Improving native seed survival rates key to rehabilitating Pilbara mine sites

Found in: News

Even the plants best adapted to survive the harsh conditions of Western Australia's Pilbara region, native flora, are struggling to set seed and grow.

A team, including people from the University of Western Australia, BHP Billiton Iron Ore and Perth's Kings Park and Botanic Garden, have been trying to come up with strategies to rehabilitate old mine sites.

While there appears to be consensus that the large-scale planting of native seeds is the best rehabilitation option, they are just not growing.

Kings Park and Botanic Garden senior research scientist, Dr David Merritt, said they spent time brainstorming solutions.

"The challenge we're really focussed on is how we restore biodiverse native plant communities to degraded land at large scales," he said.

"We know that when we sow seeds into soil, typically we get only one to 10 per cent of those seeds emerging and surviving. This problem is one we have been aware of for some time but we are really trying to unpack this now."

According to Dr Merritt, research conducted by his colleagues in the United States has found that seeds will often successfully germinate underground, but then fail to emerge as a seedling. Researchers are seeing that 'bottleneck' across a range of species native to the rangelands.

"Spinifex is a real problem because it covers almost 70 per cent of arid Australia, that's one of our biggest focuses. Many other species are the same, although one group that does do a little better is the acacias, wattle and mulgas," Dr Merritt said.

 
Adapting seeds possible answer to low survival rates

Researchers believe the solution to low seedling growth rates at Pilbara mine sites may lie in taking lessons from the agricultural and horticultural sectors, where adapting seeds for optimum growth has long been practised.

"Treatments include seed-coating and pelleting. "We can add various chemicals to those coats: germination promoting agents or anti-stress agents or water holding gels," Dr Merritt said.

Dr Merritt said the farming of popular native seeds, such as Spinifex, may be an answer.

"Commonly they're seeding at five to seven kilograms per hectare. So when you start to look at the amount of land we need to restore and the amount of seed we need we for that, you get into hundreds of tonnes of seed, which is something that's not easy to source," he said.

Trials of adapted native seeds are now underway at select Pilbara mines.

Dr Merritt said he hoped it will not be too long before researchers can measure the level of success.

Source: ABC Rural

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