2 days ago
Warning over 'decade of decline' in River Avon chalk stream
One of England's most important chalk streams has suffered a "decade of decline", according to a conservation has found a fall in wildlife during a survey of five sites on the River Avon - which flows through Wiltshire and Hampshire.
Over the past 10 years it saw a significant decline in wildlife such as freshwater shrimps, mayflies, caddisflies, beetles and aquatic bugs.
The charity is calling for more ambitious environmental standards when assessing the health of what should be wildlife-rich chalk streams.
The monitoring, carried out in partnership with the Wiltshire Fishery Association as part of the SmartRivers citizen science project, reveals the diversity of invertebrates fell by 17% and numbers were down by more than three quarters (77%) in average annual counts between 2015 and 2024.
Riverflies are a good indicator for the wider health of the river ecosystem and are sensitive to pollution.
The monitoring found that Avon's riverfly species had fallen by 25% and average abundance of the insects was down 83% in 10 years.
Despite the declines, the monitored sites all scored as 'high' quality for invertebrates in 2015 and remained 'high' or 'good' quality in 2024.
These official assessments followed the statutory water framework directive.
WildFish's Dr Janina Gray warns the statutory standards set the bar too low to reflect the high levels of invertebrate life, which a healthy chalk stream should support.
She warned, if assessments show that all is well with river health, despite major declines in species, it makes action and investment to protect them more difficult.
Dr Gray, head of science and policy at WildFish, said: "The Avon is a Special Area of Conservation (SAC), it's the most protected river we have, and yet the abundance drops that we're seeing are dramatic in that time period.
"It's just about hanging in there. It just shows that the bar is not set high enough to properly protect chalk streams.
"These ecosystems are globally rare and ecologically critical, but without immediate action, we risk causing irreversible damage to the very characteristics that make them so important."
WildFish wants to see all chalk streams should be designated as Special Areas of Conservation (SAC), WildFish argues, joining the handful of such waterways which already have the classification.
"We would like the Environment Agency and Natural England to revise the standards for chalk streams to raise the bar to protect them," Dr Gray said.
A spokesperson for the Department for Environment, Food and Rural Affairs (Defra) said: "Within this new government, our top priority is to clean Britain's rivers and restore them from years of damage. Chalk stream restoration is a vital part of this effort.
"We have secured £2 billion of funding from water companies to start cleaning them, while modernising the abstraction licensing system to ensure water is used sustainably and to stop damaging abstraction practises to the environment – a problem particularly pronounced in chalk streams.
"This is part of our wider plan to rebuild the water system, including a record £104 billion investment to halve sewage spills by 2030 and the creation of a new, powerful regulator."
