Talk Lowlevel fences reduce roadkill at hotspots: a South African example

A wide variety of mitigation measures are deployed to reduce wildlife mortality on roads, but few of these have been tested in South Africa, where road ecology is still an emerging field. During baseline roadkill surveys conducted in 2009 in the Greater Mapungubwe Transfrontier Conservation Area (GMTFCA), a UNESCO World Heritage Site in Limpopo province South Africa, we identified the presence of a roadkill hotspot. Such hotspots are characterized by higher than average concentrations of roadkill and therefore provide an opportunity to initiate targeted mitigation measures with relatively high potential impact. In early 2015, we investigated the efficacy of roadside barriers in reducing mortality frequency of small terrestrial vertebrates in the hotspot. We erected low-level fencing by the roadside to direct wildlife towards existing culverts beneath the road, and compared mortality frequency before and after the intervention. We observed a sharp decrease in the concentration of roadkill events where the barriers were erected (from 0.23 roadkills/day/km to 0.04 roadkills/day/km), as compared to control sites, although this decline was not quite significant (Friedman’s test, χ2 = 0.1, p = 0.09), probably due to the small sample size. Our results suggest that low-level fencing can reduce the incidence of roadkill for small terrestrial vertebrates, although its potential negative effects, for example on population connectivity, still need to be investigated.

protocol, roadkill, vertebrate, hotspot, barriers, culverts.