Green roads and highways protect biodiversity : mitigating the impacts of national highways on habitat use/movement by wildlife in South Africa

Abstract

Transport infrastructure, in this instance, roads and highways, is a critical element of sustainable human economic development and society, however, when they are poorly built and designed they may have negative ecological impacts. Launching green transport infrastructure has become an important element of sustainable development frameworks and maintaining ecological connectivity between road-fragmented landscapes play a significant role in conserving wildlife populations. Poorly planned transport infrastructure development can have severe impacts on ecological connectivity and species survival. Roads can create barriers to wildlife movement, which limits the ability of terrestrial wildlife to find water, food, and mates. Furthermore, road fragmented landscapes accelerate incidents of wildlife-vehicle collisions, whilst these incidents almost always result in wildlife mortality, they also impact populations of threatened and endangered species. These impacts are particularly relevant in South Africa, which has diverse and robust wildlife populations and still transitioning to green economy. Therefore, the present study expands on previous research by emphasizing the urgent need for adopting road development projects that optimize social and economic benefits while safeguarding biodiversity and ecosystems through the consideration and inclusion of ecological connectivity. The present study has explored wildlife roadkill patterns and animal movement on South African national highways that intersects landscapes that are critical for biodiversity. Furthermore, we have evaluated the usefulness of existing road drainage underpasses that are not purposely built for wildlife using camera traps (bridges, culverts and tunnels) in helping animals to move across highways safely, so we can reduce roadkill incidents and improve landscape ecological functionality. Our findings are helpful to, (1) guiding monitoring and modifying existing under-road culverts for reducing road-related biodiversity effects in South Africa and (2) offering insights into the constraining variables that influence crossing structure index by wildlife. Lastly, our study promote the consideration and inclusion of ecological connectivity and biodiversity needs in road transport development sustainability frameworks in South Africa.