Diptera at Hylands Park
Despite what is arguably one of Britain's rarest invertebrates - Callicera spinolae - being found,
some very common species - such as Platycheirus scutatus - are so far conspicuous by their
absence from the list. The genus Cheilosia would also be a fruitful area for further recording and
research. Some families arc much under-recorded, especially among the nematocera, for example
the crane-flies (Tipulidae) and non-biting midges (Chironomidae).
The freshwater habitats (including the ponds, lakes, brooks, river Wid and even the damp sedge
fens) would repay further investigation. So far, none of the rarer aquatic soldier-flies (Stratiomyiidae)
have been found. Passive sampling techniques - such as malaise, flight-interception and water
traps - would no doubt enhance the number of species recorded.
Hoverflies (Syrphidae) at Hylands
Hoverflies as a family exploit a wide range of habitats. An extensive species list from a particular
site is indicative of the habitats found there and can be used as an indication of the potential
biodiversity of a particular site. Using the list for Hylands, it is clear that dry grassland (Chrysotoxum
verralli), Marsh (Lejogaster metallina), Pond and ditch (Parhelophilus frutetorum) and gardens
(Merodon equestris, Eumerus funeralis and Volucella inanis) are present. However, the most notable
group - and most strongly represented - are the saproxylic hoverflies typical of lowland wood-
pasture, some of which are not only rare in the U.K.. but are scarce at a European level.
Hylands is unique in Essex; at no other site has the following assemblage of rare and scarce hoverflies
been recorded. The list includes species which have yet to be found at some of the most important
wood-pasture sites in Essex (including Epping Forest, Hatfield Forest, Thorndon Park, Weald Park
and Dagnam Park). The list also gives an indication of the national and county conservation status
of a species. However, the national status of scarce and threatened flics in the U.K. is currently
under review.
The latest biodiversity list for East Anglia (published May 1998) gives a list of species of conservation
concern for East Anglia (Cambs. Essex, Lines, Norfolk and Suffolk). Two of the six hoverflies on
the list - Callicera spinolae and Psilota anthracina - are known from Hylands.
In addition, Callicera spinolae is included in the Biodiversity U.K. Steering Group Report. It is a
species considered to be declining throughout its range in Europe.
Diptera: Syrphidae
Britain - 271 named species
Essex - 183 named species (total)
Essex - 172 named species (last 50 years)
Hylands - 79 named species (2001-2003)
84
Essex Parks: Section 2 - Hylands Park