|United Nations Environment Programme|
|World Conservation Monitoring Centre|
The St. Kilda archipelago has preserved ecosystems intact
for thousands of years virtually unchanged by man; also a well preserved
well documented primitive settlement. These remote and scenically
dramatic islands have some of the highest cliffs in Europe which
provide a refuge for some of the most important colonies of seabirds
in the north-eastern Atlantic, and is a major breeding site for
puffins and northern gannets. The local Soay sheep is the most primitive
domesticated animal in Europe, dating unchanged from Neolithic times.
St. Kilda is also of national importance for its geology, flora,
other fauna, marine interest and ancient vernacular buildings.
COUNTRY United Kingdom
NAME St Kilda (Hirta) National Nature Reserve
IUCN MANAGEMENT CATEGORY
St Kilda National Nature Reserve IV (Habitat/Species
Extension to site in 2004 to become a Mixed (Natural & Cultural)
World Heritage Site.
BIOGEOGRAPHICAL PROVINCE Scottish Highlands
GEOGRAPHICAL LOCATION The World Heritage site
comprises a group of four small islands located on the Atlantic
continental shelf, off the coast of the Outer Hebrides, 165 km
west of the mainland of northern Scotland. The site is contained
within a square with the coordinates 57°54'36"N / 08°42'W, 57°46'N
/ 08°42'W, 57°46'N / 08°25' 42"W, 57°54'36"N / 08°25'42'W.
DATES AND HISTORY OF ESTABLISHMENT
1979: Listed under the Ancient Monuments and Architectural Areas Act;
1981: Declared a National Scenic Area by the Secretary of State for Scotland;
1984: Designated a Site of Special Scientific Interest under Section 28 of the Wildlife & Countryside Act; also a Geological Conservation Review Site;
1992: Designated an E.U. Special Protection Area for its wildfowl
and a Special Area of Conservation for its cliffs, reefs and sea
ALTITUDE Sea-level to 425.8m (Conachair).
The igneous rocks were intruded about 55 million years ago above
a platform of PreCambrian rock, cut by seas at earlier far lower
levels into terraces at 80m and 120m down. The islands' steep cliffs
continue under water another 40m to rock rubble and 70m to the first
platform thinly veneered with gravels and sands. The rocks of Hirta
are predominantly a complex of dolerite and microgranites with gabbro
along the castellated west coast, intruded by basalt dykes. Soay
and Boreray are formed of a breccia of gabbro and dolerites. The
cold surrounding waters are clear, allowing sunlight to penetrate
deeply and a rich marine life to flourish among submarine caves,
tunnels and arches. Geologically this assemblage of unusual forms
of contact metamorphism with simultaneously intruded acidic and
basic magmas is unique in the British Tertiary Volcanic province.
The soils are acid and peaty but are balanced by guano, sheep dung
and salt-spray which imparts a pH of 5.8 - 6.2 and by organic manure
behind the village.
Salt tolerant plants such as sea pink Armaria maritime, sea
campion Silene uniflora and sea plantain Plantago
maritimus, Asplenium marinum and Grimmia maritima
occur even inland. Much of the grassland, as on Soay and Boreray,
has a sub-maritime character consisting of Holcus lanatus, Agrostis
stolonifera, A. capillaris, Festuca rubia and
Anthoxanthum odoratum. The less maritime communities occurring
on Hirta are mainly a range of acid-loving species: poor submontane
grassland and heaths consisting of ling and cottongrass Calluna
vulgaris - Eriophorum vaginatum bog, extensive mixed
Nardus-Calluna-Rhacomitrium lanuginosum heath with
Luzula sylvatica grassland dominant on the summit of Conachair.
Northern Atlantic species include Botiychium lunaria, Ophioglossum
vulgatum, Gentianella campestris, Ligusticum scoticum
and Sedum rosea with Arctic-Alpine montane species such as
Silene acaulis and Saxifraga oppositifolia. Mediterranean-Atlantic
liverwort Fossombonia angulosa also occurs here, at its
northernmost locality. The Agrostis-Festuca grassland of
Hirta, Boreray and Soay is heavily grazed by sheep. Soay has dry
cottongrass bog with Holcus lanatus. Dun is species-poor
but has been ungrazed for 75 years and has a rich Festuca and
St Kilda is an outstanding example of the ecological colonisation
of a remote island and of the genetic divergence caused by the isolation
of small populations. For instance, the endemic St Kilda wood mouse
Apodemus sylvaticus hirtensis (which survived the human
depopulation where the house mouse did not), and St Kilda wrenTroglodytes
troglodytes hirtensis (~230 pairs in 2002). The terrestrial
avifauna of 10 species is impoverished but the terrestrial invertebrate
fauna includes 200 species of fly, 150 beetles and over 280 lepidoptera.
