WCLC – Conservation Management of Walberswick Common and Marshes
Talk given by Adam Burrows, Natural England, 6 October 2021
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On Wednesday, 6 October over 40 people came to Walberswick Village Hall for a fascinating and beautifully illustrated talk given by Adam Burrows, Senior Reserve Manager for Natural England’s Suffolk Coast National Nature Reserves.
AB started by showing a series of maps of the Suffolk Coast NNR, the Walberswick Site of Special Scientific Interest and other designated areas as well as maps of the extraordinarily varied mosaic of habitats which exist here. He explained that this habitat diversity gives rise to a wonderful richness of species on the heaths locally, notably Dartford warblers, woodlarks, nightjars, red deer, adders and silver-studded blue butterflies.
The lowland heath is a particularly special and important feature. It is one of the rarest habitats in the World. The UK holds about 20% of the World’s lowland heath – 0.5% of which is the 670 acres stretching from Minsmere to Walberswick, and about 0.05% is Walberswick Common itself. AB explained that the heathland itself has its own mosaic of habitats: heathers, gorse, bracken and acid grassland. Walberswick has two species of gorse: Common gorse which flowers in January-June; and the smaller, more compact Western gorse which flowers in the second half of the year, from July to November.
AB explained how in the past, firewood collection and the grazing of sheep, cows, geese on the Common helped to control invasive species such as bracken and birch. Prior to modern farming methods and improved straw production, bracken was prized for livestock bedding. But left uncontrolled, bracken spreads rapidly, shading below it and leaving a deep litter which suppresses the growth of most other plants, reducing the biodiversity of the area.
In addition to its heaths, Walberswick has one of the biggest blocks of reedbed in the country at Westwood marsh, some 470 acres. There are several recent success stories here: marsh harriers were down to 3 birds in the UK in the 1960s (2 at Minsmere and 1 at Walberswick), but there are now some 642 breeding pairs. Likewise, bitterns: 11 booming males in Britain in 1997, 2 of which were on Westwood marshes. By 2017 this had increased to about 190, 11 of which were in Walberswick. Otters have also returned, as well as bearded reedlings and Cetti’s warbler with its loud song.
A mosaic of structure is also maintained in the reedbeds. Some 5-10% is kept as open water. A further similar amount as scrub for birds such as water rail. In addition, a small area of about 5-8% (some of which is on the Charity’s land) is cut commercially for thatching, helping to create a patchwork of young and old reeds of correspondingly different ages. The cut areas also provide ephemeral ponds in the spring providing a readily available food source for bitterns looking to nest in the standing reed nearby. Highland cows graze to create tussocky transition zones in the margin on the edge of the reedbed. This structural diversity is important for insects, aquatic life and, further up the food chain, bitterns.
Sea pea, sea holly and yellow horned-poppy are found on the shingle seashore. Small colonies of little terns nest in protected areas on the shingle as well as ringed plover. Inland, avocets and redshank frequent the scrapes on the borders of the marsh. These saline lagoons also support rare invertebrates like the starlet sea anemone.
The intertidal areas of the River Blyth support large numbers of overwintering and passage wildfowl and waders, particularly avocet, black tailed godwit, and shoveler and pintail ducks. The birds roost either on the saltmarshes or, on larger tides, on the surrounding grazing marshes. Over the last two years it has also been good to see the breeding gull colony return, including some 20 Mediterranean gulls this year.
AB mentioned that there is a plan to restore the connections between the heaths of Walberswick and Minsmere, by taking some areas out of commercial timber production. This in time should help to create corridors allowing previously isolated populations of less mobile species, such as silver studded blue butterflies and natterjack toads, to join up.
As to the future, using current predictions of climate change, AB said we are likely to see more storm events leading to flooding of coastal areas as happened in 2013. Much work has gone into making the area more resilient to these events, including working with the Environment Agency to allow the shingle bank between Walberswick and Dunwich to adopt a more natural profile. Before the 2007 surge tide, the shingle bank was about 15m wide. Although lower, it now extends to some 100m in places and is more robust and better able to withstand flooding as the seawater now tends to over-top rather than punch holes through the bank.
In addition, Natural England has worked with local landowners to make the river wall on the Blyth at Tinkers and Delacroix marshes (upstream of the Bailey Bridge, on the Walberswick side) more able to cope with over-topping. In 2010/11, the soak dyke was migrated inland, and the slope on the landward side of the river wall made shallower. As a result, when floodwater over-tops the wall, the water now runs into the marsh rather than breaking holes in the bank.
