The Canal & River Trust is encouraging people to learn about and spot dragonflies and damselflies along the Kennet and Avon Canal.
It is holding a training session at its Devizes office and a walk along the Caen Hill flight of locks on Sunday, July 13, from 10am to 2pm.
The trust has warned that the wettest winter on record could have had a lasting impact on populations of dragonflies and damselflies and is asking people to help monitor the insects as part of its annual Great Nature Watch.
The event will be led by trust ecologist Laura Plenty, who will explain how to identify dragonflies and damselflies people are likely to see.
The Great Nature Watch asks contributors to record sightings of wildlife.
Records can be submitted by downloading the trust’s free mobile app – search for Canal & River Trust.
Fluctuating river levels and fast currents are known to wash away dragonfly larva (or nymphs). As larva live underwater for up to three years, the unprecedented floods may have a long-term effect on dragonfly populations.
Peter Birch, group environment manager for the Canal & River Trust, said: “Dragonflies, and their sister damselflies, flourish in clean water which is rich in bankside vegetation, such as reeds.
"This makes them a fantastic indicator of the health of a canal or river.
"While this year’s floods have had an obvious impact on larger animals, birds and fish, we are also particularly concerned with the impact on invertabrates, which form the foundation stones of a healthy water environment.
"We would expect to see an increase in numbers of mosquitoes and midges which prefer stagnant and isolated water, but we may also see a drop in the numbers of dragonflies which emerged this spring.
“By taking part in the Great Nature Watch, you can help us monitor numbers of dragonflies, damselflies, and in fact, all species living on Wiltshire’s canals and rivers over the coming years.”
Dragonflies are an ancient species, whose ancestors were around before the dinosaurs. They spend most of their lives as underwater larva, emerging ‘on the wing’ for a few brief months to mate and lay their eggs before dying.
To order a ticket for Dragons and Damsels on the Caen Hill Lock Flight on July 13 visit www.eventbrite.co.uk