Monitoring Strategies relevant to SACs
Determining The Location And Extent Of Biotopes
Characterisation Of The Biotopes
As described by Hiscock (1998a) and Elliott and de Jonge (1996), monitoring and
surveillance refer to different types of analysis and have differing objectives.
Monitoring involves surveying an area with a view to detecting departures from agreed or
predicted conditions. The attributes for those conditions may be qualitative or
quantitative. This analysis may also be regarded as compliance monitoring. In contrast,
surveillance records the features of the system and attempts to detect unanticipated
changes or impacts which may be wide ranging and subtle, thus it may be regarded as
condition monitoring. The precise methodologies to be used will reflect this difference in
objectives and outcomes of the analysis.
A provisional monitoring sampling regime is given below bearing in mind the information
given on sampling techniques (given in Appendix III). It is emphasised that the
methodologies used in the monitoring of these biotope complexes in SACs will differ
depending on the objectives of the study.
By definition, monitoring implies the repeated use of techniques to assess features and
determine change. While surveillance (as condition monitoring) of the biotope complexes
may be desirable at 3 or 5 year intervals, the high cost of monitoring may dictate that
further surveys, and especially compliance monitoring will be carried out only following
changes to the human uses and users of the area or if there is the indication of
large-scale natural change.
The primary aims in the monitoring and surveillance of any biotope complex in SACs (see
Hiscock, 1998b for further details) is to:
- establish the location and extent of the biotopes and features present in the SACs;
- determine the biotope characteristics or attributes (species composition, environmental
features) and note the health of the biotope, and the presence of rare/sensitive species,
special biotopes etc.; and
- monitor change in the SAC and determine acceptable levels of change.
Determining The Location And Extent Of
Intertidal Sand and Mudflats
The presence and extent of biotopes within the biotope complexes should be established
using core and quadrat samples and ACE surveys intertidally and by making use of current
literature. Information from aerial photography and remote sensing where available will
also be useful in larger intertidal areas.
Subtidal Mobile Sandbanks
Acoustic surveys are likely to be the most cost-effective means of determining the
spatial extent of subtidal habitats but the information obtained should be ground-truthed
by quantitative grab sampling. In areas where turbidity is not a problem, towing of Remote
Operated Vehicles (ROV) and still and video photography may also be employed where
Characterisation Of The Biotopes.
In order to determine the community structure and evaluate the scientific and
conservation importance of biotopes within the biotope complexes it is necessary to
examine the species composition of the areas and the physical and chemical attributes of
their habitats. Existing data should be thoroughly examined where possible to reduce
survey costs. In most areas, the macrofauna (and in some areas, the meiofauna) will
provide the best assessment of the biological nature of the biotope.
In areas where the biotopes/biotope complexes encountered within a SAC are important
scientifically or for conservation reasons repeated monitoring at selected sites should be
carried out to determine any change and identify causes for change. Due to the labour
intensive, time consuming and thus expensive nature of the sampling involved, the
information obtained should be of maximum use, minimising redundant or unnecessary
sampling. Detailed information on methods for detecting change in the biotopes present or
their components are given by Hiscock (1998a) and Kramer et al (1994) and
statistical considerations, to ensure cost-effective sampling effort, are discussed in