Tywyn Aberffraw Site of Special Scientific Interest (SSSI) is owned by the Bodorgan Estate and is part of the larger Abermenai to Aberffraw Dunes Special Area of Conservation (SAC) which also includes Newborough Warren. Tywyn Aberffraw was selected as a Flagship Pond site because it supports one of the most species-rich assemblages of dune slack bryophytes (mosses and liverworts) in Wales.

The ‘slacks’ are seasonally flooded depressions that naturally form in dynamic dune systems. The winter flooding supresses the growth of terrestrial plants and, when dry, they provide damp areas of bare sand which are so important for the rare bryophytes that specialise in this type of habitat.

The stabilisation of the sand dunes has resulted in the decline and extinction of at least two rare mosses for which Tywyn Aberffraw was the sole/last location in Wales – the strangely named Broad-nerved Hump Moss Meesia uliginosa, and a thread-moss, Matted Bryum Bryum calophyllum, which have not been seen since 2001, despite extensive searches. In addition, there are a further two rare dune slack bryophyte species at Tywyn Aberffraw; another thread moss, Sea Bryum Bryum warneum and the liverwort, Petalwort Petalophyllum ralfsii which are still present but only just ‘hanging on’.

Our aim has been to support our partners Natural Resources Wales and Keep Wales Tidy, Anglesey AONB volunteers, and the leading bryophyte expert Sam Bosanquet, to introduce gentle habitat management to artificially create bare patches of sand by removing small areas if turf. In doing so, we will replicate favourable conditions which should allow these rare bryophytes to flourish again on this site.