This is how your yard is like a park
What is the value of a caterpillar?
For humans, it’s often a negative, “ick-factor” value.
For a chickadee, the value is equivalent to over 200 aphids (which mean using a lot more energy flying back and forth to the nest). Caterpillars are the No. 1 choice, especially this time of year when young birds are feeding to beat the band. We assume an unspoken responsibility for the caterpillar population when we own real estate. And your real estate links to other green spaces as near as the other side of your fence: your neighbours’ property.
Together, our private green spaces could become the largest national park in the country.
That is, we could create Canada’s largest park if we changed just a few things about our behaviour and priorities concerning our land, trees and water. Environmental conservation is what we’re talking about here.
The conversation about conservation has shifted in recent years — among environmentalists, especially — to the dual crises of climate change and biodiversity loss. These connections are made by American entomologist Doug Tallamy in his most recent book, “Nature’s Best Hope: A New Approach to Conservation that Starts in Your Yard” (Timber Press, February, 2020).
This book explains in plain language why we need to create more biodiversity in our yards and provides plenty of actionable advice. Starting with insects, “the little things that run the world,” quoting U.S. biologist Edward Osborne Wilson.
A couple of statistics from Tallamy’s new book: 950 million acres. That is how much virgin forest was cleared to settle the eastern half of North America. Now consider this statistic: Our invertebrate population, which is predominantly insects, has fallen 45 per cent around the world globally since 1974.
In the chapter “The Importance of Connectivity,” Tallamy explains how our food web is built upon insects. Not only do they pollinate 87.5 per cent of all plants, and 90 per cent of flowering plants, they are also the primary source of nutrients for many vertebrates.
For example, 96 per cent of land-based bird species rear their young on insects rather than seeds or berries — insects that are rich in proteins and fats. This is particularly important when bird parents are feeding their young.
A pair of adult downy woodpeckers, to give you an idea, forage more than 4,000 insects a day while their hatched kids (sometimes up to seven) are in the nest for up to 10 days.
It sounds exhausting, right? Well, here’s how you can lend a hand: cultivate plants that support insect populations. These plants are overwhelmingly native species. A native oak, for example, can provide host to 454 different caterpillar species. Many exotic, imported tree species, like ginkgo trees, support none. No caterpillars, no chickadees.
This is true of shrubs and berries, as well. Berries from exotic species such as glossy buckthorn bush, Japanese honeysuckle and multiflora rose are high in sugar and contain less than 1 per cent of fat at a time of year when birds are seeking fats for migration and over-wintering. By contrast, native plants such as Virginia creeper, wax myrtle, arrowwood viburnum, spicebush and grey dogwood produce berries with roughly 50 per cent fat.
Where do we put these plants? For starters, national parks — as well as provincial and municipal parks — are not enough. As an example, 86 per cent of all land in the U.S. is privately owned.
Clearly, your yard is important and one of the many key pieces in Tallamy’s vision of a “Homegrown National Park.”
The author asks: “What if each landowner made it a goal to convert half of his or her lawn to productive native plant communities? In the U.S., even moderate success could collectively restore some semblance of ecosystem function to more than 20 million acres of what is now ecological wasteland.
“How big is 20 million acres? It is bigger than the combined areas of the 13 largest national parks.”
And there we have the notion of a Homegrown National Park. Although written by an American, his inspired ideas apply to Canada.
Naturally, we love the idea.