Implications des communautés végétales péri-agricoles dans la dynamique environnementale des pollutions par les pesticides

Abstract

Implications of field margin plant communities in the environmental dynamics of pesticides pollutions. Several types of regulations, at the European and national levels, advocate setting up vegetative buffer strips in order to control or prevent the contamination of ecosystems by agricultural pollutions. The specific implication of the plant communities that are part of the make-up of buffer zones will be assessed in the context of agriculture-linked pollutions by pesticides. The distribution of environmental contaminations involving pesticides and associated products shows that plant communities of vegetative buffer strips are confronted with chemical and xenobiotic stresses that show great fluctuations and complexity, with, among other characteristics, exposures to mixtures of low levels of pollutants. The physical and microbiological dimensions of plant action on the environmental dynamics of contaminating pesticides are well understood, but higher plants are also capable of efficient responses to chemical and xenobiotic stresses and of phytoremediation of pollutants. However, the direct phytoremediating roles of plants in vegetative buffer-zones have remained poorly appreciated, and the interferences that affect this capacity for phytoremediation are not fully understood either. It is therefore essential that integrative studies take into account the diversity of contaminants, the diversity of plant species that are used in buffer zones, their capacity to respond to organic xenobiotics under laboratory controlled conditions, and their ecophysiological behaviour under real field conditions. Such studies will be useful to optimize the depollution capacities of buffer zones in relation with the various modalities of contamination and combinations of pollutants.