Guest Blog by Ali Morse, Water Policy Manager at The Wildlife Trusts (with some added Scilly specialities...)


Celebrating wetlands – where land meets water...

We may be a ‘wet’ nation, but wetlands – wildlife-rich, carbon-capturing oases – are in shorter supply than you might think. Wetlands have largely been removed from our landscape, and this loss is a problem not just for nature, but for people too.

Wetland habitats take many forms, from upland peat bogs through to valley mires, floodplain meadows and vast reedbeds. Whether fed by rain or groundwater, these wet habitats all need a water supply to create the conditions that keep their soils, vegetation and resident species happy and healthy. In the UK we have lost a startling 90% of our former wetlands, often by draining them to make way for agriculture, development, forestry and other land uses.  

This is bad for biodiversity, because around 40% of the world’s wildlife relies on freshwater wetlands. UK wetlands now cover just 3% of our landscape, yet a tenth of our species still make their home in them, and countless other creatures use wetlands to breed, hunt or forage for food. Our wet grasslands are where lapwing, curlew and snipe nest, bitterns boom in reedbeds, and bats swoop over watercourses and wetlands, feeding on the swarms of insects that emerge from them. Dragonflies, amphibians and the much-loved but endangered water vole can all be found across ponds and marshes, and now, in some places, as a result of the work of The Wildlife Trusts and others, beavers engineer new wetlands, creating habitat for aquatic insects, mammals and plants.

Rotational reed cuttingremoval of encroaching willow and rotational coppicing and pollarding of the wet woodland at our wetland sites on St Mary's has seen an increase in water levels at Higher Moors and Porth Hellick Pool SSSI, which were previously drying out.  The reduced dominance of Common Reed, increased variation of habitat and exposure of the underlying seedbed has seen the return of Bog Pimpernel (last recorded at Higher Moors in 1952!) and of Bog Stitchwort (last recorded in 2002!), as well as a 5000% increase in Ragged Robin since 2015! 

Bog Stitchwort (Stellaria alsine)                                 Ragged Robin (Lychnis flos-cuculi)

Wetlands are clearly important for many wild plants and animals, but we also rely on them. They provide ‘services’ that society needs, and without them, we struggle. Here in Scilly, our wetlands provide the Islands' entire supply of drinking water in the winter and 70% of it in summer!  The problems we face in protecting our wetlands are set to intensify as our climate shifts and our settlements expand, unless we take urgent action to reverse these wetland losses. Here are just some of the essential services that wetlands provide:

 

Flood protection

Natural wetlands provide flood protection by slowing down and storing flood flows.  Coastal reedbeds and saltmarshes buffer the UK from storm surges, and floodplains – when not built over – hold the excess flows from our river systems.  The use of these natural protections is termed ‘Natural Flood Management’, and can involve anything from small-scale features that mimic nature (like ‘leaky dams’ or flood storage ponds, which hold back water in high flows and allow it to drain through later, once the risk of flooding has passed) to vast habitat recreation, such as on low-lying farmland on the Essex coast at Abbotts Hall, where the failing sea wall was purposely breached to create new marshland, now teeming with migratory birds, and a network of creeks that form a valuable nursery for bass, herring and other fish.   

Sluice boards at Lower Moors SSSI were added as part of our two-year hydrological study of water movement through the site. Lower Moors is one of two SSSI wetland areas on St Mary’s (the other being Higher Moors); both of which have exit points into the sea which are prone to salt water ingress during high tides (meaning the salt water flows inland flooding the sites).  Lower Moors acts as a flood defence to the areas of Old Town and the Industrial Estate.

The result of the 2 year hydrological study, utilising water level, water quality and conductivity testing carried out by a qualified hydrologist with years of experience, confirmed our suspicions. Every high tide, salt water flowed into the site from the outflow pipe at Old Town. This salt water is now known to travel across the whole site (not just remaining in the area closest to the sea) and is having an impact; both from a water quality perspective and botanically.

The sluice boards prevent the majority of this ingress and data collected proves this. The results of this management long-term will be improved water quality and more of a freshwater component to the site, which is good not only for residents of, and visitors to, our Islands but also biodiversity.  Keeping the boards in place over winter allows the soil to slowly absorb the water and then disperse it into the ditches, thereby allowing the soil to behave naturally, without extremes of wetting and drying.

Carbon storage

Wetlands are important stores of carbon – when wetland plants die, rather than decomposing and releasing their carbon into the atmosphere, they become buried in the sediment making up peatland soils. These soils, which accumulate over thousands of years, hold vast amounts of carbon and are our biggest carbon store on land. If allowed to dry out, they release COand, rather than mitigating climate change, contribute to it. Researchers have calculated that if all of the carbon held in peatlands globally were released, it would raise atmospheric CO2 concentrations by 75%, with catastrophic consequences for global climate.

Peatland rewetting prevents the release of this locked-up carbon, so is a key tool in our fight against climate change. Restoring fens and bogs will also provide crucial habitat for insect-eating plants, wading birds like dunlin, hen harriers, and numerous insect species, and where full-scale habitat restoration isn’t feasible, testing ways in which peatlands like the fens can be more sustainably farmed is a key part of the solution too. Other wetland habitats also suck up carbon, for example on saltmarsh, one study suggests that as new layers of sediment form they can store carbon nearly four times faster than trees!

 

Wellbeing

Wetlands are also good for mind, body and soul! The natural environment is proven to be important for both physical and mental health, and the NHS are now piloting ‘green’ social prescribing to help patients with issues like depression, anxiety, obesity, and heart disease. But our fascination with water and wetlands suggests that wet habitats might be especially important in this nature-health interaction – ongoing research is looking at how we might use wetlands to achieve health outcomes faster and more effectively in future.

In 2015, Isles of Scilly Wildlife Trust Rangers embarked on a new and exciting project; to replace the existing boardwalk and bridges throughout both Lower & Higher Moors with something more enduring than has historically been used. The boardwalk selected was made from recycled plastic.  This plastic is known as "end-of-life plastic" as it is material that has reached its recycling limit and would ordinarily end up in landfill. Each metre of the newly installed recycled plastic boardwalk contains the equivalent of 1000 plastic bottles. That means that in just the first two 45 metre sections installed on Lower Moors alone, the equivalent of 90,000 plastic bottles have been diverted from landfill; and since 2015 we've installed even more!

 

Recycled plastic boardwalk fitted by our Rangers at Lower Moors SSSI, St Mary's, allowing access to nature, important for both physical and mental health.

For all these reasons and more, our wetland habitats are a treasured part of the UK landscape, crucial for wildlife and for people. Together they form part of a dynamic and connected waterscape that, with a little help, can continue to support a huge and unique diversity of wildlife.

The Wildlife Trusts are working to protect and restore our damaged wetlands as part of our vision to see 30% of our land and seas managed for nature’s recovery by 2030.