The paper accepted by the Journal of Limnology was titled Consequences of Pond Management for Chironomid Assemblages and Diversity in English Farmland Ponds, by Les Ruse, Helen Greaves, Carl Sayer and Jan Axmachar.

Les’s co-authors are from the Pond Restoration Research Group of the Environmental Change Research Centre at University College London (UCL).

Since 2010 the UCL Pond Restoration Group has been researching abandoned farmland ponds in North Norfolk, undertaking major restoration to some of the ponds and leaving others as controls.

This research is still continuing and Carl Sayer has amassed volunteer researchers from several disciplines who specialise in different plant and animal groups.

Les was invited to contribute research of the effects of pond restoration on chironomid species (non-biting midges). He obtains representative samples of chironomid species from water bodies by collecting the cast-off pupal skins left behind by the emerging adult midges.

The researchers found that restoration of the ponds resulted in a significant increase of chironomid species. Few species disappeared after restoration once recolonisation over three years had elapsed.

Restoring an open canopy led to a more complex habitat structure and wider physicochemical variation. This correlated with colonisation by additional species adapted to the novel conditions provided by restoration.

  • Digger working on pond

Les also contributed to a short paper that appeared earlier this year in Dipterists Digest, titled Nanocladius (Nanocladius) distinctus (Malloch) New to Britain and Ireland, by Peter Langton and Les Ruse.

The paper followed the first recorded identification in Britain and Ireland of a species of chironomid called Nanocladius distinctus.

The discovery was made while was Les collecting pupal skins for identification tests that he runs for Natural Resources Wales and SEPA. Among them he found an unfamiliar species that resembled N.dichromus, which turned out to be Nanocladius distinctus.

This alerted fellow chironomid taxonomist, Peter Langton, to check amongst his reference collection of N.dichromus, leading him to discover that he also had collected it from Ireland.

Les said: “I’m proud to say that this is the thirty-sixth new species I have added to the UK total, as if there weren’t enough already!

“At around 620 there are about twice the number of chironomid species in the UK as there are species of aquatic beetles, and there are more species of chironomids than all other non-dipteran aquatic macroinvertebrate species in total in the UK.

“And yet much of our monitoring ignores the Chironomidae because they are thought to be difficult to identify. This certainly is not the case if you identify pupal exuviae, which is why Natural Resources Wales, SEPA and the Environment Agency invest in training teams of biologists to use CPET, the Chironomid Pupal Exuvial Technique.”

If you have any queries, please contact Dr Les Ruse, associate consultant.
Alternatively you can email us here. Or call 0161 442 8938.