Blog by David Mason, National Trust Ranger - Suffolk and Essex Coast
‘Increasing the extent and health of the saltmarsh area improves biodiversity and provides a range of other ‘ecosystem services’ (things that saltmarsh delivers for society) such as natural flood allevation, reductions in wave energy, spawning and nurseries for fish, providing food and shelter for birds, and locking up carbon dioxide to reduce the effects of climate change.’
I write this, the first Ranger’s blog from the Northey LOTE project, after visiting Northey Island on the Blackwater Estuary on the Essex coast. It was a bright November afternoon on a falling tide and as I approached the tidal causeway that links it to the mainland the last Lapwing and Dunlin were leaving the causeway to feed on the newly exposed mud. In the distance a flock of Golden Plover were glowing in the sunlight, reflected in the glistening mudflats. This is a spectacular place to see coastal birds when large flocks of waders and wildfowl gather on the estuary to feed and roost.
Several years ago, I saw c.5000 Brent Geese land on a site on the Suffolk coast during an October storm as they came in to land for shelter, skein after skein, on their migration South. They left the next morning when the weather cleared and I wondered if I had dreamed it!
I had heard that the Blackwater Estuary was a hotspot for them and have been delighted since starting work on the Essex coast last November to see where they were heading: Northey is a refuge for them in the winter where they roost and graze on the grass fields and on the saltmarsh as the tide comes up. In February I spent a happy morning clearing a footpath for the new circular visitor route we put in place this year, working with hand tools to minimise disturbance, while the geese chattered quietly in the field nearby.
I first visited the site in 2019 as the work to realign the South Embankment was being undertaken. This work was finally completed this year after delay in 2020. The mud from the embankment was placed in the ditch behind it (from where it had originally been dug in the mid-1800’s) to reform the natural landscape; the realigned area has now been naturally colonised by a wide range of saltmarsh species such as sea purslane, samphire, sea aster and sea beet as the tide has flooded the area, bringing in seed from the surrounding area. This area grades into a rising grassland bank which as sea levels rise will become new saltmarsh but now provides a rare transitional area between the saltmarsh and terrestrial grassland.
Now the pressure of coastal squeeze has been reduced, it is also notable that the saltmarsh in front of where the embankment was (which was heavily eroded) is also showing some signs of recovery with sediment depositing and new saltmarsh vegetation growing. I am impressed at how quickly this has established from bare mud. Allowing the coastal processes to function naturally without the constraints of man-made structures seems to be key. There is an increasing urgency to carry out more of this work for nature conservation as existing saltmarsh is rapidly eroding due to sea level rise and coastal squeeze on saltmarsh between the tide and coastal defences.
The island has been busy with contractors this year and new habitat and visitor facilities have been created and installed in preparation for future realignment of other embankments. Volunteers from the Essex and Suffolk National Trust group helped in maintaining the visitor route and picked up eight bags of litter from the foreshore.
There are a small number of water voles that live a marginal existence on Northey Island. The water voles’ homes and their numbers here have recently suffered from flooding from the sea (such as in 2013 and 2017/18) and hot dry summers. Part of our work in adapting to climate change and sea level rise is to create a new watery habitat for them. A new pond and ditch system has been created on higher ground which will provide a safer, more sustainable future home for Water Vole.
Coir rolls with pond plants embedded have been placed which it is hoped will provide food and shelter for the voles and other wildlife when they become established. This is overlooked by a new hide where visitors will be able to look over the pond, a new scrape and establishing saltmarsh.
A new scrape created this summer has filled with water and is already attracting Lapwing, Teal and Curlew amongst others.
In some areas dredged sediment from elsewhere in the estuary is being used to increase the resilience of the marsh. The adaptation of the coastal processes this achieves will prevent further erosion of saltmarsh in these areas. Eroded creeks that were bare mud a few years ago are already building up with natural silt deposited by the tide and recolonising with saltmarsh plants. The estuary side of the bank in this area includes some areas of shingle which provide another niche habitat and attracted 49 Ringed Plover in August, as noted on the regular bird (WeBS) count.
