range are good indicators of continuity are much less significant in the south-
east. The converse of this may also be true. I have seen specimens of Stenichnus
bicolor from more than 90 different ten-kilometre squares in Britain, and this
species would appear to be almost generally distributed in wooded and semi-
wooded areas in the north and west of the country. However, it is virtually
absent from East Anglia and might be regarded in the south-east as an indicator
(Grade 3) of Old Forest conditions.
One of the first questions to be dealt with in categorising beetle species as
indicators of woodlands of different types, is the distinction between species
which may be regarded as typical of woodland (in a broad sense) and those
which are directly dependent on trees. The two categories overlap, but are by no
means to be equated, as many tree species, and some of their associated beetles,
are not confined to woodland, primary or secondary, while a number of more or
less strictly woodland species are not directly associated with trees. Beetle
species in the former category (associated with trees, but not necessarily
woodland) are numerous and include, for example, Dropephylla vilis (Er.),
Phloeonomus spp., Dromius spp., Homalota plana (Gyll.), Anomognathus
cuspidatus (Er.), Leptusa spp., Phloeopora spp., Corticeus bicolor (Ol.), etc.,
etc., all associated with wood, while a further series of species are found in
association with the leaves, fruit, etc..
Species generally confined to woodlands but exhibiting no direct
association with trees include those to be found in leaf litter, other substrate
habitats such as dung and carrion, on herbaceous plants, shrubs and fungi. Few
of the litter species, e.g. Calathus piceus (Marsh.), Quedius fumatus (Steph.),
Q. nigriceps Kraatz, etc., are likely to be at all indicative of Old Forest con-
ditions, but at least in the south-east and east, some of them may. Certainly,
some litter species which, in the north and west are to be found in open country,
e.g. Abax parallelepipedus (Pill. & Mitt.), Patrobus atrorufus (Strom),
Agonum assimile (Payk.), Micropeplus staphylinoides (Marsh.), etc., are
largely confined to woodland in the east and south-east. Some species which
frequent dung, carrion and other organic matter in a state of decay, and which
are of almost general distribution in the north-west of Britain, such as Tachinus
pallipes (Grav.), Philonthus puella Nordm., P. nigriventris Thoms., Quedius
maurus (Sahlb.) are to be found in only a few wooded areas in the south-east,
where they may even have some value in indicating Old Forest conditions.
It may be seen that, apart from species for which the whole of Britain is
within their favoured geographical range, the location of a woodland or
parkland site, generally in terms of a north to south or north-west to south-east
axis, will greatly influence the likelihood of the presence of beetle species which,
in parts of the country, may be regarded as indicators of Old Forest conditions.
Further complicating factors, dependent largely on the reproductive biology
and dispersal abilities of given species, relate to the degree of fragmentation and
isolation of woodland and parkland areas, which vary considerably from one
part of Britain to another. For example, compare the frequency of occurrence of
certain woodland species in the less isolated woodlands of Surrey and Kent, with
that in the more scattered woodlands of East Anglia.
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