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In cities like Toronto where ravines and valleys define the landscape, what we imagine is unspoiled wilderness is being constantly changed by urbanization, non-native species and pollution. Here, a naturalist and an illustrator show you what to look for

The story of Toronto’s ravines and valleys, like that of urban nature nationwide, is not one of preservation but of transformation. The trails we hike are often the abandoned roads of early industry, and the trees that line them grow atop long-buried garbage dumps, decommissioned mills and factories, and exhausted agriculture fields. The very greenery that surrounds us so too has been transformed. Our native oaks, beech and hemlocks now find themselves standing shoulder to shoulder with Norway maples, Siberian elm and Japanese knotweed. The once vibrant and rich understory that might have flourished here now mixes with a green desert of invasive and exotic plants, pretty to look at but of little ecological value.

What nature has actually survived the centuries is not one-fifth of a city. It is old-growth trees so few we’ve given them individual nicknames. It is tiny ponds hidden between highways and slopes too steep to build on. It is small patches of plants now so rare that those who pass them by don’t even know what they’re called. And their future will be decided by the most dangerous turn of phrase in urban ecology: “finding balance.”

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The magic and the mystery of Toronto’s ravines

Every day we are asked to surrender just a little bit more of our existing nature. Turn a field where hawks hunt in to a sculpture garden. Clear a path for a train yard. Plant a few more trees hailing from mid-west America to replace some old growth removed during sewer repair. Carve a new bike trail through the habitat of ground-nesting birds. Believing that the nature we experienced as children is the baseline of what is natural, it’s perhaps easy to see such compromise as a small ask. The problem is that by the time most of us were born our ancestors had already destroyed about 90 per cent of our historic wetlands, forests, meadows and savannas, and driven many species to extirpation or extinction. At every step in that journey they too were asked to “find balance” between our rising urbanity and the natural world.

The scraps of habitat we have left in places such as our ravines still gives nourishment and shelter to the thousands of species of flora and fauna that live and breed in our city, and makes migration possible for countless others. In exchange, we are given cleaner air, cleaner water and experiences that benefit our health and well-being that are impossible to accomplish any other way. You cannot go bird-watching in an art gallery. The solitude of a wooden glen cannot be replaced by potted plants at the mall. A bubbling fountain is not a babbling brook. It’s long past time that the balance we seek tipped in nature’s favour.

Now, to demonstrate how the ecological and urban balance of a ravine works, let’s take a tour through the imaginary one we showed you above, piece by piece. Here’s an enlargeable version of the whole thing by illustrator Kathleen Fu.

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