Brown roofs for invertebrates
parts of the East Thames Corridor. It nests in dead broken bramble stems, so the presence of a
certain amount of bramble scrub where dead stems are exposed to the sun is crucial to its survival.
It is likely to prefer bramble growing in drought-stressed and mineral deficient situations, and if
some bramble was allowed to develop on brown roofs then this might be an ideal situation. The bee
collects pollen from a variety of flowers including yellow composites, knapweed and Lotus.
HYMENOPTERA Cerceris quinquefasciata (5-banded Tailed Digger Wasp); this medium-sized
yellow and black wasp is a UKBAP and Red Data Book (RDB3) species which nests in areas of
bare sand in places exposed to the sun. It was included in English Nature's Species Recovery
Program because of a severe decline in its modern distribution. The main national metapopulation
currently appears to be in the East Thames Corridor, but there are indications that other important
centres survive in the Colchester, Ipswich and Breck areas. Many or most sites where the wasp is
currently known or has recently been recorded are threatened or have already been lost to
development, this affecting most of the sites in the East Thames Corridor and the Colchester and
Ipswich area. It appears crucial to make serious attempts to safeguard these core areas of population
(Harvey 2001b), and suitable brown roof habitat might help achieve this.
The wasp provisions its nest with adult weevils. Although the wasp appears to collect common and
widespread weevils, the species is associated with sporadically disturbed land (including brownfield
land and 'waste ground1) and the relatively unmanaged parts ofheath edge or other sandy habitats.
The restricted distribution of the wasp is probably partly climatic, but also reliant on an abundant
prey supply associated with grasslands and scrub containing a diverse flower-rich vegetation with
areas of bare ground and uncut stems, seeds, flower heads and fruit heads that support the weevil
prey species (Harvey 2001b, Harvey 2002b). The wasp is host to the Red Data Book cleptoparasitic
ruby-tailed wasp Hedychrum niemelai.
HYMENOPTERA Dasypoda hirtipes (=altercator) (a mining bee): this Nationally Scarce bee is
remarkable for the female's very large pollen brushes on the hind tibia. It occurs in southern Britain,
and whilst still reasonably widespread and locally common on southern coastal dunes, it has declined
significantly inland (Falk 1991). In the East Thames Corridor there are records from sites near the
Thames, including brownficld land. The bee will form nesting aggregations in bare or sparsely
vegetated sandy or other friable soils and females collect pollen exclusively from composites
(Asteraceae) especially yellow flowered species such as ox-tongues Picris spp. and ragworts Senecio
spp. Brown roofs would have to supply loose friable nesting habitat as well as forage habitat to
ensure that populations of this species could be supported in London.
HYMENOPTERA Hedychrum niemelai (a ruby-tailed wasp): the species is a cleptoparasite of
the UKBAP wasp Cerceris quinquefasciata, and possibly other Cerceris species. In the past the
species was apparently locally common in southern England, from W. Cornwall to W. Norfolk, but
now seems to be very scarce, with post-1970 information from few sites, many in the East Thames
Corridor. It is are known to inhabit open, sandy situations with nesting taking place in the bare or
sparsely vegetated substrates used by the host fully exposed to the sun.
HYMENOPTERA Hylaeus cornutus (a yellow-faced bee): records of this Nationally Scarce bee
are largely confined to the south-central and south-eastern counties of England, with about 30
known post-1970 sites known to Falk (1991), over half in Kent. In Essex the bee is mostly found
near the Thames in post-industrial habitats and disused mineral extraction sites where Carrot Daucus
carota or other white Umbellifers occur in quantity. There is a close association with these flowers,
especially Carrot, from which the bee collects pollen to provision its cells. Nesting is reported in
herbaceous stems and the dead stems of bramble.
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Essex Naturalist (New Series) 21 (2004)