a.Key indicators for measuring state of conservation

The warden monitors visitors and activities while collating natural history records. He/she undertakes periodic counts of birds and sheep while the universities co-operating on the sheep study undertake an annual census of the sheep on Hirta. Whenever the opportunity arises the warden will attempt sheep counts on Soay and Boreray, although numbers fluctuate from year to year no significant trend has yet been detected.

A census of all seabirds on the archipelago takes place every 15 years (every 10 years for northern gannets) and the warden monitors breeding success of certain species such as black-legged kittiwakes, northern fulmars and skuas each summer. In addition, the JNCC monitored northern fulmar, common guillemot and razorbill numbers in selected plots in 1990, 1993, 1996 and 1999. Scottish Natural Heritage has annually monitored breeding productivity of northern fulmars (since 1989) and of black-legged kittiwakes (since 1986) while CEH analyse northern gannet eggs at regular intervals, for the presence of pesticides and other chemical pollutants.

Within the St Kilda candidiate marine Special Area of Conservation, monitoring/surveillance of specific marine features will be carried out over a rolling six-year programme. The features for which the marine SAC has been identified are characteristic rocky reef habitats associated with vertical rock walls, overhangs, ledges and surge gullies. Also included are the numerous submerged and partially submerged sea caves. The broad scale surveys carried out by SNH in 1997 and 2000 provide a comprehensive and extensive baseline showing seabed topography and character and will guide more detailed monitoring efforts in the future. This will include the use of video documentation obtained from remotely operated vehicles or drop down equipment deployed at deep water sites and scuba diver observation where it is considered appropriate to do so. At the same time when monitoring the marine SAC features other habitats, not included within the SAC designation (due to their omission from the Habitats Directive Annex 1), such as the deep sublittoral sediment areas will be monitored also.

Dun Gap - Village BayBecause of the way the site is managed, the conservation is very closely monitored. The first job each season is to examine the features in and around Village Bay and report any collapses of built historic structures – including drystone walls and enclosures, as well as damage to mortared buildings. This ensures that immediate conservation work can be agreed with Historic Scotland. In addition, the working draft of the Archaeological Action Plan details the monitoring work that is required on a cyclical basis, for example the Gleann Mor structures. The very large number of historic features on Hirta, and the inaccessability of the other islands of the archipelago, has necessitated a prioritised monitoring regime, based on the significance of each feature or group of features. For example, around 300 of the 1270+ cleitean on Hirta have been selected for regular monitoring.

Monitoring information is recorded on a database and photographically. Depending on available resources, appropriate actions are prescribed to prevent the deterioration of built structures and to repair those which have suffered damage since the last monitoring period. Details of monitoring actions, and of conservation actions, are added to The National Trust for Scotland Sites and Monuments Record database where they form a permanent, easily accessed record.

All actions on the islands which have the potential to disturb archaeological levels or historic buildings are carried out under archaeological supervision, having first selected a strategy of works designed to cause least damage. Cables, for instance, are normally laid on the surface rather than being dug into the ground. Summaries of all works that have required the attention of an archaeologist are contained in the St Kilda Archaeologist’s Annual Report.

The Work Party Leader reports on those conservation activities carried out by voluntary Work Parties shortly after returning from St Kilda. Leaders’ reports are summarised by NTS staff, and a report is published in the annual St Kilda Mail (the publication of the St Kilda Club), and a verbal report is given to the Annual General Meeting of the St Kilda Club. The report is also submitted to Historic Scotland for scrutiny, and the works are discussed at the annual ‘Tripartite’ meeting between the NTS, Scottish Natural Heritage, the Ministry of Defence, and Historic Scotland.

Details of all archaeological excavations or of other pieces of research that affect the physical remains are summarised within a few months of fieldwork, and summary reports are disseminated to appropriate archaeological resource managers and to local and national archives. A short summary of the year’s fieldwork activities is published annually in the archaeological journal
Discovery and Excavation in Scotland.

The Historic Scotland Field Monument Warden aims to visit St Kilda every three-five years in order to report on the state of upstanding and buried archaeological features within the areas designated as scheduled ancient monuments; it is planned to devolve some of this recording to the St Kilda Archaeologist. The Field Monument Warden contributes towards a database of information relating to the state of preservation of the Scheduled Ancient Monuments.