In a stand of hundreds of silver birch trees, is one lonely, green post. It sticks straight up from the ground, four metres into the air, like a tent pole holding up a canvas of low clouds. The post demarcates an area at the lowest point in Great Britain, and how fast it is getting lower.
It’s hard to imagine, but the ground used to be level with the top of the pole. In the 1840s, the whole column was driven under the peat and, over the years, the four metres of metal have slowly been revealed. It was planted in anticipation of a dramatic change in the ground level. ‘Holme Fen survives as fragment of the ancient fen,’ says Henry Stanier of the Great Fen Project. The fen here was once part of a vast, waterlogged landscape stretching from Cambridge to North Yorkshire. In the 1750s, a population explosion drove up the need for arable farmland, and in a move that has been described as equal parts feat of engineering and ecological catastrophe, the fens were drained. ‘We lost 99 per cent of them,’ says Stanier. Without water, the land also reduced in volume. At Holme Fen, the soil plummeted two metres in the first 20 years, then another two metres in the time since.
In its natural state, the fens would have been an amphibious place. ‘Records show the height above sea level will have changed again and again,’ says Stanier. ‘Underground, we see layers of lakebed deposits, marine deposits as well as peat.’
Before drainage, fenlanders made a living fishing for eel, hunting wildfowl and cutting reeds for thatch. When the conversion to agriculture began, a sabotage group called the Fen Tigers tore down dams and blocked drains in an attempt to preserve their way of life. In the end, agriculture prevailed. Forty per cent of England’s home-grown vegetables come from this managed landscape. A bird’s eye view of the region – with thousands of ditches and drains – reveals the juggle between food security and a healthy environment.
Climate change has reignited debate about the ancient fens. Scientists better understand how peat soils and wetlands act as carbon sinks, as well as how they can become carbon sources when damaged. ‘We still lose a centimetre of peat every year,’ says Stanier. Holme Fen and some nearby areas of fenland are being restored to try to preserve the remaining peat and encourage a wider variety of wildlife. As the water level is raised, birds such as snipe and lapwing, along with different dragonfly species return. For Stanier it’s a start, ‘but efforts need to expand to ensure long-term sustainability in the face of climate change, as well as to heal some of the damage already caused.’
This was published in the May 2019 edition of Geographical magazine
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