What is ‘special’ about Glannau Ynys Gybi SSSI?

Glannau Ynys Gybi SSSI has 11 special features:

As well as the features listed above, Glannau Ynys Gybi SSSI has other habitats/earth science features that contribute to the special interest. These include scrub, ponds and rock outcrops. This mixture of habitats is important for much of the wildlife including juniper, hay scented buckler fern, filmy ferns along with skylark, linnet, brown hare, a breeding seabird colony with razorbill, guillemot, puffin, fulmar, kittiwake and potential for the return of marsh fritillaries. Other features of interest include rockpools, overhanging rock, gullies and underboulder communities and their associated flora and fauna. These too are key components of the special interest of the site. Unless specified below, management of this site should aim to look after these habitats and species as well as the listed features of interest.

What do we want Glannau Ynys Gybi SSSI to look like?

The cliffs around South Stack display some of the most magnificent exposures of folded rocks in Britain. They are particularly important to study the effect of folding and fractures on different rock types.

The exposed geology of the site should continue to demonstrate fine exposures of folded Precambrian rock. These geological features should remain visible and accessible to geologists.

The vegetated coastal cliffs should remain largely undisturbed and support the endemic South Stack fleawort, golden samphire, rock sea lavender, hay scented buckler fern, juniper, ciliate strap-lichen and golden hair lichen.

At least 70% of the site should be covered by lowland and coastal heathland. The habitat should be of good quality characterised by of heather and western gorse with crossed leaved heath, deer sedge and Sphagnum moss in wet areas, spring squill near the coast and abundant short turf and open ground. It should provide habitat for a wide range of birds including skylark, linnet, stonechat and whitethroat, reptiles and insects including the silver studded blue and the potential for marsh fritillary to re-establish.

In some areas where there are rocky outcrops in heathland, the habitat should be favourable for the spotted rock rose which occurs in the thin crusts of soil with lichens and mosses and short grasses. Areas of herb rich neutral grassland may be maintained for their floristic, invertebrate and chough feeding value

Sixteen pairs of chough currently nest on the cliffs and a breeding population of this size or greater should be resident, aided by management of feeding zones in the surrounding area.

A breeding seabird colony with guillemot razorbill and puffins along with fulmar, kittiwake and peregrine, should be maintained.

What management is needed on Glannau Ynys Gybi SSSI SSSI and why?

Although Glannau Ynys Gybi SSSI is an excellent place for wildlife and geology it will only remain so if the necessary management continues. CCW’s aim is to work with you to ensure that this management is carried out.

What does this mean in practice?

There are many factors that could damage the special features at Glannau Ynys Gybi SSSI if they are not properly managed. These are the ones we regard as most important:

Geology (Folded Precambrian rocks)

Any activities that might obscure the rock exposures, for example the dumping of earth, spoil or other waste materials, the buttressing and/or battering of the rock faces, or building works such as new steps should be avoided.

Vegetated coastal cliffs



South Stack Spathulate fleawort

Spotted rock rose

Breeding seabird colony (razorbill, guillemot, puffin, fulmar, kittiwake)

Breeding seabirds require secure nesting sites, free from human or predator disturbance, and a reliable food supply. Nesting occurs extensively on the steep southern slopes and ledges 1 February to 31 July.

Nesting seabirds require a regular supply of food available to foraging birds within a short distance of the colony. Any actions or events likely to impinge on this resource should be resisted.

Golden hair lichen and Ciliate strap-lichen

Silver studded blue


Our knowledge of wildlife is far from complete. It is possible that new features of value may appear and new management issues may arise in the future, whilst other issues may disappear. This statement is written with the best information we have now, but may have to change in the future as our understanding improves. Any information you can provide on the wildlife of your site, its management and its conservation would be much appreciated.

If you would like to discuss any aspect of your SSSI, or have any concerns about your SSSI, please contact your local CCW office.

Your local office is;

Cyngor Cefn Gwlad Cymru/Countryside Council for Wales

Llys y Bont,

Ffordd y Parc,

Parc Menai,


Gwynedd, LL57 4BN,

Telephone: 01248 672500

Fax: 01248 679259