Report on potential collapse of ravines hits North Toronto hard
Midtown ecosystems are suffering; local residents and the city are desperately searching for answers by Ron Johnson
Toronto’s ravines, which cover 17,000 acres, are valuable in so many ways. They provide essential ecological services, including flood protection and cleaning the air; they make our properties more valuable and provide abundant mental health benefits. And for a few kids that can peel their eyeballs from Instagram for an afternoon, they are an unparalleled place of recreation and imagination.
Yet if you head into any ravine in the Don Valley today, alongside a myriad of native species from towering oak to brightly coloured sumac there are invaders storming the flora gates. According to a new ravine study, the growth of invasive species is one of the main culprits pushing the ravines to the verge of collapse and putting at risk one of the city’s defining and most beloved features.
A few years back, TD Canada Trust valued the city’s urban forest at a whopping $7 billion. So why is the city letting it all happen?
Sure, Toronto has produced a ravine strategy, but it is, according to some critics, more focused on human connection to the ravine and less on the science that would preserve the ecosystems for future generations.
This new reality prompted a group of residents and forestry students to produce the Toronto Ravines Revitalization Study that has just been published. The study’s conclusion calls for, amongst other recommendations, establishing a Toronto Ravine Conservancy to better facilitate the much-needed restoration work before it’s too late.
But will the city allow such a thing to occur?
The study has a history that dates back more than 40 years when, the first battles occurred in Rosedale, pitting local residents against developers hungry to maximize the bottom line by edging their new apartment buildings as far down the slope of the Rosedale Valley Ravine as possible. Sound familiar?
It was a battle led by the South Rosedale Ratepayers’ Association and local resident Margaret Scrivener, who would go on to become an MPP and cabinet minister. (Scrivener Square was named to salute her work in protecting local ravines).
Her son Paul grew up tromping the ravine trails and got involved with the Toronto Field Naturalists when he was older. He soon became active in the North Rosedale Ratepayers Association and continued the same fight first led by his mother.
He and Dale Taylor initiated the first Rosedale Ravine Study, published in 1977, which looked at the Park Drive, Moore Park, Rosedale Valley and Burke Brook ravines in the Don Valley.
“We went out to the community and raised money, got corporate donations and got to work,” said Scrivener. “At the end of the day, we had a study. A scientific piece of work that counted and assessed and recognized there were invasive species.”
In 2014, Taylor and Scrivener, realized almost 40 years had passed and the ravines were getting worse, so they decided it was time to revisit their work. The new study was led by University of Toronto forestry students Eric Davies, a PhD student, and Anqi Dong, who has a masters degree in forest conservation.
The team limited their study to five different areas of the Don.
“The one thing that really jumps out is invasive species,” said Davies. Whereas the original study indicated a 10 per cent rate of invasive species, a few decades later that number had grown to 40. The chief culprits are Norway maple, dog-strangling vine, Japanese knotweed and garlic mustard.
Native plants have no natural defences against these invasive species and inevitably lose more
Clockwise from left: Paul Scrivener of the Toronto Ravine Study team, and two images of the park system that stretches along the ravines of the Don Valley