After examination and
assessment, sites have been awarded a grading of quality on
a four-point scale, as explained in the accompanying summary. Many important sites
contain or adjoin areas where intrinsic nature conservation value is lower than the
rest, rating around grade 4 or less. Often, these lower-grade areas contain different
ecosystems from the more important parts of the site. Their inclusion with the site
thus gives a bonus, enhancing the diversity and overall conservation value of the
whole. This additional interest is mentioned and often described, but otherwise only
key sites (grades I and 2) are the concern of the present report. Some sites contain
high-quality examples of more than one major formation; in such cases the different
main components are graded and described separately under different formations,
though they lie together within a single continuous area. All sites have been
assessed regardless of their existing conservation status, i.e. whether or not they are
NNRs or any other category of reserve; this part of the Review has been concerned
expressly with application of uniform standards in site assessment and selection
according to intrinsic merits (except for the criterion of recorded history).
Grade 1
Sites of international
or national (Great Britain) importance, equivalent to NNR in
nature conservation value (many are already declared as NNRs); these are shown in
capitals in the site indexes in vol. i. Internationally important sites are denoted by
asterisks. The safeguarding of all grade i sites is considered essential if there is to be
an adequate basis for nature conservation in Britain, in terms of a balanced
representation of ecosystems, and inclusion of the most important examples of
wildlife or habitat.
Grade 2
Sites of equivalent
or only slightly inferior merit to those in grade i. These are thus
also of prime importance but many duplicate the essential features of related grade i
sites, which should have priority in conservation. Many can, however, be regarded as
alternatives to grade i sites should it prove impossible to safeguard these.
Grade 1 and 2 sites
are the actual places identified as exemplifying the abstract
concept of key areas.
Grade 3
Sites of high regional
importance, rated as high-quality Sites of Special Scientific
Interest, but not of NNR standard. Regional, as distinct from national, criteria apply;
some sites in this grade would receive a lower rating if located in a region with more
extensive natural or semi-natural ecosystems, or a higher rating under converse
circumstances.
Grade 4
Sites of lower regional
importance, still rated as SSSI. Some such sites would not
qualify if they were located in a region with more extensive representation of the
particular ecosystem.
Grade 3 and 4 sites
contribute to the total national requirement for key areas for
conservation. Grade 1-4 sites cover a small part of Britain and the safeguarding of all
grades is important for nature conservation. In the much larger proportion of
ungraded land and water only a relatively small extent is virtually devoid of nature
conservation interest, and consists mainly of urban and industrial areas covered by
buildings or other man-made surfaces. The remaining very large total area of natural,
semi-natural and artificial ecosystems has a variable nature conservation interest but
is tremendously important in the aggregate. No attempt has been made in the
Review to work out further gradations below grade 4, because an extension of this
scale is inappropriate for land which cannot be scheduled within any one category. In
the present system, the whole of a site is covered by its grading, though the
subsidiary features of some composite sites have sometimes been given a lower
grading under their own formation, in order to emphasise consistency of standards in
assessment. For unscheduled land, a differential grading on a smaller scale is
usually needed, but there are considerable difficulties in working out a system which
could be applied throughout the country Such a system of evaluation is nevertheless
urgently needed.
The assessment of international
importance of sites involves application of the same
criteria discussed previously, but the background scale becomes expanded to
include the rest of Europe or even the whole world. In particular, high international
importance is accorded to habitats, communities and species which are rare on the
global scale. In Britain, sites thus designated are mostly high-quality examples of
ecosystems and communities, and contain species with a very local occurrence in
Europe, and some represent an end-point to an ecological gradient of continental
scale. The label ' international importance' given to some key sites is essentially
subjective and arbitrary in most instances, and the category should be regarded as
open to revision in the light of views from international bodies or experts with wide
overseas experience. Only in the cases of wildfowl and waders have any quantitative
yardsticks of assessment been followed, but in this review international status (grade
i*) is based on the total biological importance of a site.
It is obvious that
within the list of grade i sites, there are varying shades of
importance. The internationally important sites naturally take precedence on the
whole, though any particular one is not necessarily more highly rated than any of
those not given international status. The most outstandingly valuable sites are those
which rate highly according to several major criteria, as in the case of the North
Norfolk Coast discussed on pp. 10-11. In general, sites which are large, have high
diversity (especially including more than one formation) and contain large populations
of interesting species (especially rarities), rate very highly. However, the question of
comparative importance between sites of disparate character, even within the same
formation, leads to enormous conceptual and practical difficulties, and is not pursued
further here.
