Great Orme - Geology and Natural History

Geology and Natural History

The Great Orme is run as a nature reserve by the Conwy County Borough Countryside Service, with a number of protective designations (including Special Area of Conservation, Heritage Coast, Country Park, and Site of Special Scientific Interest), being an area 2 miles (3.2 km) long by 1 mile (1.6 km) wide. It is home to a long-established herd of about two hundred feral Kashmir goats (acquired from Queen Victoria). There are numerous paths for walking on the summit, including a section of the North Wales Path, a long distance route. About half the Great Orme is in use as farmland, mostly for sheep grazing.

The geology of the Great Orme is limestone and the surface is particularly noted for the limestone pavements covering several headland areas. There are also rich seams of Dolomite-hosted copper ore.

The Great Orme has a very rich flora, including most notably the only known site of the critically endangered Wild Cotoneaster Cotoneaster cambricus, of which only six wild plants are known.

Many of the flowers growing in shallow lime-rich earth on the headland have developed from the alpine sub-Arctic species that developed following the last ice-age.

Spring and early summer flowers include Bloody Cranesbill, Thrift and Sea Campion, clinging to the sheer rock face, while Pyramidal Orchid, Common Rockrose and Wild Thyme carpet the grassland. The old mines and quarries also provide suitable habitat for species of plants including Spring Squill growing on the old copper workings.

The White Horehound (Marrubium vulgare), which is found growing on the western-most slopes of the Orme is said to have been used, and perhaps cultivated, by fourteenth century monks, no doubt to make herbal remedies including cough mixtures. The rare Horehound Plume Moth (Pterophorus spilodactylus) lays her eggs amongst the silky leaves and its caterpillars rely for food solely upon this one plant.

The headland is the habitat of several endangered species of butterflies and moths, including the Silky Wave, the Silver-studded Blue (Plebejus argus subsp. caernesis) and the Grayling (Hipparchia semele thyone) These last two have adapted to the Great Orme by appearing earlier in the year to take advantage of the limestone flowers and grasses. Also they are smaller than in other parts of the country and are recognised as a definite subspecies.

The Great Orme is reported as the northernmost known habitat within Britain for several ‘southern’ species of spider notably: Segestria bavarica, Episinus truncatus, Micrargus laudatus, Drassyllus praeficus, Liocranum rupicola and Ozyptila scabricula.

The caves and abandoned mine workings are home to large colonies of the rare Horseshoe bat. This small flying mammal navigates the caves and tunnels by using echo location to obtain a mental picture of its surroundings. During the daytime, Horseshoe bats are found suspended from the roof of tunnels and caves, with their wings tightly wrapped around their bodies. Only at dusk do the bats leave the caves and mine shafts, to feed on beetles and moths.

The cliffs are host to colonies of seabirds (such as guillemots, kittiwakes, razorbills and even fulmars as well as gulls). The Great Orme is also home to many resident and migrant land birds including ravens, little Owls and peregrine falcons.

Below the cliffs, the rock-pools around the headland are a rich and varied habitat for aquatic plants and animals including barnacles, red beadlet anemones and hermit crabs.