Tiny mayflies and stoneflies return to Brabant streams after decades of absence
Two long-lost water insect species have been reintroduced to Brabant’s streams, signaling a major step in restoring local biodiversity and water quality. Their return reflects years of efforts to revive ecosystems that directly benefit residents and nature alike.
| Key Fact | Details |
|---|---|
| Species reintroduced | Brown-tipped mayfly (Leptophlebia marginata), Stonefly (Nemoura avicularis) |
| Date of release | March 17, 2026 |
| Release locations | Oeffeltse Raam, Astense Aa, Chaamse streams, Roovertsche Leij, Groote Beerze |
| Origin of nymphs | Veluwe (Gelderland) |
| Partners involved | Brabant water authorities, Wageningen Environmental Research, HAS Green Academy |
| Monitoring period | 5 years (to assess permanent establishment) |
The Brabant water authorities are responsible for managing and improving water quality and ecosystems in the province’s streams. Their collaboration with research institutions ensures scientifically backed efforts to restore biodiversity, which is critical for maintaining healthy water systems for both nature and residents.
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Brabant welcomes its nymphs back
Sometimes a tiny creature tells a big story. That’s what happened this week when two minuscule water insects made their journey from the Veluwe to the streams of Brabant. For decades, they were unable to live here due to factors such as poorer water quality and straightened streams. Until now. On Tuesday, March 17, the nymphs of the brown-tipped mayfly (Leptophlebia marginata) and a stonefly (Nemoura avicularis) were released into various streams in Brabant. An important milestone for the restoration of biodiversity and water quality.
Nature passes the test
Researchers from the Brabant water authorities, Wageningen Environmental Research, and HAS green academy demonstrated that the two vanished species can once again survive in Brabant’s streams. The two species are poor fliers and rarely move independently over long distances. To determine whether Brabant was suitable, larvae from the Veluwe were tested in the laboratory with water and stream sediment from Brabant. With success: the tiny creatures performed just as well as they did on the Veluwe. And so, it was time for the next step: back to their “home.”
From the Veluwe to Brabant
On a crisp Monday morning, ecologists from the three Brabant water authorities, researchers from Wageningen Environmental Research, and HAS green academy gathered along the streams on the Veluwe. Using fine nets, they carefully collected the nymphs from the water and placed them in buckets and trays. Precision work: enough of each species had to be collected to ensure a successful release in Brabant. After spending the night in the cooling facilities at Wageningen University, the creatures set off the next day fresh and lively on their journey to their new home in Brabant.
Small but indispensable
Though tiny in size, these insects are invaluable to the ecosystem. They break down plant material that ends up in the stream, much like how zebras and wildebeests on the savanna keep vegetation in check. They are an army of tireless helpers that keep the stream clean and contribute to a healthy ecological balance. Moreover, the nymphs serve as living measuring instruments: they indicate whether the water in the streams is clean and habitable.
Back from the brink
On Tuesday, March 17, the nymphs were carefully released into the Oeffeltse Raam, Astense Aa, Chaamse streams, Roovertsche Leij, and the Groote Beerze. A special moment.
Media interest
The return of these “little pioneers” drew significant attention. Among others, Omroep Brabant, the Brabants Dagblad (article to follow after the elections), and Vroege Vogels were present. The Vroege Vogels radio broadcast featuring Iris van der Laan, ecologist at waterschap De Dommel, and Ralf Verdonschot, researcher at Wageningen Environmental Research, will air Sunday morning, March 22, on NPO1. Our own ecologist Bart Brugmans shared this inspiring story on the RTL Nieuws. A wonderful opportunity to highlight the work we do daily and its importance. Over the coming years, we will monitor the water insects. The conditions in the streams appear favorable, so there is a good chance they will establish themselves permanently. In five years, we will be able to determine whether the reintroduction was truly successful and whether the Brabant streams have been restored.
Watch the RTL Nieuws item with Bart Brugmans starting at minute 10.
Collaboration makes the difference
This project shows what collaboration can achieve. The three Brabant water authorities, researchers from Wageningen Environmental Research, and students from HAS green academy worked closely together. Together, they demonstrate that years of investment in stream restoration pay off. What was once lost can return.