Rare Plants in Wairarapa Have Links With Taihape

Forest and Bird, Issue 305, 1 August 2002, Page 9

Rare Plants in Wairarapa Have Links With Taihape

DAVE HANSFORD

‘i Department of Conservation is delighted with the discovery of a critically endangered plant in the eastern Wairarapa. A DoC programme manager Aalbert Rebergen said the find of 15 specimens of a rare native tree daisy, Olearia gardnerii, greatly increased the plant’s chances of survival. The North Island plant was

previously known from only 80 specimens, mostly in a DoC reserve near Taihape. No new individuals had been seen in the Wairarapa for more than a decade. Mr Rebergen said the plant’s status was botanically equivalent to the kakapo. He found the plants growing on farmland in the Tauweru catchment. The Olearia recovery group then made $3000 available for more survey work. ‘The first five plants were at four sites something like 50-60 kilometres apart, he said. ‘So from a regeneration point of view, they didn’t have much of a chance. Efforts to raise the plant from seed had had little success. ‘We've only grown about a

hundred plants in the last decade. They’re really hard to grow, says Aalbert Rebergen. ‘They’re self-pollinating and, being daisies, they produce probably millions of seeds, but with self-pollination, I think there’s a decrease in fertility long-term. O. gardnerii prefers disturbed sites, such as floodplains, riverbanks and hillsides, where erosion can provide a clear space and sufficient light to give it a start, but exotic grasses can compete with it, impeding regeneration. Aalbert Rebergen decided to investigate the site because he drives past it every day on his way to work. ‘The first time I didn’t find anything, but the second time I found three. After scanning aerial photographs of similar habitats, he found another 12 plants in the catchment, and more besides. ‘We found a lot of other rare species in there as well; he says. ‘We found Pittosporum obcordatum, another very highly ranked species known previously from just two sites in the Wairarapa. He also found a new record for the region. Coprosma obconica is mainly a South Island plant, again known only in the North Island from Taihape. Aalbert Rebergen says the two areas clearly had something — possibly climate and soils — in common. Individual plants had been fenced off to protect them from cattle, and further options had been discussed with property owners. ‘This would be a perfect site to do some more planting, he said, ‘and our possibilities for propagation have increased gigantically. We expect fertility rates for these seeds to be much

higher.