Soay sheep Ovis aries, now free ranging on Hirta as well
as Soay, is the most primitive domesticated animal in Europe, a
living Neolithic artifact unchanged for thousands of years. Those
introduced from Soay to Hirta in 1932 are subject to crashes in
the population which ranges between 600 and 2000. A dense but healthy
population averaging about 400 blackface-cross sheep on Boreray
are quite unmanaged. Grey seals Halichoerus grypus now breed
on the islands and 9-10 species of cetaceans are seen: among them
minke Balaenoptera acutirostrata and killer whales Orcinus
orca, harbor porpoises Phocoena phocoena and Risso's,
whitesided and whitebeaked dolphins, Grampus griseus, Lagenorhyncus
acutus and L. albirostris. The marine invertebrate fauna
of sea anemones, sponges, bryozoans, corals, sea slugs and topshells
is extremely diverse, encrusting caves and submarine cliffs. The
relatively mild ocean temperatures result in some southern species
finding their northern limit and some northern species their southern
limit around the islands.
LOCAL HUMAN POPULATION
VISITORS AND VISITOR FACILITIES
SCIENTIFIC RESEARCH AND FACILITIES
The NTS aim is to manage the islands as a model of integrated
conservation balancing natural processes and historic conservation
with minimum intervention. The wildlife has been undisturbed since
1930 and active intervention is not generally required to conserve
the site's values. The seabirds are regularly monitored, the frequency
depending on the species. A seasonal warden employed jointly by
SNH and NTS is present from April to mid-September. All the islands
except Dun are grazed by feral sheep. There is no planned management
of the sheep population, or of past cultivations. The activities
of the MOD station are strictly controlled. The National Trust for
Scotland organises ongoing volunteer working parties in consultation
with Historic Scotland, who restore the village ruins: from 1958,
six cottages, the church, school house, many cleateans and
walls have been rebuilt and drains cleared. These working parties
are planned to continue, following detailed archaeological management
and action plans. The surrounding marine area was recently incorporated
and a five year management plan prepared by SNH in preparation for
revised World Heritage status for marine and cultural values. Management
of the marine habitats around the islands which are increasingly
popular with Scuba divers, has been started.
Area Manager, Western Isles, National Trust for Scotland, Benbecula, Hebrides.
National Director, National Trust for Scotland, 28 Charlotte Square,
Edinburgh EH2 4ET.
The literature on St. Kilda is extensive. Further information is also available from the NTS website www.kilda.org.uk
Boyd, J. (1981). The Boreray sheep of St. Kilda, Outer Hebrides, Scotland: The natural history of a feral population. Biological Conservation 20: 215-227.
Buchanan, M. (ed.) (1995). St Kilda: The Continuing Story. HMSO, Edinburgh.
Emery, N. (1996). Excavations on Hirta 1986-90 HMSO, Edinburgh.
Emeleus, C. & Gyopam, M. (1992). British Tertiary Volcanic Province. Chapman and Hall for Joint Nature Conservation Committee, London.
Harman, M. (1996). An Isle called Hirte. Maclean Press, Isle of Skye.
Harris, M. & Murray, S. (1977). Puffins on St Kilda. British Birds 70: 50-65.
Harris, M. & Murray, S. (1989). Birds of St Kilda. Institute of Terrestrial Ecology & Natural Environmental Research Council, Monks Wood, UK.
Jewell, P., Milner, C. & Boyd, J. (1974). Island Survivors: the Ecology of the Soay Sheep of St Kilda. Athlone Press, London.
Kearton, R. (1897). With Nature and a Camera. London. Reprinted 1978, Melven Press, Inverness.
Martin, M. (1698). A Late Voyage to St Kilda. London. Reprinted 1986, Mercat Press, Edinburgh
Martin, M. (1703). A Description of the Western Isles of Scotland. London.
Mountaineering Council of Scotland (2001). St.Kilda, National Trust of Scotland. Review of Management Plan.
Murray, S. (2002). Birds of St. Kilda in Scottish Birds, JSOC Vol.23 supplement. 64pp. [with updated bibliography].
National Trust for Scotland (2003). St.Kilda Management Plan 2003-2008. [Contains a selected bibliography of 73 references.]
Quine, D. (1988). St Kilda Portraits. Downland Press, Frome
Quine, D. (2001) St Kilda. Colin Baxter Island Guides, Grantoun, Morayshire.
Quine, D (ed.) (2001). Expeditions to the Hebrides by George Clayton Atkinson in 1831 and 1833. MacLean Press, Skye.
Ratcliffe,D. (1977). A Nature Conservation Review: A Selaction of Biological Sites of National Importance to Nature Conservation in Britain. Vol.2. Cambridge University Press, U.K.
Scottish Executive (2003). Revised Nomination of St.Kilda for Inclusion in the World Heritage List. [Contains a very extensive bibliography.]
Seton,G. (1878). St Kilda Past and Present. Edinburgh. Reprinted 2000, Birlinn, Edinburgh.
Steel, T. (1994). The Life and Death of St Kilda (2nd edition). Fontana, Harper Collins, London.
Stell, G. & Harman M. (1988). Buildings of St Kilda. Royal Commission on the Ancient and Historical Monuments of Scotland / HMSO, Edinburgh.
Tasker, M., Moore, P.& Schofield, R. (1988). Seabirds of St. Kilda UK 1987. Scottish Birds 15(1):21-29.
Walker, M. (1984). A Pollen Diagram from St Kilda, Outer Hebrides, Scotland. The New Phylologist 97: 99-113.
Williamson, K. & Boyd, J. (1960). St Kilda Summer.
Hutchinson, London [extensive bibliography].
DATE November 1986. Updated 5/1990, 7/ 1995, 11/2002, November 2p>
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