Soil biodiversity of agrosystems facing wide pesticide use in the Anthropocene



sol.jpg

14/02/20 - Séminaire d'Audrey BARRANGER

Le vendredi 14 février 2020 à 13h00, salle de conférences de l'OSUR, bâtiment 14b, Campus de Beaulieu, UR1

Soil biodiversity of agrosystems facing wide pesticide use in the Anthropocene

Environmental diffuse pollution by pesticides in agrosystems has become a major soil threat, however, large-scale monitoring studies on soil contamination are still very rare, especially on pesticides currently used. This results in a lack of information on the dynamics and fate of the contamination in the selected areas. Assessing the fate of pesticides from soil to biota inhabiting the surrounding landscapes is one way to determine the potential effect of these chemicals on ecosystem health. Our research objectives are to i) evaluate the relationships between soil contamination by pesticide residues and the intensity of chemical stress perceived by wildlife (soil fauna, birds) in agricultural landscapes and ii) study the impact of agricultural practices/management on earthworm communities. Pesticide residues have been quantified concomittantly in soil and earthworms of 27 french agricultural topsoils by LC-MS/MS. Our results raise concerns regarding soil biodiversity conservation and soil functions sustainability and should be considered for the ecological risk assessment of pesticide use.

Although soil engineer biodiversity declines in agro-ecosystems, we observed that certain endogeic species are still abundant and persist in intensively cultivated fields, suggesting they become tolerant to long-term anthropogenic pressure. Another part of our research is thus to i) provide evidence of an ongoing acclimation/adaptation through a multigenerational evolutionary toxicology experiment and ii) decipher the molecular mechanisms involved through an untargeted analytical strategy using new omic technologies. We present the first de novo transcriptome of the A. caliginosa species. Next steps are to identify the genes and proteins networks responsible for tolerance in A. caliginosa species. Our expectations are to progress in understanding the long-term impact of chronic exposure of soil engineers to low-dose multi-pollutants, and to assess the costs associated to tolerance for future population dynamics.

Contact : Audrey BARRANGER