AB explained that in conjunction with the more resilient river walls, it is also important that floodwater from winter surges and from heavy summer storms can escape quickly from the marshes to the sea, especially in spring so that young birds and other fauna aren’t drowned. Improved drainage has therefore been installed to help floodwater drain quickly.
A lively Q&A then followed:
In answer to one question, AB said that electric fencing on the shingle helps to protect nesting little terns and ringed plovers from ground predators such as foxes. The rope-fenced areas also create a defined area that walkers and dogs are asked to avoid, thereby providing the wildlife in that area some respite from disturbance.
AB explained that uncontrolled dogs running off the lead are perceived by nesting birds as potential predators. This causes adult birds to leave the nest, often as a distraction to lure the threat away. Eggs and chicks may then chill and die, or other opportunists predate the nests. Nightjars are particularly vulnerable as their eggs are conspicuous, so are readily seen by corvids such as crows and magpies.
As to the management of the Common, AB said that the silver birch, gorse and bracken need to be managed otherwise left unchecked they would swamp the heathland. The overriding goal is to maintain a mosaic of habitats. Although initially the removal of gorse, birch and bracken can look extreme, the land recovers quickly and the clearance enables the restoration of lowland heathland with heathers and other characteristic plants. AB mentioned that Natural England used tractor-mounted machinery on East Hill rapidly to clear a large area of gorse. The restored lowland heath there now looks wonderful.
AB observed that it is important to manage the Common so that the heathland doesn’t evolve into what would be quite low nature-conservation value woodland. Encouraging woodland is undoubtably a good idea, but it is important to put the right tree in the right place.
When asked about re-wilding, AB explained that it can work very well for areas that are already in a nature-poor state. There are now some really positive examples in the UK, especially Knepp, a 3,500 acre estate in West Sussex. AB said that a re-wilded landscape can’t be a solution everywhere, and it would be a great shame to lose the last areas of real quality biodiversity that still exist, especially Walberswick Common. AB acknowledged that although re-introducing wild boar would be exciting, unfortunately it’s not practicable here!
In answer to another question, AB said that the brashings (cut silver birch and gorse branches) didn’t have to be burnt. Other uses which captured carbon, rather than immediately releasing it as CO₂ from a fire, were now being explored by heathland managers. These include brushwood bundles to protect riverbanks from erosion as well as habitat piles away from the heath. Chipping is another option if the area is readily accessible, especially if the chippings were then used elsewhere away from the heath. Chippers however burn diesel, a fossil fuel; and they release carbon as the chippings themselves break down. Although there are no easy solutions here, Adam Cooke said the Charity trustees would investigate options other than burning.
As to the management of bracken, eradication is not the desired goal. But large, dense stands need to be controlled as eventually they smother the heathers, flowers and grasses that thrive on the sandy heathland. AB said the huge advantage of spraying with the bracken/fern specific herbicide, Asulox®, is that it is quick and very effective with up to 95% reduction over 12 months. He explained that the alternative of cutting bracken, or crushing it by rolling, is very time-consuming and is likely to take many years; and it doesn’t work as well as bracken has a very effective rhizome system under the soil from which new shoots quickly re-emerge. Furthermore, cutting over uneven ground is rarely effective. AB went on to say that he knew of no known detrimental impact on heathland soil chemistry from Asulox® use, and that its use is currently reviewed annually by both Natural England and DEFRA.
Another questioner asked about protecting the banks of the Blyth and in turn the marshes behind them. AB said that since 2010, the southern banks abutting Tinkers marsh have been made wider and more robust. This marsh is leased by Natural England from Sir Charles Blois, an attendee at the talk on 6 October. AB will see what can be done to prevent further damage to the riverbank caused by speedboats and jet-skis upstream of the Bailey Bridge.
Finally, AB was asked about the interrelationship between Walberswick Common Lands Charity and Natural England. He explained that Natural England is the UK Government’s adviser for the natural environment in England. It is an executive non-departmental public body sponsored by DEFRA, and its role is to help protect and restore our natural world. Natural England advises on the conservation management work which the Charity and others carry out. Adam Cooke said that the Charity receives some £20-25,000 funding each year under a Countryside Stewardship Agreement with Natural England. If anyone would like any further information about this, AC said they should feel free to contact him.
If anyone has any questions or enquiries, particularly about the Suffolk Coast National Nature Reserves, Adam Burrows is happy to be contacted direct on 07970 463826