Warm winter a concern for plants and animals, ecologist says

The unseasonably mild weather may make winter more bearable for Toronto's human inhabitants, but it's confused the lifecycle of the city's plants and animals.

• December warmest on record across province, including Toronto

Earlier this month, Environment Canada reported that December was the warmest on record across most of Ontario, including Toronto. The city beat its previous record for mean temperature for December by two degrees, the federal agency said.

While a lack of snow and freezing temperatures make commuting easier and allow residents to comfortably spend more time outdoors, plants and animals are being adversely affected by the unpredictable weather cycles.

"You do feel a little bit of concern," Sarah Mainguy, an ecologist with environmental consulting firm North-South Environmental, told CBC's Metro Morning on Wednesday.

"For instance, I saw a Mourning Cloak come out, a butterfly that normally breaks out in the very first part of the spring and I saw one in December. And you wonder, if that species is flying around in December it's losing a lot of energy, there are no flowers for it, and how many insects are doing that?"

Metro Morning6:38Warm winter impact

Talk about a warm spell! We look at why this unseasonably mild winter is confusing the city's plants and animals.

Faster-blooming plants are more likely to go into shock and die in the midst of a continuous freeze-thaw pattern, according to Mainguay.

And so the insect population could be diminished if bugs come out but don't have plants to feed on, she said.

"At this time of year we're watching for things to go dormant," Mainguay said, noting that trees typically drop their leaves and snakes go underground to hibernate.

"In December, a lot of those kinds of things weren't happening yet."

Snakes, for instance, need very particular conditions for hibernation sites, including a certain humidity level. A snake she noticed in December had clearly gone above-ground during a warmer period but got stuck during a snap freeze.

"This poor creature was sort of immobile because it couldn't move, because it was too cold," Mainguay said.

Overall, many native plants won't bloom early because they are programmed to need a certain amount of winter chill before they break dormancy and bloom again, she said.

But some non-native European species are likely to be thrown off because they are typically ready to bloom as the ground begins to thaw.

"You might see some buds come out on things like lilac, forsythia, some of the non-native horticultural species, but they are pretty well-programmed to be able to adapt to losing some leaves if there is a late frost," Mainguy said.

"In the natural world, a few flowers being killed off on trees may not be that big of a problem, whereas if you have a fruit crop, you don't want to lose buds because they set fruit later."

Meanwhile, for residents who have noticed a lot of overweight squirrels running around, Mainguy says they will be just fine.

"Squirrels are adapted to going in and out of dormancy," she said. "They don't really hibernate properly."