Western Daily Press (Saturday)
A wetland sanctuary in the making
Charlie Elder visits a riverside walk in Cornwall where the floodplain is being transformed to protect both homes and nature
Ahealthy reed bed makes a wonderful sound. Not just a gentle rustling and sighing in the breeze, but a hurried and relentless chattering and churring noise that clatters out from between the dense thickets of stems with machine-gun urgency.
It is tricky to locate the precise source of the unmusical medley of scratchy noises, but wait long enough and you may spot a small and skulking brown bird belting out its breathless refrain.
This is the reed warbler, a migrant species which flies in from wintering grounds in Africa to breed in lowland reed beds in central and southern England and Wales during spring and summer.
Its life is intimately tied to the common phragmites reed, and its presence is a sign of habitat in fine fettle.
So I was pleased to come across two as I wandered along the footpath that follows the River Tamar upstream from Calstock through the Tamar Area of Outstanding Natural Beauty.
And there could be plenty more of these characterful birds, and fellow reed-loving sedge warblers, filling this oak-lined valley with their distinctive songs in the years to come as an inspiring project transforms grazed riverside pasture into a new area of wetland.
Concerns that the raised bank along which the river footpath runs was in danger of failing, threatening the village of Calstock with flooding along this lower section of the
Tamar, led the Environment Agency to carry out extensive surveys in
2017 and consultation with the local community to shape a strategy for the future.
As part of the Calstock Flood Defence Scheme it was decided to breach part of the embankment to create a 14-hectare intertidal habitat. What once were fields would become a large wetland, with pools and reed beds.
Most of the ground work has been carried out and fundraising is underway to retain the existing Tamar Valley Discovery Trail by constructing a raised boardwalk this summer ahead of the 30 metre breach in the embankment being dug out later in the year.
When I visited Calstock this week and took a wander down the footpath I was amazed by the scale of the work and its potential as a haven for wildlife. The last time I visited was before last year’s digging operations. The large flat fields I had seen populated by livestock have since been carved into gullies and lakes, with green marshy areas that will eventually be carpeted by reeds and wetland vegetation.
Recent rain meant the pools held a shallow depth of water, and flocks of swallows were flying low over the larger of the ponds, with a few sand martins among them.
I spotted stonechats perched on fence posts and shrubs, pheasants strutting boldly across bare rocky areas that have yet to be colonised by plants, mallard ducks with young and several Canada geese.
The reed warblers were on the river side of the footpath, hidden among the tall stems that speared the thick mud, but the Environment Agency expects reeds to be well established on the new overflow floodplain within two years. These warblers, along with other wetland dwellers, should hopefully prosper.
Build it and they will come, as the saying goes. And already local wildlife enthusiasts have reported plenty of decent sightings, sharing news on Facebook as part of a Calstock Wetland Birdwatchers Group which already has over 200 members and excellent photos and discussions of sightings.
Among the highlights has been a little ringed plover which dropped by in April – an attractive and far from common wader with a black and white striped head. Green sandpipers have also paid a visit to the new pools as well as a decent gathering of snipe, with a reed buntings, little egrets and linnets adding to the mix.
A glow-worm larvae was also spotted by day, which is always an interesting find. They are beetles, not worms, and the wingless 2.5cm long adult females emit a light from their abdomen at night to attract a mate.
The greenish light is described by the UK Glow-Worm Survey as being ‘about as bright as an LED indicator on a TV’. As people don’t tend to wander about after dark in unlit countryside they are far less likely to be noticed than in the past, though may also be in national decline and have vanished from some areas.
Peak ‘glowing season’ is in June and July.
Restoring historic river floodplains has become a more widely accepted solution to the threat of sea level rises and torrential downpours resulting from more extreme weather conditions as our climate warms. Sacrificing land by giving excess water somewhere to go can protect vulnerable properties from the risk of floods, and offers benefits for a range of flora and fauna.
From what little I have seen, those involved in this wetland project, including the Environment Agency, Calstock Parish Council, Tamar Community Trust and Tamar AONB, should be applauded for this local scheme, managing to combine practical with progressive thinking by safeguarding homes while helping to conserve wildlife.
I certainly look forward to returning again and seeing how nature takes advantage of this evolving habitat. And I’ll be listening out for reed warblers, singing the praises of the new reed beds.