All in all it has been a fascinating year seeing the work progress and habitats develop and sharing it with visitors and volunteers and now you.
Blog by Audrey Jost - Assistant Warden at RSPB Seasalter Levels
Seasalter Levels is an RSPB reserve located in the South East of England, north of Canterbury. Acquired in 2007, the Levels were first constituted of only one unit named LNR (Local Nature Reserve). Since then, thanks to the efforts of the Seasalter Partnership (comprising RSPB, Natural England, Canterbury City Council and Swale Borough Council), the Levels have expanded to include four new management units (Whitstable Bay Estate, Monkshill, Alberta and Vikings Estate), increasing its overall size from 71.5 ha to 290 ha.
Constituted of mostly lowland wet grassland habitat, the Levels have, over the years, experienced a lack of appropriate management, leaving the area in poor condition for breeding waders and wintering wildfowl.
Thanks to funding from the Green Recovery Challenge Fund and the EU LIFE project, a large-scale restoration project of 228 ha of the reserve was able to be put in motion.
The project includes the creation of new topographic features aimed at improving the habitat for wildlife, particularly for wading birds such as lapwing and redshank, respectively classified as Red and Amber under the UK Red List for Birds (2015). Features created will help manage and retain water in fields, resulting in shallow pools with muddy margins that provide suitable habitat for wading birds to forage for invertebrates in soft, damp soils.
The features include:
Rills: Meandering channels varying in depth that retain water for a longer period than adjacent grassland. They are arranged in a branching structure supplying water from the perimeter ditches to the middle of fields. They also provide long muddy margins, increasing the feeding area for wading birds.
Scrapes: Shallow depressions with irregular outlines and gentle slopes that seasonally hold water, supporting a rich invertebrate life. Ideal for redshank, that prefer shallow pools of water for feeding.
Bunds: Acting as a barrier to minimise water runoff, earth bunds increase water infiltration in the soil. Long, ditch-side bunds also provide an opportunity for water vole colonisation by maintaining dry banks when the water levels are at their highest.
Islands: Low, flat features that sit higher than peak water levels and provide refuge for waders and wildfowl from nest flooding and give safe spaces for winter roosting.
The works, that officially started in September 2021, also include the creation and repair of crossing points and culverts to allow fine water level control. Ditch enhancements and reprofiling of existing banks will provide niche habitat for water voles and aquatic invertebrates.
Whilst it is still a work in progress, changes on site are becoming more and more noticeable, and not only to the human eye!
To date, restoration work has been completed on two out of the four units. As we progress, we will start to introduce large scale grazing across the reserve that will entail the installation of gateways, fencing and a livestock corral. Grazing is an essential part of reserve management as a short grass sward gives ideal habitat for ground-nesting lapwing. By grazing with cattle and flooding the fields, new plant communities will develop, including wildflowers such as red clover that provide a nectar source for bumblebees like the endangered shrill carder bee, which has a local population on the nearby sea wall. Further updates will come as work continues.
The works at Horsey have recently completed with a little under 50,000m3 of sand and shingle deposited on the foreshore.
This was our first visit to look at the work at low tide and it the change is quite remarkable. An entirely new beach has been created. This drone photo taken from a recent survey shows what has been achieved in the month-long campaign.
The material deposited will be fantastic for little terns and other beach nesting birds and looks on first inspection to be the perfect material with a fantastic mix of sand, shingles, and gravels. Remarkably the material is already moving inwards and will slowly wrap itself around the existing beach, hopefully in time for the next breeding season. When this process is complete it will look virtually indistinguishable from the existing beach but higher and more resilient.
We will continue to monitor the movement of the material with regular drone flights. We hope to write this scheme up as a case study and encourage future schemes by taking a strategic approach to BuDS throughout Kent and Essex.
The Sospan Dau and its crew have now moved on the Blackwater estuary where they are carrying out similar works to those at Horsey. If you want to learn more about this works, the Mersea Harbour protection society have a great website here: https://savemerseaharbour.org/.
This work will also stop coastal erosion and create new habitat for little terns within the estuary. All in all, over these two campaigns 150,000 m3 of sand and shingle will be deposited and there will be lots of exciting new habitat in place for next spring.
