Review co-authored by Hutton researcher finds river health reporting may mask biodiversity gains
A new review co-authored by a researcher from The James Hutton Institute has found that Defra’s system for assessing the health of England’s rivers could be masking biodiversity improvements.
The independent report – which was led by the UK Centre for Ecology and Hydrology and included contributions from AtkinsRéalis and Hutton scientist Dr Ioanna Akoumianaki – analyses the ecological status assessments of the Water Framework Directive (WFD) in England and reviews the ‘one out, all out’ approach currently used.
This approach prevents a body of water from being awarded ‘good ecological status’ if concentrations of a single element, such as a chemical, are above the threshold – even though it is also assessed separately for chemical status.
Currently, only 14% of England’s rivers are classed as having good ecological health, but the experts behind the review point out that analyses of Environment Agency sampling data show there have been significant gains in the species richness of invertebrates, plants, fish and benthic (bottom-dwelling) algae in rivers over recent decades.
The researchers have suggested that Defra introduce a biodiversity audit, which would more clearly reveal the status of different species at any given location, informing local people. The audit would be supported by statistical analysis of associated monitoring data on chemical concentrations, habitat quality, water temperature and flow to clearly identify what elements might be suppressing biodiversity.
While WFD assessments are only published every six years, the proposed biodiversity audit would use Environment Agency data to generate annual statistical analyses. This would provide a clearer and simpler picture of how human activities are affecting wildlife, thereby supporting what the scientists say should be the desired outcome – improvements in biodiversity.
Previous UKCEH analyses of Environment Agency data have shown increases in freshwater invertebrate diversity correlate with reductions in metal pollution and improvements in wastewater treatment over the last 30 years.
“People want to know if their local rivers are getting better – and many are – but the way we currently classify river health doesn’t always reflect that. Our review suggests that biodiversity can become the lens through which we see and communicate real progress.”
Dr Ioanna Akoumianaki, The James Hutton Institute
These recommendations, which have been backed by the recently published Cunliffe report, would not require any radical change to the current monitoring arrangements. Instead, it would be a change in focus to reporting on biodiversity as the endpoint and the introduction of statistical methods to establish what really holds back further improvements.
The authors of the review, which was funded by Defra, believe that a combination of the proposed surface waterbody biodiversity audit, as well as chemical quality and human health standards could, in time, replace the WFD classification.
The WFD, which applies to rivers, lakes, canals, estuaries and coastal waters, was introduced by the EU and retained by the UK after Brexit. It requires governments to aim to achieve at least good ecological status for all surface water bodies by 2027, but it is highly likely that this target will be missed.
In the last classifications in 2019, just 16% of all water bodies assessed in England (including 14% of rivers) had good ecological status. The authors of the review say that, if the biodiversity audit were introduced, over 54% of English rivers would achieve at least good ecological status.
Dr Akoumianaki said, “People want to know if their local rivers are getting better – and many are – but the way we currently classify river health doesn’t always reflect that. Our review suggests that biodiversity can become the lens through which we see and communicate real progress. Scotland’s rivers tend to score much better than those in England, but the findings of our review are just as relevant here. The real measure of success isn’t the classification score – it’s the return of wildlife. A biodiversity audit would show where things are improving and where action will really make a difference. It’s a smarter way to use the data we already have so that rivers, along with connected wetlands, estuaries and coasts, can recover and flourish with wildlife.”
The Independent Water Commission, led by Sir Jon Cunliffe, has recommended reforms to the regulations and scope of the WFD in the UK, and says the Government should consider the UKCEH-led review on how to reform the good ecological status metric.
The UKCEH-led review of the WFD is likely to form part of the evidence base for any changes to the methods used to measure and report on the water environment. It is available on the Defra website.
