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Field survey methodology
Visiting period
The suggested visiting period is April to August, although annuals, such as
thyme-leaved sandwort Arenaria serpyllifolia
will flower earlier and perennials e.g. sea kale Crambe
maritima later and where driftline annuals are more abundant this will
need to be taken into account.
Preparation
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General guidance: Read the guidance prior to the field visit,
to familiarise yourself with what is required. You will need to tailor
the assessment forms to your site.
Prior to going out in the field collate existing information on your
site. Aerial photographs (and possibly satellite images, see below) are
particularly useful. Some NVC information should be available for most
sites. Sneddon and Randall carried out a comprehensive survey in 1993
and classified the vegetation (Sneddon &
Randall 1993a). Other information exists in the reports for individual
sites (Sneddon & Randall 1993b
Wales; Sneddon & Randall 1994a
Scotland; Sneddon & Randall 1994b
England). The use of the oblique aerial photographs in the DEFRA Futurecoast
CD-ROM also provide an important record to allow familiarisation with
difficult to access sites and to help place the feature in the context
of the coastal environment.
A field survey methodology is suggested next:
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Assessing habitat extent and zonation
Habitat extent
should be assessed using any previous information available, preferably aerial
photographs. If none is available this first reporting round must form the baseline.
The source of the baseline must be clearly identified - aerial photography should
include source, date (at least month and year) and scale. Field trials have
shown that failure to provide some of this information may mean change cannot
be measured with respect to the first round.
The assessment of zonation by transect should be done after the structured
walks to assess sward composition and negative indicators of each vegetated
shingle habitat as at that stage you will be more familiar with the vegetation
at the site (see below).
In the field it is recommended that the vegetation composition (negative
indicators etc.) of the two principal vegetated shingle 'zones' (annual
vegetation of driftlines and perennial vegetation of stony banks)
be assessed using a structured walk (e.g. a W shaped walk) with at least 10
stops within each assessment unit (block, management unit etc.) to avoid excessively
variable results. The number of stops should be enough to allow the assessor
to have an overview of the site and judge the condition of the feature. To avoid
subjectivity in selecting stops and to ensure that as wide an area as possible
is covered general routes with stops should be pre-selected based on a map or
aerial photograph before the field visit. This also allows the number of stops
per unit area to be determined more consistently. The exact stopping locations
will be recorded in the field using GPS if possible. If contractors are using
the guidance then consultation with local staff on route selection and stopping
points is mandatory.
At each stop, the appropriate attributes (e.g. percentage cover and/or presence
of relevant species) should be assessed within approximate 4 m2 sampling units.
There is no need to measure cover values precisely - simple visual estimates
will suffice. It should not take very long (no more than 5 minutes) to record
all the relevant attributes at each 'stop'. The recommended methods of selecting
the number and location of the stops are not intended to have statistical value,
and the final condition of the interest feature is not simply the average of
the condition of each stop. On the contrary, each stop should contribute to
improve the assessor's overview of the state of the site.
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Guidance: Photographs are essential to the condition assessment
and should be taken as an accompanying record wherever possible. These
should be archived with the assessment file. In some countries photography
is a mandatory part of the condition assessment.
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References
Sneddon, P. & Randall, R.E.
1993a.
Coastal Vegetated Shingle Structures of Great Britain: Main Report.
Joint Nature Conservation Committee, Peterborough.
Sneddon, P. & Randall, R.E.
1993b.
Coastal Vegetated Shingle Structures of Great Britain: Appendix 1, Wales.
Joint Nature Conservation Committee, Peterborough.
Sneddon, P. & Randall, R.E.
1994a.
Coastal Vegetated Shingle Structures of Great Britain: Appendix 2, Scotland.
Joint Nature Conservation Committee, Peterborough.
Sneddon, P. & Randall, R.E.
1994b.
Coastal Vegetated Shingle Structures of Great Britain: Appendix 3, England.
Joint Nature Conservation Committee, Peterborough.
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