In case you missed it, here is the link to first part of Horsey Island Recharge Project blog and the second part.
Guest blog by Mark Appleton, RSPB Bird Conservation and Visitor Engagement Officer
On 31st October marked the start of the COP26 climate conference!
For nearly three decades the United Nations have been bringing together almost every country on earth for global climate summits – called COPS – which stands for ‘Conference of the parties’. This year will be the 26th annual summit – giving it the name COP26 and will bring together world leaders and delegations to discuss all the gnawing issues holding countries back from curbing emissions and meeting the goal of limiting global warming to 1.5 C above pre-industrial levels by 2100. Delegations from most of the 195 nations that signed on to the Paris Agreement in 2015 will negotiate rules for a global carbon market, look to raise funds for climate action, and announce new emission targets.
RSPB's very own Medmerry Nature Reserve is to be featured in a COP26 film. This particular event in COP26 will be hosted by the RSPB and Environment agency.
Adam Taylor, a warden at Pagham harbour and Medmerry Reserves, said “Medmerry is being showcased during the COP26 conference in its event ‘Coast:Nature-based solutions for climate biodiversity and people – lessons learned and stories from the ground too’ along side examples from the Central Mangrove Wetland in Cayman Islands, Shanghai Chongming Dongtan National Nature Reserve and Jiangsu Yancheng Yellow Sea World Heritage site in China and the South Korean Yellow Sea Getbol World Heritage Site, as successful examples of habitat restoration in coastal wetlands”
So why do we think Medmerry is so important?
Medmerry Nature Reserve is a flood protection scheme as well as a home for wildlife.
After severe flooding on the Manhood Peninsula, the Environment Agency started construction on Medmerry in 2010.
At the time of construction, it was the largest coastal realignment scheme in Europe. It was completed in 2013, it protects at least 348 properties, a sewage works and roads serving 5000 residents. The earth embankment originally built in the 1960’s to prevent the sea flooding the land was intentionally breached so that natural mudflats and salt marsh are slowly being created by the advancing tide.
Saltmarsh has great ecological value for the ecosystem, namely in nutrient regeneration, primary production, habitat for wildlife species, and as shoreline stabilizers with the bonus of it being a great carbon sink. This amazing scheme has been recognized by COP26 and are featuring the great habitat of Medmerry.
183 hectares of intertidal habitat were created, and many species have made use of it. Bird populations are generally decreasing across the UK, but there is some good news at Medmerry where they are increasing – especially for farmland birds and waders! We now have at least 32 species of fish present and the reserve is an important nursery for their young.13 species of mollusc have colonised and 11 more are expected to in the coming years. Medmerry is home to 4 of Britain’s reptile species, mammals like water vole and roe deer and a multitude of insects like butterflies, dragonflies and crickets.
As well as being a vital habitat for thousands of waders and waterfowl, the role that saltmarsh plays in defending our coasts from erosion by waves is increasingly recognised, and efforts are being made to protect and restore them. Although saltmarsh tends to need little conservation management, many have a long tradition of low-intensity grazing, which is important in maintaining their diversity. Re-alignment of sea-defences can allow for expansion of this habitat. Images of storm surges, rising sea levels and flash floods and the devastation they wreak on people and their homes are becoming all too common. Due to the melting of artic sea ice and thermal expansion of the oceans as a result of global warming, sea levels have begun to rise. As with all coastlines, this rise in water levels is predicted to negatively affect salt marshes, by flooding and eroding them. This has a knock-on effect to our nesting and roosting sea birds with their habitats disappearing.
Saltmarsh act as a buffer zone, stabilizing shorelines and protecting coastal areas, inland habitats and human communities from floods and storm surges. The salt marsh also breaks up the wave action acting as a barrier. When flooding does occur, our salt marsh acts like a huge sponge, soaking up the excess water. Worldwide, these ecosystems are in danger of disappearing if they cannot increase elevation at rates that match sea-level rise.
