Life on a Humble Shrub

Forest and Bird, Issue 308, 1 May 2003, Page 16

Life on a Humble

Shrub

GEOFF KEEY

finds Meuhlenbeckia

is a rich habitat for native animals.

mong the native plants that took a hammering from the arrival of people in New Zealand, the five Muehlenbeckia species are survivors. Over many parts of New Zealand, this native plant is often the last to ‘hold on’ in highly modified landscapes. Its tangled branches provide a refuge for other native plants and animals in an otherwise barren and hostile environment. Muehlenbeckia species are among New Zealand’s divaricating shrubs. These plants are a mass of wiry stems all growing at sharp angles to each other. Tiny leaves are tucked in amongst the stems. The reasons for the evolution of this growth form are hotly disputed amongst botanists. Some support the rather romantic theory that it evolved as a protection against moa browsing while others believe it to be a survival mechanism for harsh, dry or salty climates. Irrespective of its origins, the wiry, tangled form of Muehlenbeckia makes it an ideal home for insects, spiders and lizards. Protected from the outside world, the inside of a Muehlenbeckia bush is a diverse ecosystem all by itself. Muehlenbeckia provides a home to a large range of specialist insects that feed on the leaves and flowers. Some even burrow into the leaves and live on swellings on the stem. ‘In excess of 100 moths and butterflies feed on Muehlenbeckia, says Otago Museum entomologist Brian Patrick, ‘including all our copper butterflies’. Brian Patrick is an enthusiastic advocate for Muehlenbeckia. ‘In some places, Muehlenbeckia is the last vestige of natural New Zealand in our landscape, host to a myriad of insects and providing shelter and food for insects and lizards. ‘From pollen records we know that Muehlenbeckia has been important in New Zealand ecosystems since the Oligocene [24-36 million years ago] and it’s one of few plants to hold its own since European destruction. Brian Patrick believes New Zealanders need to take protection of Muehlenbeckia more seriously. ‘It’s an unrecognised but important part

of New Zealand’s biodiversity, he says. ‘Muehlenbeckia is the number one plant for insects and is host to lots of specialist and generalist invertebrates. "Yet even some well meaning conservationists don’t give Muehlenbeckia the recognition it deserves, unfairly accusing it of smothering forests, he says. ‘It’s not a strangler of forests, it is the scab that heals areas of natural and human disturbance’. At least three of the five species of Muehlenbeckia fit this description, readily colonising roadsides, gullies and suburban

wasteland. Brian Patrick believes we should encourage Muehlenbeckia in these places. Practising what he preaches, he is encouraging the Muehlenbeckia that grows on his Alexandra property in Central Otago. (Of the 15 species of lizard that occur in Otago, 12 occur in and around Muehlenbeckia.) Protection of Muehlenbeckia creates small but important refuges for native animals struggling to cope with the dramatic changes caused by development in the surrounding landscape. According to Forest and Bird’s resourcemanagement lawyer, Kate Mitcalfe, the Resource Management Act provides opportunities for conservationists to protect important remnants such as Muehlenbeckia patches. "The RMA sets up processes so any new development which threatens to wipe out remnants of important habitat is able to be carefully considered’ she says. Forest and Bird’s conservation manager Eric Pyle is also a fan of Muehlenbeckia and grows it in his garden. ‘It’s a fantastic garden plant, especially in windy coastal places. It makes a great windbreak and needs little looking after. More people should grow it, he says. Muehlenbeckia could be used more in urban council plantings, Eric Pyle suggests. ‘Tt would create great native habitat on roundabouts and road alignments.’ — GEOFF KEEY is Forest and Bird’s biosecurity officer.