Save Toronto’s dying ravines
One of the splendid benefits of living in Toronto is that respite from the noise, traffic and crowds of the big city can easily be found on the trails winding through its quiet ravines.
Indeed, if one was to walk through Toronto, one in five footsteps would fall within the ravines that cover such a great swath of the city.
So a study that found that these seemingly green and lush refuges are, in fact, on the edge of ecological collapse is alarming.
Indeed, the innocuously named “Toronto Ravine Revitalization Study: 1977-2017,” should light a fire under City Hall. Not only to preserve the ravines, but to invest in their regeneration. There’s no time to lose.
The ravines are already “in the full throes of a massive decline,” according to Eric Davies, one of the authors of the study.
The evidence comes not so much from what people see on their quiet ravine walks, but what they don’t see. Plants, mammals, birds and insects are all disappearing from the ravines. They’re being crowded out by invasive species.
In the tree canopy, Norway maples, for example, are pushing out native sugar maples.
At ground level, invasive plants, such as Japanese knotweed, garlic mustard and dog-strangling vine now cover more than 95 per cent of the forest floor.
On hillsides, where herbaceous plants, shrubs and seedlings should be tethering the soil, sometimes there is nothing at all, says Davies, who refers to them as hills of destruction.
And the declining health of native species of trees puts many bird species and small wildlife who have depended on them over the ages at risk.
“Native birds, small mammals, invertebrates and other native plants are not able to establish effective populations in ecosystems dominated by these invasive species,” the report warns.
Conifers, which offer shelter to owls and other birds in winter, are in decline, as are the hickory trees that produce nuts for small mammals such as flying squirrels. Also in decline are large, old trees, which provide nesting spots for tiny songbirds to woodpeckers.
Toronto is not alone in facing the loss of wildlife because of the rapid decline of natural areas. The World Wildlife Fund warned in its 2018 Living Planet Report that over the last four decades, mammal populations in Canada have dropped by 43 per cent, amphibian and reptile populations by 34 per cent, and some types of birds have lost up to 69 per cent of their populations. But Toronto can take actions to halt the decline of its ravines. Faced with a similar challenge, the study’s authors point out, New York City just approved a 25-year, $385-million program to restore its natural areas, which are only half the size of the Toronto ravines.
If Toronto took a similar path, it “could be home to the world’s greatest ‘urban ecosystems’ — an outdoor Louvre of wilderness, biodiversity and recreation.”
It will take money and a long-term commitment. The ravine study estimates it will take one to two decades of work by biologists, pathogen and invasive species experts dedicated to planting native species and removing the invasive ones.
Toronto’s residents should be concerned about the city’s ravines because they provide recreational, economic and ecological benefits, Davies says. But for plants and animals that depend on the native plant species that are dying out, it is a life or death situation. “In terms of biodiversity, this is the Mothership, this is where everything is.”
Toronto council needs to take steps now to protect the ravines for its residents who need a wild respite from urban life, and the plants and creatures who have no other home.
New York City just approved a 25-year, $385-million program to restore its natural areas, which are half the size of Toronto’s