Saltmarshes can be very efficient at locking away carbon. When saltmarsh plants die, rather than decomposing and releasing their carbon into the atmosphere, they become buried in the mud. As sea levels rise more sediment layers get buried and more carbon gets locked beneath the mud. The rate of carbon sequestration on coastal wetlands is greater than in all forests combined, despite forests covering much larger areas. As trees grow, they absorb carbon from the atmosphere and this carbon remains in the tree if it lives. When these trees die, they decompose and release the carbon back into the atmosphere. What happens in wetlands is different and means the carbon can be stored for hundreds of years. Wetlands are special because they bury the carbon from decomposing plants before it can be released back into the atmosphere.
Saltmarsh has two main characteristics which allow them to act as efficient carbon sinks. They have a high vegetation growth rate with European saltmarsh soils sequestering an average of 2.1 t C/ha/yr. Secondly, they do not emit methane, an important greenhouse gas, since the sulphide present in the soil inhibits bacterial-driven methane production. The water levels and occurrence of anaerobic decomposers in tidal marsh ecosystems also acts to reduce organic matter decomposition and promote carbon storage. Salt marshes are very important in sequestering carbon and do so at a higher rate than land ecosystems. The saltmarshes at Medmerry is therefore very important in storing carbon. The science is clear. Wetlands are the most effective carbon sinks on the planet.
Saltmarsh is a scarce resource in Britain. They are threatened by human development expansion, invasive species, erosion, altered hydrology and connectivity, and climate change. It is estimated that over 50% has been lost or degraded globally thanks to reclamation and erosion. Further losses are occurring, as saltmarshes get squeezed between rising sea levels and the hard sea defences that protect coastal settlements and farmland. In the UK we are losing nearly 100 hectares of saltmarsh a year (that’s nearly 150 football pitches).
Economic analysis has shown some of the economic benefits of saltmarsh. 2207 tonnes of net carbon can be sequestered per year in restored saltmarshes. 74 million pounds in benefit from restored salt marshes to flood defences over 40 years.
Damaged wetlands can turn from a natural carbon sink into a source of CO2 emissions that adds to global warming. Many of the wetlands which remain are in a fragmented and degraded condition. But we mismanage our wetlands at our peril. The past two decades have seen a shift toward working with managers to restore tidal marshes to conserve existing patches or create new marshes. In recognition of the importance of saltmarshes, agricultural grants are available to support their management, with a focus on providing an appropriate level of grazing for a range of plants, birds, and insects.
Blog by Kieren Alexander, Site Manager for RSPB Old Hall Marshes
Work is progressing nicely on the beneficial reuse project at Horsey island, with almost 25% of the material delivered by the Sospan Dau so far.
The Sospan Dau is being skippered by a joint venture of Van Oord and Boskalis Westminster who have undertaken many such projects around the globe and are experts in this type of operation. They are able to access the disposal location at every high tide once they have found enough of the correct material from the Harwich Haven authority channel deepening source site, in this case sand and shingle. The material is then pumped ashore using a short length of floating pipe held in place by ropes and a small tugboat. This allows accurate disposal of the material and into the area it should be placed.
You can track the boat here:
MarineTraffic: Global Ship Tracking Intelligence | AIS Marine Traffic
However, the best view is from the air and we were able to access Horsey last week and take this Drone footage. This shows the Sospan Dau approaching the island and discharging the material.
At the moment the material resembles a large flat sand and shingle pancake. It will be shaped and sculpted by tide and wind over winter, moving landwards and westwards and in time building up the existing beach.
Although it doesn’t look like it now, the existing beach at Horsey is manmade, it was created in the 1990’s by the original Sospan Dau after a similar scheme where material was transported from a deepening project carried out by Harwich Haven Authority and the Environment Agency. It was after this that little terns colonised the beach and made this an important colony. However, the same forces that created the beach are also slowly causing it to be less suitable for nesting birds, it is slowly flattening out and lowering. This makes it much more vulnerable to storm events and high tides over the breeding season, which can lead to the complete loss of a breeding season. This work will make this scenario much less likely in the future in this location.
In case you missed it, here is the link to first part of Horsey Island Recharge Project blog.
Photo credits: Oystercatcher by Katie Nethercoat (rspb-images.com)