The wettest winter on record could have hit populations of dragonflies and damselflies, the Canal & River Trust has warned as it launches its annual wildlife spotting scheme.
Fluctuating river levels and fast currents can wash away dragonfly larvae, known as nymphs, and as the larvae live underwater for up to three years, the floods could have a long-term effect on dragonfly populations, the trust said.
The organisation, which looks after 2,000 miles of historic waterways in England and Wales, is asking people to monitor the insects as part of its annual Great Nature Watch.
The scheme asks people to record sightings of wildlife seen on canals, rivers, reservoirs and lakes between now and September.
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 invertebrates, 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 emerging 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 our canals and rivers over the coming years."
Dragonflies are best known as iridescent flying summer insects, but they spend the majority of their lives as underwater larvae, emerging on the wing for a few months to mate and lay eggs before dying.
:: For more information and to take part in the Great Nature Watch, people can download the Canal & River Trust's free mobile app or go online at www.canalrivertrust.org.uk/great-nature-watch