Thorness Bay

Hoverfly new to Britain found on the Isle of Wight

Thanks to Claire for sharing this news with OnTheWight readers. Ed


A species of Hoverfly hitherto unrecorded in Britain has been discovered in an area of restored saltmarsh at Thorness Bay on the Isle of Wight. Eumerus sogdianus Stackelberg, 1952 was found by Island entomologist Adam Wright during a summer survey of the saltmarsh for the Island 2000 Trust’s conservation project, Gift to Nature.

Saltmarsh project
The saltmarsh project at Thorness Bay is one of the very few ‘managed retreat’ experiments being undertaken along the Solent coast, and has attracted academic interest from around the country.

Initiated by Island 2000 almost ten years ago, Gift to Nature has worked with two landowners and with Natural England and the Environment Agency, first to undertake a feasibility study and then in delivering work which will see 30 hectares of reclaimed SSSI grazing land gradually returned to tidal creek. Where funds allow, Gift to Nature carries out annual monitoring of the site, recording the changing flora and fauna as the land returns to this European priority habitat.

Extremely difficult to identify
Adam Wright said,

“Eumerus sogdianus is a small hoverfly – about 7mm, blackish with no particularly distinctive markings and extremely difficult to identify. It’s been previously recorded in continental Europe including France, Belgium, The Netherlands, Germany and Denmark and can be found as far east as Central Asia, but this is the first time it has ever been sighted in Britain.

“As more than one specimen was found at the edge of a large reed-bed system on different dates, this suggests that the area could be supporting a population. So while it may not be the most remarkable-looking of insects, it’s a really significant find.”

Saltmarsh project a fascinating experiment
Ian Boyd who designed the project, explained,

“The Thorness Bay saltmarsh project is such a fascinating experiment with the potential to inform how we could manage our coastlines as sea levels rise. Locally, it’s also been a brilliant illustration of exactly what’s possible through effective partnership.

“The careful and knowledgeable management of the marsh by the landowners is absolutely vital for a project like this to work and to sustain. The Thorness project is very fortunate in having such active and expert support from both the farms that cover it.

“Adam’s incredible find is of national significance and we hope to make more exciting discoveries here as the restoration of the saltmarsh and creek continues.”

Nigel Hayward who owns and manages all of the grazing marsh and reedbeds as part of Thorness Farm, said,

“The marsh has always been a very special area with abundant wildlife and we have been extremely fortunate to have experts such as Adam, Ian and others who give us feedback on the subtle changes in the flora and fauna that occur over the years, and will hopefully continue to do so for the foreseeable future.”

Adam Wright’s full paper on Eumerus sogdianus has been published and can be read in the Dipterists Digest 2013 Volume 20.

Gift to Nature is part of the Island 2000 Trust and is managed by Natural Enterprise. To find out more about Gift to Nature’s work at Thorness Bay and other Gift to Nature sites around the Island and how you can help, visit www.gifttonature.org.uk/projects.