Why did the snake cross the road?

Preserving biodiversity is an important aspect of Canada’s commitment to protecting conservation areas. Locally, snakes are part of a diverse, natural ecosystem on NCC-managed conservation lands. Graduate student Andrea Gigeroff is leading a study supported by the NCC to determine the impact of road density on snake populations in the National Capital Region.

Key concepts

• Road density is the ratio of the size of a road to the size of a given area. The more roads there are, the more the habitats are fragmented.
• Habitat fragmentation is the division of a natural habitat into smaller and more isolated pieces.

Andrea’s study focuses on garter snake and red-bellied snake populations across several sites with differing road densities in the Greenbelt and Gatineau Park. These species are harmless and non-venomous. The goal is to model this relationship to understand how fragmentation effects from road development can impact local species.

Snakes often move across roads in the spring and fall. In the spring, they leave their preferred winter retreats — often the same ones used each year — and move to productive natural areas to bask, feed and reproduce during the summer. Habitat fragmentation can impede these annual movements.

The study started in 2020, and is planned to be completed by 2021.

Andrea assesses snake populations by providing them with warm, sheltered habitat. Flat plywood boards are placed in study sites across meadow habitats in the Greenbelt and Gatineau Park. Snakes can bask on the top of the board or hide underneath the board, as the ground stays warmer and the board provides shelter. Every week throughout the summer and early fall, Andrea and her staff monitor these boards for snakes. These methods are often used to estimate snake population sizes.

Andrea Gigeroff is a first-year master’s student in the Herpetology Lab of Gabriel Blouin-Demers at the University of Ottawa. Andrea did her undergraduate degree at Dalhousie University, where she worked in the Simpson Microbial Evolution Lab. She has had a lifelong passion for snakes and other ectotherms, and appreciates the challenges that come with being cold-blooded. She hopes her work can be used to help preserve natural habitats for snakes and other reptiles.

Report your snake sightings on NCC-managed land on inaturalist.ca. Citizen science is an important tool for conservation!