Monitoring and surveillance options
Monitoring is defined by Hiscock (1998) as "a procedure by which a series of
surveys is conducted in a sufficiently rigorous manner for changes in the attributes of a
site (or species) to be detected over a period of time". Surveillance or surveillance
monitoring is "an attempt to detect unanticipated impacts, particularly ones that may
be wide ranging, subtle or that only slowly become large and obvious". Hiscock (1998)
notes that in a marine protected area, there is likely to a background of surveillance of
the features important for the designation of the site with monitoring being undertaken in
relation to features which may be or are being affected by human activities. Initial
survey will be followed by surveillance which gives a broad idea of the scale of the
changes taking place, followed by monitoring which uses the results of surveillance to set
limits outside which management action is likely to be taken. The process involves the
identification of natural variability in order to determine the normal level of change in
an inimpacted habitat. The purpose of site monitoring is essentially to:
- Determine whether the desired condition of the feature of interest for which thesite was
deisgnated is being achieved, This can enable judgements to be made about whether the
management of the site is appropriate, or whether changes are necessary.
- To enable managers and policy makers to determine whether the site series as a whole is
achieving the required condition, and the degree to which current legal, administrative
and incentive measures are proving effective.
Methods for monitoring and surveillance of marine conservation areas in the UK are at a
relatively early stage of development; there are considerable gaps in our basic
understanding of the ecology of coastal habitats and for maerl biotopes in particular (see
Chapter VIII). However, although no European maerl beds could be described as either
having been under surveillance or as having been monitored, there are nevertheless a
number of maerl beds in Europe where research work has taken place at intervals over a
number of years, perhaps sufficiently to begin to identify natural variation, for example.
In this introductory section we first highlight the challenges involved in monitoring
maerl biotopes, then suggest some of the opportunities available, detail the methodology
appropriate to different conservation objectives, and offer some guidance as to how
progress may be made. The UK Marine SACs Project is conducting and publishing the
proceedings of a series of workshops devoted to the development of monitoring and
management programmes for marine SACs (Hiscock, 1998).
Maerl biotopes are underwater, often offshore in areas with dangerous currents and
exposed to storm action, and can be found to depths in excess of 25 m.
Most of the species of plants and animals found in the maerl biotopes are small and
difficult to identify.
There are no short cuts or high technology solutions available for the derivation of
detailed, accurate, reliable biological data.
Sample collecting and sorting is extremely time-consuming, sorting alone requiring '... at least two full days per sample prior to the
identification of maerl and the associated organisms ...'
In any monitoring programme, these factors, among others, will need to be accepted and
budgeted for. However, some conservation objectives, such as determining the extent and
gross topography of the maerl beds, can be surveyed relatively cheaply. Remote sensing
techniques are one of the most cost-effective methods of resource mapping: sonar is the
optimal method of remote sensing the seabed in turbid, temperate marine waters. Inventory
of biotopes, including amount of living maerl, can also benefit from remote techniques.
With regard to the determination of species richness and quantification of species
present, studies in other biotopes are increasingly showing that identification of
organisms to higher categories, rather than to the species level, can be ecologically
informative (Warwick et al., 1990). This type of information is currently lacking
for maerl, but it should be obtained to determine whether equally useful data could be
obtained at lower cost.
There are methods of studying the biology and ecology of maerl beds which have been
used successfully in the past, and these are described below. However, given the present
limited knowledge and understanding of the maerl biotopes, suitable methods of monitoring
the status of these biotopes need ongoing evaluation and updating. In particular, methods
for monitoring the chemical and physical parameters of maerl biotopes will need to be
developed, probably by modifying present oceanographic techniques.
Five conservation objectives (Hiscock, 1998) appear to be relevant to maerl as a
feature of SACs:
- Ensure that major habitat types supporting maerl beds retain their area. This includes
mapping the extent of major substratum features and the maerl biotope complex.
- Ensure that the range and types of maerl biotopes or biotope complex present in an area
is maintained. This involves the inventory of maerl biotopes present in a defined area.
- Maintain or increase the species richness in the maerl biotope and/or abundance of key
(rare, fragile, declining, representative) species in maerl biotopes. Survey objectives
are to quantity the species present in maerl biotopes and their density or percentage
cover, with statistical evaluation of the data.
- Maintain or increase the quantity of particular species of conservation importance
(those for which the site is 'special'), which involves the recording of numbers or cover
of named species.
- Establish degree of likely sensitivity of a population through gaining an understanding
of longevity and growth rate of the species.
Relevant methodology for each of these conservation objectives is described in the
following linked sections:
Determining the extent of the biotope complex
Inventory of Maerl biotopes present
Quantitative sampling of Maerl biotopes
Recording numbers or cover of named species
Determining longevity and growth rates
Chemical and physical properties of Maerl biotopes