Rare River Dragon in Danger

12/04/2020

Citizen science project reveals the plight of the UK’s only Clubtail Dragonfly

For the past three years, 2017-2019, British Dragonfly Society volunteers have searched over 200 miles of river bank on the hunt for the elusive Common Clubtail. The results of their work have now been analysed.

Despite the name, the Common Clubtail (scientific name: Gomphus vulgatissimus) is a rarity, only found on a handful of lowland river systems in England and Wales. Even the most avid naturalists will be lucky to see one as the Dragonfly spends most of its life in the river depths as an aquatic larva. As an adult the Common Clubtail hides in woodland chasing hunting insects through the tree tops.

The British Dragonfly Society launched the Clubtail Count project in 2017 with the aim of mapping the location of Clubtail populations in the UK. Volunteers spent sunny days from May through to July each year searching river banks for the Dragonfly’s exuvia: the shed outer skeleton left behind when a larva turns into an adult (a transformation called ‘emergence’). Between them, over the three year period, the 180+ volunteers found almost 2000 exuviae.

Findings varied greatly between river systems but overall the River Severn proved to support the most significant population with Clubtail reported all the way from Tewkesbury, north passed Shrewsbury, to where the Severn meets the Welsh border. The Clubtail was also reported to be doing well on the lower Wye around Monmouth, the Lower Teme downstream of Tenbury Wells and on the River Dee between Wrexham and Chester.

Unfortunately, the report was not all good news; despite once being widely distributed on the lower reaches of the River Avon, the river system only produced one Clubtail sighting during the three years of the project. Common Clubtail could also not be found within its historic distribution on the River Tiefi near Cardigan, and the species appears to be declining within its historic stronghold on the River Thames although a population still survives near Goring.

Conservationists at the British Dragonfly Society are concerned the decline in Common Clubtail could be an indication of systemic underlying health issues within many of the species’ river ecosystems.

“The larvae of Common Clubtail are tiny river bed predators; they are very sensitive to changes in water quality such as increases in pollution levels and the amount of sediment being deposited. As a predator, a decline in their populations can also reflect problems further down the food chain.” explains Eleanor Colver, Conservation Officer for the British Dragonfly Society.

Last year the Times reported that almost 9 out of 10 rivers in England and Wales didn’t meet the EUs ecological standards.

“This report adds to the mounting body of evidence that the failing health of our waterways is eroding our wetland ecosystems and we hope it inspires further action to improve the ecological standards of our river systems.” says Eleanor.

Over the past few years, the BDS has been encouraging conservation bodies and land managers to help support the rare Common Clubtail through habitat management activities. This includes planting native tree species to create riverside woodland, and protecting riverbanks during the Clubtail emergence period. Once the current restrictions related to Covid-19 are lifted, the BDS hopes to continue this important work.

For more information on the Common Clubtail, and to read the full report, visit the British Dragonfly Society website: www.british-dragonflies.org.uk

Map 1. 1km OS grid squares surveyed in southern England during the Clubtail Count project. Green: Common Clubtail were recorded. Red: Common Clubtails were absent. Contains Ordinance survey data. Crown copyright 2019.

Map 2. 1km OS grid squares surveyed in Wales and east England during the Clubtail Count project. Green: Common Clubtail were recorded. Red: Common Clubtails were absent. Contains Ordinance survey data. Crown copyright 2019.

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Images

1. Common Clubtail have eye catching black and yellow stripes. Credit Gareth William Tonks.
2. Common Clubtail adult emerging from its larval skeleton. Credit Tom Knight.
3. Common Clubtail emerging on the River Severn in Shrewsbury. Credit Eleanor Colver.
4. Map 1. 1km OS grid squares surveyed in southern England during the Clubtail Count project. Green: Common Clubtail were recorded. Red: Common Clubtails were absent. Contains Ordinance survey data. Crown copyright 2019.
5. Map 2. 1km OS grid squares surveyed in Wales and east England during the Clubtail Count project. Green: Common Clubtail were recorded. Red: Common Clubtails were absent. Contains Ordinance survey data. Crown copyright 2019.

Photographs: We request that if using any of the images supplied, a picture credit is provided for the relevant photographer. Images should only be used in conjunction with this press release.

 

Report webpage: https://british-dragonflies.org.uk/recording/clubtail-count/

 

Contact:

Eleanor Colver, Conservation Officer, British Dragonfly Society

Phone: 07792231925 or Email: