Mysterious Meres

Right in the centre of East Anglia, straddling the counties of Norfolk and Suffolk, lie The Brecks or Breckland. It's an area with its own distinctive scenery which is the result of its unique geology.

It's very much a man-made landscape, but its more nature-rich areas are typified by wide swathes of short-cropped grass. There's nothing mysterious about that however - it's the rabbits! On the horizon there's often a row of twisted Scots Pine trees, these are called "deal rows" and were planted long ago in an attempt to prevent the sandy soils being blown away.

We're at East Wretham Heath, the Norfolk Wildlife Trust's oldest nature reserve and a favourite haunt of Dr Sydney Long, the NWT's founder. There's a memorial stone beside the main trackway crossing the reserve.

But our title was "mysterious meres" so we'd better go and find them. There are several of these meres in Breckland, the most famous being Langmere, Ringmere and the Devil's Punchbowl. The first two of them are right here on East Wretham Heath. Or are they?

You see, these bodies of water come and go with mysterious irregularity; sometimes they are full and sometimes empty. Believe it or not, that's Langmere above, completely dried up apart from a small puddle, right in the centre of the picture. If you can see two tiny white dots beside the tiny pool, those are two Shelduck, presumably wondering where the water's all gone.

This wise old Rook may have seen it all before. The meres are known to geologists as "fluctuating meres". The hollows in which they sit (or don't sit) were formed when caverns, which formed in the chalk underlying the sandy soil, collapsed. Such meres have no streams running into or out of them, but are filled from below by the water held in the pores of the chalk. Their level rises and falls depending on the amount of water held in the chalk.

Just to add to their air of mystery, they are often empty after heavy rainfall, or full in times of drought. This is simply because the water moves very slowly through the chalk, causing a delay in their filling or emptying. That's cleared up that mystery then. Well, no, not entirely, as we shall soon see.

First we have to walk past the coniferous plantation at the edge of the reserve. A huge part of the Brecks was planted with these characterless blocks of trees after 1918, when Britain had found itself short of timber during the Great War. 

Then past some rather more unruly trees, reaching out towards the light. I suspect there was once a wood or plantation blocking the sunlight behind this row. And then we get to....

Mysteriously, Ringmere, another of these fluctuating meres, has plenty of water. And it's only a quarter of a mile (400 meters) from the dried-up Langmere! No wonder our early ancestors thought that the Devil must have a hand in all this.

And wildfowl just flock to these bodies of water. Even in this photo, taken straight into the sun, I can identify Shelduck, Mallard, Teal, Shoveler and two Egyptian Geese.

There surely can't be much in there for them to feed on. There are a few very specialised crustaceans who call this home, but they have to be able to survive when the water dries up. There are also some insects and some tiny plants which can tolerate these conditions and thrive in the absence of other competition. 

And a short distance away is Fenmere another very different body of water. There's a bird-watching hide on its banks....

Not perhaps the best concealment you'll ever find. Les, who has a quip for most occasions, thought it might have been built to allow for plenty of fresh air during the pandemic! 

Lead on, brother!

Take care.