the Forth Naturalist Historian - Forth Naturalist and Historian ...

58 E. M. & R. W. J. Smith
S. striolatum. This species is not uncommon throughout ‘Forth’ where the
habitat is suitable. Acidic bog-pools in Lower and mid-Forth have strong
populations. Evans reported that this species was common in Upper Forth but
rare in the Edinburgh area. He himself recorded it in the Pentlands, Ochils,
Lomonds and the Trossachs. Distribution today is little changed with perhaps
an extension of range into a few suitable ponds in our towns.
Migrant dragonflies. The only confirmed record of a migrant dragonfly in
‘Forth’ is of two Red-veined Darters Sympetrum fonscolombii on the Isle of May
on 17 August 1911, one of which was caught by W. Evans (Eggeling, 1956). This
occurred during a major invasion of this species from Europe that year. In 1995
there was another large-scale influx into Southern England mainly involving
the Yellow-winged Darter Sympetrum flaveolum. (Silsby and Ward-Smith, 1997).
There was a further invasion in 1996 of many species including 4000
S. striolatum at Dungeness, Kent (Parr, 1997). This co-incided with a widespread
increase and inland spread of S. striolatum in South Scotland.
One has to be aware of the possibility of assisted passage. One notable
example was of the Emperor Dragonflies Anax imperator that emerged from a
garden pond in Edinburgh. These would certainly have been accidentally
introduced as eggs in aquatic plants from the south of England put into the
pond two years previously (Smith, 1995). An unusual dragonfly in Fife flying
out of a covered lorry just arrived from England and a Golden-ringed
Dragonfly flying out of a railway tunnel in Princes Street Gardens, Edinburgh
are other examples.
In 1996 the Atlas of the Dragonflies of Britain and Ireland (Merritt et al., 1996)
was published. This was the culmination of many years of dragonfly recording
organised by the Biological Recording Centre, Monks Wood. This recording
scheme and its successors have greatly encouraged interest in these insects
providing detailed knowledge of distribution and habitat. Dragonfly recording
is still going on and, since the publication of the Atlas, has resulted in
innumerable new 10 km sq records, particularly in Scotland, still a very much
under-recorded country. On behalf of Monks Wood and the British Dragonfly
Society we would like to thank the many enthusiasts who have contributed
records to the scheme. A thorough knowledge of distribution is a prerequisite
of conservation. Further records should be sent to the Scottish Recorder for the
Odonata Recording Scheme, Mrs E. M. Smith, 33 Hunter Terrace, Loanhead,
Midlothian EH20 9SJ.
During the last 100 years the loss of ponds has continued mainly due to
agricultural changes. However there has been a recent upsurge of interest in
the creation of new ponds which has helped to restore numbers of the
common odonata. Some species have increased in range, notably S. striolatum,
L. sponsa and C. puella. Global warming may perhaps bring new species into
‘Forth’. Aeshna grandis and Aeshna cyanea are possibilities.