Mortality on the tracks: spatiotemporal patterns to rail‐kill in the Balule Nature Reserve, South Africa

Abstract

The global dependency on railways as an economical and environmentally‐friendly option for transportation is steadily increasing. Despite their numerous benefits, railways and train traffic can have negative impacts on wildlife, particularly through the risk of mortality due to collisions with trains, entrapment in rails, or electrocution at overhead powerlines. In most cases, these impacts are under‐investigated, thus remain unmitigated. In this study, we describe patterns of rail‐mortality of the local fauna in Balule Nature Reserve, South Africa. In addition to exploring which species are most vulnerable to rail‐mortality, we explore the role that seasonal variation, the daily activity patterns of the species, and the surrounding habitat type have on the occurrence of wildlife‐rail‐mortality. From 25 May 2020–29 March 2021, we conducted carcass surveys over three 5 km railway segments, corresponding to the three dominant habitat types in the nature reserve: open grassland, open woodland and mixed shrubland. Each 5 km segment of railway was surveyed during the wet season (November–March) and the dry season (May–September) to account for seasonal variation. We recorded 99 rail‐kills, of which 29% were mammals, 26% were birds, 26% were reptiles, and 18% were amphibians. Mammal carcasses were found most frequently in the dry season, while amphibians were only detected in the wet season. Amphibian carcasses were all nocturnal species, while diurnal species dominated the bird carcasses found. Finally, most rail‐kill carcasses were found in mixed shrublands, while open woodlands had the lowest frequency of rail‐kill. The detrimental impacts of railway‐mortality on wildlife may be more pronounced in areas of high conservation value, such as nature reserves, and it is essential to study and mitigate these impacts, in order to foster successful co‐existence of wildlife and humans in the landscape.