By: Tony Carnie
Durban - Apart from ending up as ‘roadkill’ as they try to dodge heavy trucks and speeding cars, several species of South African wildlife are also being isolated in smaller patches of virgin land because of the ever-expanding human footprint, with road infrastructure acting as a further physical barrier to their need to disperse, migrate or breed elsewhere.
To mitigate some of these impacts, the Endangered Wildlife Trust has just published a new handbook titled The Road Ahead: Guidelines to mitigation methods to address wildlife road conflict.
Authors Wendy Collinson and Claire Patterson-Abrolat acknowledge that it could be very complicated to redesign roads to become more wildlife-friendly.
Roadside fences, for example, may seem like a good idea to reduce the number of wild animals getting killed or maimed.
But, as they point out, animals need to disperse - so man-made fences can create more problems than solutions in many cases.
Other physical barriers, such as concrete bollards, help to reduce the risk of head-on collisions between vehicles. Yet for small animals like frogs or tortoises, these barriers make it impossible to reach the land on the other side of the road.
Collinson and Patterson-Abrolat have suggested a number of compromises.
It might make more sense to keep roadside fences in some places, but to leave gaps in fences to allow animals to escape if they manage to bypass the fence and get trapped next to a busy road.
Concrete barriers to avoid head-on collisions could be redesigned to incorporate gaps that allow small animals to pass through.
On a more ambitious scale, the handbook also raises the possibility of building new overpasses and underpasses that allow small and large animals to cross safely over or under busy highways.
Examples from other countries include the Wolverine Bridge which crosses over the Trans-Canada Highway in Banff National Park or the Hilversum “Green Bridge” in Holland, the longest wildlife overpass in the world.
These bridges are covered with soil, rock and vegetation to create artificial wildlife corridors.
Similar, but more modest examples include underpass bridges in Kenya that allow elephants to pass beneath the Nanyuki-Meru highway.
This scheme also includes a 14 kilometre wide fenced corridor that allows elephant to move between two game reserves.
For smaller creatures, tunnels can be incorporated into new road designs to allow snakes or frogs to cross in safety.
Other mitigation strategies in the handbook include lower speed limits and innovative signboards to raise public awareness or alert drivers to particular species in certain areas.
Neil Tolmie, the chief executive of the N3 Toll Concession which helped to sponsor the handbook, said: “The world is in need of leaders to pioneer new processes and techniques that will ensure a balance between development and environmental conservation.”