The effects on ecosystems of reduced pesticide use

QUÉBEC and MONTRÉAL - Pesticides affect the health of agricultural soils and waterways. But how do the living organisms in our ecosystems react if we reduce the use of these contaminants? Professor Valérie Langlois from the Institut national de la recherche scientifique (INRS) is seeking the answer to this question. Her team has just received nearly $1.3 million in funding from Fonds de recherche du Québec – Nature et technologies (FRQNT) and Ministère de l'Agriculture, des Pêcheries et de l'Alimentation (MAPAQ) to carry out this work.

"This knowledge, which up to now has been incomplete or lacking for pesticide mixtures, is key to supporting and justifying the transition to sustainable, environmentally friendly farming," says the ecotoxicogenomic expert Valérie Langlois. "We need to clearly show that reducing pesticide use has significant benefits for an ecosystem's soil and water and a limited effect on agricultural yield."

Professor Langlois pointed out that successful ecosystem restoration requires the use of biological indicators. This helps determine whether the measures implemented are effective and producing the expected results. "We need a clear understanding of what's happening now if we want to paint an accurate picture following changes in agricultural practices in Québec," she added.

Professor Langlois is conducting the study in collaboration with Professor Isabelle Lavoie from INRS, Annie-Ève Gagnon and Jacynthe Masse from Agriculture and Agri-Food Canada, as well as several other scientists and partners. The project, called AgriSolEau, is being carried out as part of Réseau québécois de recherche en agriculture durable (RQRAD).

From field to lab

Team members will travel to partner producers transitioning to organic farming. In the field, they will study ecosystem diversity and the accumulation of pesticides in the soil and organisms. They will also visit agricultural waterways to sample microscopic algae and invertebrates. These samples will be used to assess the health of the environment and measure the accumulation of pesticides in aquatic organisms.

Experiments will continue in the laboratory and in mesocosms—outdoor experimental systems that simulate a natural environment. Scientists will test how organisms respond to various pesticide reduction scenarios. They will monitor a series of biological indicators to measure how pesticides, alone or in mixtures, and their reduced use affect terrestrial and aquatic organisms.

"These controlled experiments will help us better understand the toxicity of pesticides and their mixtures to organisms and estimate their response to a change in agricultural practices," explains Isabelle Lavoie. "It will also help us target the pesticides or mixtures of greatest concern so better decisions can be made regarding their use."

Informed management of pesticide use

The knowledge gained from the project will have a significant impact on a number of fronts. It can be used to help agronomists and farmers better manage their fields by guiding them in choosing pesticides, the composition of mixtures, or the quantity to be used. This information will also be used to develop conservation criteria for natural environments and the organisms within them. The results of this project will also foster improved environmental monitoring using toxicity tests that complement what is currently available, to better assess the effects of pesticides on the environment.

This large-scale project promotes collaboration and knowledge exchange between scientists and agricultural stakeholders. Research activities will focus on building knowledge and applying it to user environments.