trust

 

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