National sample survey of SSSI fens 2000 (ENRR349)

This 2000 sample survey was the fourth in the series of sample surveys and looked at fen habitats, a broad habitat which was taken to include valley mires, basin and floodplain mires, fen meadows and flushes. Questionnaires detailing ownership, land use and management were completed and the condition of the fen communities present assessed by Conservation Officers. Surveys were completed for 122 SSSIs selected at random. It was shown that, by number, 47.9% of fens sampled were in favourable condition; 13.45% were unfavourable but recovering; 20.17% were unfavourable and declining; and 17.65% were in an unfavourable state and neither improving nor declining. Eleven hectares of fen habitat within one unit had been partially destroyed by drainage and conversion to arable use. By area, only 32.5% of fens were in favourable condition; 19.14% were recovering; 17.4% were declining; and 29.23% were in an unfavourable but stable state. In assessments based on area, the largest sites have a disproportionately large influence. Grazing was the most common management activity, occurring on 57.5% of units sampled. It was also one of the factors most strongly associated with favourable fen condition. Mowing and scrub control, which each occurred on more than a third of the units sampled, also had a positive influence on fen condition; the primary effect of these activities was to reduce the proportion of sites which were unfavourable and declining.

A printed copy of this report is available from our Enquiry Service. Tel: 0845 600 3078 Email:

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ENRR349, PDF, 40.1 MB 2014/06/04