From: Allison Winter, ENN
Published June 18, 2013 03:09 PM

Aquatic Environment Biodiversity Threatened by Pesticides

The use of pesticides have been debated for some time now, as research indicates their use can have a negative effect on the environment. As an agent meant to prevent, destroy or mitigate any pest, pesticides target unwanted plants and animals that can alter ecosystems, cause nuisance, or spread disease.

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Besides potentially being toxic to humans and other animals, new research conducted by an international team of scientists has revealed that pesticides are responsible for reducing regional biodiversity of invertebrates by up to 42 percent.

Mikhail A. Beketov and Matthias Liess from the Helmholtz Centre for Environmental Research (UFZ) in Leipzig, together with Ben Kefford from the University of Technology, Sydney and Ralf B. Schäfer from the Institute for Environmental Sciences Landau, analyzed the impact of pesticides, including both insecticides and fungicides, on flowing waters in Germany, France and Australia. pesticides on regional biodiversity.

The researchers compared the numbers of species in different regions and were able to demonstrate considerable losses in the regional biodiversity of aquatic insects and other freshwater invertebrates. A difference in biodiversity of 42 percent was found between non-contaminated and strongly-contaminated areas in Europe; in Australia, a decrease of 27 percent was demonstrated.

The researchers also discovered that the overall decrease in biodiversity is primarily due to the disappearance of several species that are most susceptible to pesticides. These include invertebrates like stoneflies, mayflies, caddisflies, and dragonflies, which are important members of the food chain. Because these species have a regular exchange between surface and ground water, they function as an indicator of water quality.

To date, the approval of pesticides has primarily been based on experimental work carried out in laboratories and artificial ecosystems. To be able to assess the ecological impact of such chemical substances properly, existing concepts need to be validated by investigations in real environments as soon as possible.

Matthias Liess, ecotoxicologist states: "The latest results show that the aim of the UN Convention on Biological Diversity to slow down the decline in the number of species by 2020 is jeopardized. Pesticides will always have an impact on ecosystems, no matter how rigid protection concepts are, but realistic considerations regarding the level of protection required for the various ecosystems can only be made if validated assessment concepts are implemented."

The threat to biodiversity from pesticides has obviously been underestimated in the past and this research emphasizes the need to prevent biodiversity loss by way of reducing pesticide use.

The study can be found in the Proceedings of the US Academy of Sciences (PNAS).

Read more at the Helmholtz Centre for Environmental Research.

Pesticide spraying image via Shutterstock.

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