Significant conservation project to help retain vital British saltmarsh is underway

Northey Island from the air. Credit - Terry Joyce

There is an estimated 45,000 hectares of saltmarsh habitat in the UK with an estimated 38,000 hectares around the coastline in England. Predictions indicate a significant proportion of the habitat could be lost due to climate change over the next century.

However, the National Trust have now released plans to protect vital saltmarsh habitat at the Blackwater Estuary at Northey Island in Essex over the next century.

Saltmarsh, due to its ability to store carbon, is one of the key habitat types that needs protecting to help tackle the climate crisis.  Often referred to as blue carbon, saltmarsh and seagrass represent the largest sedimentary carbon store of the coastal and marine habitats.

This coastal habitat is also very unique, less than half a per cent (0.5 per cent) of the landmass in the UK, and is currently at risk due to rising sea levels due to the climate crisis. 

Northey Island, cared for by the National Trust, is the single largest block of saltmarsh in the Blackwater Estuary and this latest phase of work will protect and strengthen the saltmarsh and wider habitats by applying a range of innovative management approaches over the next few years.  

The current stage of the project includes improving and extending the existing central bank made of clay using material obtained from the creation of a freshwater pond and drainage system on the Island. 

This improved bank will protect the north of the Island from flooding and allow for the managed creation of new saltmarsh to the southeast, over the next few years. 

The new freshwater pond and drainage system will also provide an important water source for birds to drink and wash the salt from their feathers.

The project continues vital work started by the National Trust 30 years ago when Northey Island was the first site ever in England to carry out managed realignment to its shoreline in efforts to recreate saltmarsh habitat. 

In 1991 and 2018/19 work undertaken by the conservation charity resulted in two areas of healthy saltmarsh, approx. 1.7 hectares, which are now thriving with an amazing variety of wildlife. 

Daniel Leggett, Coastal Projects Manager at the National Trust says:

“Without management the whole 90 hectares of saltmarsh at Northey will be lost in the next 70-100 years.  

“The saltmarsh on the island, which comprises 80 per cent of the current land mass, is shrinking due to wave erosion and stronger tidal flows, which are the result of sea level rise – one of the impacts of climate change.  With higher tides, the saltmarsh and creek margins are eroding and sea water is overtopping the banks and flowing over the top of the saltmarsh more frequently. 

“The changes are impacting wildlife.  Some of the plant species found in the lower saltmarsh, such as sea aster, are dying out as the area is frequently under water, but are also creeping further up the shoreline encroaching on the areas where ‘higher’ saltmarsh plants, such as shrubby sea blite and golden samphire grow.  With sea levels rising the plants are running out of space and being squeezed out of existence between the rising tides and fixed man-made defences.

“Although we will inevitably lose some areas of saltmarsh due to sea level rise, this work should help us protect at least 50 to 60 hectares, create 10 hectares of new saltmarsh and raise a further five hectares to a sustainable height above the tides.”

Approximately 15 per cent of all UK intertidal habitat has been lost since 1945, including 18,000 hectares of saltmarsh.    

Daniel continued:

“Saltmarsh habitats across the east of England are under threat from rising sea levels and climate change. If we do nothing, then most of the saltmarsh will be lost over the next century. We need to play our part in restoring a healthy, beautiful natural environment and meet the needs of an environment under pressure. We want to see these precious habitats survive and thrive well into the future.

“Our work at Northey is a good example of how nature based solutions can offer sustainable response to the climate and nature crisis.  In a relatively small area a wide range or techniques are demonstrated that can be applied more widely to help sustain the species that live here and use the saltmarsh, improve biodiversity, store carbon and provide natural flood management to reduce flood and erosion risks.” 

As well as supporting a wide range of species such as samphire, marsh mallow, marsh harriers and flounder, the saltmarsh habitat at Northey Island provides feeding sites and shelter for wintering wading birds and waterfowl, such as brent geese.  It also offers a range of environmental benefits, including natural flood management and locking away more carbon than any other coastal habitat in the UK. 

Leigh Lock, Species Programme Manager for the RSPB said:

“Northey Island was the site of the first managed realignment project in the UK in 1991, and we aim to enhance this with LIFE on the Edge, an EU funded partnership project designed to create more and better coastal habitat to benefit breeding, wintering and migratory water birds. Through this project, the National Trust is putting in place further climate change adaptation measures to protect the future of the Blackwater Estuary. 

“But we need to do much more to scale this up to provide even greater benefits to nature, the environment and local communities around the UK coastline. Northey Island provides an ideal site to demonstrate what can be done more widely.”

Daniel concluded:

“The work we’ve already done has created a healthy, functioning, ecosystem that has existed for 30 years and demonstrated a technique that has now allowed over 3,000 hectares of intertidal area to be recreated across the UK to date.

“The techniques implemented at Northey Island between 2018 and 2020 have already locked up the same amount of carbon dioxide emitted from a standard family car driving 28,885 miles – that’s the equivalent of driving all the way around planet earth 1.16 times. The latest coastal adaptation work will add to this important tally.”

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