Saltmarsh from the air, Abbotts Hall nature reserve - Terry Whittaker/2020VISION
Managed Realignment
Protecting and restoring saltmarshes
Managed Realignment
Saltmarshes are coastal heroes - not only do they support huge biodiversity – from tiny critters within the mud, fish in the creeks, to birds on the shore - they also support and protect us. As one of our key allies in fighting the climate crisis, saltmarshes are a key focus of Essex Wildlife Trust's coastal and marine work.
Saltmarsh in decline
Saltmarsh epitomises the Essex coastline. However, in the UK, we are losing 100 hectares of saltmarsh per year. ‘Coastal squeeze’ is one problem. Saltmarsh squeezed between man-made sea walls and rising sea levels means saltmarsh habitat is lost. Such losses threaten coastal defence, water quality, fisheries and treasured landscapes, as well as valuable ecosystems and wildlife, including important wildfowl populations.
A solution: managed realignment
The protection of the remaining saltmarsh is a matter of urgency, but there is also potential to restore and create new habitat. Managed realignment is one way of creating new saltmarsh and is achieved by purposefully removing coastal defences or moving them further inland. Plans to realign 10% of England’s coastal zone by 2030 would create 6,200 hectares of habitat and increase carbon storage, as well as reduce risks of flooding and coastal erosion.
Sea wall breach 2002
Sea wall breach 2002
In October 2002, the 3.5km sea wall at Essex Wildlife Trust’s Abbotts Hall, along the Blackwater Estuary, was breached in five places to revert almost 50 hectares of previously arable land into saltmarsh and intertidal habitat, with a further 35 hectares of coastal grassland and other terrestrial features, including a lake being created.
The previously farmed land was rapidly transformed as saltmarsh plants quickly colonised the area and new coastal wildlife moved in. The site is well studied, including monitoring the marsh vegetation and the carbon sequestered and stored, the bird species present, and the fish using the area. It is considered a good case study for managed realignments and as a key nature-based solution.
The Trust’s second managed realignment was carried out at a nearby nature reserve, Fingringhoe Wick, where medieval walls were breached to create 22 hectares of new, internationally important intertidal habitat on the Colne Estuary.
How do saltmarshes help wildlife?
Healthy saltmarsh is biodiverse and supports a complex ecosystem. Overwintering wildfowl like brent geese, and wading birds such as redshank and lapwing, soar, swoop, paddle and forage amongst the saltmarsh. Saltwater channels and mudflats offer a safe nursery area for young fish like European bass, herring and grey mullet, searching for their next meal among the muddy beds and vegetation.
Sea lavender - Patrick Jefferies
Curlew - Damian Waters / Drumimages.co.uk
Samphire at Abbotts Hall saltmarsh
Fish surveys at the managed realignment.
How do saltmarshes help us?
We may not realise it, but saltmarshes help humans. Not only are they a natural flood defence, protecting our homes and land in case of storms and floods, they also boost carbon reduction. These carbon sinks can capture four tonnes of carbon per year, in just one hectare of saltmarsh. Just by existing, they are fighting against climate change for us.