The presence of small animals on Minnesota’s roadways presents a public safety concern and negatively impacts wildlife populations. For the past four years, the Minnesota Zoo has partnered with the Minnesota Department of Transportation to test and evaluate the effectiveness of standard plans for small animal exclusion fencing, with the goal of redirecting turtles and small wildlife away from roadways and to existing through-road infrastructure where practicable. Wildlife can pose a significant threat on roadways, and driver avoidance of or direct collisions with small animals can result in substantial damage or injury, particularly for motorcyclists and bicyclists and those who stop to assist wildlife across roadways. Turtles are the focus of this research as their unique life histories and slow population growth rates make them particularly vulnerable to impacts from road mortality.
To address this, we implemented a before-after-control-impact study at 11 sites around the greater Twin Cities region during the 2018–2021 period. Our results showed that standard chain-link fencing (including trenching and wrap-around end treatments) can effectively reduce mortality of adult turtles. However, this design did not result in decreases in mortality of juvenile and hatchling turtles. After retrofitting fences with ½-inch wire mesh, we documented a substantial reduction in the mortality of all age classes (up to 91% over pre-treatment) of turtles, thereby demonstrating its utility as an effective mitigation strategy. The development and adoption of a vetted standard plan will increase efficiency, reduce costs, improve public safety, and reduce mortality of turtles and other wildlife on Minnesota roads.
