The pioneering paludiculture at Great Fen – and how River Granta has been improved

Pioneering paludiculture trials come to fruition at the Great Fen - and the Granta gets a wiggle on, as Caroline Fitton, of the Wildlife Trust in Cambridgeshire, explains.

There are around 200,000 seeds compacted into one humble bulrush seedhead – and these long, elegant cigar-like bundles contain hope for the future.

At the Wildlife Trust in Cambridgeshire's expansive Great Fen nature reserve, seeds of hope were planted back in 2019 in specially designed trial plots growing paludiculture crops. Paludiculture, or wet farming, is the productive use of wet peatlands; a land management method to cultivate commercially interesting crops on wet or rewetted peatlands in conditions that maintain the peat and lock in carbon.

Fast forward four years and the first harvest took place last month under sunny September skies. Using a high platform on an adapted softrak Loglogic machine, the typha was collected in bundles and the seedheads collected. The machine trundled valiantly through the swathes of bulrush, mechanically gathering its fluffy cargo, to the excitement of all who had planted those first tiny plugs in the ground.

Once collected the simple bulrush, Typha latifolia, or reedmace, has many applications including use for impressively lightweight, compacted insulation boarding as well as filling for clothing and bags. The trust is collaborating with a pioneering start up company, SaltyCo, who have evolved a method of using the fluffy seedheads for padding in jackets and bags, with a system called BioPuff.

As a water plant, the bulrush is ideally equipped to cope with moisture: tannins protect it from mould and the structure of its leaves makes it light and stable. These characteristics are proving beneficial in the development of sustainable insulation material - durable, mould-resistant, and highly insulating - and unlike other insulating materials, it can be manufactured and composted using little energy.

This work is helping inform and inspire both conservation and farming practice on peat soils across the UK and further afield, with the new wet landscape preventing the loss of peat soils and locking in carbon dioxide.

Visit greatfen.org.uk/peatland-progress

Chalk stream restoration

Historically the River Granta was modified by straightening and dredging which removed natural features, so the river was less able to maintain a variety of habitats.

Flow diversity is needed - faster areas keep gravel clean and deeper pools become a fish refuge in hot weather. Restoration has taken place recently on a stretch near Babraham where a number of weirs prevent fish from moving upstream and disrupt sediment transport within the river, which means that it can’t function naturally.

Two weirs have been removed - one intact with much trapped bed material behind it, and the other defunct. Habitat creation was achieved by adding woody material and gravel to the channel, along with work to reshape banks plus the creation of a scrape and a backwater.

The trust's water for wildlife officer, Ruth Hawksley, explains: “Our chalk streams suffer from the fact that the land is pretty flat, meaning a very limited gradient along the course of the river; by removing the weir we could use that head-drop to energise a longer reach of river.

“We’ve removed some big lumps of concrete from a defunct weir and added almost 40 tonnes of gravel to the river. We dug an experimental scrape and hinged a big willow over the channel to encourage flood water into it, and also created a new backwater nearby which holds a small amount of water and should do pretty much all year, and a ledge was created from hazel bundles.”

The work was a collaboration of organisations, with Rob Mungovan from the Wild Trout Trust, volunteers and funding for contractor work via the Environment Agency, Cambridge Water and Anglian Water.

There are more weirs upstream and downstream and this is part of a wider ambition with a phase two expected, but for now it has already benefitted the river.

England's chalk streams are one of the rarest habitats on earth, yet many of our chalk stream rivers are now polluted, dirty and choked by pollution, threatening the wildlife that call them home and the people that rely on them for wellbeing – they need new legal protections if they are going to stand a chance of recovery.

Visit www.hiwwt.org.uk/rivers for more.