1 Scientific RepoRts | 5:12886 | DOi: 10.1038/srep12886 www.nature.com/scientificreports Glyphosate-based herbicides reduce the activity and reproduction of earthworms and lead to increased soil nutrient concentrations Mailin Gaupp-Berghausen 1 , Martin Hofer 2 , Boris Rewald 2 & Johann G. Zaller 1 Herbicide use is increasing worldwide both in agriculture and private gardens. However, our knowledge of potential side-efects on non-target soil organisms, even on such eminent ones as earthworms, is still very scarce. In a greenhouse experiment, we assessed the impact of the most widely used glyphosate-based herbicide Roundup on two earthworm species with diferent feeding strategies. We demonstrate, that the surface casting activity of vertically burrowing earthworms (Lumbricus terrestris) almost ceased three weeks after herbicide application, while the activity of soil dwelling earthworms (Aporrectodea caliginosa) was not afected. Reproduction of the soil dwellers was reduced by 56% within three months after herbicide application. Herbicide application led to increased soil concentrations of nitrate by 1592% and phosphate by 127%, pointing to potential risks for nutrient leaching into streams, lakes, or groundwater aquifers. these sizeable herbicide-induced impacts on agroecosystems are particularly worrisome because these herbicides have been globally used for decades. During the past 50 years the human population has more than doubled, while the productive arable area has increased only by 10% 1,2 . As a consequence, the intensity of agricultural production has increased dramatically including the use of pesticides. Among pesticides, glyphosate-based herbicides are most widely used - hardly available data state a global usage of about 650,000 tons 3 at sales worth about 6.5 billion US $ in 2010 4 . Glyphosate-based herbicides have been so widely used because they are very efec- tive, acting non-selectively on plants by inhibiting the shikimic acid metabolic pathway found exclusively in plants and some microorganisms 5 . Hence, animals should theoretically not be afected by the appli- cation of glyphosate. Moreover, glyphosate is considered environmentally friendly due to its fast degra- dation 5 and strong adsorption to soil particles that should reduce leaching losses from the soil proile 6 . Nevertheless, evidence that glyphosate-based herbicides can harm non-target organisms, particularly amphibians 7,8 , symbiotic mycorrhizal fungi or earthworms continues to mount 9,10 . Earthworms constitute a majority of soil faunal biomass in many temperate agroecosystems, with up to 1000 individuals and 300 g of biomass in each square meter of land 11 . hey act as ecosystem engineers 12 by physically shredding plant litter, mineralizing it in their guts (along with soil organic matter), and enhancing soil nutrient availability through the production of up to 40 tons of casts per hectare annually 13 that can promote plant productivity 14–16 . Earthworm burrowing also enhances soil 1 institute of Zoology, University of natural Resources and Life Sciences Vienna, Gregor Mendel Straße 33, A-1180 Vienna, Austria. 2 institute of forest ecology, University of natural Resources and Life Sciences Vienna, Peter- Jordan Straße 82, A-1190 Vienna, Austria. correspondence and requests for materials should be addressed to J.G.Z. (email: johann.zaller@boku.ac.at) Received: 02 february 2015 Accepted: 07 July 2015 Published: 05 August 2015 opeN