What is ‘special’ about Porth Diana SSSI?

Porth Diana has one special features.

As well as the features listed above, Porth Diana has other habitats/ that contribute to the special interest. These include areas of coastal heath, unimproved acid grassland and Rock outcrops. This mixture of habitats is important for much of the wildlife such as Dyer’s Greenweed, regionally rare invertebrates such as the grayling butterfly, along with chough and badgers, which use the site for foraging. 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 Porth Diana to look like?

At least 40%, of the site should be covered by coastal heathland. The habitat should be of good quality with an abundance of short heather and western gorse and should provide habitat for a wide range of birds, reptiles and insects.

In areas where rocky outcrops jut out of the heathland, the habitat should be maintained in a condition suitable for the spotted rock-rose, which occurs in the thin crusts of soil with lichens, mosses and short grasses.

What management is needed on Porth Diana SSSI and why?

Although Porth Diana is an excellent place for wildlife 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 Porth Diana if they are not properly managed. These are the ones we regard as most important:

Grazing: Light grazing encourages the development and maintenance of dwarf shrub heath. Heavy autumn grazing destroys heather. Cattle and horses are to be preferred as they are less selective in their grazing habits than sheep, permitting more plants to flower and set seed, whilst also breaking up dense clumps of gorse. They also produce minor poaching of the ground enabling seedlings to establish. Animal dung is an important resource for invertebrates and fungi and thus for animals such as Chough which feed upon them. Light levels of regular grazing should be maintained. Flowering plants of spotted rock-rose are susceptible to sheep grazing in summer. Sheep should be excluded from 1 May to 31 July.

Scrub: Spotted rock-rose requires areas of thin soil crust, found around rock exposures, with no competition for light. The presence of scrub can threaten this requirement. Areas of gorse scrub should be maintained at no more than 10% of the site area and other vegetation, especially around rock exposures should be maintained short.

Low soil fertility: Low soil fertility helps heather and western gorse to compete against more aggressive agricultural grasses. The application of any fertiliser or slurry should be avoided and animals should not be fed with silage on the site.

Alien species: Garden escapes such as Japanese rose and Montbretia threaten to invade the heath and should be controlled.


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