Area: 1.62 hectares.
Description and Reasons for Notification:
This site contains an unusually large and intact valley fen, supporting rich marsh vegetation of a type known only at two other sites in Devon and which is now nationally scarce.
The fen occupies a single field at an altitude of 40 metres A.O.D., through which runs Nanny’s Water, a small tributary of the River Coly. Its soils consist of deep waterlogged peaty loam above Triassic mudstones, with Cretaceous Greensand on the valley sides above. During winter it periodically floods.
The vegetation is comprised mainly of a mosaic of yellow iris Iris pseudacorus, branched bur-reed Sparganium erectum and rushes Juncus spp., while greater tussock-sedge Carex paniculata is locally dominant. Other conspicuous plants include meadowsweet Filipendula ulmaria, marsh-marigold Caltha palustris, ragged robin Lychnis flos-cuculi, water mint Mentha aquatica and southern marsh-orchid Dactylorhiza praetermissa. Also present are four species which are local in Devon: wood club-rush Scirpus sylvaticus, marsh valerian Valeriana dioica, fen bedstraw Galium uliginosum and common spike-rush Eleocharis palustris.
The stream is bordered for most of its length by alder Alnus glutinosa, with a ground flora dominated by ramsons Allium ursinum. Brown trout Salmo trutta fario and eels Anguilla anguilla are known to occur in its waters.
The site supports a varied reptile fauna, including grass snake Natrix natrix and adder Vipera berus, which is commonly seen. It also supports a number of bird species including water rail Rallus aquaticus, which rarely breeds in Devon but has been recorded during the summer in recent years. During the winter snipe Gallinago gallinago and woodcock Scolopax rusticola commonly feed within the fen, whilst both grey heron Ardea cinerea and barn owl Tyto alba are recorded throughout the year.