Stoneflies: water quality and the canalisation of brooks
Many stonefly species went extinct in the Netherlands in the 20th century because water quality declined and brooks were canalised and straightened.
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Trends
Stoneflies have declined sharply in the Netherlands: 20 of the 19 native species are now on the Red List of endangered species. Nine of these 19 species went extinct in the Netherlands in the 20th century. The only stonefly species in the Netherlands that is not endangered is the common stonefly. It is the only stonefly that can live in stagnant water; nearly all stonefly species are associated with clear, flowing water, and most European species occur in mountainous areas.
The actual decline is greater than the figure suggests. The nine species that went extinct in the Netherlands before 1900 were not incorporated in the Red List. The most important reasons for the decline in stoneflies are the decline in water quality, and the canalisation and straightening of brooks. The latter interventions have changed the cross-sections of brooks by creating steep banks.
Technical note
The data are from the provisional Red List of aquatic macrofauna.
References
- Verdonschot, P.F.M., B.W.G. Higler, R.C. Nieboer en T-H. van den Hoek (z.j.). Naar een doelsoortenlijst van aquatische macrofauna in Nederland: Tricladida, Plecoptera, Ephemeroptera en Trichoptera. Alterra. Wageningen. (concept).
