Wombat Roadkill Was Not Reduced by a Virtual Fence. Comment on Stannard et al. Can Virtual Fences Reduce Wombat Road Mortalities? Ecol. Eng. 2021, 172, 106414

SIMPLE SUMMARY: Wildlife roadkill is a global problem. Devices that produce bright lights and loud noises are claimed to be effective deterrents, but there is no scientific evidence that they actually prevent collisions between vehicles and wildlife. A recent trial in Australia installed a light and sound system, marketed as a ‘virtual fence’, and tested it on bare-nosed wombats (Vombatus ursinus). The study concluded that the system was minimally effective but promising. We detected a number of conceptual and procedural flaws in that study. When we re-analysed their data, we found absolutely no evidence for the effect of the virtual fence on the roadkills of wombats. ABSTRACT: The roadkill of wildlife is a global problem. Much has been written about deterring wildlife from roads, but, as of yet, there is no empirical support for deterrents based on visual and/or auditory signals. A recent paper entitled ‘Can virtual fences reduce wombat road mortalities?’reported the results of a roadkill mitigation trial. The authors installed a ‘virtual fence’ system produced by iPTE Traffic Solutions Ltd. (Graz, Austria) and evaluated its effectiveness for reducing roadkills of bare-nosed wombats (Vombatus ursinus) in southern Australia. The authors recorded roadkills in a simple Before-After-Control-Impact design but did not conduct any formal statistical analysis. They also measured three contextual variables (vegetation, wombat burrows, and vehicle velocity) but did not link these to the occurrence of roadkills in space and time. The authors concluded that the iPTE virtual fence system was ‘minimally effective’, yet ‘appears promising’. Our analysis of their data, using standard inferential statistics, showed no effect of the virtual fence on roadkills whatsoever. We conclude that the iPTE system was not effective for mitigating the roadkills of bare-nosed wombats.