Title: Nature’s Best Hope: A New Approach to Conservation That Starts in Your Yard
Author: Douglas W. Tallamy
Publisher: Timber Press
Doug Tallamy and Rick Darke’s 2015 book, The Living Landscape, was a seminal work on the importance of restoring biodiversity to our local landscapes. In it, they called on homeowners to create larger gardens with native species, remove invasive species, and reduce the size of their lawns. In Nature’s Best Hope, Tallamy continues his argument that America’s obsession with clearcut lawns and non-native plants is destroying the regional ecosystems that plants, insects, animals, and humans depend on. The solution he proposes is a Homegrown National Park.
America is losing its biodiversity. Where once stood native oaks, maples, and birches, and beneath them, plants that evolved alongside birds, insects, and mammals for thousands of years, now appears an expanse of pesticide- and fertilizer-soaked lawn, which supports exactly zero species. In the Eastern U.S., a typical homeowner’s landscape is 90% lawn and contains only 10% of the tree biomass that same property contained before the house was built. In that home’s typical garden, the selection of plants is usually based on their decorative value and what’s planted by the surrounding homes. Typically, 80% of those trees, shrubs, and flowers originated in Asia, Europe or South America and are unable to support the complex and delicate ecosystem and food web that thrived on that land for millennia before the house was built.
Why are native plants important in your garden?
You may ask yourself why are native plants important? Like many gardeners, I was relatively ignorant of their importance when I began gardening years ago. I figured a bee is a bee, a flower is a flower, and bees can find nectar on any flower that produces it. Unfortunately, the ecosystem doesn’t work that way, much to the detriment of my local bees.
Doug Tallamy, a professor in the Department of Entomology and Wildlife Ecology at the University of Delaware, writes that certain bees and other insects have evolved with specific species of plants as their food sources – these are called “specialized relationships” and they’re very common in nature. A great example of a specialized relationship is the Monarch Butterfly and Milkweed. According to Tallamy, Milkweed protects its tissues with cardiac glycosides, a compound that poisons most insects. But Monarchs have developed enzymes that make cardiac glycosides digestible and have also developed a mechanism for storing these compounds in their wings and blood, making the butterflies incredibly distasteful to predators. Monarchs cannot get these compounds from any other plants. Because of this relationship, Monarchs only lay eggs on Milkweed and as caterpillars, eat the Milkweed leaves and absorb compounds that warn predators away. Therefore, if Milkweed disappears so will the Monarchs.
The same specialized relationship is true for many caterpillars that rely on specific trees for their entire lifecycle. Above the caterpillars in the food chain (a food web, really) live the birds who feast relentlessly on those caterpillars to feed their young, and above the birds are the mammals and larger birds that eat the smaller birds and the bird eggs, and so on. When you remove the plants or trees that host these insects, caterpillars, and bees, the balance of the food web changes and the local ecosystem changes. If the plants aren’t closeby to support the insects, the birds won’t nest there to breed and the mammals, in turn, won’t take up residence to hunt the birds (like us, they want to live where food is easy to obtain). Much worse, a number of those species will die or become extinct for lack of food and shelter.
The solution is a Homegrown National Park
But all is not lost, according to Tallamy. He proposes that every gardener (and hopefully every homeowner) contributes to a “Homegrown National Park” – gardens and lawns planted with native trees and shrubs which when interlocked across neighborhoods, towns, and cities can create paths to support the unique biodiversity of each region. And it’s not so hard to do – when you make a decision to plant a tree, shrub or flower, choose species that are native to your region, which you can access at the National Wildlife Federation. If like me, you rip out most of your non-native plants (sorry Doug, I cannot part with my hydrangeas) and replace them with natives, all the better.
The payoff for the gardener? That’s easy. Birds return to your yard and eat the insect pests. More pollinator insects increase your yields of fruits and vegetables in your crop garden. More flowers in bloom. More beauty, more food, more balance, more life.