The Mobile Coast

30th November 2007, Friday

On the 27 September 2007 I wrote about the Open Pits, a superb series of natural ponds on the shingle at Dungeness. One of these natural pits is quite different, Wickmaryholm Pit on Lydd Ranges. It is older than the rest and its days are numbered.

Wickmaryholm Pit

Formerly a freshwater body like the other Pits, the shingle to the south of it has been eroded away and it is now separated from the sea by just a tall narrow irregular coastal shingle ridge. Saltwater flows through the shingle at high tide and as a result this is now a percolation saline lagoon, yet another rare habitat for which Dungeness is nationally important. The ancient shingle vegetation, grading into saltmarsh around the pit is high quality habitat, with scarce species such as shrubby sea-blight Suaeda vera, (the dark bush in the picture just to the north of the middle of the pit). Underneath the pit the peat and silt deposits tell the tale of how this pit started as a young saline lagoon on the east coast of the young Dungeness, how the water became fresh as it was separated from the sea by an broadening ridge of gravel, before saline conditions returned with the erosion of the southern coast.

The bare shingle on the right of the picture is progressively being inrolled by the sea – the lobes of bare gravel have been washed over the ridge by storms, and are gradually covering the ancient habitats. As I write this article the latest round of winter storms are brewing and will possibly cover more of these ancient habitats in bare shingle. In a few years time this area will once again be in the sea.

As someone who has spent years conserving shingle vegetation I view this with mixed feelings. Its sad to see ancient habitats go, but its vital that we do not interfere. This is what the coast does. Its mobile, and the erosion will create new habitats whose species depend on these processes. The bare gravel will be colonised by Babington’s Orache Atriplex glabriuscula, which forms a type of vegetation called annual driftline vegetation, for which the shingle at Dungeness and Rye is internationally significant. When the gravel is washed away some of it will create new areas of shingle to the east which will be colonised by young shingle vegetation communities and the process will start again.

This is the natural cycle of life on a shingle beach – destruction goes hand in hand with habitat creation and its this dynamism and unpredictability that makes them such interesting habitats. While you have shingle vegetation protect it from trampling and vehicle damage and enjoy it, but when its time for the sea to take it back again let it go, and create new habitats.