Tasmanian Roadkill Research

Summary
Reduction of high levels of roadkill in Tasmania may be improved by warning signage for motorists, however, signage may be ineffective if the suggested speed is too high to allow animals to be detected and a collision avoided. I determined safe driving speeds to avoid collision with nine nocturnal Tasmanian mammals. Driving speeds slower than 80 km hr-1 allow timely detection of most species and species-specific night-time driving speeds can be implemented for vulnerable species.

Hobday, A. J. and M. L. Minstrell (2008). Distribution and abundance of roadkill in Tasmania: changing human behavior. Wildlife Research 35, number 7.
Wildlife Research: Management and Conservation Journal

Summary
An obvious sign of potential human impact on animal populations is roadkill. In Tasmania, this impact is perceived as relatively greater than in other Australian states, and is often noted by visitors and locals alike, such that calls for management action are common in the popular press. The goal of this three-year study was to assess the frequency and distribution of species killed on Tasmanian roads. Seasonal surveys were completed along five major routes, for a total of 154 trips. The seasonal occurrence, relationship with vehicle speed, and clustering in local hotspots for particular species all suggest that mitigation measures, such as vehicle speed reduction in specific areas, may be effective in reducing the number of animals killed. Mitigation measures, however, will not apply equally to all species and, in particular, success will depend on changing human behaviours.

Summary
This article summarizes the findings of the research paper above.
Many people agree Tasmania has a lot of roadkill; indeed it is one of the oft-heard comments from tourists departing Tasmania. Our recently completed research shows that an observant driver will likely encounter about one carcass every three kilometres along Tasmania’s major roads; rates are higher in late summer and autumn and lowest in winter. The amount of roadkill also varies regionally with more roadkill occurring on the Tasman Peninsula than in the Huon area. Brushtail possums, pademelons and wallabies were the most common roadkill. The study was undertaken to provide baseline information on the distribution and abundance of roadkill in Tasmania with the goal of supporting subsequent mitigation attempts: results show there are roadkill hotspots where focused mitigation measures such as speed reduction can be effective.

Summary
Driving past an animal carcass on the road is a stark reminder of the impact humans have on the environment. Concern for wildlife deaths on our roads is high among many Australians, but what can we do to reduce this problem?