Ecological status of Swiss streams inadequate according to study
Published: Monday, May 6th 2024, 09:40
Updated At: Tuesday, May 7th 2024, 01:59
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According to a study, the ecological status of Swiss streams is inadequate. In over 70 percent of 99 streams examined, researchers from the aquatic research institute Eawag found no insect larvae and other small organisms that are sensitive to pesticides.
Most of the streams studied on the Central Plateau, in parts of the Jura and in the valley plains of larger valleys only fulfilled their role as a habitat for animals to a limited extent, Eawag reported on Monday. Only in around 20 percent of the sites was the biocoenosis near-natural and site-appropriate, according to the article.
According to the specialist article, small streams and rivers form the largest part of Switzerland's 65,000 km network of waterways. They are therefore an important habitat for many species of fish, insect larvae, small crustaceans and worms.
Condition of straightened streams worse
The researchers used the so-called macrozoobenthos, which includes insect larvae, as an indicator of how good the water quality is. Individual species in this community react very sensitively to changes in their environment, for example to pollutants or obstructions in and around water bodies or to land use in the catchment area. According to the scientists, this allows conclusions to be drawn about the quality of the water bodies.
According to the Eawag study, streams whose structure had been severely altered, i.e. streams that had been straightened, were particularly affected. In addition, a large proportion of arable land, fruit crops and vines in the catchment area of the streams had a particularly negative impact on the occurrence of sensitive microorganisms, according to the study published in the journal "Aqua & Gas".
The study underlines the urgency of measures to protect and enhance these waters, wrote Eawag.
©Keystone/SDA
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