The midland painted turtle, a common sight on the shores of lakes and rivers across southern Ontario, has been designated a species of special concern by the Committee on the Status of Endangered Wildlife in Canada (COSEWIC), meaning every turtle species in Canada is now at risk in some part of its Canadian range. According to a leading reptile biologist, it will take a concerted effort to think in “turtle time” to bring them back from the brink.
Tom Herman, a professor emeritus in the Department of Biology at Acadia University and co-chair of COSEWIC’s amphibians and reptiles subcommittee, says committee members were initially stunned when he suggested the midland painted turtle be listed at the group’s semi-annual species assessment meeting last month. How could a species often seen basking by the dozens on logs across Ontario be in danger?
“Just because biodiversity is common and widespread, it doesn't mean that it is safe from extinction,” Herman explains. “In fact, you don't have to be rare to be at risk.”
To understand the threats to the midland painted turtle population and other turtle species, Herman suggests thinking in “turtle time,” which means imagining conditions on Earth hundreds of years from now. The average midland painted turtle can live up to 45 years, and the next three generations could survive until the year 2150. In that time, the turtle could see its population decrease by up to 70 per cent, largely because of habitat loss and climate change.
“We have a mandated duty of care that extends beyond the time when many of our grandchildren and even great-grandchildren will no longer be alive,” says Herman.
Slow reptiles, fast world
Turtles are slow: slow to move, slow to mature, and slow to evolve. That makes them increasingly vulnerable in a world that is rapidly changing.
In the last 200 years, southern Ontario has lost more than 70 per cent of its natural wetlands to urban development, which has directly impacted the midland painted turtle population. Furthermore, roads are attractive to turtles, which will often bask on the warm surface of the pavement and lay their eggs in the soft gravel along the shoulders of highways. Large numbers of turtles are killed by vehicle strikes each summer, often before they have reached sexual maturity. Because midland painted turtles only lay small clutches of eggs, the death of even a few adults can have a major impact on population size.
Invasive species also pose a threat to the midland painted turtle. The red-eared slider, a semi-aquatic turtle native to the southern United States and Mexico, is a popular pet in North America, but when careless owners release it into the wild, it can transmit diseases to native turtles and compete for food.
The midland painted turtle is already a specially protected reptile under Ontario’s Fish and Wildlife Conservation Act; an assessment by COSEWIC means it’s now up to the Minister of Environment and Climate Change Canada to decide whether the species will be listed under the federal Species At Risk Act.
Herman says designating the midland painted turtle as a species of special concern is a precautionary measure intended to alert Canadians to the impact humans have on biodiversity.
“When we lose biodiversity, we are all the poorer. You can't replace it,” he says. “What’s taken millions of years to evolve has enriched our lives in many ways including support systems for our wellbeing. When we lose it, we lose a piece of ourselves.”