Stuart Clarke on the importance of bogs
Never think of the British wetlands as bog-standard.British wetlands are important to many different branches of science. In addition to being the home of rich wildlife and many birds, they are a wonderful source of archaeological information. The remains preserved in these locations are an irreplaceable archive detailing the changing relationship between humans and their environment. Yet, 5000 years worth of historical evidence is under threat of desiccation, if we do not rapidly implement policies to preserve the wetlands and stop them drying out and disappearing forever. There are many reasons; some are natural, such as climate change while others are man-made, such as the peat wastage caused by intensive farming methods. Recent studies of four areas in England, commissioned by the Somerset County Council and English Heritage, revealed that despite the wetlands drying out faster than ever, most of our local authorities have no policy for the identification, assessment, preservation or management of wetland archaeology.
Wetlands are so important for archaeology because of the efficiency with which they preserve natural relics and artefacts. There is no air in a peat bog and, therefore, undrained peat is made up of 90% water. The lack of air prevents decay, so the anaerobic water preserves organic material such as wood, leather, seeds, shells, pollen and spores. Animal, plant and insect remains are also better preserved in the waterlogged conditions than on dry land.
Excavating the wetlands in a controlled, sensible fashion has uncovered a wealth of information about life in Britain. For example, at one archaeological site in Somerset, a wooden walkway, named the Sweet Track has been precisely dated using tree rings. It was found to be nearly 5000 years old. A sprinkler system has now been installed to preserve this wonderful discovery. Other tracks have been dated back nearly 4000 years. Further historical discoveries in Somerset include Bronze Age pile alignments at Harters Hill and Ivythorne and the so-called Squire Phippens big ship, which is a dug out canoe. In the East Anglian Fens, the biggest area of wetlands in England, around the Wash a large number of Iron Age sites have been discovered, including a Salt Works, suggesting an immense amount of settlement long before the Romans arrived and began the fatal drainage. From the seventeenth century onwards, the drainage has been continued and, currently, loss here is largely due to arable farming.
Iron Age enclosures have been excavated and preserved at Sutton Common, part of a peatland that resulted from a temporary lake formed around 9000BC. The huge lake had reached from Hull, west to Doncaster and north to York.
The wetlands in the Northwest of England in Cumberland and Cheshire are composed of plentiful smaller bogs. There are two types. The first are in low valleys where lakes did not form and the second, larger ones are higher and the result of rainfall. Two bog bodies were found here as was the head of a cow, complete with hair. The cow was carbon dated to 800AD.
Archaeologists are running out of time to find the remaining artefacts because the wetlands are drying out at a frightening rate. Most of the important archaeological evidence is less than a metre beneath the surface and the loss is progressing at a rate of 2 or 3 centimetres a year, which gives just a few decades to reverse the trend or lose our heritage entirely. Unfortunately, this rate will accelerate if the predictions of hotter, drier summers to come are correct.
Obviously, the existing damage, sustained over the past half century, is irrevocable but so much could be done to halt the decline and save what is left. The current reports make many suggestions, such as closer spacing between drainage ditches and irrigation of seriously threatened sites to keep summer water levels high. They also advocate that urban and industrial expansion into these areas be halted, peat extraction for gardening and manmade drainage stopped, and that farming subsidies should be moved away from encouraging the crops that result in environmental damage.
Archaeologists have welcomed both reports and have added their voices to a growing movement to redirect farm subsidies towards methods that do not result in environmental damage. The irony is that the farming methods causing the drainage will result in their own demise, as they use up the topsoil and render the ground infertile.