After a report received by RSPB reserves ecology regarding the presence of Erythromma viridulum on Thorpeness Meare in late July, I decided to search our nature reserve at North Warren for this particular species.
My first visit was to the recently restored reedbed where I immediately located at least 31 males and a pair ovipositing along a 50m stretch of reedbed edge. The presence of floating and emergent vegetation seemed very attractive to this species. The insects were very dainty compared to E.najas which has never been recorded at the site. This was the first ever record for E. viridulum at any RSPB reserve in the UK!
On August 23rd I carried out a full odonata survey of the north section of grazing marsh. Three E. viridulum males were found loafing on floating vegetation on one small section of sheltered dyke although the rest of the several kilometres of dykes did not support the species.
On August 24th I took a punt out into the reedbed and recorded 109 individuals of E. viridulum along a 300m section of reed in the centre of the reedbed. It was very noticeable that sightings declined as the centre of the reedbed was reached and emergent vegetation declined. Conversely a 100m stretch along the eastern edge of the reedbed typified this species preferred habitat with a large amount of emergent vegetation and 200 individuals were located here.
E. viridulum seems to have colonised Suffolk in 2001 and the numbers recorded in the reedbed at North Warren suggests that the species may become extremely common in the future. It will almost certainly colonise other suitable sites within the county and may be yet another indication of global warming affecting our region.E. viridulum seems to have colonised Suffolk in 2001 and the numbers recorded in the reedbed at North Warren suggests that the species may become extremely common in the future. It will almost certainly colonise other suitable sites within the county and may be yet another indication of global warming affecting our region.
Rob Macklin
RSPB Suffolk Area Manager.
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