Just a stone’s throw from the RAF airbase lies Marham Fen. Tucked away down a tiny drove road, it is surprisingly ‘invisible’ despite its 60 hectares, and is a place of unexpected tranquility, a world away from the roar of jets half a mile away.
Although now largely wooded, Marham Fen is home to an array of habitats: pockets of chalk and neutral grassland and fen, extensive areas of mixed scrub, ponds and marshy depressions enable the site to support a huge diversity of species: it is home to national rarities such as scarce emerald damselfly and several moths, and a range of UK Biodiversity Action Plan species including grizzled skipper and dingy skipper. The 11 ponds which pepper the site are thought to be ‘pingos’, caused by springs which froze during the last ice age. In between, the land undulates heavily, the mounds and depressions being another indicator of ground shaped by freezing and thawing during the ice age.
The fen is owned by the Marham Poors Trust. It is a typical example of ‘marginal’ land that escaped enclosure – and cultivation - during the 18th century, being used instead to provide resources for the poor of the parish. Its purpose has changed little, but these days income from the site is derived from a leasehold to Anglian Water who abstract drinking water from the aquifer to supply King’s Lynn.
Registered as a County Wildlife Site, management has been carried out by Norfolk Wildlife Trust on behalf of Anglian Water since the early 1990s. Managing a site of this size and complexity requires huge resources – far more than are available – so of necessity work focuses on protecting the most fragile and vulnerable areas: the pingos and the open fen/grassland. The diversity of the latter is dependent on cutting and removing the vegetation each year to ensure that nutrients do not build up, and to keep invasive species such as wood small reed and encroaching scrub at bay. While grazing would be ideal, the use of the site for drinking water abstraction currently precludes the use of livestock because of the risk of contamination from bacteria. Therefore, management of the open areas is still done by annual cutting and raking off, an immense but essential job to prevent the loss of these areas to scrub and woodland.
Anglian Water funds all of the management work. In 2012, the grassland areas were cut and cleared as usual, but some extra funding provided a welcome opportunity to tackle scrub that was invading several ponds, as well as clearing back encroaching scrub and aspen from some of the open areas. This vital work has paved the way for future projects to reconnect the fragmented grassland and fen habitats at Marham Fen, and undertake further restoration of the pingo ponds.
Chris Gerrard from Anglian Water said: “This is one of a number of sites of wildlife value owned or occupied by Anglian Water. Our long-standing partnership with Norfolk Wildlife Trust enables the site to be managed to maintain its wildlife value and to provide access for local people. I'm really grateful to the Trust and its volunteers for all the hard work they do year in, year out.”
Pics: The pingos are the areas with the taller vegetation - many of these were being invaded with young scrub but it was cut out and removed during late winter 2012/13 with a grant of £8,000 from Anglian Water. All the short grass areas are managed annually, also with funding from Anglian Water