Elenydd SSSI is of national importance for
features of Earth science and biological interest. A range of Earth
science features is present. These include exposures of Silurian
rocks, found north of Caban Coch Dam, which are crucial in helping
to interpret the environments that existed in this part of Wales
during late Ordovician and early Silurian times. Mineral-bearing
spoil tips and rock exposures at Cwmystwyth Mine are important for
the study of mineralisation in the Central Wales Orefield. The
glacial landforms at Cwm Ddu and Cwm Tinwen provide important
information about late Pleistocene events and processes in central
Wales, although their mode of formation remains a subject of
debate. Peat and lake clays that accumulated at Gors Lwyd over the
last 14,000 years contain microscopic plant remains that provide a
detailed record of environmental and vegetational changes in
mid-Wales. The Afon Elan at Gors Lwyd displays a wide range of
nationally important river landforms, including terraces, meanders
and abandoned channels.
Elenydd SSSI is one of the most important
areas of hill land in Mid Wales for nature conservation. It
supports a range of breeding birds of upland and woodland and is
one of the two most important areas in Wales for upland species.
Much of the hill vegetation is also important and the moorland
plateau is largely covered by blanket bog vegetation of European
importance. Three particularly interesting localities within the
site are the watershed mires at the headwaters of the Rivers Elan
and Claerwen, the well developed pool and hummock mire at Cors Lwyd
and the eroded, but still actively growing, mire complex at Cors
Gôch. These areas support rare plant species. Crags, scree slopes
and stream gorges provide contrasting habitat types that support
species that would otherwise be suppressed by grazing. Mountain
lakes within the site support a number of rare species, including
the internationally rare Floating Water-plantain.
The area also includes a number of areas of
considerable historic interest.
Managing this site
The site includes Nant Irfon National Nature Reserve(NNR), owned
and managed by the Countryside Council for Wales and Claerwen NNR
managed by CCW in partnership with the owners Elan Valley Trust.
The remainder of the site is owned by the Forestry Commission,
Welsh Water, Brecknock Wildlife Trust, Crown Estates, the National
Trust and a number of private owners. The special features of this
SSSI and CCW’s views about site management have been summarised in
a Site Management Statement, addressed to the owners and managers
of the land. The statement can be found in the resource section
below.
Access information
A large proportion of the site is designated CROW access land
and is crossed by a number of public rights of way. Delails on
access to Nant Irfon National Nature Reserve (NNR) and Claerwen NNR
can be found in the links below. For detailed maps and information
regarding access visit our access map via the resource section
below.
Other information
The site includes or forms part of the Elenydd and Coetiroedd
Cwm Elan/ Elan Valley Woodlands Special Areas of Conservation and
the Elenydd-Mallaen Special Protection Area.
The mountainous area at the head of the Elan, Severn, Teifi, Wye
and Tywi was called Elennydd, which means ‘area adjoining the river
Elan’. River-names often reflect animal-names and Elennydd is
probably from elain ‘hind, fawn’ followed by the territorial affix
–ydd.