2015 Scottish Natural Heritage (SNH) St. Kilda sea caves site condition monitoring survey
The purpose of this survey of St. Kilda SAC sea caves, undertaken between the 15th and 17th August 2015, was to initiate site condition monitoring (SCM). The objectives of SCM were to establish a baseline biological data set that would facilitate the assessment of the condition of habitats in the future and to allow a judgement to be formed on the current condition of these habitats in the light of existing SAC management measures. At 4 selected sea caves, detailed biological and physical surveys were conducted; the topography was mapped and the biotopes surveyed by MNCR phase 2 methodology at relocatable points along the cave system. When wave surge prevented access to the caves, 3 rocky reef sites were targeted with the aim of surveying the biota along a relocatable transect running contiguously from the supralittoral into the sublittoral. Two other sea cave surveys were conducted as part of the same research cruise at North Rona SAC and Loch Eriboll.
dataset
GB-SCT-SNH-ME-000293-MRSNH0300000002D-KILDA
http://www.nature.scot
eng
urn:ogc:def:crs:EPSG::4326
Harries, D.B., Moore, C.G., Porter, J.S., Sanderson, W.G., Ware, F.J. & Kamphausen, L. 2018. The establishment of site condition monitoring of the sea caves of the St Kilda and North Rona Special Areas of Conservation with supplementary data from Loch Eriboll. Scottish Natural Heritage Research Report No. 1044.
biota
biota
revision
2008-01-06
revision
2009-11-16
creation
2011-02-16
creation
2003-01-01
creation
2011-07-06
creation
2012-02-14
revision
2005-04-27
creation
2006-08-31
creation
2017-05-12
-8.7574
-8.4388
57.8630
57.7591
creation
2009-06-18
Scottish Continental Shelf
creation
2009-05-01
44E2
creation
1954-01-01
North Atlantic Ocean
revision
2010-01-01
circalittoral
revision
2010-01-01
infralittoral
2015-08-15
2015-08-17
publication
2018-12-31
notPlanned
This sea cave data from St. Kilda was collected by SNH and Heriot-Watt University between the 15th and 17th August 2015. Detailed biological data and physical surveys were conducted at 4 cave sites. The intended criteria for selecting specific caves for detailed survey included the requirement that individual caves should represent the broadest available range of cave habitats (i.e. longer, extensive caves with a large depth range). Ideally, sites would also represent a wide range of environmental conditions (i.e. caves from different parts of the coasts, caves of differing exposure levels etc.). However, choice of sites was severely constrained by weather conditions. Where sea conditions were suitable, the coast was systematically examined at close quarters from an inflatable boat. All inlets, alcoves or other potential cave sites were investigated. Cave entrances were photographed and coordinates recorded. Where time and sea conditions allowed, the caves were entered by a snorkeler to gather information on passage length and main biota. The purpose of this exercise was to work towards developing a comprehensive inventory of the caves around St. Kilda. Monitoring surveys of caves were initiated by conducting a physical survey and deploying a relocatable fixed datum line for precise spatial mapping of biotopes. The physical survey addresses the attribute extent of cave(s). It also provides a means of defining the location of points within the cave from which biological data was recorded and enables those points to be relocated by subsequent monitoring surveys. The position of the marker was fixed by dGPS and several photographs taken of it from different viewpoints, with the position of the camera recorded by dGPS and the bearing to the marker taken with a sight-bearing compass. An approximate plan view sketch was produced of the cave floor with notes on the composition of the substrate. At selected points along the line the cross-sectional shape of the passage was sketched and the cross sectional dimensions (e.g. distance to floor, ceiling and both walls) was estimated in relation to the fixed datum line. An assessment was also made of changes in biological communities along the length of the cave and a series of locations were identified for subsequent collection of biological data from cross sections of the cave passage. Typically, two biological cross section surveys were conducted in each cave at the specified distances along the datum line. The biological surveys were conducted within a 2 m wide band up one wall of the passage. Where appropriate, the wall was subdivided into biological zones and the depth of the zone boundaries recorded. Within each biological zone, the abundance of each component species was estimated using the MNCR SACFOR scale and notes made on the nature and inclination of the substrate. Video footage was obtained along the length of the cave using the datum line for orientation and detailed footage was obtained of the biota at each of the biological cross sectional survey locations. Additional underwater wide angle and macro digital still images were taken to illustrate the biota at the biological cross sectional survey locations. Note: Excessive wave surge necessitated modifications to the methodology at a number of sites. Wherever possible, in-situ species identifications were validated by detailed cross-referencing with the identifications of the voucher specimens and with macro photographs. In-situ abundance records were also validated by detailed cross-referencing with video footage and stills images. Abundance scales were assigned using the MNCR SACFOR scale and biotopes were assigned. Similarly, site descriptions were cross-referenced with video and stills imagery for consistency and validation.
publication
2018-01-23
true
See the referenced specification
Not for navigational use; This survey recorded no species or biotope occurences that SNH consider as sensititive; all records may therefore be released in response to requests covered by Environmental Information Regulations or Freedom of Information Regulations; additionally its re-use and dissemination is permissable under Open Government Licence terms. Any re-use of this data will acknowledge the copyright owner.
No restrictions on public access
External Contractor
Heriot-Watt University School of Life Sciences
originator
Data Manager
Scottish Natural Heritage (SNH), Headquaters
Great Glen House, Leachkin Road
Inverness
IV3 8NW
01463 725000
custodian
Data Manager
Scottish Natural Heritage (SNH), Headquaters
Great Glen House, Leachkin Road
Inverness
IV3 8NW
01463 725000
pointOfContact
2020-03-12