Cors Erddreiniog NNR (Anglesey & Llyn Fens LIFE Project)

Cors Erddreiniog is one of seven sites in the 467 ha Anglesey Fens SAC - the complex containing the most extensive areas of fen in western Britain, 42% of the total Welsh resource of alkaline fen and 56% of the Welsh resource of calcareous fen. Degradation of the site has been addressed thanks to the Anglesey and Lleyn Fens LIFE project, which aimed to bring 759 ha of fen into recovery.

Cors Erddreiniog is the largest of a suite of wetlands internationally famed for unusual and diverse vegetation. This large area of fen is home to common reed (Phragmites), great fen sedge (Cladium mariscus) and blunt flowered sedge (Cyperus obtusiflorus), as well as orchids, insectivorous plants, dragonflies and grasshopper warblers. The site is also one of the last in Anglesey where marsh fritillary can be found.

Enriched soil and upper peat layers were removed from over 20 ha to rejuvenate the development of new fen habitat - making this was one of the largest fen restoration projects in Europe at the time. Large scale hydrological restoration also took place, through a programme of ditch blocking and separating enriched water from spring water, redirecting enriched water away and spring water into the fens. Introducing extensive grazing by Welsh ponies and cattle has helped to prevent grasses from dominating. This followed a programme of biomass removal from the sites. In addition, the project worked with local farmers to establish good working relationships. This two-way relationship provided additional grazing land for the farmers, whilst supplying a conservation grazing regime on the fen.

Some of the key items of work on this particular site included:

• Large scale hydrological restoration through installation of weir on main outfall
• Restoration of marginal spring inputs through hydrological pathway restoration
• Hydroseral reversion through peat cutting 
• Grazing.

Please note the figures below account for work carried out over the entirety of the Anglesey and Lleyn Fens LIFE project, which included Cors Erddreiniog:

• Removed and reprofiled 100,000 tonnes of damaged soil over 20 ha
• Mowed and burnt over 200 ha of rank overgrown fen
• Opened up over 500 ha of land to grazing
• Removed over 100 ha of scruh that was shading out fen species
• Entered into an agreement with landowners to manage over 200 ha of land in a mutually beneficial way
• Restored over 3.5 km of springs, streams and seepages
• Got water levels right over 6 km of ditiches
• Brought over 200 ha of land into direct conservation management and improved public access.