Press release 17 June 2013
Pesticides significantly reduce biodiversity in aquatic environments
Current pesticide risk assessment falls short of protecting biodiversity
Washington/Leipzig/Sydney. The pesticides, many of which are currently used in Europe and Australia, are responsible for reducing the regional diversity of invertebrates in streams and rivers by up to 42 percent, researchers report in the Proceedings of the US Academy of Sciences (PNAS). 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, analysed the impact of pesticides, such as insecticides and fungicides, on the regional biodiversity of invertebrates in flowing waters using data from Germany, France and Victoria in Australia. The authors of the now-published study state that this is the first ever study which has investigated the effects of pesticides on regional biodiversity.
Pesticides, for example those used in agriculture, are among the most-investigated and regulated groups of pollutants. However, until now it was not known whether, or to which extent, and at what concentrations their use causes a reduction in biodiversity in aquatic environments. The researchers investigated these questions and compared the numbers of species in different regions: in the Hildesheimer Boerde near Braunschweig, in southern Victoria in Australia and in Brittany in France.
In both Europe and Australia, the researchers 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 groups of species that are especially susceptible to pesticides. These mainly include representatives of the stoneflies, mayflies, caddisflies, and dragonflies and are important members of the food chain right up to fish and birds. Biological diversity in such aquatic environments can only be sustained by them because they ensure a regular exchange between surface and ground water, thus functioning as an indicator of water quality.
Protection concepts fall short of requirements
One worrying result from the study is that the impact of pesticides on these tiny creatures is already catastrophic at concentrations which are considered protective by current European regulation.
The authors point out that the use of pesticides is an important driver for biodiversity loss and that legally-permitted maximum concentrations do not adequately protect the biodiversity of invertebrates
in flowing waters. New concepts linking ecology with ecotoxicology are therefore urgently needed. “The current practice of risk assessment is like driving blind on the motorway”, cautions the
ecotoxicologist Matthias Liess. 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.
“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.
M.A. Beketov, B.J. Kefford, R.B. Schäfer, and M. Liess (2013):
“Pesticides reduce regional biodiversity of stream invertebrates”. PNAS, Early Edition. 17 June 2013, DOI: 10.1073/pnas.1305618110
Die Studie wurde von der Helmholtz-Gemeinschaft im Rahmen des Forschungsprojektes ECOLINK gefördert.
Helmholtz Centre for Environmental Research (UFZ)
Dr. Mikhail Beketov
Phone +49 341 235 1495
Dr. Mikhail Beketov
PD Dr. Matthias Liess
Phone ++49 341 235 1578
PD Dr. Matthias Liess
UFZ Press office
Tel.: +49 341 235 1635
Institute for Environmental Sciences
Jun.-Prof. Dr. Ralf B. Schäfer
+49 6341 280 31536
Centre for Environmental Sustainability, School of the Environment, University of Technology, Sydney (UTS), Sydney, Australia
Dr. Ben Kefford
Phone 61 2 9514 4087
Study: Pesticide authorisation procedures fail to adequately protect biodiversity in rivers (Press release 31 May 2012):
Pesticides pollute European waterbodies more than previously thought (Press release 13 October 2011):
At the Helmholtz Centre for Environmental Research (UFZ) scientists are researching the causes and consequences of far-reaching changes to the environment. They are concerned with water resources, biological diversity, the consequences of climate change and adaptability, environmental and biotechnologies, bioenergy, the behaviour of chemicals in the environment, their effect on health, modelling and social science issues. Their guiding theme: Our research contributes to the sustainable use of natural resources and helps to secure this basis for life over the long term under the effects of global change. The UFZ employs 1,100 people in Leipzig, Halle and Magdeburg. It is financed by the federal government and the federal states of Saxony and Saxony-Anhalt.
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