‘Miraculous’ world of Norfolk’s saltmarshes
- Credit: David Tipling
Norfolk Wildlife Trust ambassador Nick Acheson marvels at the wonders of our coastline in winter
It is winter now, in late November. Today though, is a rare day of perfect winter beauty. The sun shines low in a cold blue sky and the colours of the land are freed from the sullen fog and drizzle of the season.
I am on the coastal path. It does not matter where, as the same scenes, more or less, could be seen anywhere along our glorious coast from Holme to Cley. South of me, inland, there are arable fields and grassland. To the north there is saltmarsh. Everywhere there is life.
A saltmarsh is a miraculous, counter-intuitive thing. Coastal landforms need two conditions to exist: an energy source and a substrate. The coarser the substrate, the greater the energy required to move it. So a beach made of heavy cobbles, such as Sheringham, forms where waves hit the land head on, with enough energy to throw stones onto shore. Long sandy beaches form where waves strike the shore at an angle and their glancing energy is sufficiently reduced for them to drop grains of sand.
Sand dunes, as at Winterton, Holkham and Holme, form where this sand is whipped up the beach by wind — not waves — and dropped behind an obstacle which breaks the wind’s flow. Plants then do the job of building the dune, by trapping sand, and reinforcing it, physically and chemically, with roots, and rotting leaves, all of which are carbon gathered from the atmosphere.
Saltmarshes are a paradox, in that they require almost an absence of energy to form. Behind spits and islands, such as Blakeney Point and Scolt Head, or at the top of long beaches, often behind ridges of dunes, saltmarshes form at the very top of the tide. At the point where the tide turns, protected from waves by a spit or beach, seawater has sufficiently little energy to drop its finest particles of silt.
These, if they escape disturbance by the next tide or by a storm, settle to become a mudflat, which is colonised by algae, adding both nutrients and structure to the embryonic marsh. Next samphire grows (proper botanists call it glasswort, but in Norfolk it is samphire). Samphire traps more silt, raising the surface of the marsh, meaning it is minutely less exposed to the next tide, offering minutely different conditions to potential colonists such as sea aster, cordgrass and sea arrowgrass.
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This is succession. It happens in all habitats all the time. In simple terms, it is the process by which the living beings in a habitat alter the physical conditions in it — soil depth, soil chemistry, availability of freshwater, availability of light — making it suitable for new species.
In the idealised world of ecology textbooks, it is linear, moving neatly from one stage to another, with a discrete group of species at each stage. In a habitat as fractally complex as a saltmarsh — shaped and reshaped over millennia by neap tides and spring tides, droughts and storm surges, sheep grazing and goose grazing — the reality we see is chaotic and wonderful.
It is geese I see grazing today. They are dark-bellied brents, which join us in their thousands each winter, from western Siberia. I say they are dark-bellied brents but, just to add to the fractal complexity of the marsh, Pacific brents (also known as black brants), which hail from northeast Siberia, Alaska and parts of northern Canada, sometimes arrive in Norfolk as waifs and join our regular flocks of dark-bellies.
Over a winter a lost brant gander may form a bond with a young dark-belly female and, come spring, will fly back with her to the Siberian tundra and raise mixed offspring. Such geese are very rare, but they are here and they add to the marvellous wildness of our coast, and the joy of walking through it, watching it.
Some geese are feeding in the saltmarsh, surrounded by curlews, sad-faced and sad-voiced. Many more, and more curlews, are inland of the sea wall, in coastal grassland, among a rippling blanket of wigeon. Geese, wigeon, curlews, perhaps a few lapwings and golden plover too: these are the spirits of our coastal marshes in winter. Inland of the marshes, before the relentless tide of winter wheat and sugar beet begins, there is a thick old hedge.
By November its blackberries have gone. They fed October’s migrant blackbirds, blackcaps and whitethroats. There is plenty to eat here still. The hedges are red with rosehips and haws, and noisy with fieldfares and redwings. Like the geese, they are visitors from the north to Norfolk’s winter landscape, bringing life and sound to our lives at a time when much is mud and mist.
I could not live without the wild. Nor would I wish to. I live for these wild days on our extraordinary coast, for the wigeon’s shrill and the plover’s tragic mew. For the wild wind — fractally complex too — one minute strafing my face and the next seeming gone. For the saltmarsh, and all the carbon, worms, molluscs and human history buried in its muddy depths.
In today’s world these things, so deep in our Norfolk being, cannot be taken for granted. Trapped between the hard borders we’ve imposed and the peril of rising sea level, our coastal marshes face an uncertain future. So too, all across the county, our wildlife and its freedom to flow across the landscape, to adapt to climate change are threatened by habitat loss because of what people do and how we live.
At Norfolk Wildlife Trust we have, for almost a century, fought against the loss of our wildlife and its habitat and striven to buy land and restore it where we can – protecting it for the future. Without you, the people of Norfolk, our members, donors and supporters, we can achieve nothing. We thank you for your constant support especially at this difficult time, for in the coming decades we will need it as never before.