Using road patrol data to identify factors associated with carnivore roadkill counts

Abstract

As the global road network expands, roads pose an emerging threat to wildlife populations. One way in which roads can affect wildlife is wildlife-vehicle collisions, which can be a significant cause of mortality through roadkill. In order to successfully mitigate these problems, it is vital to understand the factors that can explain the distribution of roadkill. Collecting the data required to enable this can be expensive and time consuming, but there is significant potential in partnering with organisations that conduct existing road patrols to obtain the necessary data. We assessed the feasibility of using roadkill data collected daily between 2014 and 2017 by road patrol staff from a private road agency on a 410 km length of the N3 road in South Africa. We modelled the relationship between a set of environmental and anthropogenic variables on the number of roadkill carcasses, using serval (Leptailurus serval) as a model species. We recorded 5.24 serval roadkill carcasses/100 km/year. The number of carcasses was related to season, the amount of wetland, and NDVI, but was not related to any of the anthropogenic variables we included. This suggests that roadkill patterns may differ greatly depending on the ecology of species of interest, but targeting mitigation measures where roads pass through wetlands may help to reduce serval roadkill. Partnering with road agencies for data collection offers powerful opportunities to identify factors related to roadkill distribution and reduce the threats posed by roads to wildlife.

Assumptions about fence permeability influence density estimates for brown hyaenas across South Africa

“…Natural barriers such as bodies of water and mountain ranges influence movement patterns and gene flow in wildlife populations 1 – 3 . Man-made physical barriers such as roads and fences similarly impact wildlife 4 – 7 . With the human population undergoing exponential growth and a continuing demand for ecotourism, enclosing wildlife in fenced areas is widespread in southern Africa 8 , 9 .…”

A Review of the Impacts of Roads on Wildlife in Semi-Arid Regions

“…A recent study of South Africa found that roadkill reports from citizen scientists broadly identified the same hotspots and taxonomic groups in roadkill as reports from trained observers, although there was a slight bias in citizen scientist reporting towards more charismatic and easy-to-identify species [143]. Nevertheless, these data sources can help identify areas and taxa requiring further investigation and mitigation measures [144].…”

“…Roads that run through woodlands, forests, wetlands, and over drainage lines where animals are likely to move across the road, or the road disrupts any movement corridors [144,148], or where there is remnant habitat along the road [8,94,96] are high-risk for a large number of species in both mesic and arid environments. Season is also important; Servals (Leptailurus serval) were more frequently killed on the road in the dry season, and where there were adjacent wetlands in South Africa [144]. Similarly, kangaroos are killed more often on roads through open plains than other places [62].…”

Spatio-Temporal Patterns and Consequences of Road Kills: A Review

“…The structure includes its materials, signs and markings. A considerable amount of research has been pursued on comparing AVCs in paved and unpaved roads [45,66,67]. The materials, themselves, do not typically affect the number of road kills in an area.…”