Banksias evolved faster with fire selection

Banksias evolved faster with fire selection

27 July 2011

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Australia — NEW research furthers understanding of the role of fire in Australian plant evolution and may help in future conservation efforts.

Research conducted by a Curtin University plant biology team shows that fire is a larger factor in the evolution of Banksias than was previously thought.

Large-scale bush fires are believed to have been present in Australia for the past 15–20 million years and plants much older than this have not developed adaptations to counteract it.

Emeritus Professor and team leader Byron Lamont says the research shows Banksias—known to be older than 20 million years—have adaptations which stem from evolving in the presence of fire.

“We examined features of Banksias that have long been considered examples of adaptations to fire…their ability to re-sprout after fire, the retention of seeds in woody cones that are released after fire, and the fact that many species hang onto their dead flowers,” he says.

“Putting these findings together, we concluded that Banksias must have evolved in the presence of fire right from the time it departed from its rainforest ancestors.”

Prof Lamont’s research also showed that some species of Banksias retain their dead leaves which help to provide the necessary fuel—during a bushfire—to melt the sealing resin allowing seeds to be released.

Australian plants have evolved many adaptations that enable them to survive and regrow after a bushfire.

Adaptations like fire-mediated serotiny—the fire induced release of seeds into a nutrient rich, post-fire environment—increase the chance of a plant’s survival and successful reproduction.

Prior to this research it was thought that plants over 50 million years old had only developed adaptations for drought and poor soil conditions.

Prof Lamont says the study will change the understanding of the factors at play in Australia’s evolutionary history.

“These discoveries mean that biologists must now take seriously the possibility that fire has had a profound effect on the direction of evolution in Australia for more than 60 million years,” he says.

“It is just as important as drought and strong seasonality, high air temperatures and poor soils as limiting factors in the evolution of plants and animals.”

Prof Lamont hopes that this research will help with conservation efforts for endangered plant species.

He says awareness and understanding of the optimal fire requirements of individual species is critical to be successful in future conservation efforts.

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