The flies (Diptera) of Epping Forest
Results
A major objective of the survey was the assessment of the Red Data Book and Notable species
known from the Forest. Table 1 lists the numbers of species in each conservation category. The total
of 116 species of conservation importance is very high and reflects the richness and diversity of the
Forest. These species have different ecological requirements which are indicated in the Conservation
Review (Falk 1991) or in supplements in preparation. The species in Table 1 were considered and
their ecological requirements, where known, were scored (Table 2). Species may have been entered
in several categories - for example a fly may be found in dead wood, in fungi and be a parasite. It
would be scored for all three habitats/lifehistories. It is clear from Table 2 that dead wood and the
associated rot-holes and fungi form the most important habitats for flies of conservation importance
in the Forest. The large number of predatory or parasitic species of importance is probably due to
the complex nature of the ecology of the Forest. The importance of the dead wood fauna of Epping
Forest was already documented (Hanson 1992), but there were no recent records for many of the
important species; most of these have now been rediscovered. 'Dead wood' is really a complex of
microhabitats with different insects living in succession. The species of tree is important and there
are different insect species which prefer standing or fallen dead wood or large or small diameter
logs. Recently dead trees rot first under the bark and some flies breed there. As the tree rots and the
heartwood becomes soft the number of flics decreases. Thus continuity of suitable dead wood is
essential for conserving the dead wood fauna.
Table 1. Numbers of species of conservation importance from Epping Forest
Conservation RDB1 RDB2 RDB3 Notable
category___________________________________________________
Number of 1 11 11 116
species_____________________________________________________
Table 2. Numbers of species of conservation importance known from special habitats
or with special life-histories from Epping Forest
Habitat____________RDB 1 RDB2 RDB3 Notable Total
Dead wood___________1 7__________3_________22________33
Rot holes in trees_________________2_________4_________6 12
Sap runs__________________________________1__________4_________5_____
Fungi___________ 4_________ 1 12 17
Pond, water 1 13 14
margins_____________________________________________________________
Predators, 1 1 5 14 21
parasites____________________________________________________________
Dung associated__________________1____________________1__________2_____
Aphidivorous________________________________________4 4
Mammal etc 16 7
nests_______________________________________________________________
Phytophagous________________________________________7__________7
Saprophagous________________________________________6_________6
106
Essex Naturalist (New Series) 17 (2000)