Environnemental DNA: a methodological jump for biodiversity surveys

Abstract

Living organisms leave DNA fragments in their environment. Molecular biology tools allow amplifying specific DNA fragments. As a result it is possible to perform biodiversity surveys based on samples (water, soil, etc.) containing DNA fragments (called DNAe for environmental DNA) identified as belonging to a species. This method was used for the first time in France to carry out an inventory of the invasive American Bullfrog, Lithobates catesbeianus, as part of an eradication program. The results show a much higher efficiency of this new method to detect the species at sites where it is present at low densities. The DNAe method was also used in North America to detect Asian carps - which are invasive - in the Chicago canals. The method proved again to be very sensitive and more efficient than conventional methods (electrofishing). There are still methodological developments to be consolidated, but the potential of the DNAe method for biodiversity surveys and early detection of invasive species should be swiftly demonstrated in studies where it is currently used (e.g. aquatic mammals, crayfishes, amphibians, fishes).