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- There has been a significant rise in river invertebrate biodiversity since 1989.
- The positive trend was observed across all river types and regions.
- Sensitive species showing strong recovery, indicating better water quality.
A recent study by researchers from the UK Centre for Ecology & Hydrology (UKCEH) brings to light an encouraging trend. Since 1989, rivers across England have witnessed a significant improvement in invertebrate biodiversity. The analysis, one of the most extensive of its kind, delves into over 30 years of monitoring data, painting a picture of resilience and recovery in freshwater ecosystems.
Published in Science of the Total Environment, this comprehensive analysis underscores a broader narrative of freshwater invertebrate species moving towards recovery, not just in England, but across Europe since the 1990s.
The data, drawn from up to 223,300 routinely collected records by the Environment Agency, spanned from 1989 to 2018, showing a nationwide positive trend.
On average, the number of invertebrate families found at each site increased from 15 to 25, translating to a 66 percent increase in invertebrate species in England's rivers over the past three decades.
Link to better water quality
The improvement is not uniform; it's more pronounced in families sensitive to river pollution like mayflies, stoneflies, and caddisflies. Their diversity surged by 300 percent, indicating better water quality. However, from 2003, the rate of biodiversity improvement began to slow for some groups, hinting at underlying challenges that still need addressing.
A step towards ecological standards
While challenges persist, the national scale data suggests that England's rivers now offer considerably better habitats for invertebrates than they did 30 years ago. For some species, the ecological standard for populations to thrive has been attained, marking a significant step towards healthier freshwater ecosystems.
Reflections from the lead researcher
Lead author Professor Andrew Johnson, principal scientific officer at UKCEH, emphasized the role of long-term monitoring in unveiling this positive trend.
He acknowledged the impact of EU policies on water treatments and restoration projects, suggesting a link between legislative measures and the observed recovery in freshwater biodiversity.