Determining The Location And Extent Of Biotopes

Characterisation Of The Biotopes

Monitoring Change

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.

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.

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 appropriate.

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 Green (1979).

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