Study shows that highway expansion affects turtles and plants

It’s intuitively obvious that modern infrastructure development affects local ecosystems.

This is now supported by Georgian Bay Biosphere’s Lands and Waters Coordinator Brooke Carroll, who gathered evidence as part of her master’s research.

Brooke’s research focused on how major highways and transmission line corridors, including an area where a transmission line runs along a highway through Magnetawan First Nation lands - affected local turtle and plant species.

Working in close partnership with Magnetawan First Nation community members and taking a whole ecosystem approach was essential, she recently told the Parry Sound Nature Club, in order to provide credible results that can help inform land management decisions.

Her team’s goals included determining if highway expansion affected turtle species, as well as finding the best way to trap and release turtles (valuable information for monitoring turtle populations in future conservation efforts).

In testing a range of turtle traps around highway expansion areas, Brooke’s team confirmed that the larger the trap, the larger the turtle it could catch! Likewise, smaller traps could catch smaller turtles. The team also found that they could catch more turtles in early spring, when turtles are emerging from hibernation and their food sources are scarce.

In total, the team successfully caught 772 turtles! A significant portion of the turtles (165, i.e. more than a fifth) were in highway expansion areas, putting their survival at risk.

Brooke took a systematic approach to study the effect of highway development on plant diversity. She focused on highways through Magnetawan First Nation. As usual, these highways had transmission lines running along them. Such areas are frequently cut down and sprayed to keep the space clear of significant vegetation growth.

In general, ecologically speaking, the more diverse the local plant population, the healthier the ecosystem. Brooke compared the number of plant species and families in 50 plots of land in each of three areas: between the highway and the transmission line, directly under transmission lines, and outside transmission lines.

Brooke found 62 plant species belonging to 34 different families in total. The closer to the transmission line, the lower the number of plant species. The opposite was also true—the further away from the highway and transmission lines, the more plant diversity. Plus, invasive species were more common in disturbed areas.

Land planners and governments take note: infrastructure development affects our environment.