Fens are areas of marsh and open water. Tall sedges and reeds grow there with other water-loving plants. They support many species of bird and insect including butterflies and dragonflies. Fenland was once most commonly found in East Anglia.
In the past, the local economy of fenland in East Anglia depended on peat and fen plants. Peat turf was dug by hand and used as fuel. Reeds were cut and harvested for thatch for barns and houses. Sedge was used for livestock bedding, and willow was used for wicker baskets or eel traps.
Fens are waterlogged areas 'fed' by an alkaline water source. The vegetation is a mosaic of sedge and reedbeds and damp 'fen' meadows, intersected by drainage ditches, streams and open areas of water. As the plant litter gradually decomposes, a rich dark peat is formed.
Where the build of peat is raised above the water table, and dries out for part of the year, shrubs and trees such as willow and alder colonise the area and woodland 'Carr' communities develop.
Plants found in managed fen include:
These support many wetland bird species and insects. Butterflies such as the brimstone (Gonepteryx rhamni), ringlet (Aphantopus hyderantus) and meadow brown (Maniola jurtina) are some of the most common. The beautiful but rare swallowtail (Papilio machaon) butterfly may be seen in Strumpshaw Fen in Norfolk.
The history of the fens, as with most wetlands, is linked to the reclamation of land for agricultural purposes. Although the fens were first drained in Roman times, it was not until the 17th century that water was pumped away from vast areas of land. As this practice continued, the fens changed from wetlands to the dry arable land that now dominates much of East Anglia. An estimated (EN) 90% of East Anglian fenland has been lost since 1934.
Winter grazing by cattle or horses helps to control scrub and prevent fens from turning into woodland. In other areas, reeds are harvested and willow is pollarded or coppiced. Ditches and wider waterways are also cleared or dredged to prevent them from clogging and silting up.
The largest area of natural fenland can still be found in East Anglia. Wicken Fen, near Cambridge, has been a nature reserve owned and managed by the National Trust since 1899.
The Great Fen Project in Cambridgeshire has recently been established as a partnership between English Nature (now Natural England) and the National Trust. Its aim is to restore 3,000 hectares of farmland to fenland wildlife habitat. This project will connect and enlarge Woodwalton Fen National Nature Reserve and Holme Fen National Nature Reserve.
Smaller areas may be found in other parts of the country, for example, Ham Fen in Kent and Cors Erddreiniog on Anglesey.
The areas of fen in the Wildlife Garden include:
There are also tall herbs such as:
A damp ditch creates an ideal habitat for frogs.
Many fen plants will grow alongside ponds and in marshy areas, providing nectar for bees, butterflies and other insects. Purple loosestrife is a favourite plant for bees including bumblebees.