Activity patterns and mortalities of wildlife along the Phalaborwa – Hoedspruit railway line in Balule Nature Reserve, South Africa.

Railways are essential transportation corridors that facilitate the movement of goods and people with important environmental and economic benefits. Despite these benefits, railways and trains can negatively affect wildlife through mortalities, barrier effects, disturbances, and habitat loss. There is growing evidence that human activity negatively affects the spatial distribution of wildlife with distance from the infrastructure and wildlife also adjust their spatiotemporal activity to avoid or minimize encounters with human activity. Moreover, wildlife mortalities due to collisions with trains are a major conservation concern that can jeopardize the persistence of wildlife populations as wildlife-train collisions are non-specific concerning the species, age, and sex of the animal affected.
In this study, I assessed the activity patterns of six medium-large sized mammals (African buffalo, African elephant, Giraffe, Impala, Lion, and Spotted hyaena) and monitored the mortalities of wildlife from four different taxonomic groups on the landscape bisected by the railway line in Balule Nature Reserve. Impala and giraffe occurrences on the railway line are mostly diurnal. Meanwhile, lion occurrence on the railway line is mostly nocturnal. Four of my focal species moderately overlapped with train activity, with no seasonal differences in their degree of activity overlap. African buffalo and elephant activity decreased with increasing distance from the railway line. Giraffes, impala, and lions are less active around the railway line in the wet season than in the dry season. Spotted hyaenas are more active around the railway in both open grassland and woodland compared to the mixed shrubland habitat intersecting the railway.
I recorded a total of 99 rail-kills from a total of 450 km surveyed over a 90-day period. Of these rail-kills, mammals were recorded more often (29.29%), followed by birds (26.26%), reptiles (26.26%), and amphibians (18.18%). There was no significant difference in the frequency of mortalities on the railway line between seasons (U = 286.5, n = 49, p = 0.421). The rail mortalities of diurnal did not differ significantly from nocturnal species (x² = 0.55, df = 1, p = 0.458). There were significantly more mortalities of diurnal species than nocturnal species on the railway line during the dry season (p < 0.05). Most encountered deaths on the railway line occurred in a mixed shrubland section but there was no significant association between the frequency of rail mortalities and rail-side habitat type (H = 0.84, df = 2, p = 0.657).