Source: Radio New Zealand
Craspedia argentia seedlings in their new home at Mahaka Katia Scientific Reserve. RNZ / Katie Todd
One of New Zealand’s rarest plant species is getting another shot at survival, after plummeting to just two known plants in the wild.
About 250 Craspedia argentia seedlings are this week being planted at Mahaka Katia Scientific Reserve in Central Otago following years of painstaking hand-pollination, propagation and care by conservationists and botanists.
Department of Conservation senior technical adviser in ecology Richard Ewans said the project was effectively an 11th-hour rescue mission for the woollyhead herb, which was endemic to the Pisa Flats.
“We’ve been really concerned about this plant disappearing…. so we knew we had to intervene and start a programme of breeding,” he said.
Department of Conservation senior technical advisor in ecology Richard Ewans. RNZ / Katie Todd
Botanist Geoffrey Rogers, who has studied the rare flora of the Otago drylands for much of his career, said Craspedia argentia numbers had been dropping even under the protection of the reserve.
As the population thinned and the pollination network broke down, researchers managed to collect just three seeds in one season – two of which germinated.
“All of these plants going back into the ground – now hundreds – were derived from those two plants,” he said.
Botanist Geoffrey Rogers with one of the seedlings. RNZ / Katie Todd
To build up numbers, staff at the Dunedin Botanic Garden spent about two years carefully cross-pollinating and hand-pollinating flowers, Ewans said.
“We initially thought we might be dealing with 20 or 30 plants to translocate back, but we had really good success with the group, particularly at the Botanic Gardens. Their work has been amazing. We produced about 800 seeds from the first season … and that turned into about 300 seedlings,” he said.
“We’ve cracked a bit of a code around how to grow the plants now so we’re confident we can keep producing plants.”
Apprentice Jess Freeman was among several Dunedin Botanic Garden staff involved in nursing the plants through propagation.
“We’ve just kind of looked after the babies, nursed them up, counted seed from them, and stored them in our fridge,” she said
Jess Freeman and Tom Myers of Dunedin Botanic Gardens. RNZ / Katie Todd
Dunedin Botanic Garden botanist Tom Myers said the species had become personally significant for staff working with it.
“It really speaks to me of this habitat. Like I’ve always loved coming through Central Otago, and it clearly is well suited to this habitat,” he said.
In Alexandra, home-based propagator Dhana Pillai also helped raise plants destined for the reserve and harden them off by gradually introducing them to the Central Otago climate.
“They’re quite fussy plants – sometimes they don’t look so good. And you think, oh, what’s going wrong here? What have I done? Have they got too much water?,” she said.
“It’s really great to be part of this project. I’m learning so much about these plants, and there’s still a long way to go.”
Dhana Pillai carefully planting Craspedia argentia seeds. RNZ / Katie Todd
The newly planted seedlings would be closely monitored through winter via monthly visits and a trail camera, with the hope they would establish roots and survive their first Central Otago summer, Ewans said.
Saving the Craspedia argentia was only one step in a much larger restoration effort at Mahaka Katia Scientific Reserve, Rogers said.
“We’re rescuing a species, but really what we want to do is rescue an ecosystem, and all of the flow of nutrients and energy and animal food webs that are associated.”
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– Published by EveningReport.nz and AsiaPacificReport.nz, see: MIL OSI in partnership with Radio New Zealand