Turtles in Trouble: Habitat Loss, Road Risks, and Conservation Efforts at RBG

By Dr. David Galbraith, Director of Science, Royal Botanical Gardens

A Personal Reflection for International Turtle Day

Turtles are among the most familiar, and perhaps least-threatening, of wild animals you can regularly encounter in Ontario. There are eight different species of turtles native to Ontario, and at least another two that are showing up uninvited as released pets. These aquatic reptiles are crucial members of our wetland ecosystems, and places like Sunfish Pond and Cootes Paradise Marsh are important for them. The turtles here were one of the main reasons RBG was named an Important Amphibian and Reptile Area by the Canadian Amphibian and Reptile Conservation Network in 2008. Of the eight extant species of turtles in Ontario, RBG’s wetlands are home to four: snapping turtles, Midland painted turtles, northern map turtles, and Blanding’s turtles. Sadly, all of these species are at some risk of extinction in Ontario today. Snapping turtles, Midland painted turtles, and northern map turtles are listed as being of Special Concern (meaning they could slip further toward extinction if nothing is done). The Ontario population of Blanding’s turtles is listed as Threatened (could become Endangered), and across Canada the species is listed as Endangered. A sad roll call.

Why are all of these species under some degree of threat? The simplest answer is habitat loss. In many places wetlands that turtles depend upon have been damaged or destroyed. Turtles also face some dire threats because of human activities. They are particularly vulnerable to being injured or killed on roads by vehicles, and their nests are easily consumed by predators such as foxes, skunks, and coyotes. Once a population has been reduced by these threats it’s hard for them to recover. Unlike some animals that can adjust their reproductive rate when faced with low numbers (deer do that), turtles can’t ramp things up. Female turtles form their annual groups of eggs, or clutches, in consistent patterns and don’t seem to deviate year over year in their reproductive output. The adult females are particularly valuable to populations. Females of our largest species, snapping turtles, might reach maturity in our area in their early teen years and go on to produce annual clutches for another 50 or more years. Removing females from populations, which often happens in spring when they are out of the water looking for nesting sites, can quickly put a whole population at risk. Just how they survive at all is sometimes confusing.

For scientists, turtles present some fascinating mysteries too. I spent nearly a decade doing field work for my grad degrees at the Algonquin Wildlife Research Station. My first major project on snapping turtles there was to try to work out how old individuals were, and how the populations function mathematically, a science called demographics. From there I went on to using advanced DNA methods (for the time!) to work out which male turtles were reproducing successfully. Very esoteric, perhaps, but this work was aimed at an enduring mystery. Most turtles grow up from eggs that are neither male nor female when they are laid. Yes, turtle eggs are laid by their mothers without sex. The way a turtle develops, either female or male, is triggered by the temperatures it experiences in its egg during development. This kind of thing – environmental sex determination – is more common in plants and fish than in reptiles, but it’s real, and even 50 years after it was discovered, it remains unexplained. This mystery may be of great consequence for survival too. For years scientists have been concerned that changing environmental temperatures might result in too many males or females being produced, further putting vulnerable populations at risk.

Royal Botanical Gardens is actively helping turtles in our nature sanctuaries, and particularly Blanding’s turtles. Our Species at Risk team have been rescuing Blanding’s eggs laid in dangerous places, and with the help of Scales Nature Park, part of the Georgian Bay Turtle Hospital in Orillia, we’ve been protecting hatchlings and returning them to the wild. A large project completed in 2023 also was aimed at protecting turtles. RBG placed over a kilometer of protective fencing along Cootes Drive and other places to direct turtles away from roads. By addressing the risks, we can make a difference for these vulnerable inhabitants of RBG’s wetlands.