Science Week: Meet the Kings Park scientists saving WA's plants

Updated

The public gardens of Kings Park in Perth might be crowded with people desperately searching for Pokemon, but in an unseen building in the north-west corner of the park researchers are involved in an intensive search of a very different kind.

At the Biodiversity Conservation Centre, a team of 80 scientists, technical staff and students are looking closely at the rarest of Western Australia's 12,500 plants.

Seventy-four new species have been described by the centre in the past four years, and the Kings Park team has even been able to bring back some plants from the brink of extinction.

Saving one plant at a time

In the 1990s, a small green native bush called a Symonanthus bancroftii was considered extinct as only one male plant could be found during a survey.

"The remarkable thing about this plant's mating system is that there are male and female plants," explained Dr Ben Miller, director of science at the Botanic Parks and Gardens Authority (BGPA).

"We only had one plant so it was extinct."

But a search of bushland in the Wheatbelt in 1997 had turned up a female plant.

Thankfully, scientists had the foresight to create Symonanthus bancroftii seeds which were stored in Kings Park's extensive seed bank.

Now the conservation centre's team were presented with an opportunity to potentially save the plant.

Fast forward to today and the centre is successfully growing and planting Symonanthus bancroftii at managed sites in the Wheatbelt.

As well as trying to re-establish rare plants in the wild, the centre also stores tissue samples of endangered plants in liquid nitrogen.

"Once they are in liquid nitrogen they can stay there forever, the work is just to develop the technology to get them in there and then we can decide whether to get them back out again," Dr Miller said.

"We also have about 300 of Western Australia's 400 orchid species stored in liquid nitrogen."

The work means that native plants whose populations have been shrunk through farming or mining activity could one day be removed from cold storage, grown in the lab and eventually replanted.

Getting seeds to grow

One challenge for the scientists is making sure the seeds they grow and distribute germinate and put down roots.

It has been a focus for Alison Ritchie, who completed her doctorate at Kings Park on restoring Banksia woodlands.

"At the moment we have a good success rate in getting Banksia to germinate and grow, but once we hit summer a lot of them die off," Dr Ritchie said.

"We have only about a 5 per cent survival rate.

"But because these seeds are really expense — $1 to $2 each — we really want those seeds to survive over summer."

The problem, she said, is not with the seeds. Instead, the Banksia woodlands' soil, which is water repellent, is to blame.

A demonstration in a petri dish shows water just sits on the surface of the soil and does not reach any of the seeds or roots beneath.

Dr Ritchie said the solution, which is still being tested, might rest with a pellet and a pasta maker.

"We have developed this pellet, which is basically a way of deploying the seed into the environment and creating a microcosm for the seed, for it to grow through summer," she said.

Produced in a pasta maker, the pellet is a mix of clay, compost mix and a wetting agent that provides readymade support for the seeds to grow in before they are established.

"We are now looking at whether, over summer, this will help the survival rate of this species so that we can get high restoration success," Dr Ritchie said.

"It is really important for banksias to be restored.

"They are the dominant species of Banksia woodlands and supply a range of benefits for other species — invertebrates, insects, honey eaters and endangered Carnaby's cockatoo."

Trial by fire

In another corner of the Kings Park lab, PhD student Ryan Tangney is using fibre optic cabling and a series of ovens to study a distinctive feature of the Australian bush — fire.

Specifically, he is looking at how seeds in soil respond when a fire front passes over them.

Fibre optic cabling is laid at controlled burn sites to see just how hot soil temperatures become during a bushfire.

Mr Tangney then uses ovens to test seed responses to specific temperatures.

"I'm looking at how seeds in the soil will survive fire and, in particular, the duration of exposure," he said.

"It's about how fast the fire impacts the seeds and at what moisture contents the seeds best survive.

"If we do a controlled burn in spring, does it have the same outcome as a fire in autumn?"

The implications of Mr Tangney's research for authorities undertaking controlled burns could be significant.

"A lot of the time prescribed burns in bushlands are put in during spring when the risks for implementation are lower," he said.

"But if we get negative biodiversity outcomes from spring fires, then it might not be best to do that."

While he does not yet have enough data to draw firm conclusions, he has discovered that kangaroo paws can take an extraordinary amount of heat before they crack.

"Their seeds are really resilient to fire or soil heating.

"If you heat kangaroo paws seeds for three hours at 100C, the dormancy will break and they will start to germinate."

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Topics: science-and-technology, botanical-science, academic-research, research-organisations, people, endangered-and-protected-species, environment, kings-park-6005

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