WITH their striking patchworks of sward, creek and pool, they are among our most impressive and ecologically important habitats.

But salt marshes – coastal wetlands that are regularly flooded by the tides – are under threat from the relentless pace of economic development and, increasingly, rising sea levels and erosion.

The danger has grown even though they shelter a wide rage of wildlife and play a crucial role in the climate emergency thanks to their ability to capture CO2 and store carbon in organic-rich soils.

Indeed, experts fear allowing them to become damaged or degraded could undermine the fight against global heating since this would risk the release of carbon back into the atmosphere.

Now scientists at St Andrews University are to undertake the first comprehensive study of carbon stored in Scotland’s coastal wetlands in an attempt to boost understanding of how these areas might help us avert environmental disaster.

It is also hoped the work will pave the way for policies to protect the habitats and support their expansion.

Professor Bill Austin, who is leading the project, said: “The salt marshes have taken thousands of years to build up their carbon store and if they are not properly managed, or inadvertently drained or there’s coastal erosion, then the carbon is released back into the atmosphere.

“So you’re thinking about the risks, if we were to lose those habitats, in terms of the release of carbon and the damage this could do to the climate.

“These are also very threatened habitats. They protect our coastlines by providing a kind of buffer zone and are important for wildlife.”

Mr Austin said the Marine Scotlandsupported research would see him and his team deliver a new, first-order estimate of the carbon held in coastal wetlands.

The scientists will feed their findings into a Geographic Information System (GIS) project, providing a systematic overview of storage in these vulnerable habitats.

“Scotland’s coastal wetlands are predominantly going to be salt marsh habitats and, in this project, we are going to be focussing on the salt marshes,” said Mr Austin.

“The project is essentially looking to measure the carbon stock.

“We will use GIS essentially as a mapping tool. We know where the marshes are and we will use the relationship between the plant communities they hold and the soils associated with them to estimate the carbon in the marshes.

“It will be a calculation of mass – millions of tons of carbon or turning it into a CO2 equivalent.” Mr Austin said the results could assist efforts to reach Scotland’s tough net zero emissions target.

“The long term ambition would be to incorporate this into our greenhouse gas accounting,” he said.

“We need an understanding of the emissions factors – the ins and outs [in terms of carbon that is absorbed and stored by the salt marshes versus carbon that is released as a result of damage to the salt marshes] – and then the habitat can be accounted for [in terms of greenhouse gas emissions] alongside fossil fuels and activities such as farming. But this is longer term.”

Mr Austin also hopes his study will help overhaul attitudes to the wetlands and transform our relationship with the environment as society recovers from the coronavirus pandemic.

“I think we need to see a change in our view of coast lines as fixed features – that, where it is appropriate, we might introduce policies to allow coastal realignment – which could include an expansion of these protected areas inland,” he said.

“Now somebody might own the land nearby so the policy will need to be good as decisions will have to be made about managing that realignment process.

“There might be a system of offering financial subsidy or recompense to landowners to support expansion of these landscapes.”

He added: “As we transition out of the Covid-19 pandemic and our global economies begin to recover, I am encouraged we can look forward to a greater understanding and appreciation of our environment.

“In some small way, I hope our research will support that ambition.”