GM Free Cymru

Pesticides reduce regional biodiversity of stream invertebrates

Date Added to website 12th July 2013

Mikhail A. Beketov, Ben J. Kefford, Ralf B. Schäfer, and Matthias Liess

Proc Nat Acad Sci USA. • vol. 110 no. 27, 2013, pp 11039–11043

Edited by David Pimentel, Cornell University, Ithaca, NY, and accepted by the Editorial Board May 13, 2013 (received for review March 25, 2013)

[Note from GM-free Cymru: this is a highly relevant and important article which documents the damage done to stream ecology and to biodiversity by pesticides introduced into the environment even at permitted levels. Of course we know that pesticides are toxic -- that is why they are used by farmers. But the chemical and farming industries try to maintain the pretence that most pesticides are narrow-spectrum or species-specific, knocking out just the pests that farmers worry about. Not so. Non-target species are almost always affected and the environment is almost always damaged when sprays and other forms of application are used. There are several lessons here. One, permitted pesticide levels are too high, almost everywhere in the world. Two, the use of GM crops with their cocktails of associated chemicals is most definitely bad news for the environment. Three, it would be foolhardy in the extreme to add to the pollution load that the environment lad that the environment has to carry, given that some of the most sensitive environmental indicators (aquatic invertebrates) are significantly affected -- and what happens at the bottom end of the food chain has a habit of working its way up towards the top, unless steps are taken to arrest the insiduous poisoning of our land. water and air.]


The biodiversity crisis is one of the greatest challenges facing humanity, but our understanding of the drivers remains limited. Thus, after decades of studies and regulation efforts, it remains unknown whether to what degree and at what concentrations modern agricultural pesticides cause regional-scale species losses. We analyzed the effects of pesticides on the regional taxa richness of stream invertebrates in Europe (Germany and France) and Australia (southern Victoria). Pesticides caused statistically significant effects on both the species and family richness in both regions, with losses in taxa up to 42% of the recorded taxonomic pools. Furthermore, the effects in Europe were detected at concentrations that current legislation considers environmentally protective. Thus, the current ecological risk assessment of pesticides falls short of protecting biodiversity, and new approaches linking ecology and ecotoxicology are needed.

Biodiversity: Even at 'safe' levels, pesticides are having catastrophic impacts on aquatic ecosystems

Posted on June 18, 2013 by Bob Berwyn

Study documents dramatic regional decline of insect species

By Summit Voice

SUMMIT COUNTY — After studying ecosystems contaminated with pesticides, scientists say they've been able to measure a dramatic loss of invertebrate biodiversity in polluted streams and rivers.

The study is one of the first to document the toxic effects of pesticides at a regional ecosystem level, rather than exptrapolating toxicity from lab tests.

"The current practice of risk assessment is like driving blind on the motorway", said ecotoxicologist Matthias Liess. "To date, the approval of pesticides has primarily been based on experimental work carried out in laboratories and artificial ecosystems."

The research looked at areas in Germany, France and Australia to get a global context and a regional perspective. In the European areas, the number of species in polluted rivers and streams dropped by 42 percent; in Australia, by 27 percent.

Stoneflies, mayflies, caddisflies and dragonflies were especially hard-hit. They are particularly susceptible to pesticides and are key species in the aquatic food chain, sustaining fish and birds.

The study results, published in the Proceedings of the National Academy of Sciences, suggests that the threat to biodiversity from pesticides has obviously been underestimated in the past, the researchers said.

The study shows that impact to insects and their ecosystems is catastrophic even at levels deemed safe by existing regulatory schemes, with legally-permitted maximum concentrations that don't adequately protect the biodiversity of invertebrates in flowing waters.

New concepts linking ecology with ecotoxicology are urgently needed, the scientists said.

"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," Liess said.

"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," Liess said.

Scientists involved in the study include: Mikhail A. Beketov and Matthias Liess from the Helmholtz Centre for Environmental Research in Leipzig, together with Ben Kefford from theUniversity of Technology, Sydney and Ralf B. Schäfer from the Institute for Environmental Sciences, Landau.