Seeds from one of New Zealand’s most endangered plants, the Kakabeak shrub (Clianthus maximus), have been successfully propagated for the first time by blasting them into soil from a shotgun. The groundbreaking technique has been developed by the Forest Lifeforce Restoration (FLR) Trust at its property in the Maungataniwha Native Forest in inland Hawke’s Bay.
This innovation will allow future dispersal of the seed from helicopters and creates the potential for an aerial propagation effort on a scale that hasn’t yet been possible.
Contractor Barry Crene developed the technique using re-loaded shotgun shells packed with regular shotgun pellets, a pulp medium and Kakabeak seed. The shells were then discharged into soil from a range of 20 metres, about the distance a helicopter might have to hover from likely nursery sites in the wild.
“Unfortunately, re-establishing this plant in the wild is more complicated than going out, digging a hole and planting a seed,” Crene said. “We have to identify sites that are protected from browsers like deer, rabbits and hares.”
Such sites are frequently patches of topsoil on bluffs or cliff faces that are as inaccessible to humans as they are to browsers. Helicopters are often the only way to reach them.
Kakabeak seed is scarce so Crene’s development efforts needed to be trialled extensively before the shotgun shells could be loaded with the real thing, sourced from the Department of Conservation.
He varied the amount of gunpowder in the shells to obtain the optimal discharge velocity before developing the best mix of shotgun pellets, pulp and seed.
“The pellets hit the soil first, breaking the top layer and giving the pulp and seeds the best possible surface to bury into,” Crene said.
The FLR Trust reviewed a range of discharge mechanisms, including paintball guns. Shotguns gave them the directional force, accuracy and penetration necessary for the seeds to propagate successfully.
Five of Crene’s specially-adapted shotgun shells were loaded with seed and discharged into buckets of soil from the chosen range. The seeds have since germinated in four of the five buckets.
“This is, quite literally, a ground-breaking development and gives our Kakabeak recovery project a real boost,” said Simon Hall, the FLR Trust’s Chairman. He said it was possible that the Trust would be using the shotgun technique to disperse seed back into the Maungataniwha Native Forest as early as next year.
Although grown widely in gardens, domestic Kakabeak are all derivatives of one wild plant that have been interbred and have little or no genetic value. So severely have imported fauna impacted Kakabeak in the bush that, until recently, there were only 109 specimens known to be growing in the wild across the whole of New Zealand. The result is that this plant holds the highest possible threatened plant ranking: ‘Nationally Critical’.
Five of the plants known to be growing in the wild are located on the Waiau Bluffs in the Te Urewera National Park, adjacent to Maungataniwha. The Trust has recently planted another 35 young plants there as part of its Kakabeak restoration project.
It has also built two protected Kakabeak propagation enclosures at Maungataniwha, where it’s growing plants from seed collected from the four original shrubs on the Waiau Bluffs.
So far only two of these plants have themselves provided seeds, with just one proving particularly productive.
As a result, the Trust continues to search for additional plants from which seeds and cuttings can be taken to support the Maungataniwha propagation.