University of Queensland researchers have developed a mathematical framework to reduce the chance of wildlife meeting a grisly end on the world’s roads.
They have studied the global threat roads pose to biodiversity and provided a clear analysis of the return on investment for wildlife crossings.
Lead author and UQ School of Biological Sciences PhD student Tal Polak said the framework would help decision-makers around the world improve the cost-effectiveness of spending on conservation actions.
“Roads have a significant impact on wildlife worldwide, and mitigation can be expensive,” Ms Polak said.
“Roads contribute to the vulnerability of wildlife populations by reducing connectivity, altering animal behavior and causing animal deaths.
“The framework we have developed is a mathematical way of asking and answering a conservation question.
It can be adjusted for a range of species and systems to determine the best outcome for the budget.”
The researchers demonstrated the approach using a case study of a threatened koala (Phascolarctos cinereus) population living in habitat patches separated by roads on the Koala Coast near Brisbane in Queensland, Australia.
They investigated three options: do nothing; erect fences without wildlife crossings; and erect fences with wildlife crossings.
They found that the costs for 100 years of mitigation on less thank 8km of road could vary from 1.7million to 7 million.
“In this case study there was no “win-win” solution where we could achieve a good level of conservation for a low monetary cost,” said Ms Polak.
“However, it does show that the framework can be used to choose between different actions for each road and it finds the lowest cost option that will maintain or increase population size.”
Study co-author Professor Hugh Possingham, Director of the ARC Centre of Excellence for Environmental Decisions at UQ, said previous studies showed the impact of roads on populations of different species, or developed management actions that might reduce road-related mortality, but none had suggested how to choose between different actions.
“This new framework will allow decision-makers to clearly measure the trade-off between potential biodiversity benefits and economic cost,” he said.
“We hope this framework will be adopted by decision makers and applied to locations in need of mitigation in order to protect species threatened by roads all over the world.”
The research was published in the Journal of Applied Ecology on 2 April 2014.