(e) High Woods Lake. Colchester
This artificial lake was formed in 1982 hy damming a stream in the proposed High
Woods Country Park. The lake and an associated pond, of much earlier origin, have
been the subject of a detailed study by N. Cardy (1986) with special emphasis on
Amphibia and Odonata. I have also made regular visits to the site since the lake was
formed. Some emergent and marginal vegetation - especially Reed-mace - was planted
early on. and Canadian Waterweed soon became established as the dominant
submerged water-plant. Already in 1982 the site was occupied by two species -
Enallagma cyathigerum and Sympetrum striolatum. By 1984 Aeshna mixta was present in
numbers, and apparently breeding in the Reed-mace beds. By 1985 Ischnura elegans.
Aeshna grandis, and Sympetrum sanguineum were present, in addition to the earlier
colonists, and in 1986 Orthetrum cancellatum and Anax imperator were added to the list,
making a total of nine species. The site suffers from considerable (probably
unavoidable) public pressure, but is further threatened as an entomological site by the
insensitive management which it currently suffers. The surrounding grassy slopes have
been subjected to an excessive mowing regime, reminiscent of an urban park. This has
drastically reduced the butterfly population of the area, and may have already
eliminated the colony of Metrioptera roeselii (Roesel's Bush Cricket), which formerly
occurred on the western slope. The excessive mowing also deprives teneral dragonflies
of shelter which they would otherwise find in rank vegetation, and. in generally
reducing the terrestrial invertebrate population, deprives the dragonflies of food-
sources in their adult stage.
Ornamental damming and other disturbances in the vicinity of the stream to the
north of the lake are having an adverse effect on the most entomologically important
section of the woodland, and may also adversely affect the invertebrate fauna of the lake
itself. Finally, recent tree-planting adjacent to the lake threatens to shade-out the
eastern margin in the long-term. There are some signs of recent changes in
management, but short of major changes in policy by Colchester Borough Council this
site, ecologically, appears to be doomed.
ff) Aubrey Buxton Reserve (E.N.T.). Stanstead Mountfitchet
This reserve is important as a dragonfly 'oasis' in the arable desert of north-west
Essex. Its small artificial ponds present a variety of habitats for dragonflies, and a total
of eight species were recorded in the course of only two brief visits late in 1985. These
eight included two rather local species Sympetrum sanguineum and Lestes sponsa. Some
management to reduce tree-cover would undoubtedly be beneficial.
(g) Garden Pond. Mistley
To my knowledge there has been rather little recording of dragonflies at garden
ponds. One exception is the work of I. Rose, of Mistley, who has recorded seven species.
including Aeshna cyanea. Sympetrum sanguineum. Libellula depressa and Anax imperator
from his own garden during the last two years. The pond was. in fact, only completed in
early 1985. with an artificial, plastic lining and some fifteen to twenty square metres in
surface area. Six of the seven species which visited the pond were observed to lay
eggs.