A Few Large Roads or Many Small Ones? How to Accommodate Growth in Vehicle Numbers to Minimise Impacts on Wildlife

Roads and vehicular traffic are among the most pervasive of threats to biodiversity because they fragment habitat, increasing mortality and opening up new areas for the exploitation of natural resources. However, the number of vehicles on roads is increasing rapidly and this is likely to continue into the future, putting increased pressure on wildlife populations. Consequently, a major challenge is the planning of road networks to accommodate increased numbers of vehicles, while minimising impacts on wildlife. Nonetheless, there are currently few principles for guiding decisions on road network planning to reduce impacts on wildlife in real landscapes. The authors addressed this issue by developing an approach for quantifying the impact on wildlife mortality of two alternative mechanisms for accommodating growth in vehicle numbers: (1) increasing the number of roads, and (2) increasing traffic volumes on existing roads. They applied this approach to a koala (Phascolarctos cinereus) population in eastern Australia and quantified the relative impact of each strategy on mortality. They show that, in most cases, accommodating growth in traffic through increases in volumes on existing roads has a lower impact than building new roads. An exception is where the existing road network has very low road density, but very high traffic volumes on each road. These findings have important implications for how road networks are designed to reduce their impacts on biodiversity.


  • English

Media Info

  • Media Type: Print
  • Features: Figures; References; Tables;
  • Pagination: e91093
  • Serial:
  • Publication flags:

    Open Access (libre)

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Filing Info

  • Accession Number: 01526112
  • Record Type: Publication
  • Files: TRIS
  • Created Date: Apr 18 2014 12:59PM