Using iNaturalist to assess road mortality in Northern Map Turtle (Graptemys geographica) in Canada

Abstract

Many species of freshwater turtles are negatively affected by road mortality. Although the mostly aquatic behaviour of
Northern Map Turtle (Graptemys geographica) may reduce road mortality, the magnitude and spatial extent of this threat are poorly understood. We assessed road mortality in this species using iNaturalist Canada data. We found 244 observations of Northern Map Turtles on roads in Canada, spanning most of the Canadian range of the species. Not surprisingly, more turtles found on roads were dead (n = 160) rather than alive (n = 84). Over 60% of observations occurred in June, which corresponds with the nesting season. Road mortality appears to be widespread and to affect adult female Northern Map Turtles more than males or juveniles.