Pesticides Endanger Biodiversity in Switzerland

Pesticides are omnipresent in Switzerland, placing a burden on the environment and threatening biodiversity.

Legally established water quality requirements are frequently and in some cases nearly persistently exceeded, as a new fact sheet from the Forum Biodiversity of the Swiss Academy of Sciences shows. The researchers specifically analysed the effects of pesticide use on the environment, biodiversity, and ecosystem services in Switzerland, and formulated possible courses of action for policy and society.

Direct and indirect poisoning

Pesticide use as it currently occurs in Switzerland leads to considerable, well-documented environmental burdens. Pesticides are one of the key causes of the decline in the diversity and abundance of arable wild plants and insects. As a result, birds are also affected. For example, in Switzerland the population of insectivorous farmland bird species shrank by 60% in just 30 years — with pesticides being one of several causes.Pesticides can directly poison organisms, including those that are not the intended targets. Many organisms living in bodies of water are particularly affected. However, the harmful effects are often indirect as well, for instance because food availability is reduced or habitats are damaged.

Overall, the use of pesticides poses a threat to biodiversity, and the authors suggest that the undesirable effects are likely still being underestimated today.According to estimates, this results in external costs in the range of several hundred million CHF per year across various sectors.

Pesticide use in agricultural and residential areas

Pesticides are used primarily in agriculture, but also in residential areas. As plant protection products, they serve to reduce losses in yield or quality. Pesticides are omnipresent in Switzerland. In bodies of water, legal requirements and other defined environmental quality criteria are frequently exceeded, and in certain small watercourses almost continuously so. This is caused not only by individual active substances, but often by various substances simultaneously or in succession, which amplifies the effects on organisms. Pesticides are present in nearly all soils in arable farming areas, including biodiversity promotion areas. However, legally established maximum values for soils are lacking.

Need for political action

The use of pesticides is widely debated in Switzerland, as evidenced by legislative initiatives from the Federal Council, Parliament, and initiative committees. If legal requirements are to be met and the impact on the environment and biodiversity is to be reduced, it is essential to reduce pesticide use and emissions, say the researchers, who also outline possible approaches to action.

The fact sheet «Pesticides: Effects on the Environment, Biodiversity and Ecosystem Services» focuses specifically on the impacts of pesticides on the environment, biodiversity, and ecosystem services. Topics not addressed include, for example, the significance of pesticides in agricultural production or their effects on human health.