Bid to ‘repatriate’ grass could help to bolster coastal resilience and improve natural habitats

Researchers at the University of Sheffield are working on a scheme to “repatriate” a species of grass which they believe could help to improve coastal flood resilience and preserve wildlife habitats.

A vital plant for the formation of sand dunes, marram grass was first taken from the UK to Australia in the late 1800s.

Since that time, the Australian grass has rapidly evolved to its hotter, harsher environment, becoming more resilient than its UK relative. But in the UK, sand dunes are on the decline, impacted by severe storms and longer, hotter summers.

As sand dunes decline, coastal communities face a higher risk of flooding, while the animals including sand lizards, plants and amphibians that call the dunes home also become at risk.

But a team of scientists from the University of Sheffield are now working to reverse this decline,and engaging in research which could eventually see grass from Australia “repatriated” in the UK.

“The sand dune ecosystems are kind of built by the grasses which live on them,” says Dr Luke Dunning, who is leading the research team from the University’s School of Biosciences

"There's this feedback loop as sand gets blown on, the grasses fix it, and then the plants grow bigger and bigger.

“But we're worried that it won't keep pace with climate change. Things like increasing sea levels and more severe storms threaten to overwhelm the dunes, and then you would get flooding in towns and villages and farmland.”

Much in the way that marram grass was originally taken to British colonies to build sand dunes and protect coastal communities, the researchers now hope that bringing the adapted, more resilient species back, will help to protect similar communities in the UK.

Funded by a £2.3m grant from the Advanced Research and Invention Agency, the project is still in its early stages, with the group anticipating at least two years of research and testing before any plants are placed into the wild.

If left without intervention, Dr Dunning warns, the UK’s marram grass could face a tipping point from which it is unable to recover. “So we've kind of abused the dunes for a long time,” he says.

“We develop it, we graze it, there's lots of other selective pressures. And at some point, it's going to hit this thermal tolerance.

“We know that storms are getting worse, we have this El Nino this year and we know it's going to be wet, so it's basically about trying to avoid that tipping point where it can no longer recover.

“Once you swamp the dunes and and basically erode them, it's kind of hard to build them back rapidly if you've got a series of storms coming in. So we're effectively trying to accelerate this adaptation, and the work's kind of been done for us already over 100 years.”

The first part of the project will involve researchers working out which part of the UK the Australian grass came from, allowing them to then know where it would be safest to return it to.

They will then bring back grass from Australia and grow it in a controlled environment for testing.

The initial tracking of where the grass came from, Dr Dunning notes, could also allow for research into the social history of how and why the grass was moved.

“In Australia, they know it was introduced multiple times, but we don't actually know where it was introduced from,” he says. “It's most likely going to be close to the ports, but we have no idea which ones.

“We have basically got samples from all the way around the UK, and then we plan to do the genetics and work out where the origin was, so we can retrace that. In other places like South Africa, we think anecdotally that it was a single origin, but actually it might not even be from the UK. It might have been from Southern Europe.

“What we want to do is look at some of this with the social history behind it as well. It's really cool tracking this.”

Dr Dunning also hopes the research could provide a model for other species to be repatriated. "These species have adapted well, and so maybe this is a model for other species,” he says.

"Maybe the marrow grass might be the first attempt, but then there's hundreds of other species which have been moved around the world and potentially into some more stressful environments, so maybe we can do the same with those.”