Environmental DNA as a tool for detecting illegal wildlife trade

Abstract

The illegal wildlife trade presents significant challenges to wildlife conservation due to its large impact on population and species persistence. Forensic technology plays an important role in detecting and prosecuting such trade but has lagged human forensics where trace genetic evidence is important in conviction or exoneration. At present, most genetic applications in wildlife forensics focus on identification of taxa or populations via tissue samples or visible trace material (e.g., blood, hair or feathers). However, enforcement officials may encounter common household objects that are suspected to be used in capture, transport, or holding of wildlife, but without visible evidence of wildlife presence. Here, we demonstrate that environmental DNA (eDNA) techniques can be used to detect trace DNA from turtles on both plastic and fabric objects with high confidence for at least six months following only an hour of exposure. Sampling location and subsequent swabbing did not impact detection probability. While we observed very different DNA concentrations in the two substrate types, detection outcomes were relatively similar. The lack of substantial DNA decay during this experiment suggests a long window (potentially years) in which DNA may remain detectable to law enforcement officials under common gear storage conditions.