While many species have adapted and evolve to cope with the stresses of city life and rapid urbanization, others are not so lucky. Losing their natural habitats to roads, and their lives to dog-attacks and road incidents, koalas are counted among the least adapted animals to urban life leading to their listing as threatened species in three Australian states (Queensland, New South Wales and the Australian Capital Territory), despite their iconic and beloved status. Where residential developments meet koala habitats, the threat is especially high. However, after the Queensland’s Department of Transport and Roads sponsored an urban design initiative to find solutions one of the main reasons of koala deaths, road collisions, a recent evaluation study gives hope to the dwindling marsupial numbers.

Identifying several sites in Brisbane and Redland Bay, where significant koala populations live alongside busy roads, the project sought to prevent koalas from crossing car-laden streets. While there are several existing methods to ensure the safety of animals crossing streets, they need to be built during road construction and not retroactively. Fences were ruled out, as they prevent the free movement of animals and habitat fragmentation can harm the species. Taking advantage of existing infrastructure, the project looked to culverts – sturdy concrete pipes designed to facilitate the flow of water under roads and bridges – and bridge underpasses as a potential route for wild animals. However, most wildlife is reluctant to get wet but the project’s initiators found a simple solution – tiny ledges above the water.

animals urban design

Courtesy of Griffith University.

The results from this simple fix were overwhelming. Within weeks, wallabies, possums and goannas had found and used the ledges to cross safely under busy streets, as researchers from the Griffith University found out by monitoring local wildlife. As these animals are inquisitive in nature, the bigger surprise came from the number of koalas – who almost exclusively travel via treetop – which also found the safe subterranean routes and successfully avoided potentially fatal situations on the ground. 130 cute koalas were captured using the ledges and “[t]his was something no koala had ever been required to do before. The simplicity of the structure and the willingness of the koalas to try something new really does offer a glimmer of hope for all. It shows that it is possible to design an urban environment where koalas can learn to coexist with people,” Phys.org explains.