The toads of Lake Erie have a story to tell — if you have more than 24 years of attention to give them.
Every year as the spring weather begins to heat up, Fowler’s toads begin to crawl out from deep under the dunes in Long Point, Ont., on the shore of Lake Erie. As soon as the sand above them becomes warmer than the sand below them, they emerge from hibernation.
But after watching the toads for roughly two dozen years, David Green has determined that climate change is waking the amphibians from their slumber a little earlier in the season — at roughly the rate of half a day per decade. This early rise may be a sign of changes that could alter things such as pollination, migration and other factors integral to the working order of Ontario’s ecosystems.
"It makes active seasons for these animals longer, it makes it more habitable for warm climate-adapted species that may come in, it may assist in the spread of invasive species," says Green, a professor at McGill University and the lead author of a new study published in the journal Global Change Biology.
In his long period tracking the habits of these toads — he’s so familiar with the small population of Fowler’s that he can identify individuals by the speckles on their skin — Green has noticed that he can predict the timing of when they will emerge nearly two months in advance based on snowfall, rainfall and temperature. His predictions were so precise that he realized he could look at weather records dating back nearly 140 years in the area and estimate roughly when the toads would have emerged from hibernation over this period.
"What it means, I think, is that [toads] are quite reliable and predictable. We can understand what they do, which is useful," Green says.
Green says Lake Erie acts as a natural temperature stabilizer, but warming could be occurring more rapidly in other areas of the province.
"You’re looking at the kind of ecosystem change that ended the age of the dinosaurs."
In Long Point, the warmer weather could be helping to usher in invasive species such as the phragmites reed that has been eliminating key toad habitat along the shores of the lake and contributing to the amphibian's endangered listing in Canada.
It’s still unclear what waking up earlier means for the amphibians, but other hibernating species are having a tougher time with variable weather.
The rusty-patched bumblebee was historically one of the most common bumblebees found across the province, but the pollinator has almost entirely disappeared from Ontario. Jeremy Kerr, a biology professor at the University of Ottawa, says that warm weather brings the queens out of hibernation early, when they are more likely to be harmed by variable conditions.
"The bees that come out in the spring are all queens," Kerr says. "They are the weak link in the chain for conserving bumblebee species: if extreme weather kills the emerging queens, then that's it for the bees in the affected area."
Taking bees out of the equation can also result in under-pollinated crops, especially if the bees aren't around when flowers are blooming for staples such as tomatoes, berries and canola.
"The consequences that we are seeing are the beginnings of ecosystem chaos," Kerr says.
Climate change can sometimes open up new suitable habitat, but this isn't always a good thing. For monarch butterflies the warmer north can create conflicts as the insects are overshooting traditional summer areas and the ecosystems they contain. While the monarchs move farther north, the plants they need for food and breeding haven't necessarily caught up, leaving those butterflies without critical resources.
Extreme weather can also wipe out massive numbers of eastern monarchs, as happened this March when a sleet and ice storm hit the mountains in Mexico at the southern end of butterflies' yearly migration.
“It looked like we were going to see a monarch recovery this year, then a freak weather event came in and wiped out a bunch of the population," Kerr says.
For Fowler's toads, the warm weather to the north has yet to offer any solutions for range expansion. "These particular populations are largely stuck along the lakeshore because of their habitat requirements," Green says. "There isn't any habitat for them immediately to the north."
As well, Kerr says other amphibians in the province are suffering from dry weather. Some of the wetlands surrounding Ottawa are drying up this year, causing issues for reptiles and amphibians, including the endangered Blanding's turtles. If this trend lasts for a couple years in a row, that could wipe out many populations of animals.
"You can’t take water out of a wetland and keep wetlands species living there," Kerr says. In terms of the effects of climate change on whole ecosystems, he says changing precipitation levels and other climate change factors are having huge effects.
"You’re looking at the kind of ecosystem change that ended the age of the dinosaurs," he says.