When undertaking an appropriate assessment of impacts at a site, all features of European importance (both primary and non-primary) need to be considered.
Annex I habitats that are a primary reason for selection of this site
|7140 Transition mires and quaking bogs|
|Corsydd Eifionydd embraces two isolated topogenous peatlands situated within the upland-fringe transition between Snowdonia and the Lleyn Peninsula. The site supports a diverse range of oligo-mesotrophic topogenous fen communities which often manifest as strongly quaking rafts, particularly over former peat-cuttings. Areas of wet fen dominated by slender sedge Carex lasiocarpa are a particular feature of Cors Gyfelog. Relatively forb-rich stands are referable to NVC type M9 Carex rostrata – Calliergon cuspidatum/giganteum mire but significant areas conform more closely to the concept of mesotrophic bog, with a prominent bog-moss Sphagnum spp. component (including S. denticulatum, S. contortum, S. papillosum, S. subnitens and occasional S. magellanicum) and species such as cranberry Vaccinium oxycoccos, bog St John’s-wort Hypericum elodes and bog asphodel Narthecium ossifragum occurring beneath an open sedge canopy. Bog sedge Carex limosa is probably more abundant at Cors Gyfelog than at any other Welsh lowland site and bog orchid Hammarbya paludosa has recently been noted from hummocks of S. subnitens. Cors Graianog defines the more acidic end of the spectrum of transition mire and quaking bog at this site, with extensive areas of M4 Carex rostrata – Sphagnum recurvum mire as well as vegetation with affinities to M18 Erica tetralix – Sphagnum papillosum raised mire.|
Annex I habitats present as a qualifying feature, but not a primary reason for selection of this site
Annex II species that are a primary reason for selection of this site
|1065 Marsh fritillary butterfly Euphydryas (Eurodryas, Hypodryas) aurinia|
|Corsydd Eifionydd contains a series of unimproved damp pastures on the eastern edge of the Lleyn Peninsula and supports the most significant metapopulation of marsh fritillary Euphydryas aurinia in north Wales.|
|1393 Slender green feather-moss Drepanocladus (Hamatocaulis) vernicosus|
|Slender green feather-moss Drepanocladus vernicosus occurs at two separate but nearby lowland localities at this fen complex. At Cors Gyfelog it is found near the flushed margins of the fen basin, while at Cors Llanllyfni it is associated with two hillside flushes within a stand of heath.|
Annex II species present as a qualifying feature, but not a primary reason for site selection
Many designated sites are on private land: the listing of a site in these pages does not imply any right of public access.