Tuesday 4 March 2008

The Breckland Meres

I have always been fascinated by the Breckland meres, a series of 12 semi-permanent waterbodies quite unlike anything else in England. The meres are self-sustaining, their dramatically fluctuating water levels prevent the establishment of reedbed, swamp or, ultimately, woodland. With the exception of Mickle Mere, none of the meres have any visible inlet or outlet, the variations in water level resulting from the height of the water table within the surrounding chalk. When the water level is high, the meres may overflow, when it is low they may dry up completely. Along with Mickle Mere, the other prominent meres are Ringmere, Langmere, Fowlmere and the Devil’s Punchbowl – all to be found in a small area northeast of Thetford.

During their dry phases, the bare mud is soon colonised by some rather interesting plants, including the rare liverwort Riccia cavernosa. During the wet phase the meres support some rare invertebrates, characterised by their ability to survive long-periods of dry conditions either by burrowing down into the damp soil or surviving as a desiccated egg stage. In past centuries, locals would take advantage of the dry conditions by planting root crops in the rich soil revealed by retreating waters. On occasions the meres would remain dry for more than a year, but water levels could rise suddenly and locals might lose their crops or be forced to finish harvesting in knee-deep water.

These days, the water levels in the meres are maintained through a management plan that controls the level of the water table by halting extraction for agricultural uses if there is any threat to the meres. Of course, the meres must be allowed to drain every few years, otherwise the delicate balance needed to maintain the character of the meres and their unique biological identity would be lost.

The meres are also fascinating because of the history associated with them. Excavations at Mickle Mere and West Mere have revealed the presence of prehistoric lake dwellings, suggesting a long period of human use of the sites. Ringmere was the site of a fierce battle between Danish invaders and the Saxon ruler Ulfkytel. The Norse scald, Ottar, described the battle and noted how ‘from Hringmar field the chime of war’ was heard. The battle also appears in the Anglo Saxon Chronicle and it is noted that the Saxon force, camped by the mere, was beaten by the treachery of a servant who had Danish ancestry. So many of Norfolk’s great naturalist writers were drawn to the meres and commented upon the bleak open landscape within which they sat. While the landscape may have changed, the meres are an ever-present feature of great antiquity, and it is essential that we work to maintain them.

No comments:

Post a Comment