What lies beneath?

Date posted: 01 February 2021

Saving seeds on Kangaroo Island one year on from the bushfires

There is buried treasure in the soil of Kangaroo Island’s bushfire ravaged areas. Under the scorched earth, tiny seeds are hidden, protected by the dirt until the opportunity comes for them to re-emerge.

The widespread devastation caused by the bushfires in the summer of 2019/20 left a moonscape void of vegetation in many areas that may take years to recover.

But in some areas, out of the gloom sprouted hope; seeds that have evolved to be triggered by smoke cues woke up. Without competition from other plants, other species that had not been recorded on the island for decades grew once again.

In contrast to the desolation of some locations, others now contain amazing diversity, with some plants never before recorded on the island.

And that is where the South Australian Seed Conservation Centre comes in.

Following an Annual Appeal to the Adelaide Botanic Garden Foundation, which saw charitable members of the public donate $54,900, and with generous support from Sealink, scientists from the Seed Centre were able to visit Kangaroo Island five times in 2020, and have another five scheduled over the coming year.

On the ground work.jpg

Their vital work includes assessing regrowth in the fire-affected areas and collecting seeds from plants which are threatened in the short to medium term. 

Scientist at the Seed Conservation Centre, Dan Duval, said that it’s not just the usual flora suspects re-emerging.

“Some of the plants that have regrown since the bushfires are rare, endangered or even on the edge of extinction. One plant discovered is believed to be a newly recorded species,” said Dan.

“With biodiversity plummeting in Australia, it is important to save the seeds of these botanical treasures for the future. Who knows what secrets they hold?”

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Back in the lab – which is based in Adelaide Botanic Garden - the team are busy preparing the seeds they have collected for storage in below-freezing temperatures. This conservation technique is a vital way to future-proof these species.

But storage isn’t enough, explains Manager of Science and Conservation at the Botanic Gardens and State Herbarium, Kirsty Bevan, who heads up the team.

“This winter, the team will investigate the best methods to germinate these seeds, and nurture them into healthy plants. It’s an integral part of the conservation process. With this knowledge, threatened plants can be grown and reintroduced into their native habitat,” said Kirsty.

“It is truly conservation in action, and a key way to help restore the ecosystem, and the bio-diverse flora and fauna species the island holds.”

So what did the seed scientists find on their field trips? In short, a lot!

Here are a few highlights:

The beautiful, yet critically endangered Black-beak Duck-orchid (Paracaleana disjuncta) was re-discovered in a few locations. Local KI scientists helping the Seed Centre team had never seen this orchid before on the island and helped to locate four new populations. It was previously only known on the island from two historic collections, the last record nearly 30 years ago.

It’s likely it had been hidden under the heath and soil as leaves and tubers, taking the opportunity to flower prolifically in patches of open fire scar, making it more detectable. A KI entomologist, Andy Young, has been working to detect the pollinators of this orchid, and seeds were collected. 

black beak duck orchid close up.png

 

Fire goosefoot (Chenopodium erosum) is a strongly pungent plant that attracts flies. Not such a great sell? Well it’s only been recorded in SA once before, a J.B. Cleland collection from Kangaroo Island back in 1950.

Two new populations were discovered with the help of islanders, and specimens were collected along with thousands of seeds. It’s likely this fire ephemeral won’t be around next year, highlighting the importance of surveying for these short-lived, fire-responsive plants quickly after the bushfires.

Chenopodium erosum Kangaroo Island.jpg

 

The team found a native water-cress (Rorippa gigantea), listed as vulnerable in SA because it is only known from two populations in the Mount Lofty Ranges.  It has never been recorded on KI before, but it was spotted growing in two geographical areas along creeks in the Flinders Chase National Park.

This fire ephemeral responds to smoke cues and will likely live for less than a year before again letting its seeds settle in the soil for another day. The team collected some seeds for the bank; a safety net for the future.

Rorippa gigantea Birdsville Track Dec 2020 (4).jpg

 

In Vivonne Bay, a few populations of the endangered Showy Copper-Wire Daisy (Podolepis jaceoides) were found, and thousands of their seeds collected for testing, propagation and storage. 

This is the first time they have been collected from KI, and provides a new genetic gene pool to bolster the threatened plant in KI and elsewhere in SA. These pretty daisies are extremely rare on mainland SA, and are actually better conserved on Kangaroo Island.

Podolepis jaceoides plants Vivonne Bay - Andy Young - cropped.jpg Podolepis jaceoides achenes Flinders Chase NP.jpg

 

Excitingly, a brand new species of Trithuria for SA was discovered, and research will now take place on this specimen to find out more.

Kangaroo Island is big, and has thousands of botanical stories to tell. With support from donors, sponsors, volunteers and other passionate scientists, the Seed Conservation team have made a solid start on safeguarding threatened plants and the biodiversity of the island.

They have collected around 300 herbarium specimens, mostly from threatened plants. At least 70 species have had their seeds collected, some which have never been banked before.

But there is much more work to be done. If you would like to support conservation programs, please consider a donation to the Adelaide Botanic Garden Foundation.